Electronics in Motion and Conversion July 2009 · Electronics in Motion and Conversion July 2009....

ZKZ 64717

07-09ISSN: 1863-5598

Electronics in Motion and Conversion July 2009

Typ. solder layer Sinter layer

Unbreakable sinter joint:Melting temp. is 6 x higher than operating temp.

TypTypTypT sssoldoldere laya erere SiSiSintter lllayer

220oC 150oC

>900oC

6 x higherSolidus temperature

Operatingtemperature

Sintered chips - for high operation temperaturesSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSiiiiiiiiiiiiiiiiiiiiiinnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnntttttttttttttttttttttttttteeeeeeeeeeeeeeeeeeeeeeeerrrrrrrrrrrrrrrrrrrreeeeeeeeeeeeeeeeeeeddddddddddddddddddddddd ccccccccccccccccccccccccchhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhiiiiiiiiiiiiiiiiipppppppppppppppppppppppppsssssssssssssssssssssss fffffffffffffffffffffffffffffffoooooooooooooooooorrrrrrrrrrrrr hhhhhhhhhhhhhhhhhhhhhhiiiiiiiiiiiiiigggggggggggggggghhhhhhhhhhhhhhhh oooooooooooooooppppppppppppppppeeeeeeeeeeeeeeeeeerrrrrrrrrrrrrrraaaaaaaaaaaaaaaaattttttttttttttttttiiiiiiiiiiiiiiioooooooooooooooooonnnnnnnnnnnnnnnn tttttttttttttttteeeeeeeeeeeeeeeeeeemmmmmmmmmmmmmmmmmmmmmmmmmmmmpppppppppppppppppppeeeeeeeeeeeeeeeerrrrrrrrrrrrraaaaaaaaaaaaaaaaaattttttttttttttttuuuuuuuuuuuuuuuurrrrrrrrrrrrrrrrrrreeeeeeeeeeeeeeeeeeeeeeeesssssssssssssssssSKiiP®

4th generation

Intelligent Power Module: IPM

3 in 1: Driver, semiconductor, cooling

400 kW – 1,8 MW

33% more power, same volume

5 x higher thermal cycling capability

Sintered chips

Australia +61 3-85 61 56 00 Belgium +32 23 00 07 93 Brasil +55 11-41 86 95 00 Cesko +420 37 80 51 400 China +852 34 26 33 66 Danmark +45 58 10 35 56 Deutschland +49 911-65 59-0 España +34 9 36 33 58 90 France +33 1-30 86 80 00 India +91 222 76 28 600 Italia +39 06-9 11 42 41 Japan +81 68 95 13 96 Korea +82 32-3 46 28 30 Mexico +52 55-53 00 11 51 Nederland +31 55-5 29 52 95 Österreich +43 1-58 63 65 80 Polska +48 22-6 15 79 84 Russia +7 38 33 55 58 69 Schweiz +41 44-9 14 13 33 Slovensko +421 3 37 97 03 05 Suid-Afrika +27 12-3 45 60 60 Suomi +358 9-7 74 38 80 Sverige +46 8-59 4768 50 Türkiye +90 21 6-688 32 88 United Kingdom +44 19 92-58 46 77 USA +1 603-8 83 81 02 [email protected] www.semikron.com

www.bodospower.com July 2009

C O N T E N T S

Viewpoint

It is Summer, Beach Time! . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

News . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-7

Green Product of the Month

Energy-Efficiency Calculator Navigates the Maze of External Power Supply Standards

Power Integrations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Blue Product of the Month

Power Pack Offers 33% Increase in Power Density

Semikron . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Market

Electronics Industry Digest

By Aubrey Dunford, Europartners . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Guest Editorial

Have No Fear: Digital Power is Here!

By Chris Young, Sr. Manager, Digital Power Technology, Intersil . . . . . . . . . . . . . . . . . . . . . . . 12

Market

Incentives Fuel PV Inverter Opportunities

By Richard Ruiz Jr. , Research Analyst, Darnell Group . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-15

Cover Story

The Bi-mode Insulated Gate Transistor (BIGT)

By Munaf Rahimo, Arnost Kopta and Ulrich Schlapbach, ABB Switzerland Ltd, Semiconductors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-19

Power Management

Integrated Digital Isolation Delivers Enterprise Energy Efficiency Benefits

By Amit Gattani, Akros Silicon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-22

Transformers

Planar Transformers are Essential for Truly Efficient Electric/Hybrid Vehicles

By Dean Curran, Managing Director at Himag Solutions Ltd., United Kingdom . . . . . . . . . 24-25

Power Supply

Smarter Rectification

By Helen Ding, International Rectifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26-27

Power Supply

Get <1ppm Performance from a 10ppm Precision Reference

By Bob Frostholm, VP Marketing – Microbridge Technologies Corp . . . . . . . . . . . . . . . . . . 28-29

Power Modules

Power Module Testing with Combination Testers

By Günther Dörgeloh, MRS Electronic GmbH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30-32

Sensors

Low Consumption Flux-Gate Transducer

By Manuel Román, Guillermo Velasco, Alfonso Conesa and Felipe JerézPremo and TU of Catalonia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34-37

Power Supply

Choosing The Right Topology

By Andrew Skinner, Advanced Development Manager, TDK-Lambda . . . . . . . . . . . . . . . . 38-39

Motion Control

Comparison of Sensorless Algorithms for PMSM Rotor Position Detection

By Stello Matteo Bille, Dino Costanzo, Antonio Cucuccio,STMicroelectronics andAlfio Consoli, Mario Cacciato, Giuseppe Scarcella, Giacomo Scelba, University of Catania . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40-43

New Products . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44-48

Future precision.Future performance.Now available.

CAS-CASR-CKSRThe transducers of tomorrow. LEMcreates them today. Unbeatable in size, they are also adaptable and adjustable. Not to mention extremely precise. After all, they have been created to achieve great perform-ance not only today – but as far into the future as you can imagine.

Several current rangesfrom 6 to 50 ARMS

PCB mounted Up to 30% smaller size (height)Up to 8.2 mm Clearance / Creepage distances+CTI 600 for high insulation

+5 V Single Supply Low offset and gain driftHigh Accuracy @ +85°C Access to Voltage Reference Analog Voltage output

www.lem.com

At the heart of power electronics.

Biricha Digital Power offering

Digital Power Workshop based on

TI´s F28x family.

For more information and your free drill

hole stencil please visit

www.biricha.com

2 Bodo´s Power Systems® July 2009 www.bodospower.com

TThhee GGaalllleerryy

Naturalmatch!

Features+15V/-10V gate voltage

3W output power

20A gate current

80ns delay time

Direct and half-bridge mode

Parallel operation

Integrated DC/DC converter

Electrical isolation for 1700V IGBTs

Power supply monitoring

Short-circuit protection

Fast failure feedback

Superior EMC

2SP0320 is the ultimate driver platform for PrimePACKTM IGBT

modules. As a member of the CONCEPT Plug-and-play driver

family, it satisfies the requirements for optimized electrical

performance and noise immunity. Shortest design cycles are

achieved without compromising overall system efficiency in

any way. Specifically adapted drivers are available for all

module types. A direct paralleling option allows integrated

inverter design covering all power ratings. Finally, the highly

integrated SCALE-2 chipset reduces the component count

by 80% compared to conventional solutions, thus signifi-

cantly increasing reliability and reducing cost. The drivers are

available with electrical and fiberoptic interfaces.

PrimePACKTM is a trademark of Infineon Technologies AG, Munich

2SP0320

SAMPLES AVAILABLE!

CT-Concept Technologie AG, Renferstrasse 15, CH-2504 Biel, Switzerland, Phone +41-32-344 47 47 www.IGBT-Driver.com

Bodo´s Power Systems® July 2009 www.bodospower.com

Enjoy the summer and recharge your enthu-

siasm for a return to work.

Three lucky winners at the PCIM Europe

walked away with a large toy excavator truck

for creative summertime engineering in the

sand. Games were sponsored by Microchip

and a few more goodies were raffled off to

kids there - they are our future.

Here’s an engineer of the future.

PCIM showed technology on the move.

From talking with a number of exhibitors, it is

clear that all forms of renewable energy are

key. Reducing energy consumption in any

application through improved efficiency and

using renewable energy sources will keep

the world in better shape – our children will

benefit.

Each percent of increased efficiency will

count. The new semiconductor materials, Sil-

icon Carbide (SiC) and Gallium Nitride

(GaN), presented at my PCIM Podium dis-

cussion, will be key to progress in achieving

higher efficiency. Many inverter applications

in wind and solar renewable energy will ben-

efit from the new technology. Inverters in

solar sources already realize the benefits of

SiC rectifiers and active switches will soon

be in use. All applications in renewable ener-

gy have a great opportunity to minimize loss-

es and together will have a huge impact on

the grid and its transition towards a “Smart

Grid”.

PCIM China and PCIM Europe both indicat-

ed a great deal of interest in efficient design

for the future. Many of the shows’ visitors

were decision-makers in high-level positions

- a good indicator that plans are already

underway for a better future and recovery in

the in the second half of 2009. Now’s the

time to begin preparing for a number of good

shows in fall.

Bodo’s Power Systems magazine has estab-

lished more than two dozen agreements with

conferences and trade shows around the

world. I am proud to announce that I have

published about 350 pages so far this year -

a result of reliable delivery each month since

June 2006. In times of an uncertain econo-

my, I am happy to present you with the

leading voices in power electronics and to

help all my contributors, whether authors or

advertisers. There is no better way to com-

municate. We all share one world. As a pub-

lisher I serve the world: one magazine, on

time, every time.

My Green Power Tip for a summer month:

Treat yourself to a computer-free week and

turn off your cell phone. Life will continue

without all of these communication toys.

Afterwards you might reconsider the impor-

tance of such devices. Enjoy the break,

save energy and reflect on what life was like

just a quarter of a century ago.

Hope to see you at the beach, it is summer

time.

Best regards

It is Summer – Beach Time !

Events

SEMICON West

San Francisco

July 14-16

http://www.semicon.com

EPE Barcelona

Spain

September 8-10

http://www.epe2009.com

Digital Power Forum

Costa Mesa CA

Sept. 21-23

http://www.darnell.com

Digital Power Seminar

Freising Germany

Sept. 15-18

http://www.biricha.com

V I E W P O I N T

4

A MediaKatzbek 17a

D-24235 Laboe, Germany

Phone: +49 4343 42 17 90

Fax: +49 4343 42 17 89

[email protected]

www.bodospower.com

Publishing EditorBodo Arlt, [email protected]

Creative Direction & ProductionRepro Studio Peschke

[email protected]

Free Subscription to qualified readers

Bodo´s Power Systems

is available for the following

subscription charges:

Annual charge (12 issues) is 150 €

world wide

Single issue is 18 €

[email protected]

circulation

printrun

25000

Printing by:

Central-Druck Trost GmbH & Co

Heusenstamm, Germany

A Media and Bodos Power Systems

assume and hereby disclaim any

liability to any person for any loss or

damage by errors or omissions in the

material contained herein regardless of

whether such errors result from

negligence accident or any other cause

whatsoever.

Winner of one of the toy excavator truck


N E W S

Texas Instruments announced that it will

expand its microcontroller (MCU) portfolio

with the acquisition of Luminary Micro, the

market-leading supplier of ARM Cortex-M3-

based 32-bit MCUs. The addition of Lumi-

nary Micro’s Stellaris® family of Cortex-M3

processors will accelerate TI’s ability to pro-

vide the industry’s most complete MCU port-

folio. This acquisition means that customers

can now enjoy the innovative capabilities of

Stellaris MCUs along with the proven experi-

ence and technical strength TI brings as a

global semiconductor provider.

Stellaris devices will allow TI to address

mainstream 32-bit MCU markets, giving cus-

tomers access to the general-purpose pro-

cessing power of the industry-standard ARM

Cortex-M3 core and the Stellaris family’s

advanced communication capabilities,

including 10/100 Ethernet MAC+PHY, CAN,

USB On-The-Go, USB Host/Device,

SSI/SPI, UARTs, I2S, and I2C. The transac-

tion closed on May 14, 2009.

(Seewww.ti.com/stellarispr.)

“Combining Luminary Micro’s design experi-

ence in Cortex-M3 processors with TI's

expertise in ultra-low power MSP430 MCUs

and high-performance C2000™ real-time

controllers now gives TI customers one MCU

source for almost any application – all com-

plemented by the industry’s most expansive

embedded processing and analog portfo-

lios,” said Brian Crutcher, vice president of

TI’s Advanced Embedded Control (AEC)

business.

www.luminarymicro.com

www.ti.com/mcu

TI acquires Luminary Micro

American Superconductor announced that it

has received an order worth more than $10

million from ACCIONA Energy, a division of

ACCIONA SA (MC: ANA) and a world leader

in renewable power, for its new Dynamic

VAR Ride Through (D-VAR RT) solution.

Building on AMSC’s highly successful D-VAR

platform, which provides critical dynamic

reactive compensation required to connect

many wind farms around the world to the

power grid, the company’s D-VAR RT prod-

uct enables individual wind turbines to con-

tinue operating smoothly by “riding through”

voltage disturbances on power grids that

might otherwise interrupt their operation.

The D-VAR RT product meets stringent grid

interconnection requirements, including

Spain’s new Procedimiento de Operación

12.3 requirement for both existing and new

wind turbines.

According to the Global Wind Energy Coun-

cil, Spain was the world’s third largest wind

power market at the end of 2008 with an

installed base of more than 16,000

megawatts (MW). Disturbances such as

momentary voltage dips can disconnect

many wind turbines and cause instability on

the transmission grid. Developed by Spain’s

transmission system operator Red Electrica

de España (REE), P.O. 12.3 requires that

wind turbines remain connected to the grid

through such events.

www.amsc.com

AMSC Signs Contract with Acciona Energy

ANSYS, Inc., a global innovator of simulation

software and technologies designed to opti-

mize product development processes,

announced a first milestone in coupling

ANSYS® and Ansoft™ products, successful-

ly performing multiphysics simulations that

involve electromagnetic applications. As

electronics become more embedded into

automotive, aerospace, industrial and con-

sumer products, engineers must consider

factors such as circuitry’s ability to withstand

vibration shocks, heat generation and elec-

tromagnetic interference. The combined

depth and breadth of solutions from ANSYS

is key to solving problems that involve these

complex systems. In performing several

case studies, ANSYS engineers deployed

the electromagnetic effects determined by

Ansoft software directly in ANSYS thermal

and structural simulation. Work is ongoing to

fully integrate Ansoft software directly into

the ANSYS® Workbench™ platform for

future bidirectional and seamless operation.

For example, a high-power electronic con-

nector used in a military radar application to

connect a transmitter to an antenna must be

engineered from electromagnetic, thermal

and structural perspectives to ensure suc-

cess. The simulation was performed by cou-

pling Ansoft’s HFSS™ software with the

ANSYS Workbench environment, using

advanced thermal and structural capabilities.

Engineers used HFSS to ensure that the

device was transmitting in the proper path,

by calculating the high-frequency electro-

magnetic fields, power loss density distribu-

tion and S-parameters. In such high-power

applications, it is critical to determine the

temperature distribution to ensure the device

stays below temperatures that cause materi-

al failure, such as melting. The power loss

density results from the HFSS simulation

were used as the source for the thermal sim-

ulation performed within ANSYS® Mechani-

cal™ software, which simulated the tempera-

ture distribution of the device.

www.ansys.com

Physics Brought Together In Complex Electronic Design Application

IPC — Association Connecting Electronics

Industries® released the spring 2009 edition

of its quarterly business report, Supply Chain

Tracker, this week and although it showed

continuing economic contraction, it also indi-

cated the first signs of recovery in the elec-

tronics industry.

IPC's global statistical programs for several

key industry segments all show worsening

year-on-year growth rates in first quarter

2009, after growth rates turned negative in

late 2008. IPC's North American Electronics

Industry Performance Index fell 29 percent.

This is the third straight quarter the index

has declined. This index, a new addition to

Supply Chain Tracker, monitors the perform-

ance of the North American electronics sup-

ply chain.

Some leading indicators, however, are

beginning to show improvement. The April

2009 book-to-bill ratio for the North American

printed circuit board (PCB) industry climbed

for the third straight month from 0.89 to 0.97.

This ratio still indicates lagging demand, but

it is trending toward 1.0, the point of parity

between bookings and shipments. The North

American EMS book-to-bill ratio inched up to

0.95 at the end of first quarter. Semiconduc-

tor sales, while still in negative territory,

improved in first quarter 2009.

www.IPC.org

First Signs of Recovery

7www.bodospower.com July 2009 Bodo´s Power Systems®

N E W S

Rogers Corporation has made two important

announcements at the PCIM Europe 2009

Exhibition. The first time that the UL746C

registration has been granted to a supplier of

laminated busbar components. The RO-

LINX laminated busbars are used in industri-

al drives, mass transit, and alternative-ener-

gy power-distribution systems.

The laminated busbars are a critical compo-

nent in medium-to-high-power variable-

speed drives (VSDs) in these systems.

Rogers' components are designed to

achieve higher efficiency by limiting switch-

ing losses. In addition, the new UL746C rat-

ing provides the assurance of safety and

reliability backed by Underwriters Laborato-

ries. Previously, busbars and other power-

conversion components had been limited to

the UL94 safety rating for flammability.

The UL746C rating encompasses UL94, but

also covers hot-wire resistance to ignition

(HWI), high-current arc resistance to ignition

(HAI), comparative tracking index (CTI), and

relative thermal index (RTI) safety areas.

With the UL746C rating, Rogers' customers

are assured of reducing internal engineering

validation time, with a corresponding shorter

time to market for their own products.

Rogers ' second major announcement at

PCIM Europe 2009 comes from a joint effort

between their Thermal Management Solu-

tions Division (www.rogerscorp.com/tms)

and materials innovator Element Six. The

two companies will introduce HEATWAVE™

AlSiC D3 Technology as an advanced solu-

tion to their existing high-performance ther-

mal management products. The AlSiC D3

thermal materials are based on Element

Six's unique silicon cemented diamond

(ScD) technology combined with aluminum

encapsulation.

The thermal-management materials, which

are well suited to three-dimensional designs,

feature high thermal conductivity and low

coefficient of thermal expansion. Element Six

(www.e6.com), with more than 50 years in

materials development, has refined

advanced processes such as chemical vapor

deposition (CVD) to develop diamond-based

supermaterials with superior optical, thermal,

electrical, and chemical properties for a wide

range of industries.

www.rogerscorp.com

Breakthrough UL Rating & Advanced Thermal Solution

Isabellenhütte, Semikron and Siemens Drive

Technologies have cooperated to develop a

3 phase shunt module for the Siemens

SINAMICS G120 frequency inverter series.

This series is intended for measuring phase

currents of up to 20 A through shunts on the

circuit board. Apart from this, currents of up

to 400 A can be measured with outstanding

precision and long-term stability using the

jointly developed shunt modules in Semi-

kron’s Semitrans housing.

The PM240 high-performance parts for

SINAMICS G120 inverters make it possible

to extend the current range of Isabellen-

hütte’s Type BVR electron-beam welded

composite material precision resistors to 800

A and power output to 132 KW. For this pur-

pose, the resistance of shunts used in this

area was reduced from 3 to 1 mOhm, and

the module’s layout was optimized. The

housing’s interior was also adapted to the

terminal link design. The isolated shunt

installation, integration of 3 phases in one

case and optimized power loss heat dissipa-

tion by a DCB substrate, as well as the mod-

ule’s size, were not changed. Generally, the

module’s resilience and reliability were

improved. www.isabellenhuette.de

Shunts Replace Transformers in Large Inverters

The Korean company LS Industrial Systems

and Infineon Technologies AG announced

the establishment of the joint venture LS

Power Semitech Co., Ltd. which will focus on

the development, production and marketing

of molded power modules for white good

applications. The establishment of the joint

venture paves the way for Infineon and LS

Industrial Systems to more rapidly access

the promising market for energy efficient

household appliances, such as washing

machines, refrigerators and air conditioners,

and also for other low-power consumer and

standard industrial applications. The use of

variable-speed motors to reduce the energy

consumed by household appliances is grow-

ing in response to regulatory requirements

and consumer demand. Concurrently, smart

design of drive control electronics to make

best use of these motors presents manufac-

turers with further opportunities for efficiency

and savings.

www.infineon.com

Molded Power Module Business for White Goods

According to the latest update of the SEMI

World Fab Forecast database, spending on

fab construction projects has seen a consis-

tent quarterly decline since 2008, and on a

year-over-year basis is expected to fall by 56

percent in 2009. On a global scale, construc-

tion spending is at its lowest level in 10

years. However, the latest data from the

report suggest an increase in investments

for both fab construction projects and fab

equipping in the second half of 2009, with

the trend continuing into 2010. In 2010,

investments in fab construction projects are

expected to almost double and spending on

equipping fabs may increase by as much as

90 percent year-over-year from the signifi-

cant declines expected in 2009, according to

the report.

Investments are actually increasing in the

Americas, with a total quarterly spending

increasing to almost US$1 billion, mainly due

to major investments announced by Intel, as

the company moves forward on a planned

upgrade to 32nm.

According to the report, 19 fab facilities

closed in 2008, and about 35 facilities will

close in 2009, though the number of clo-

sures should decline in 2010 as only 14

facilities are expected to close. Nine fabs

are expected to launch operations in 2009.

Overall the trend of new facilities commenc-

ing operations has slowed since 1995, due

to the fact that most new fabs are 300mm

Megafabs for memory production, meaning

fewer but larger fabs are needed.

www.semi.org

SEMI World Fab Forecast Reveals Signs of Increased Investment

Power Integrations, the leader in high-volt-

age integrated circuits for energy-efficient

power conversion, introduced a new online

tool that enables designers of external

chargers and adapters to instantly determine

whether their product complies with world-

wide energy-efficiency regulations. The new

External Power Supply Efficiency Compli-

ance Calculator quickly and easily compares

power supply performance measurements

against the maze of specifications that now

apply to external chargers and adapters, sig-

nificantly simplifying the design engineer’s

task of verifying compliance. The calculator

currently checks compliance to the following

standards:

ENERGY STAR EPS (version 2.0): Spon-

sored by the U.S. Department of Energy and

the Environmental Protection Agency,

ENERGY STAR is one of the most visible

efficiency certifications worldwide.

EISA 2007: The first mandatory U.S. federal

EPS efficiency standard, the EPS limits in

EISA 2007 were adopted from the California

Energy Commission’s Appliance Efficiency

Regulations.

European Commission Code of Conduct

(version 4): The European Commission

Code of Conduct (CoC) issued version 4 of

its EPS specification in April 2009.

EC Eco-design Directive: The European

Commission’s Eco-design Directive for exter-

nal power supplies, scheduled to take effect

in April 2010, will align with the EISA 2007

standard for Tier 1 and ENERGY STAR (ver-

sion 2) for Tier 2.

China USB Charger Specification (YD/T

1591-2006): China’s Communication Indus-

trial Standard mandates a USB connector

and power output with a no-load consump-

tion of ≤300 mW for mobile telecommunica-

tion terminal equipment power supplies.

EC Integrated Product Policy (IPP): In

2008, a group of leading mobile-phone man-

ufacturers developed a “Five-Star” rating

system for mobile phone adapters/chargers,

specifying no-load power consumption down

to ≤30 mW -- well below any current or pro-

posed government standards.

Comments Rich Fassler, manager of energy-

efficiency programs at Power Integrations:

“Energy-efficiency specifications and stan-

dards have become increasingly complicat-

ed, and the landscape is constantly chang-

ing. For example, in April 2009 alone, two

important updates occurred -- the EC Code

of Conduct issued version 4 of its specifica-

tion, and the upcoming EC Eco-design stan-

dard was approved by European Parliament.

More than ever, power supply designers and

those sourcing external power supplies for

use with their end products need an easily

accessible, up-to-date database of world-

wide current and proposed regulations.”

Continues Fassler: “Power Integrations’ new

External Power Supply Efficiency Compli-

ance Calculator means that designers no

longer have to consult multiple sources

when checking the efficiency compliance of

their EPS designs – they can simply enter

their data and achieve an immediate, com-

prehensive, and accurate analysis.”

For more information about energy-efficiency

standards and standby energy waste, please

visit Power Integrations’ Green Room web-

site at www.powerint.com/greenroom.

References:

PI Energy-Efficiency Compliance Calculator:

www.powerint.com/sites/default/files/images/f

inal_final.swf

ENERGY STAR:

http://www.powerint.com/en/green-room/reg-

ulations-agency/energy-star-us

EISA 2007: http://www.powerint.com/green-

room/agencies/u-s-federal-government

EC CoC: http://www.powerint.com/en/green-

room/regulations-agency/eu-code-conduct

EC EuP Ecodesign Directive:

http://www.powerint.com/en/green-

room/agencies/ec-eup-eco-directive

China USB Charger Spec: http://www.pow-

erint.com/sites/default/files//greenroom/docs/

china_usb_spec_050409.pdf

EC IPP: http://www.powerint.com/en/green-

room/regulations-agency/ec-ipp-mobile-

device-charger-rating

Power Integrations is the leading supplier of

high-voltage analog integrated circuits used

in energy-efficient power conversion. The

company’s innovative technology enables

compact, energy-efficient power supplies in

a wide range of electronic products, in AC-

DC, DC-DC and LED lighting applications.

Since its introduction in 1998, Power Integra-

tions’ EcoSmart® energy-efficiency technolo-

gy has saved an estimated $3.4 billion of

standby energy waste and prevented mil-

lions of tons of CO2 emissions. The compa-

ny’s Green Room web site

(www.powerint.com/greenroom) provides a

wealth of information about “energy vam-

pires” and the issue of standby energy

waste, along with a comprehensive guide to

energy-efficiency standards around the

world. Reflecting the environmental benefits

of EcoSmart technology, Power Integrations

is included in clean-technology stock indices

sponsored by the Cleantech Group (Amex:

CTIUS) and Clean Edge (Nasdaq: CELS).

www.powerint.com

G R E E N P R O D U C T O F T H E M O N T H


Energy-Efficiency CalculatorNavigates the Maze of External

Power Supply StandardsOnline Resource for Design Engineers Quickly Determines

Compliance with Worldwide EPS Energy-Use Rules


SKiiP4, the new generation of intelligent

IGBT power modules, boasts a longer serv-

ice life than non-sintered modules and can

be used in higher temperature applications.

The SKiiP power pack is the most powerful

intelligent power module on the market and

is 33% more powerful than its predecessor

SKiiP 3. The IPM is used predominantly in

wind and solar power applications, traction

applications, elevator systems and industrial

drives with high outputs of between 400 kW

and 1.8 MW.

For comparable conditions and module

sizes, the SKiiP4 provides 33% more power

than the current version of this module fami-

ly, SKiiP3. On the one hand, this allows for

the development of more powerful or more

compact frequency converters, thus reducing

costs. This increase in power is down to the

use of an innovative pressure contact sys-

tem, an improved heat sink and IGBT4 and

CAL4 chip technology. In addition, six paral-

lel half bridges have been used for the first

time at the upper power end instead of four,

as was the case up till now.

In SKiiP4 modules, the semiconductor chips

are not soldered to the ceramic substrate but

are joined using sinter technology, meaning

that higher operating temperatures are pos-

sible with no compromise to – or in some

cases even increased - reliability. The sinter

bond is a thin silver layer which has a lower

thermal resistance than a bond with solders.

Thanks to the high melting point of silver,

premature material fatigue can be prevent-

ed.

Like its predecessors, SKiiP 4 is based on

well matched components: heat sink, power

module, driver and protective sensors/func-

tions. Here, the mounting and connecting

technology, which is based on a pressure

system, plays a crucial role. Customers can

also opt to have unique burn-in tests where

the IPMs are run under real operating condi-

tions performed. These tests enable prema-

ture silicon failure to be identified and the

defective chips removed. In the tests the

modules are exposed to the maximum possi-

ble junction temperature.

The solder-free pressure contact system and

the integrated laminated power rails ensure

homogenous current distribution. Every

IGBT and diode chip is connected to the

main terminal separately, keeping the mod-

ule resistance very low. The chips are not

soldered to the ceramic substrate but are

joined in a sinter process. As these modules

have no base plate, the solder-free connec-

tion between DCB and heat sink is quasi-

flexible, which is why the thermal cycling

capability has no upper limits. SKiiP4 will be

available with blocking voltages of 1200V

and 1700V in dual-pack topologies with

three, four or six parallel half bridges per

IPM.

Digital signal transmission for the switching

signals is the key to ensuring both a very

high degree of reliability and interference

immunity for switching signals. In addition to

various technical advantages, this ensures

high signal integrity and, consequently, inter-

ference immunity. Transmission depends on

component parameters, is highly robust and

not sensitive to temperature fluctuations or

ageing effects. The switching and sensor

signal transmission channels feature galvan-

ic isolation, meaning the user does not have

to provide additional isolation. To round off,

the new SKiiP4 IPM also features a multi-

stage output stage which ensures the reduc-

tion of overvoltage and includes various

other protective functions. Finally, a diagno-

sis channel is available for optimum evalua-

tion on the customer side.

.

www.semikron.com

B L U E P R O D U C T O F T H E M O N T H

Power Pack Offers 33%Increase in Power Density

Up to 33% more power in the new SKiiP 4 IPM.


M A R K E T

ELECTRONICS INDUSTRY DIGESTBy Aubrey Dunford, Europartners

GENERAL

After an 8 percent decline

in 2008, the German elec-

tronic components market

is expected to decline 16

percent in 2009 to € 13.2

billion, so the ZVEI. Indus-

try observers however are

optimistic that the market will recover in

2010, growing at most 5 percent.

During the current year, the world market will

decline by 16 percent to $ 333 billion (in

euro, a decline of 9 percent to € 246 billion,

before increasing by 5.5 percent to $ 351 bil-

lion in 2010.

SEMICONDUCTORS

Utilization of worldwide semiconductor

capacity is expected to rise to 60 percent in

the second quarter of 2009, up from 49 per-

cent in the first quarter, so iSuppli. This will

mark the first quarterly sequential increase

since the second quarter of 2008.

More than 60 companies and research insti-

tutions in Germany develop technologies on

a large scale that will significantly reduce

energy consumption of microchips and infor-

mation technology. The group, called the

'Cool-Silicon-Cluster', which is located in the

Dresden area, officially starts its project

financed by both the Federal and the State

governments. Altogether the federal govern-

ment as the initiator of the cluster research

will make € 40 M in funding available. With

the additional funds from the Saxony's Min-

istry of Science and the Arts, the cluster will

be able to apply for funds totaling more than

€ 100 M in the coming years. Combined with

contributions from Cool Silicon partners a

total volume of more than € 150 M will be

available.

The management of the Swindon foundry in

Cheney Manor had acquired the semicon-

ductor foundry business from MHS Electron-

ics UK. MHS had acquired this business in

February 2008 and the company was subse-

quently placed into administration in Febru-

ary 2009.

Worldwide silicon wafer area shipments

were 940 million square inches during the

first quarter 2009, a 34 percent decrease

from the previous quarter. The new quarterly

total area shipments are 57 percent below

Q1 2008 shipments and at the lowest levels

since 2001, so SEMI.

North America-based manufacturers of semi-

conductor equipment posted $ 253 M in

orders in April 2009 and a book-to-bill ratio

of 0.65, so SEMI. The bookings figure is

three percent greater than the March 2009

level and about 77 percent less than in April

2008.

European Investment Bank (EIB) lends €

400 M to Wacker Chemie for its new polysili-

con production plant construction which will

locate in Saxony region of Germany. Wacker

now secured € 800 M for the construction of

the plant. The new plant will have 10,000

tons in annual production capacity which will

begin from 2011. The plant is expected to

create 450 jobs.

PASSIVE COMPONENTS

World connector sales of $ 7.363 billion in

1Q09 are comparable to sales levels in

2003, so Bishop & Associates. The first

quarter of 2009 is over, ending with orders

down 41.7 percent, and sales down 35.7

percent. The industry consensus for 2009

sales appears to be a decline of 25 percent

at $ 32.983 billion.

Revenues for the PCB industry in Germany

continue declining in February; compared to

last year, the market was down 40 percent

for the month, so the ZVEI/VdL. Both incom-

ing orders for February, as well as the cumu-

lative orders for the first two months of the

year, were less than half compared to the

same periods last year. The book-to-bill-ratio

reached 0.78.

Littelfuse announced restructuring plans

which include the transfer of manufacturing

from the company’s Duensen, Germany site

to Mexico. Research and development,

sales and other functions will remain in Ger-

many.

Epcos has acquired the development activi-

ties of Mems microphones from Technitrol.

The acquisition sum is in the mid single-digit

million euro range. This acquisition opens up

the growth market for miniaturized MEMS

microphones to Epcos. They are used espe-

cially in mobile phones and Bluetooth head-

sets. The market volume of these applica-

tions is in the triple-digit million euro range.

Planned investments for financial 2009/10 at

AT&S amount to € 30 M, half of which

relates to projects begun in 2008/09. AT&S

sales compared with the last financial year

fell by 7.4 percent to € 449.9 M. Final con-

solidated net income came out at -€ 5.8 M

for the biggest European PCB provider.

OTHER COMPONENTS

Seagate Technology has initiated a restruc-

turing plan that includes a reduction of

approximately 1,100 employees or 2.5 per-

cent of the company's global workforce.

K2 Energy Solutions, a manufacturer of

rechargeable battery systems, has

announced the construction of a lithium-ion

battery factory in Varkaus, Finland. The $ 44

M facility is expected to be completed in fall

of this year, with full battery production

beginning in early 2010.

GE Transportation announced plans to build

a $ 100 M plant for advanced storage batter-

ies. GE has invested more than $ 150 M to

develop advanced battery technologies,

including a high energy-density sodium-

based chemistry battery.

DISTRIBUTION

European distribution billings in 1Q09

declined by 3 percent, when compared to

the previous quarter and declined by 21.4

percent compared to the same period last

year, so the IDEA.

TTI, a global distributor of passive, connec-

tor, electromechanical and discrete compo-

nents, has signed a Europe and North Amer-

ica franchise agreement with Epcos, a Ger-

man supplier in power capacitors, SAW com-

ponents, surge arresters, thermistors, varis-

tors and piezo actuators. In Europe, Epcos

is the top manufacturer of aluminium elec-

trolytic capacitors, EMC components and fil-

ters, ferrites, film capacitors, and transform-

ers and chokes. Omron Electronic Compo-

nents also announced TTI, as their 2008

Distributor Partner of the Year. Awards were

presented to both companies that comprise

the TTI group --Mouser Electronics and TTI.

The MSC-Gleichmann group and Vectron

International signed a pan-European distri-

bution agreement for Bulgaria, Germany,

Greece, Austria, Poland, Rumania, Slovakia,

Ukraine and the Czech Republic.Vectron is a

supplier of high-precision frequency control,

sensor and hybrid product solutions.

This is the comprehensive power related

extract from the « Electronics Industry Digest

», the successor of The Lennox Report. For

a full subscription of the report contact:

[email protected] or by

fax 44/1494 563503.

www.europartners.eu.com


Change is scary. But,

change is inevitable.

In fact, you should be

happy that change is

inevitable because it is change that facili-

tates your gainful employment! If it were not

for change, your career would have been

over after the first design.

Not only is change inevitable but, especially

related to power design requirements, the

rate of change (the change of change) is

increasing. Thus, it is the happiest of times

and the scariest of times.

Technology evolution, regulatory adjust-

ments, and economic factors, drive change

in power conversion requirements. Yet it is

not this change that we, as power conver-

sion engineers, fear. In fact, this is the

change that we embrace; it brings challenge

and excitement to our jobs; it is, in many

ways, what makes us happy. We are more

than happy to use what we know to solve

ever evolving challenges.

What is so scary? Changing our toolset is

scary. Using what we know is comfortable;

using what we don’t know is unsettling.

Changing to a new controller is a scary thing

to do. Let’s face it, there are no perfect con-

trollers. But, you have figured out how to

use the controller that you are using right

now. You have found ways to work around

all of the little “issues”…the little “surpris-

es”…that popped up when you first tried to

use it. We’ve all had our disasters along the

way, though, where those little surprises

were no so little and came at exactly the

wrong time. We live with the scars from

these encounters. We are wary, very wary

of changing controllers.

This fear of changing controller technology is

both real and justified. Let’s examine what

could go wrong:

# The features do not behave the way you

understood them to behave. For example,

you thought that the response to a current

fault was foldback or hiccup but it turns

out that it shuts down and does not

restart.

# You need more features than the part can

provide so you add circuitry that takes

more time and money than you had

planned. For example, it does not handle

prebias adequately so you need to add

additional circuitry to take care of prebias

startup.

# The part has features that interfere with

what you need to do so you add circuitry

to negate the feature and this takes more

time and money than you had planned.

# When you first selected the controller, it

met or marginally met your needs but now

that you are well into the design, your

needs have changed and the part is going

to take a lot of work to fix.

# There is a bug in the part. 3-6 months for

a metal mask spin. 6-12 months for an all

layer change.

# The part is more noise sensitive than your

lab testing initially revealed. You find this

out in production…too late to add filters.

# The manufacturer had a process change

between you designing with the samples

and the production parts were made avail-

able.

# Your competitor used a different part and

now offers features that your controller

cannot provide.

In each of these examples, the common ele-

ment is the inflexibility of the controller to

adapt to your needs. You get what you get

and for good reason. Imagine the task of

your controller manufacturer when deciding

on what part to build. The manufacturer will

talk to a dozen or more customers and each

will have a different set of requirements.

The result is a compromise in terms of the

lowest common denominator of controller

requirements. Although intended to have

something that pleases everyone, the result

falls short of everyone’s expectations.

Digital controllers break this paradigm.

Today’s advanced digital controllers combine

the best of analog (for high speed events)

and digital (for flexibility) technologies.

These controllers typically have a dedicated

function PWM engine that is configurable by

way of an onboard microcontroller with non-

volatile memory and a communications link.

The controller is a hybrid of a sort in that it is

fixed function (power converter) but config-

urable through firmware. Not only are the

operational parameters (voltage, current,

switching frequency, etc.) configurable, but

also the response (faults, transients,

enable/disable) and features. Additional

capability includes telemetry, flexible pin defi-

nition, and adaptive behavior to optimize the

performance in real time.

So, when changing over to digital controller

technology, fear no more:

# Digital controllers can provide multiple

behaviors for any given feature. Simply

open up the provided graphical user inter-

face (GUI) and point and click on the

behavior that you prefer. Not exact what

you are looking for? Then most likely the

behavior is defined in firmware and you

can get a fast fix in a few days with a

qualified part in a few weeks.

# The nice thing about digital is that is

comes with, most likely, more features

than you need. Turning them on or off

takes a simple point and click on the GUI.

Don’t see the feature that you need. You

guessed it…it’s probably a firmware addi-

tion that can be realized in a few days.

# Is noise a problem? Digital controllers

come with digital noise filters…again,

point and click to turn on and configure.

# The competitor has come up with some-

thing new or you have an idea that can

increase your sales…work with your digi-

tal controller supplier…there is a good

chance you can see your ideas realized

with firmware.

# Do you need to make an adjustment to

the design at the last minute? Put away

the soldering iron…open up the

GUI…take a few seconds to make the

change and you are done. No more lifting

traces, no more searching for the right

replacement component, no more late

nights!!

# In fact, stop guessing about what is going

on when you first turn it on. With the

onboard telemetry you can analyze the

operation and faults in real time.

Changing power controller technology is no

longer scary. In fact, controller change is

exciting and enabling. Have no fear…Digital

Power is here!

www.intersil.com

G U E S T E D I T O R I A L

Have No Fear: Digital Power is Here!By Chris Young, Sr. Manager,

Digital Power Technology, Intersil

ElektrischeAutomatisierungSysteme und Komponenten

Fachmesse & Kongress24.–26. Nov. 2009Nürnberg

SPS/IPC/DRIVES/

Mes

ago

Mes

sem

anag

emen

t G

mb

H, P

ost

fach

10

32 6

1, 7

0028

Stu

ttg

art,

sp

s@m

esag

o.c

om

, Tel

. +49

711

619

46-8

28

Ihre kostenlose Eintrittskarte

www.mesago.de/sps


Led by the growing photovoltaic (PV) market, the outlook for inverters

used in alternative energy resource technology is expected to remain

strong. Industry growth in this application will be driven by a combi-

nation of government incentives and declining PV module prices.

Projected to make up over 95% of the market, the inverters used in

PV installations, both small (1-5kW) and large (>6MW), will far out-

pace those used in either wind or fuel cell applications. In fact,

according to the Electric Power Research Institute (EPRI), grid-con-

nected PV systems are expected to account for more than 90% of

PV capacity additions in 2011, up from about 50% in 2000, and from

less than 10% a decade earlier. The accelerating worldwide growth in

grid-tied PV will be driven by continuing technology performance and

cost improvements, strong deployment incentives, and growing con-

sumer interests, as well as renewable portfolio standards, concerns

about climate change, and other policy mandates.

In Europe, the primary driving force in the PV market are feed-in tar-

iffs, which have been successfully used in 16 EU countries, most

notably Germany, Italy and Spain. In fact, in Europe renewables com-

prise the fastest- growing segment of the energy market. The primary

factor driving the PV industry in Germany is the Renewable Energy

Sources Act (EEG in German) which mandates feed-in tariffs. A key

feature of the German Renewable Energy Act is that it guarantees

feed-in tariffs for 20 years, and as a result, no price fluctuations need

to be taken into consideration during the planning process of a

renewable energy program. This law provides an incentive for Ger-

man property owners to own PV installations, providing a ready-

made domestic market for PV products made in Germany. In Ger-

many, installations are 80% residential, creating local installation jobs

and making PV visible as a source of electricity generation, with grid

parity expected between 2012 and 2015.

The other large European feed-in tariff program is in Spain. Together,

in 2008, they made up over 84% of the region’s installed PV capacity.

The PV boom in the Spanish market was significant for a number of

reasons, most notably for the generous feed-in tariffs which led to a

global market explosion of more than 100% compared to 2007. How-

ever, the feed-in tariffs implemented in the Spanish PV market result-

ed in a number of unintended consequences, including the overpro-

duction of solar modules, which many felt were already headed

towards an oversupply situation. Due to a number of issues, includ-

ing an overwhelming backlog of solar PV applications, difficulty

financing projects, falling oil prices and other challenges, the new

government in Spain halted the costly stimulation of solar PV. The

result was a 40% decrease, or more than 2500 MW of global market

volume in 2009. So although Spain’s PV market grew by >2.66 GW

of new installed power in 2008, new laws will cap that growth at

500MW in 2009.

The photovoltaic systems resulting from these programs range from

small off-grid installations providing hundreds of watts to large central

utility power plants. However, the fastest-growing sectors of the PV

industry are large commercial and central power generation systems.

These systems can range in size from tens of kilowatts for commer-

cial rooftop systems to over 100 megawatts for utility-scale central

power generation plants occupying many acres of land. The inverters

for these systems are central inverters, although a parallel combina-

tion of several string inverters may also be used. Some of the com-

panies manufacturing these inverters include SMA Technologie AG,

Xantrex, Satcon Technology Corp, Studer Innotec, Fronius, Advanced

Energy Industries, Magnetek, PV Powered, Solectria Renewables

and others. Each of these companies should see significant opportu-

nities as the size of PV installations continues to increase.

Typical of these installations is a 300 kilowatt (kW) solar tracker plant

in Toledo, Spain. The objective of the project is to combine water, ani-

mal life, plants and buildings into an integrated facility. The solar plant

will be composed of six 100 kW installations, with the first phase

including three Xantrex GT100E central inverters. The GT100E com-

mercial solar inverter is a 100 kW three-phase advanced power elec-

tronics system for grid-connected solar arrays. An even larger facility

can be seen in Germany at the Waldpolenz Energy Park, which will

eventually comprise 40 megawatts (MW) of production capacity. SMA

will provide 70 central inverters, the Sunny Central 500HE, each with

a capacity of 500 kWh. In each case, two inverters are located in one

station for a single module field. A total of 35 of these stations will

make up the facility.

As PV facilities continue to increase in size, inverter technology will

need to meet the challenges presented with the trend towards larger

installations. An example of this can be seen in SMA America Inc.,

the U.S. subsidiary of SMA Solar Technology AG, which introduced

the Sunny Central 250U, a 250kW inverter designed to be the heart

of a large-scale commercial PV system. Generally acknowledged to

be the largest manufacturer of inverters in the world with an estimat-

ed global market share of 35%, SMA’s entrance into the higher-

wattage commercial market is a significant development for the entire

industry. Discussions with SMA indicate that the company sees a

growing industrial/commercial market and wants to expand outside

the residential sector. Other companies featuring inverters in the

250kW to 500kW range are Xantrex, Advanced Energy and PV Pow-

ered, followed by Satcon and Magnetek, which each introduced a

1MW inverter system. The new generation of photovoltaic inverters

fueled by this growth present system integrators with new solar array

design and installation challenges.

In addition, the growing trend towards large-scale developments is

evident in the number of partnerships and cooperative efforts being

formed in the PV industry. In 2009, Xantrex Technology Inc., a sub-

sidiary of Schneider Electric, announced the launch of the Solar

M A R K E T

Incentives Fuel PVInverter Opportunities

By Richard Ruiz Jr., Research Analyst, Darnell Group

www.bodospower.com

Power Conversion Substation (SPCS) for the North American mar-

ket. Sustainable Energy Technologies Ltd. also announced that it

had entered into an agreement with FOTOVOLTAICA 10 CM SA

(“Grupo Diez”) to collaborate on an inverter system solution for a 33

kW solar concentrator tracker developed for Grupo Diez. Grupo

Diez is a large solar project developer based in Toledo, Spain.

Other significant business combinations and cooperative efforts

include Sunfilm AG and Sontor GmbH, which merged to become

what they claim will be one of the world’s largest providers of tan-

dem junction silicon-based thin-film modules, which is one of the

most significant growth areas within the photovoltaic industry.

Given this trend, a large number of existing manufacturers and

new entrants are seeing the market for PV inverters becoming more

competitive. As a result, prices are expected to fall, and products

with innovative features and greater efficiency are expected to flood

the marketplace. This anticipated activity is being reflected in the

number of new investments in production capacities that have been

announced over the past year. As an example, Sputnik Engineering

AG is increasing its annual production capacity for string and cen-

tral inverters with its new facility, which went into initial operation in

March in Biel, Switzerland. According to the company, its goal is to

see its capacity reach 400 MW annually by the end of 2009.

The new Sputnik plant will assemble central inverters with outputs

from 50 kW upwards. The company identified Germany, Spain and

Italy, along with France and Greece as areas showing significant

opportunities for market growth. In addition, in 2008, SMA Technolo-

gie AG, began construction on what the company says is the world’s

largest solar inverter factory in Kassel, Germany. SMA expects con-

tinuous growth in the coming years, and to meet this increasing

demand the company is developing a new 15,000 square meter

production facility that is designed to be completely CO2-neutral

and has a virtually independent power supply with a MW-scale

Building Integrated PV (BIPV) system. A BIPV system involves inte-

grating photovoltaic modules in to the building envelope material

and power generators. Common in residential buildings in many

countries including Japan, Germany, the US, Switzerland and oth-

ers, the further expansion of BIPV in commercial projects will help

expand the PV industry and provide additional opportunities for

manufacturers of inverters for years to come.

http://www.darnell.com/store/product_info.php?products_id=92

www.powerpulse.net

MAKING MODERN LIVING POSSIBLE

DANFOSS SILICON POWER

SILICONPOWER.DANFOSS.COM

Wind power the cool wayCustomized power modules made for high performance

It cannot be stressed enough: Efficient cooling is the mostimportant feature in power modules. Danfoss Silicon Power’s cutting- edge ShowerPower® solution is designed to secure an even cooling across base plates. In addition, our modules can be customized to meet your wind power requirements in detail, offering: High quality, high performance, extended life and very low life cycle costs. In short, when you choose Danfoss Silicon Power as your supplier you choose a thoroughly tested solution withunsurpassed power density.

Please go to siliconpower.danfoss.com for more information.

ShowerPower®

Digital Power Workshop

based on

TI´s F28x family.

For more information and

your free drill hole stencil

please visit

www.biricha.com


The past two decades has seen major improvements in silicon power

semiconductors in terms of reduced losses and wider Safe-Operat-

ing-Area (SOA) performance. The main drive behind these advances

is the continuous need for higher power densities in new power sys-

tem designs. Therefore, devices such as the IGBT and the free-

wheeling diode continue to provide Megawatt applications such as

traction, industrial drives and transmission and distribution with opti-

mum components which have enabled with each improved genera-

tion a clear leap in power levels.

The IGBT in particular with its inherent advantages including a con-

trolled low power driving requirement and short circuit self limiting

capability has experienced many performance breakthroughs, which

has resulted in its wide employment in many high power applications.

The most recent low loss and high SOA improvements were mainly

due to the introduction of the Soft-Punch-Through (SPT) or Field-

Stop (FS) thinner silicon concepts combined with advanced planar or

trench emitter structures. Similar advances were also achieved for

the anti-parallel freewheeling diode to match the continuously improv-

ing IGBT. Today, high power IGBT modules have voltage/current rat-

ings ranging from 1700V/3600A to 6500V/750A.

High Power Semiconductor Devices and the Future Options

Currently, it could appear that the development of high voltage silicon

power devices has reached a limit with regards to further reductions

in the device total losses. The state-of-the-art SPT/FS structures are

close to the so-called “Silicon Design Limits” and the emitter plasma

enhancement will only provide smaller steps with fine optimization of

the IGBT cell designs. In addition, the extremely robust modern IGBT

designs already provide the necessary SOA performance with ade-

quate margins. Hence, one can conclude that the possibility for

achieving major leaps in increased power densities for silicon is

becoming more restricted. Although, increasing the device total area

monolithically or equally through device paralleling can provide the

higher power solution for some applications, this approach will

remain selective due to its negative impact on the cost, size and

complexity of the overall system. Therefore, the quest for more

advance device concepts will remain as the trend continues for next

generation Megawatt systems with increased efficiencies.

The assumed technological barrier or silicon limit has led to the

recent trend towards increased operating temperatures compared to

the traditional 125°C maximum junction temperatures operation limit.

The low losses and high SOA of modern IGBTs and diodes has

enabled this step to be taken while also focusing on reduced leakage

currents and improved package reliability as the major limiting fac-

tors. An increase of around 10-15% in total output current capability

can be predicted with this approach.

Furthermore, there are continuous developments in Wide Band-Gap

(WBG) materials such as SiC and GaN for power semiconductors

due to its ten fold thinner base region structures having substantial

loss reduction potentials and the high operating temperature capabili-

ty when compared to silicon. With the clear progress achieved for

ultra fast unipolar power diodes rated up to 1700V and many switch

concepts demonstrated recently, WBG power devices are now being

regarded as the next major performance leap. Nevertheless, the cur-

rent cost of such devices and some technological and performance

aspects yet to be fully resolved especially for higher voltage/current

devices will continue to seriously delay the introduction of WBG com-

ponents in Megawatt applications. This while also taking into account

that silicon power devices could still provide another breakthrough in

performance.

The Limits of Silicon Power Devices

To further explore the potential of silicon based power devices in gen-

eral, and IGBTs/diodes in particular, the performance/design limits

must be clearly defined in order to determine a future development

trend. Today, by carrying out a standard performance study of state-

of-the-art high power IGBT modules, one can clearly see that the

main limiting factor in terms of maximum output current capability (i.e.

power density) is the diode in both inverter and rectifier mode opera-

tion. In addition, the diode also presents another major restriction

with regard to its surge current capability. Both limits are clearly a

result of the limited diode area available in a given package footprint

design which has a typical IGBT to diode area ratio of around 2:1.

This limit in diode current capability was fundamentally established

after the introduction of modern low-loss IGBT designs. As mentioned

earlier, the simple solution of increasing the diode area is not a pre-

ferred one and in any case remains restricted by the package stan-


C O V E R S T O R Y

The Bi-mode Insulated GateTransistor (BIGT)

A High Voltage Switch for Next Generation Megawatt Applications

An advanced high voltage reverse conducting IGBT concept referred to as the Bi-modeInsulated Gate Transistor (BIGT) is currently being developed. The BIGT can operate atthe same current densities in both IGBT and diode modes by utilizing the same available

silicon volume as it targets to fully replace the traditional IGBT/Diode two-chip approachwith a BIGT single chip.

By Munaf Rahimo, Arnost Kopta and Ulrich Schlapbach, ABB Switzerland Ltd, Semiconductors


dard footprint design. This leads to the conclusion that the develop-

ment effort must target an improved diode performance to match at

least the current IGBT designs. In other words, there is currently no

need for improved switch generations unless the diode experiences a

major revolution in terms of reduced losses and thus, higher power

capabilities. As discussed above, while ignoring cost and material

issues, WBG based diodes could provide the required performance

due to the low switching losses, but the high conduction losses of

high voltage WBG unipolar and bipolar diodes compared to current

silicon diodes will restrict their application to relatively high frequen-

cies for Megawatt applications. Other aspects to consider are the soft

reverse recovery performance of WBG diodes in general under high

currents and high voltages which have not yet been thoroughly evalu-

ated.

The above analysis leads to the following conclusion; in order to

increase the power density of high voltage IGBT modules while also

solving the real limiting factors due to the diode performance, an

IGBT and diode integration solution is needed, or what has been nor-

mally referred to as a Reverse Conducting RC-IGBT. The practical

realization of a single-chip technology will provide an ideal solution

for next generation high voltage applications demanding compact

systems with higher power levels, which is proving to be beyond the

capability of the standard two-chip approach.

The Bi-Mode Insulated Gate Transistor (BIGT)

Similar to power MOSFETs, the traditional goal for a reverse con-

ducting device having an integral diode is to obtain higher power for

a given footprint package area by eliminating the need for a separate

anti-parallel diode. This approach has been demonstrated experi-

mentally in recent years for medium voltage IGBTs (600V-1200V)

mainly operating at low currents and/or soft switching conditions in

special applications. On the other hand, we at ABB have been inves-

tigating the RC-IGBT concept by demonstrating its feasibility for high

voltage chips under heavy paralleling. The realization of the RC-IGBT

concept has always faced a difficult challenge due to a number of

technological design and process barriers such as (a) the conflicting

requirement for plasma enhancement for the IGBT and diode (b)

matching the silicon and buffer design parameters for both the IGBT

and diode with regard to device softness (c) the inherited on-state

snap-back phenomenon associated with RC-IGBTs and finally (d) the

layout and alignment design of the shorted collector for minimizing

non-uniform charge distributions during device operation.

Further development work to resolve the above issues and improve

the device characteristics has resulted in a clear breakthrough in per-

formance by adopting an advanced collector backside P/N layout

design, fine doping profiles and controlled lifetime reduction for

enabling optimal operation in both IGBT mode and diode mode. The

new device concept is referred to as the Bi-mode Insulated Gate

Transistor (BIGT). The results obtained show that the BIGT exhibits

C O V E R S T O R Y

Figure 1: The BIGT basic structure

Power Your Recognition InstantlyBased in Munich, Germany, ITPR Information-Travels Public Relations is a full-service consultancy

with over a decade of experience in the electronics sector.

As a small exclusive agency, we offer extremely high ROI,

no-nonsense flexibility and highest priority to only a handful of companies.

Strategical SupportCorporate/Product Positioning, Market/Competitive Analysis, PR Programs, Roadmaps,

Media Training, Business Development, Partnerships, Channel Marketing, Online Marketing

Tactical PRWriting: Press Releases, Feature Articles, Commentaries, Case Studies, White Papers

Organizing: Media Briefings, Road Shows, Product Placements in Reviews and Market Overviews,

Exhibitions, Press Conferences

Monitoring and Research: Speaking Opportunities, Editorial Calendars, Feature Placement,

Media Coverage, Competitive Analysis

Translations: Releases, By-Lined Articles, Websites, etc.

Call or contact us today for a free consultation on how PR

can dramatically affect your company’s bottom line.

ITPR Information-Travels Public Relations

Stefanusstrasse 6a, 82166 Gräfelfing-Munich, Germany

Tel ++49 (89) 898687-20, Fax ++49 (89) 898687-21,

w w w . i n f o r m a t i o n - t r a v e l s . c o m

low losses in both modes of operation with no typical snap-back

behavior in the transistor on-state mode when compared to a stan-

dard RC-IGBT, while also maintaining high levels of SOA perform-

ance. The BIGT offers in addition a number of device performance

advantages as described below. The BIGT technology consists of a

hybrid structure integrating an IGBT and an RC-IGBT into a single

chip as illustrated in figure (1). A circuit symbol is also proposed for

the BIGT.

The main target of this combination is to eliminate snap-back behav-

ior at low temperatures in the BIGT transistor on-state mode by

ensuring that hole injection occurs at low voltages and currents from

the P+ collector region in the IGBT section of the BIGT. The BIGT

provides an optimum solution especially for thin devices with SPT

type buffer designs where the snap-back phenomenon is pronounced

in RC-IGBTs. The backside layout design and dimensioning provides

smooth transition into full chip IGBT conduction while maximizing the

RC-IGBT area for diode conduction. Therefore, the BIGT concept has

resulted in a better trade-off between the above mentioned parame-

ters compared to the standard RC-IGBT design.

To optimize the BIGT for low dynamic and switching losses, the other

main challenge was to enable low diode mode recovery losses while

not having a considerable effect on the transistor mode on-state loss-

es. A three step approach is utilized to achieve this target. The first

step is the fine control of the doping profiles of the emitter p-well cells

and collector P+/N+ regions. As shown in figure (1:top), the

Enhanced Planar (EP) cell design does not include any highly doped

P+ well regions and provides the BIGT with a fine pattern p-well pro-

file for obtaining low injection efficiency for better diode performance

while maintaining the typical low IGBT losses associated with EP

designs. The second optimization step employs a Local p-well Life-

time (LpL) control technique utilizing a well-defined particle implanta-

tion which further reduces the diode recovery losses without degrad-

ing the transistor losses and blocking characteristics. Further reduc-

tion in the reverse recovery losses is achieved with a uniform local

lifetime control employing proton irradiation. A further optional 10%

reduction of in recovery losses can be obtained with a MOS Control

Diode function as demonstrated in the module results presented in

the following sections.

The BIGT technology has mainly been developed for high voltage

devices and the work presented here was carried out on a

3300V/62.5A BIGT (active area = 1cm2). The on-state characteristics

of the BIGT in transistor and diode modes are shown in figure (2) at

25°C and 125°C. For safe paralleling of chips, the curves show a

strong positive temperature coefficient even at very low currents in

both modes of operation due to the optimum emitter injection efficien-

cy and lifetime control employed in the BIGT structure.

A remarkable performance feature of the BIGT is that it provides soft

turn-off behavior under all operating conditions in both transistor and

diode modes. The optimized collector P+ doping profiles will ensure

that during the turn-off tail in both modes, the passing electrons

towards the N+ regions will induce a large potential across the collec-

tor PN junction forcing a controlled level of hole injection into the

base region. The main advantage of this method lies in the fact that

normally the diode silicon specification does not match the IGBT sili-

con for obtaining soft recovery performance. Thus, such conflicting

requirements could result in diode mode snappy behavior in an inte-

grated structure. However, in a BIGT, soft behavior is granted under

all conditions for both the transistor and diode modes even under

extreme conditions as shown in figure (3) and (4) respectively.

3300V BIGT Module Results

High current 3.3kV BIGT (140 x 130)mm modules were fabricated

and tested under conditions similar to those applied to state-of-the-art

IGBT modules. The BIGT module contained 24 BIGT chips for the

estimated current rating of 1500A. The nominal transistor mode

switching characteristics of the BIGT modules are shown in figure (5)

along with the associated switching losses at 125°C. The BIGT diode

mode reverse recovery performance is mirrored in the turn-on wave-

forms. The freewheeling reverse recovery losses were approximately

2.3J. The SOA performance of the BIGT in transistor and diode

mode at a high DC link voltage is shown in figure (6). Both modes

show rugged characteristics similar to the current IGBT and diode

modules. Furthermore, the BIGT also provides improved short circuit

and softness performance compared to state-of-the-art IGBTs.

The BIGT advantage is clearly demonstrated here since this module

can practically replace a similarly rated larger (140 x 190)mm module

which normally contains 24 IGBTs and 12 diodes. The larger stan-

dard IGBT module has the further disadvantage of employing much

C O V E R S T O R Y


Figure 3: 3.3kV/62.5A BIGT in transistor mode turn-off softness test

Figure 4: 3.3kV/62.5A BIGT in diode mode reverse recovery softnesstest

Figure 2: 3.3kV/62.5A BIGT on-state in transistor and diode mode


less diode area which is normally a limiting factor in rectifier mode of

operation and surge current capability. On the other hand, when the

larger (140x190)mm module employs only BIGT chips i.e. 36

devices, its rating can potentially reach up to 2250A. Figure (7)

shows the targeted scaled output current performance for the BIGT

compared to today`s EP-IGBT module at 125°C in both Inverter and

Rectifier modes. The curves show that the diode performance is a

limiting factor for the standard module approach while for the BIGT

module the transistor mode defines the limit. The curves show

approximately a 30% increase in output current capability up to 2 kHz

with the BIGT technology.

Finally, the expected thermal cycling load pattern in a BIGT module is

shown in figure (8). Due to the fact that no inactive periods are pres-

ent per IGBT/Diode compared to the standard approach, a lower

temperature difference and more efficient thermal utilization of the

module will result in better thermal cycling capability and eventually

improved reliability performance.

www.abb.com/semiconductors

C O V E R S T O R Y

Figure 5: 3.3kV/1500A BIGT (140x130)mm module nominal turn-on(left) and turn-off (right) and associated losses. (I: 500A/div, V:500V/div, Vge: 10V/div, Time(x): 1usec/div)

Figure 6: 3.3kV/1500A BIGT (140x130)mm module SOA transistormode turn-off (left) and diode mode recovery (right) and associatedpeak-power. (I: 500A/div, V: 500V/div, Time(x): 1usec/div)

Figure 7: 3.3kV (140x190)mm BIGT module performance chart.

Figure 8: Predicted BIGT thermal load cycling in PWM application

www.we-online.com

E M C C O M P O N E N T S

I N D U C T O R S

T R A N S F O R M E R S

R F C O M P O N E N T S

P O W E R E L E M E N T S

C O N N E C T O R S

C I R C U I T P R O T E C T I O N

A S S E M B LY T E C H N I Q U E

Eco TransformerTransformer for energy saving electronic devices

Universal input voltage: 85-265 VAC

Samples free of charge

4kV isolation voltage

Guaranteed in stock

High efficiency

Reference design of all major IC manufacturers

To reduce energy consumption in the enter-

prise, it’s critical to focus on all aspects of

energy: usage, allocation and management.

With advent of the new PoE Plus (IEEE

802.3at) compatible PSEs, there is the

added control functionality that allows for

dynamic allocation of per-port Power Device

(PD) power by the PSE. Using this

approach, power can now be allocated and

managed much as data bandwidth is today.

A new PoE System-on-a-Chip (SoC) that

integrates an isolation barrier has been

specifically developed to affect significant

energy savings in the enterprise. The

device’s integrated isolation increases the

power-conversion efficiency of individual

PDs in a simple and cost effective way, while

also enabling network software to reduce

enterprise energy consumption with better

allocation and management of power. The

overall energy saved by using this device

can offer considerable benefits in an enter-

prise setting where thousands of IP phones,

WAPs, thin-client PCs and security cameras

all draw power from more efficiently-loaded

power supplies at the network center.

PD Efficiency Improvements

The cumulative effect

of efficiency improve-

ments at each of the

PD nodes can be

quite substantial

across the enterprise.

For example, if on

average a PoE Class 2 IP phone draws an

average power of 5.2W from the PSE,

improving the PD power conversion efficien-

cy by 5% (example from 86% to 91%) will

provide over 500mW of savings at the PD,

and approximately 700mW of savings

referred back to the PSE input. Similarly a

20W IP camera can save 1.3W at the PD

and over 1.6W referred to PSE input. Table

1 below shows savings for different types of

appliance, assuming average power con-

sumption based on the device PoE Class.

In a simple model of 1,000-employee enter-

prise that consists of 1100 IP phones, 60

wireless access point nodes, and 40 IP cam-

eras, power savings at each PD node due to

efficiency improvements will lead to over 860

Watts of power saving, and over 16.6kWH of

energy saving per year when reflected to the

PSE input, including savings from less heat

dissipation in the data-center.

Intelligent Power Allocation

Allocation of PSE power in a traditional PoE

environment consists of setting aside the

maximum power that each port will be

expected to deliver to a PD at any phase of

its operation. In addition, maximum cable

power losses must also be set aside. Gener-

ally there is a significant margin between the

maximum advertised power and the actual

power consumed. These maximums force

the significant over-design of PSE power

supplies. In addition, power supplies are

much more efficient when used near their

peak capacity, rather than under light load-

ing.

For example, a traditional PSE will budget

7.7W of power for a Class 2 IP phone

(6.95W for PD, 0.71W for 100m cable loss),

and 30W of power for a Class 4 IP camera

(25.5W for PD, 4.5W for cable loss). If the

PSE could determine a PD’s dynamic power

consumption and the cable distance

between the PSE and the PD, the PSE

could substantially optimize its power alloca-

tion and hence reduce total required power

at the PSE. Assuming average power drawn

by the PDs, as in Table 1, and average Eth-

ernet cable length of 50m between the PSE

and the PD, intelligent allocation will reduce

the power budget at the PSE by over 35%

(7.3kW vs. 11.2kW for static allocation) in

our 1,000-employee enterprise model.

P O W E R M A N A G E M E N T


Integrated Digital Isolation Delivers Enterprise Energy

Efficiency BenefitsThe cumulative effect of efficiency improvements can be quite substantial

Power over Ethernet (PoE) standards have made it possible to deliver power to networkdevices along the same Ethernet cable used for data, eliminating the need to provide a‘wall wart’ power cube for each device. Network power is thereby consolidated at thePower Sourcing Equipment (PSE) in the data-center, which has tremendous benefits of

lowering cost, simplifying infrastructure and providing backup power management. Overall power management has been crudely addressed in previous-generation PoE

clients via power classification, but these have largely been limited and static solutions.

By Sajol Ghoshal, Chief Technical Officer and Chief Architect, Akros Silicon

Table 1 – Average Power Savings per PD Node

PD Efficiency Improvement (91% vs. 86%) Used Power (W) Savings at PD (W) Savings at PSE A/C Main (W)

IP Phone (average usage) 5.2 0.54 0.69

WAP (13W) 10.7 0.68 0.88

IP Camera / IP PTZ Camera (13W / 25W) 10.7 / 20.0 0.68 / 1.28 0.88 / 1.64

This not only reduces the power supply size

needed at the PSE, delivering direct cost

savings, but it also allows the PSE power

supplies to operate near full load conditions

for higher efficiency, reducing power

wastage and conversion to heat in the data-

center. Energy savings for the 1,000-employ-

ee enterprise example can be over

11.8kWH, including the savings from

reduced cooling requirements.

Enterprise Energy Efficiency Benefits

Using the 1,000-employee model, , if each

PD saves an average of 0.5-1.3Watts, the

total savings for the enterprise would be

nearly 16.6kWh or €3,500 annually,

assuming average European com-

mercial energy rates. With typical-

ly-rising energy costs, this factors

into a 5-year savings of over

€20,000. The total savings

approaches €35,000 over five

years (Table 2 below) after adding

in savings effect of intelligent

power allocation between the PSE

and PDs. Considering a five-year

average life span of a PD, this

translates to close to €29 in recur-

ring cost savings per PD node, a

substantial direct monetary benefit.

It also helps enterprises achieve

their energy efficiency objectives.

PoE Device with Integrated Digi-

tal

Isolation

A new device by Akros Silicon

called the AS1854 integrates Akros

GreenEdge™ 2kV digital isolation

technology with next-generation

PoE PD and power conversion

technology. This combination deliv-

ers groundbreaking power integra-

tion, and enables a new range of

Digital Power PoE PD capabilities

and solutions. A Type 1 (IEEE®

802.3af) and Type 2 (IEEE® pre-

802.3at) compliant PD is integrated

into the device with high-voltage

isolation and quad-output digital

power DC-DC converters – result-

ing in a complete PoE and power

management solution in a single

device with minimal external com-

ponents.

The number of required voltage

sources in a PoE-PD platform is

similar to many embedded plat-

forms that include a processor,

DRAM/SRAM, Flash memory and

I/O, each with different voltage and

power requirements. For a VoIP



Table 2 – 1000-Employee Enterprise Model Energy Saving Benefits

Energy savings from PD node efficiency,

including cooling

16,626 kWh

Yearly savings from PD node efficiency €3,500

Energy savings from Live Monitoring 11,836 kWh

Yearly savings from Live Monitoring €2,500

Total yearly savings

(PD efficiency and Live Monitoring)

€6,000

Total Lifetime Savings (5 Yr) €34,600 (€28.84 per node)

deadline for submission, July 17, 2009, go to web for details:

www.apec-conf.orgwww.apec-conf.org

CALL FOR PAPERS!CALL FOR PAPERS!

SPONSORED BY

2010February 21–25, 2010

Palm Springs Convention Center,Palm Springs, CA

THE PREMIER

GLOBAL EVENT

IN POWER

ELECTRONICSTM

THE PREMIER

GLOBAL EVENT

IN POWER

ELECTRONICSTM


phone, there is often a display that may

demand a unique voltage, whereas a pan-tilt-

zoom (PTZ) camera will have multiple

motors as well as low-voltage electronic

power needs. By integrating four flexible dc-

dc outputs in one power SoC, including digi-

tal isolation, the AS1854 simplifies PoE PD

system design and delivers the benefits of

power-system efficiency and intelligent man-

agement (Figure 1)

Integrated digital isolation offers a break-

through for improving power system efficien-

cy and dramatic cost savings. Using a built-

in isolated synchronous driver for secondary

side rectification, the AS1854 not only elimi-

nates the need for external pulse transform-

ers to create the sync drive, it allows the

device to intelligently manage timing of the pri-

mary and secondary drives. This optimizes “Sync delay” and “Over-

lap delay” parameters, practically eliminating PWM timing related

energy losses (Figure 2). Figure 3 shows the improvements in PoE

power system efficiency delivered by the AS18x4 series products –

which improves both light-load and full-load efficiency compared to

traditional designs. The GreenEdge technology delivers efficiency

improvements of over 8% in PoE Class 2 range, the one most com-

monly used for VoIP phones, over typical traditional designs.

Additionally, the device’s integrated isolation technology enables

direct digital management of both isolated primary power and sec-

ondary system power. Primary-side isolated ADC in the AS1854

device allows for direct power usage monitoring by the PD’s μCon-

troller across the isolation barrier. This “Live Monitoring” feature col-

lects real-time power usage to pass to the PSE’s Network Manage-

ment software via standards based LLDP messaging. This enables

the PSEs to deduce cable power loss and true PSE power allocation

needed per PD port, eliminating blind allocation of maximum power

to each PD.

This approach for the first time enables PSEs to serve the same

number of PDs with a much lower power and efficiently operating

power supply. In addition, savings can be augmented upstream using

a live monitoring capability, which allows for better power allocation

and higher-efficiency PSE power supply utilization. Although isolated

communication channels can be accomplished using discrete compo-

nents such as opto-couplers, this approach tends to be slow, bulky

and expensive, making the design more costly, much larger and

sometimes even impractical.

Summary

PD efficiency improvements and intelligent allocation capabilities can

deliver significant monetary benefits to the enterprise with lower ener-

gy usage and lower cost of power supplies in the data-center. A new

device using Akros’ GreenEdge™ integrated isolation facilitates ener-

gy-saving design improvements on the PD, reducing device power

consumption with efficient power conversion across a wide loading

range. This new approach to integrated high-voltage power manage-

ment provides a unique opportunity for cost-effective, end-to-end

“green power” applications. By employing the AS18x4 product family,

designers now can create value-added and differentiated feature sets

in a cost-effective manner, passing on recurring energy-saving bene-

fits to their end customers.

www.AkrosSilicon.com

Figure 2: Primary and Secondary PWM timing management acrossintegrated isolation

Figure 3 – GreenEdge™ Efficiency Improvement


Figure 1: Akros Silicon’s AS1854 in PoE Powered Device System

Efficiency goes hand-in-hand with the electric/hybrid vehicle revolu-

tion and designers now need to squeeze every last ounce of efficien-

cy from each part of the vehicle. It has often been the case that the

power-supply design engineer was the last person to be brought onto

a project: a topology already dictated; available space limited. How-

ever, with efficiency now at the top of the agenda, automotive drive-

train design engineers are embracing energy saving technology, and

planar transformers are at the forefront of the revolution.

Planar transformers often offer an electrical efficiency of up to 99.5%

and provide higher power density than their conventional counter-

parts. In addition to this, not only are planar transformers consider-

ably smaller than their conventional counterparts, they also offer a

significant weight advantage: the lighter the moving object, the less

energy required to move it. Hence, when you consider the added

efficiency that the reduced weight of a planar transformer provides to

an electric/hybrid vehicle, together with the improved electrical effi-

ciency, it is simple to understand why the demand for planar trans-

formers is growing rapidly.

Planar transformers are ideal for all switch-mode power supply appli-

cations and the choice of magnetic components for your design is as

important as selecting the best topologies and switching frequencies.

Electric/hybrid vehicle battery charging designs often require a power

rating in excess of 2kW, at relatively high current levels. These appli-

cations ideally lend themselves to a copper ‘lead-frame’ planar trans-

former construction, comprising thin, flat, pre-formed copper layers.

Himag Solutions is a world leader in the high-frequency 2kW+ power

range, and has now successfully manufactured single planar trans-

former components providing up to 30kW of power throughput.

Having established the weight advantage provided by a planar trans-

former, what is it that makes them so much more electrically efficient

than their conventional ‘wire-wound’ equivalents? There are a few

elements, one being the ‘construction’ method of a planar trans-

former: the pre-formed copper lead-frames (or PCB layers) are easily

interleaved between one another, primary, secondary, primary, etc...

up to five or six times is not uncommon, and are accurately posi-

tioned in-line with one another in the vertical dimension. This inter-

leaving reduces the losses: with particularly improved coupling

between windings, a significant reduction in leakage inductance and

reduced skin effect. Furthermore, by managing the interleaving with-

in the design, the leakage can be very accurately controlled to meet

the customer’s design specification.

T R A N S F O R M E R S


Planar Transformers are Essential for Truly Efficient

Electric/Hybrid VehiclesWeight advantage makes them more efficient than

conventional ‘wire-wound’ equivalentsWhen the first mass-produced motor car, the ‘Model T’, rolled off the production line in

1908, Gerald Ford famously told the world that “you can have it in any colour, as long asit’s black”. Today, a century later, the motor car has become the backbone of our

developing world, and it now appears that we can still only have one colour, although‘GREEN’ is the new black. “Necessity is the mother of invention” said Plato, and after

years of waiting it has taken a global economic downturn for the definition of ‘necessity’ tobecome: ‘replace the petrol engine with something more efficient and less polluting’. Final-ly some political and financial backing, from the likes of Obama and Brown, has turned the

automotive world’s attention away from ‘gas-guzzling’ to focus more on ‘energy-saving’

By Dean Curran, Managing Director at Himag Solutions Ltd., United Kingdom

Figure 1: E64 1kW-9kW Planar Transformer

Invariably planar transformers are custom designed (or ‘bespoke’ as

we say in the UK) for the specific end-user application. This means

that instead of the power supply design engineer having to design his

system around limited standard ‘off-the-shelf’ transformers, he can

design in the knowledge that the planar transformer will do exactly

what he needs it to do. Needless to say, the very nature of the cus-

tom designed planar transformer means that yet more efficiency is

achieved: it is obvious that if you have to ‘make do’ with a standard

part, your system will not run as efficiently as a custom designed part

specifically matching your needs.

The advantages offered by the planar winding construction are also

opening the market for ‘retro-fit’ planar transformers. Himag Solu-

tions is now frequently asked to design a planar transformer to

replace a conventional transformer that runs too hot: the planar

equivalent not only runs cooler but also improves the inverter drive

waveforms, thus reducing switching losses in the power converter as

well. We have successfully applied planar transformer design tech-

niques to conventional ferrite cores to meet the ‘retro-fit’ space con-

straints, whilst achieving an overall more efficient, cooler, component.

Beyond the electrical efficiency of planar transformer design, advan-

tages are also found in heat dissipation. Planar transformers use

‘flat’ ferrite cores that are very low profile but offer a higher

surface:volume ratio than their conventional counterparts, providing

significantly improved cooling. Furthermore the particular open con-

struction method used by Himag Solutions is very flexible and pro-

vides an excellent thermal path from the planar structure to the main

heatsink via the ferrite cores. In addition to this, it is also very easy

to incorporate ‘spacers’

between the windings to allow

airflow through the centre of

the transformer, improving

thermal performance yet fur-

ther, especially when forced air

cooling is available.

The final thing to mention is

the dreaded ‘C’ word: COST!

For some time now planar

transformers have been disre-

garded as being too expen-

sive. Contrary to popular opin-

ion, the costs have significantly

reduced in recent years

through cheaper material

costs, as the market grows,

and improved manufacturing

techniques. It is common for a

5kW planar transformer to cost

in the region of $23 nowadays,

and in volumes of 100k+

prices below $10 per piece are

easily achievable. Moreover,

in the 2kW-30kW power range,

the use of pre-formed copper

‘lead-frames’ in single and

multi-turn forms can achieve

virtually any desired turns ratio

at low cost, allowing rapid

design iteration and ultimately

improved time to market.

It is extremely exciting to be leading a planar transformer company

through the efficiency revolution that we are embarking upon. With

hybrid/electric vehicles at the forefront, we are also experiencing

huge demand from the defence/military, solar/wind power, medical

and induction heating/charging sectors. The planar transformer mar-

ket is set for significant growth over the next few years and one thing

is certain, if you’re not using or considering using a PLANAR

TRANSFORMER, then your competitors surely are.

www.himag.co.uk


Figure 2: E102 7kW-30kW Planar Tramsformer

Figure 3: E102 7kW-30kW Planar Transformer Dimension Drawing

Advantages of Planar Transformers

• High Efficiency

• Low Weight

• Low Profile

• Low Leakage Inductance

• Highly Efficient Cooling

• Multiple Topologies

• Multiple Winding Options

• Customised Terminations

• Dimensional Accuracy

• Tightly Controlled Parasitics

BICKER ELEKTRONIK GmbHPhone +49 (0)906 / 70595-0

www.bicker.de

Point Of SaleBEA-740 | 450 Watt• Additional +24 VDC output

for printers, displays, scanners,cash terminals etc.


The demands for high operating efficiency and small size in con-

sumer electronic products such as home theatre systems, game con-

soles and LCD televisions is moving power supply design towards

resonant topologies capable of operating at high switching frequen-

cies. At the same time as allowing high-frequency operation permit-

ting the use of smaller magnetic components, the resonant convert-

er’s soft commutation enables the SMPS to operate efficiently and

with low EMI.

Refining the Resonant Converter

Among the various resonant converter topologies, the LLC converter

has become the switching scheme of choice. Although as easy to

build as a basic series-resonant LC converter, it overcomes draw-

backs such as difficulty in maintaining regulation at light load. It also

effectively improves efficiency when the input voltage is high such

that switching loss is more dominant than conduction loss. The LLC

resonant topology utilises an additional shunt inductor across the pri-

mary winding of the transformer, as shown in Figure 1. This is usually

realised using the magnetising inductance of the transformer, which

is controlled by adjusting the transformer air gap. This topology pro-

duces a complex resonant tank with buck-boost transfer characteris-

tics in the soft-switching region.

Referring to figure 1, in normal operation the primary-side MOSFETs

operate at 50% duty cycle and the output voltage is regulated by

varying the switching frequency of the converter. The converter has

two resonant frequencies; a lower resonant frequency (given by Lm,

Lr, Cr and the load), and a fixed higher series resonant frequency Fr1

(given by Lr and Cr only). The secondary side half bridge can be

soft-switched for the entire load range by operating the converter

either above or below Fr1.

The secondary side half-bridge is conventionally implemented using

a pair of diodes. However, this arrangement is relatively inefficient, as

diode losses contribute significantly to the overall power loss of the

SMPS. With increasing current draw in future generations of feature-

rich consumer products, these losses will continue to increase, since

the diode rectifier conduction loss is proportional to the product of its

forward conduction current as well as the forward voltage drop.

Increasing dissipation also demands the use of larger diodes, leading

to progressively more bulky power supplies.

Hence there are two powerful factors forcing designers to demand a

more satisfactory secondary side topology for LLC resonant convert-

ers. For power supplies in the region of 50W and higher, the demand

for higher power density to minimise case dimensions is the domi-

nant concern. In the region of 200-400W, boosting efficiency to satis-

fy initiatives such as Energy Star and CEC 80+ is a major reason for

power supply designers to seek ways to eliminate the losses incurred

in the secondary side diodes.

Synchronous Secondary Side Rectification

Using synchronous rectification in the secondary side holds out the

promise of reducing the large losses incurred in the half-bridge

diodes. Since MOSFET conduction losses depend on I2 x RDS(ON),

splitting current between two synchronous MOSFETs reduces the

dissipation in each device by four, thereby halving the total dissipa-

tion.

However, the most familiar control techniques for synchronous recti-

fiers are not workable in LLC resonant converters. For example in a

primary-controlled synchronous rectifier, where the MOSFET control

signals are derived from primary side signals, the LLC resonant con-

verter has a phase lag between the input voltage of the resonant tank

and the rectified secondary side current. This prevents the primary

side gates from being used to drive the secondary side rectifiers. The

alternative self-controlled rectifier technique, where the control sig-

nals are derived from the secondary voltage across the power trans-

former, suffers from timing mismatches between the rectified second-

ary side current and the voltage across the main power transformer,

which is a 50% duty cycle square wave. These prevent satisfactory

operation below the resonant tank frequency of the converter.

Using a current transformer, on the other hand, is a workable control

technique for resonant converters. The drawbacks of this technique

include a high component count, which increases footprint and

impairs reliability, and the need for a relatively expensive fast com-

parator.

Placing a controlling IC in the secondary side to manage the switch-

ing of the MOSFETs potentially offers a simpler and more cost-effec-

P O W E R S U P P LY

Smarter Rectification Driving up SMPS Efficiency and Power Density

Performance, size and efficiency advantages have made the LLC series-resonant converter the preferred power supply topology in applications such as high-end consumerproducts. Going forward, improvements to the secondary side architecture are necessary

to further enhance efficiency and space savings.

By Helen Ding, International Rectifier

Figure 1: Half-Bridge LLC series-resonant converter

27www.bodospower.com July 2009 Bodo´s Power Systems®www.bodospower.com July 2009 Bodo´s Power Systems®www.bodospower.com July 2009 Bodo´s Power Systems®

tive alternative. By eliminating the current

transformer and fast comparator, an IC-

based solution saves size and component

count. However, to implement all the

required functions in a single component

requires certain competencies, such as the

ability to co-integrate the control functions

with high-voltage sensing capabilities in the

same device, as well as managing high

switching frequency and high current-driving

capabilities. International Rectifier’s IR1168,

for example, uses high-voltage IC (HVIC)

technology and patented techniques to deliv-

er a secondary side rectifier driver IC

designed to drive two N-Channel power

MOSFETs used as synchronous rectifiers in

resonant converter applications. In addition

to providing two gate drivers, the device also

provides adaptive shoot-through protection

to prevent both channels from simultaneous-

ly turning on. It is also capable of operating

in normal and burst-mode conditions. In

addition, clamped gate-driver operation sig-

nificantly reduces power dissipation.

Single-Chip Control

Figure 2 illustrates a typical application

schematic for the IR1168. In normal operat-

ing mode, the IC senses the voltage drop

across each MOSFET at pins VS1/VD1 and

VS2/VD2, and turns each MOSFET on and

off via pins GATE1 and GATE2.

At the core of this device are two high-volt-

age (200V) high-speed comparators. These

differentially sense the drain to source volt-

age of the MOSFET, using the RDS(ON) of the

device as a shunt resistance, and hence

determine the polarity and level of the device

currents. Dedicated internal logic then man-

ages the turning on and off of each device in

close proximity to the zero-current transition.

The device uses the SmartRectifier™ control

technique, which compares the sensed volt-

age across the MOSFET with two negative

thresholds to determine the turn-on and turn-

off transitions for the device. The most nega-

tive of these two thresholds, VTH2, detects

current through the body diode and hence,

controls the turn on transition for the power

device. Similarly, a second negative thresh-

old, VTH1, determines the level of the current

at which the device turns off. A third thresh-

old voltage, VTH3, acts as a reset threshold

governing the resetting of an internal one-

shot when the cycle is completed and the

VDS voltage turns positive and starts to

increase again. This way the system is ready

for next conduction cycle.

By governing the drive level of the second-

ary side MOSFETs according to these three

thresholds, the IR1168 ensures accurate

performance without the need of a PLL or

external timing sources. In fact, the high

accuracy of turn-off transitions is a key bene-

fit of this technique, since it prevents reverse

current across the MOSFETs and also min-

imises the body diode conduction time. Addi-

tionally, internal blanking logic is used to pre-

vent spurious gate transitions and guarantee

operation in fixed- and variable-frequency

operation modes.

The waveforms of Fig-

ure 3 show the IR1168

in normal operating

mode. When the con-

duction phase of the

MOSFET is initiated the

current begins to flow

through the MOSFET

body diode, generating a

negative VDS voltage.

Since the body diode

has a much higher volt-

age drop than that

caused by the MOSFET

RDS(on), this negative VDS triggers the turn-

on threshold, VTH2. At this point, the IR1168

will turn on the gate of the MOSFET. This, in

turn, causes the VDS voltage to drop down to

a value defined by the MOSFET drain cur-

rent (ID) multiplied by RDS(on).

Since this fall in voltage is usually accompa-

nied by some amount of ringing that could

trigger the input comparator to turn-off, a

fixed Minimum On Time (MOT) blanking

period is used that will maintain the power

MOSFET on for a minimum time duration.

Once the MOSFET has been turned on, it

remains on until the rectifier current decays

to the level where the voltage will cross the

fixed turn-off threshold VTH1. Once the

threshold is crossed, the current will start

flowing again through the body diode, caus-

ing the VDS voltage to jump negative again.

Depending on the amount of residual cur-

rent, VDS may once again trigger the turn-on

threshold. Hence, VTH2 is blanked for a time

duration called TBLANK after VTH1 is trig-

gered. The period TBLANK is shown in the

diagram, and is terminated when the device

VDS crosses the positive reset threshold

VTH3. The IC is then ready for the next con-

duction cycle.

Conclusion: Performance Advantages in

Next-Generation Products

Figure 4 compares a 240W multi-rail power

supply for an LCD TV application built using

the IR1168 synchronous-rectifier controller

against a conventional resonant converter

design with secondary side Schottky diodes.

The IC is housed in a low-cost SO-8 pack-

age and delivers a single-chip solution capa-

ble of generating the control signals for both

MOSFETs. The four Schottky diodes were

replaced by IR1168 with four SO-8 MOS-

FETs daughter card. The two large heatsinks

cooling the Schottky diodes for the 12V and

24V rails are also eliminated.

In practice, this smaller SMPS featuring sec-

ondary side synchronous rectification has

shown a 1.5% increase in efficiency. A 25°C

reduction in operating temperature for the

SMPS has also been recorded, leading to a

significant increase in overall system reliabil-

ity.

www.irf.com

www.bodospower.com July 2009 Bodo´s Power Systems®


Figure 2: Typical secondary-side applicationcircuit for IR1168

Figure 3: Operation of SmartRectifier™ syn-chronous-rectification control with IR1168

Figure 4: IR1168 retrofit in a 240W LCD TV

Selecting precision voltage references can be an arduous task.

Today, there are hundreds of products offered by dozens of chip

companies, offering various combinations of initial accuracy, tempera-

ture coefficients and cost. Selecting the right part for the right applica-

tion requires considerable research into the details of the datasheets

as well as sourcing volume pricing quotations.

While several parameters are important in the selection of voltage

references, the two that stand out as potentially contributing the

greatest errors are initial accuracy and temperature coefficient (TC).

Noise, thermal hysteresis, line and load regulation and long term sta-

bility should not be neglected when making a selection, but their con-

tributions to error are shadowed by initial accuracy and TC. It is not

surprising therefore, that chip manufactures concentrate their market-

ing efforts to proclaim best in class performance achievements in

these two domains.

Initial Error

Initial error is the deviation of the actual output voltage from the

desired specification. Many voltage references have trim pins that

allow the user to set or pre adjust the output value in an attempt to

offset the inherent initial error of the reference chip. (See Fig. 1) The

output is adjusted by setting the ratio of resistance above and below

the “wiper” shown in the figure.

Of course the ability to precisely select the desired output voltage

then becomes an issue of finding the correct resistance values, tak-

ing into consideration their initial accuracies (or perhaps more cor-

rectly, their inaccuracies) as well as their contribution to the TC of the

output voltage. The specific ratios attainable are constrained by the

limited selection of fixed resistance values.

In this application we have set about to show how to improve the per-

formance of an average precision voltage reference, the Analog

Devices ADR 425A, by more than an order of magnitude.

Analysis of the circuit requirements showed that by replacing the

470KÙ ballast resistor with a 120KÙ, resistor, and using the

MBT143E 1:9 ratio Rejustor, the Vout could be adjusted quite pre-

cisely. See Fig 2

To assure the best possible performance, the trimming is accom-

plished at the assembled board level. During this calibration process,

software algorithms provided by Microbridge automatically adjust the

two resistances of the MBT143E down from their as manufactured

values based on the real time feedback from Vout, taking about 1-2

seconds, until the desired output accuracy is achieved. The rejustor

values will be trimmed to slightly different resistances for each

ADR425A to compensate for both the minor manufacturing variances

of the precision reference as well as the differing non idealities asso-

ciated with each board layout. Thus the use of precision fixed resis-



Get <1ppm Performance from a 10ppm Precision Reference

Rejustor Technology turns a good voltage reference into an ‘industry best’

Precision References require the user to make major cost/performance tradeoffs. Untilnow, ultra-high performance came at a high price. By using a low cost, tunable resistor

divider (Rejustor) from Microbridge, precision references can be made more accurate andtheir temperature coefficients can be offset to offer unmatched performance over their

operating temperature range.

By Bob Frostholm, VP Marketing – Microbridge Technologies Corp

Figure 1: Typical external resistor configurations to trim a precisionvoltage reference

Figure 2 Fully calibrated and temperature compensated precision ref-erence design using MBT143E 9:1 Rejustor divider from Microbridge

tors would become an almost impossible task without massive reiter-

ative measurement and hand selection.

Temperature Coefficient

Temperature coefficient is the measure of the stability of the output of

the precision voltage reference with temperature changes. Precision

means nothing if it cannot be maintained over the useful operating

temperature range of the system into which the precision voltage ref-

erence is designed. TC is referred to as the second most important

specification to consider when selecting a reference. First-order tem-

perature correction (or linear temperature correction) is the largest

contributor to errors associated with temperature variations.

Datasheet examination of the ADR 425A reveals the device is speci-

fied to have an initial accuracy of +/- 3mV (+/- 0.15%) and a relative-

ly linear TC of 10ppm/°C, making it an average performer among

several competitive devices. See Figure 4.

Microbridge Rejustors provide designers with a new tool with which

to craft and adjust an application circuit. Rejustors are passive preci-

sion resistor dividers whose ohmic resistance and TC can be

trimmed independently. Once trimmed these values remain constant

and require no power to maintain their values. The TC-Offset vs. Off-

set characteristics of MBT143E divider are shown in Figure 3. The

Offset is the deviation of the divider output voltage Vin*(R1/(R1+R2)),

measured in mV per volt of divider input voltage Vin, away from

Vin*(R1o/(R1o+R2o)), where R1o and R2o are the nominal unadjust-

ed divider resistance values.

The TC-Offset is the temperature coefficient of that divider output

voltage, measured in uV per degree-C (K) per volt of divider input

voltage. Microbridge’s electrical TC adjustment software allows one

to pick target values for Offset and TC-Offset as a point within the

roughly-parallelogram-shaped region shown in Figure 3. For exam-

ple, if initially the divider input voltage were low by 5% (50mV/V) from

its designed value, and, additionally, it has an undesired +75uV/VK

temperature variation, and if it is desired that the drive level be tem-

perature-stable at the nominal Vin*(R1o/(R1o+R2o), then one pro-

grams the divider to the point (+50mV, -75uV/KV), as shown in the

figure.

The adjustment software allows you to pick a target spot within this

roughly parallelogram-shaped region. One specific example point is

shown, at Offset = +50mV/V and TC-Offset = -75uV/VK, (+50mV/V, -

75uV/VK).

For the purposes of this example the ADR425A was characterized

over the temperature range of +0°C to +85°C. Characterization and

analysis of the temperature stability of the ADR425A reveals an out-

put voltage variation of ~5000uV over the temperature, or

~12ppm/°C , close to the specification for the A grade product

(10ppm/°C) shown as the curve in Figure 4 identified as “ADR425A

as it is”.

Based on these characterization results, Rejustor calibration targets

were set and the MBT143E was adjusted “in circuit” using Rejust-it

software from Microbridge at the same time that the configuration

was being tested.

By adjusting the ohmic value of the two rejustor resistances to set the

“perfect” divider ratio, the initial output of the ADR425A was improved

from 4.99612V to 5.000125V or 0.0025% initial error. By adjusting

the TCR of the two resistances in the divider, the majority of the posi-

tive temperature coefficient was eliminated, improving the TC from

12ppm/°C to 0.8ppm/°C

Conclusion

You don’t have to pay a lot more for performance. For less than

$0.50 Rejustor technology enhances the performance of a low cost

precision voltage reference has been demonstrated to outperform

devices costing several dollars more.

www.mbridgetech.com



Figure 3: A typical plot of the achievable sets of values for voltagedivider made from a specific example of Rejustors

Figure 4: Typical performance of ADR425A precision voltage refer-ence before and after calibration and compensation with MBT143ERejustor divider

Bodo´s Power Systems® July 2009 www.bodospower.com

Parameter testing

The static parameters of power semiconductors are the most impor-

tant parameters that must undergo testing after production. The IDSS

(Darin off-state current) and IGSSf/r (forward and reverse off-state

current of the gate) leakage currents, in particular, provide informa-

tion on any possible mechanical damage to the chips. Gate threshold

voltage and breakdown voltage are important indicators of doping.

But is that still enough today?

Static tests are often inadequate to meet the high demands for quali-

ty in the manufacture of special-purpose machinery and in the auto-

mobile industry. Future requirements in the automotive industry are

clearly moving in the direction of robust design and validation. But a

robust design of components that are released according to the most

modern methods does not help if process problems occur in produc-

tion and nullify such efforts. To keep the required failure rate <10

ppm, advanced tests must guarantee the quality of production.

The Dynamic Test

Dynamic tests examine the switching behavior of the component

under a load. The component will ultimately be used as an electronic

switch in converters and similar units. For IGBT, the switch at high

environmental temperatures is especially critical RBSOA (reverse

bias save operation). Components with avalanche characteristics

must pass the switching unclamped inductive load test. This test

destroys weak components.

The Thermal Impedance Test

The production of heat in any noteworthy quantity is a very undesir-

able, yet unavoidable, property of every piece of power electronics.

In this context, it is very important that the semiconductors have the

ability to dissipate as much of the heat as possible from the place of

origin (depletion layer) to the environment (heat sink) via the enclosure.

The bubbles and voids that appear during soldering of a chip impede

the required heat dissipation. The component will work for a limited

time, but sooner or later a thermal failure will occur. Measuring the

thermal impedance, Zth, provides information on the thermal connec-

tion of the chip. It is unnecessary to examine all of a characteristic:

measurements at one or two informative measurement points are

enough.

With Only One Contact

The required quality demands that these tests (switching unclamped

inductive load test, RBSOA and Zth) be performed as a 100% test of

the components. The simplest solution would be to use specialized

testers with independent contacts, possibly even for additional hot

and cold tests. But it’s readily apparent that this approach does not

make economic sense. But it is nonetheless possible to combine the

tests mentioned above in one tester, despite the different ancillary

conditions of each test. This approach saves the effort of multiple

contacts and handling time.

And the following is also possible. First, the static parameters can be

determined to deduce the processes for chip manufacture and

assembly. Second, stress tests can be performed with an increasing

load. The static parameters would then be measured again to ensure

that the stress tests did not do any damage. And all that can be done

with just one contact.

The Test System

The testers from MRS Electronic are based on 19” components and

are assembled in a type of modular system. This approach enables

optimal tailoring of the vertices (maximum test voltage, maximum cur-

rent, and the required multiplex productions) to the requirements.

P O W E R M O D U L E S


Power Module Testing withCombination Testers

Quality requires 100% testing of semiconductors

Since the Die cannot be tested thoroughly before the assembly, all parameters have to betested after the module was assembled. A complete test consists not only of parametertesting but also the thermal connection of the chip to the heat sink and the dynamic

switching behavior. Thus a test sequence consist of a pretest measuring the cold parame-ters, then the stress test dynamic and Zth and retest to make sure the part is still functional.

To conduct all these test in one station, combination testers are available.

By Günther Dörgeloh, MRS Electronic GmbH

Figure 1: Schematic Structure of an N-Channel IGBT Cell

31www.bodospower.com July 2009 Bodo´s Power Systems®www.bodospower.com July 2009 Bodo´s Power Systems®

The tests run in real time on a high-performance digital signal

processor (DSP). A regular commercial PC is used to control the

tester.

Measuring the Static Parameters

For the static parameters, a source instrument adjusts the test volt-

age or the test current and measures the variables. The measure-

ment module works continuously.

Except for the indispensable anti-alias filter, the hardware does not

contain any additional filters. The DSP performs each processing of a

signal.

From a large assortment, the optimal FIR filter can be selected for

each test. Short filter times are used for time-critical measurements.

Sensitive measurements, such as leakage currents in the lower nA

range, require longer filters. Digital signal processing enables very

exact, reproducible measurements of leakage current even in

extremely electromagnetic industrial environments.

Measuring Dynamic Behavior

The two dynamic tests used most widely are the switching

unclamped inductive load test and the double impulse test. Both

involved stress tests that destroy problematic components.

The first, the switching unclamped inductive load test, links the test to

an inductive load without an override (unclamped). The transistor is

switched off once the specified cut-off current is reached. Because

there is no override path, the current continues to flow through the

unit being tested and drives it into the avalanche breakthrough or into

linear mode if an active clamp is required over the gate.

Within a very short time (usually <500 is), a very high rating in the

chip is converted into heat.

In cases of inhomogeneous, defective doping or defective source or

emitter gate metallization, hot spots on the silicon develop that can

lead to fusion of the crystal (see Figure 2). IGBTs, in particular have

an unavoidable parasitic thyristor structure that ignites when the fail-

ures noted above occur and that can lead to a latch-up with the

resulting destruction of the component. These kinds of components

may not leave production in any circumstances. FETs have only a

part of these parasitic structures, so that there is no danger of a

www.bodospower.com July 2009 Bodo´s Power Systems®


Figure 2: Failure of a Transistor in a Switching Unclamped InductiveLoad Test

XPT-IGBT the newest generation of short-circuit rated IGBTsDrive with the XPT-IGBT

Features:• Easy paralleling due to the positive

temperature coefficient

• Rugged XPT design results in:

– Short Circuit rated for 10 �sec.– Very low gate charge– Square RBSOA @ 3x Ic– Low EMI

• Advanced wafer technology results in low Vce(sat)

• 10-50 A in 1200 V

Used in:• AC motor drives• Solar inverter• Medical equipment• Uninterruptible power supply

For more information pleaseemail [email protected] or call Petra Gerson: +49 6206 503249

TYPE Configuration PackageMIXA20WB1200TED CBI E2-Pack

MIXA60WB1200TEH CBI E3-Pack

IXA37IF1200HJ CoPack ISOPLUS 247

IXA20I1200PB Single TO 220

www. ixys .com

For more part numbers, go to www.ixys.com

latch-up. Nevertheless, these structures are

enough to cause comparable failures (a con-

trolled increase of the parasitic bipolar tran-

sistor).

The Double Impulse Test

The setup for the double impulse test is

comparable to the setup for the unclamped

inductive load test, although an override path

exists in this case. If complete converter

modules or phase legs are being tested, the

existing diode conveniently located on the

opposite side of the transistor can be used

as an override diode. This approach corre-

sponds to later usage. A complete switching

cycle is now run: commutation of the current

into the override diode and reserve recovery

of the override diode when switching back

on. Test tester monitors the ancillary condi-

tions of the test. A rapid digital storage oscil-

loscope can also be used to perform addi-

tional detailed analysis of current and volt-

age curves online.

The dynamic tests of IGBTs are especially

interesting at high environmental tempera-

tures. The current gain of both parasitic tran-

sistors increases as the temperature rises,

as does the extrinsic base resistance. Both

increase the danger of a latch-up. An appro-

priate choice of test parameters enables

testing compliance with the safe operating

area of each component. The transformed

heat is mostly limited to the chips.

Measuring the Thermal Impedance

Measuring the thermal impedance, Zth, can

determine if the component can dissipate, in

long-term operation, the heat that is created.

Measuring the thermal impedance occurs in

three phases:

Measurement of a temperature-dependent

parameter (diode flow voltage, saturation

voltage, and so on)

Application of well-defined (electric)

energy

Second measurement of the temperature-

dependent parameter directly (in as short a

time as possible) after the power impulse

Application of well-defined energy means

that constant power must be adjusted over a

specific time. The time is determined from

the thermal time constant of the structure to

be tested, usually between 10 ms and 500

ms. The power is selected to enable good

measurement of the temperature difference

without exceeding the maximum barrier layer

temperature. The amount of warming that

has occurred can be calculated from the

change of the temperature-dependent

parameter.

This measurement of Zth corresponds exact-

ly to reality and is clearly superior to other

approaches.

Figure 3 illustrates a detailed analysis of a

module that was rejected by the tester dur-

ing the product part approval process

(PAPP) phase. Curves ZTH_1 to ZTH_4

were determined during the evaluation

phase to specify the thermal behavior of

good parts. The routine test uses a power

impulse that lasts 500 ms. It is briefly inter-

rupted after 50 ms for an intermediate meas-

urement of the temperature-dependent

parameter. No abnormalities are seen after

50 ms, but extreme abnormalities are seen

after 500 ms. The reason for the difference

is that the chip is very well soldered with

direct copper bond (DCB) and can dissipate

the heat very well to the DCB.

The bubble is located between the DCB and

the copper base plate. That’s why the bubble

cannot be seen by an X-ray. The solid cop-

per base plate absorbs so much of the X-

rays that the bubble disappears in the noise.

Only an expensive ultrasound examination

would confirm the results of the tester. Only

an analysis of both Zth results that are deter-

mined in a sort of inspection impulse con-

tains valuable information for the process

engineers.

This component was perfect in terms of the

static parameters and passed both dynamic

tests without any problems. In the field, how-

ever, it failed in a short time because of

overheating.

MRS Electronic was founded in 1971 as a

manufacturer of interface electronics and

control equipment for data processing

devices. The first test systems of MLH sys-

tems were developed in 1975 to test power

diodes and NPN transistors. The company is

headquartered in Rottweil (near Stuttgart,

Germany) and has today about 50 employ-

ees. It works with test systems for semicon-

ductors along with measurement and regu-

lating technology for industrial applications,

automotive electronics, and electronics man-

ufacturing as a service.

Increasing quality demands require compre-

hensive, 100% testing of semiconductors.

Static tests are no longer enough. Only sup-

plemental dynamic testing procedures, such

as switching unclamped inductive load and a

double impulse test can meet the require-

ments. Inspection of thermal impedance, Zth,

is very important in the process. The sim-

plest approach uses a test system that can

perform all these tests with only one contact.

www.mrs-electronic.de


Figure 3: Rejection of a Chip with Poor Ther-mal Fastening


Digital Power Workshop based on

TI´s F28x family.

For more information and

your free drill hole stencil

please visit www.biricha.com


13th European Conferenceon Power Electronics

and Applications

Receipt of synopses:Monday 3 November 2008

Receipt of full papers:Monday 11 May 2009

EPE 2009 Barcelona, Spain

www.epe2009.com

Throughout time different methods of meas-

urement of the electrical current have been

developed. The different methods are based

on purely electrical, magnetic or optical prin-

ciples, or making use of the behaviour that

some materials have in presence of a mag-

netic field [1].

The more suitable method in each case

depends on the characteristics of the current

to be measured: DC, AC or both simultane-

ously, frequency, peak value, accuracy, iso-

lation, etc. Among the different methods we

find: shunts, current transformers, Hall-effect

and Rogowski effect transducers, Flux-gate

effect transformers, and other alternative

methods of less common use.

A brief summary of the main methods is pre-

sented.

Shunt

The method is based on the measure of volt-

age that appears on a resistance (shunt)

due to electric current, according to Ohm’s

law.

The method is extremely simple and suitable

for measurement of DC and AC accurately,

but its major drawback is the absence of iso-

lation between the power and measure cir-

cuits and the high power consumption in

case of high current measurement.

Current Transformer

Based on electromagnetic principles, is an

AC transformer where the secondary current

is related to the primary according to the

transformer turns ratio.

It consists of a toroidal core, where the sec-

ondary winding is wrapped. The conductor

through which the current to be measured

circulates become the primary winding.

The transformer is carefully conceived in

order that the leakage current and the losses

in the core are very small, so that no signifi-

cant errors are introduced in the measure.

The main advantage of this method is its

simplicity and robustness, while the main

drawback is that it is only suitable for AC

measures.

Hall Effect Transformer

The Hall sensor measures the voltage that

appears in a semiconductor in the presence

of a magnetic field perpendicular to the

plane of the material when a current circu-

lates along this material (Hall effect).

The transformer consists of a toroidal mag-

netic core with a gap for the Hall probe

placement. The magnetic core is used to

direct the magnetic field originated by the

current to be measured. An additional elec-

tronic circuit processes the signal generated

by the Hall probe.

The principal advantage of this system is the

ability to measure DC and AC currents, up to

frequencies of 100 kHz, with an acceptable

precision and a galvanic isolation.

Rogowski Transformer

The Rogowski transformer has a toroidal

structure, but with a coil wrapped on a non-

magnetic core (named Rogowski coil) and its

structure can be either rigid or flexible.

The current to be measured crosses the

Rogowski coil and generates a voltage pro-

portional to the rate of change of this current

and the mutual inductance between the coil

and the conductor. The value of the current

to be measured is proportional to the integral

of this voltage.

The advantage of this transducer is the

impossibility of saturation of the magnetic

core (i.e. air or plastic), but is not appropriate

for DC measures and its accuracy and band-

width are conditioned by the integrator cir-

cuit.

Flux-gate Transformer

This transformer, with physical structure sim-

ilar to the Hall transformer, is based on the

detection of the saturation state of a magnet-

ic circuit. The magnetic core is built using a

high permeability material, which is

immersed in the magnetic field to be meas-

ured.

The magnetic material is excited by a signal

that, in absence of external magnetic field,

leads the magnetic material to the symmetri-

cal saturation. This symmetry is lost with the

existence of an external magnetic field.

S E N S O R S


Low Consumption Flux-GateTransducer

Both AC and DC High-Current Measurement is achieved

This article presents the design and implementation of a transducer system for the meas-urement of AC and DC high-current using the flux compensation technique in the meas-urement transformer, also called Flux-gate technology. The system can measure currents

greater than 700 A (peak value) with a 100 kHz bandwidth measured at -3 dB.

By Manuel Román*, Guillermo Velasco*, Alfonso Conesa * and Felipe Jeréz ***EUETIB – CEIB and **Grupo PREMO S.A.

*Technical University of Catalonia (UPC) - Department of Electronic Engineering (DEE)*Compte d’Urgell 187, 08036 – Barcelona SPAIN

Picture 1: fluxgate currents transducer range

The injection of current in an auxiliary wind-

ing creates a compensating magnetic field

that restores the symmetry of the hysteresis

cycle. The injected current compensates the

magnetic field created by the current to be

measured, and its value is proportional to

this current.

This system is suitable for the measurement

of DC and AC currents, with high accuracy,

high frequency and high current range.

Other Methods of Measurement

So far the most important methods used for

the measurement of the electrical current

have been reported.

All of them are based on the detection of the

magnetic field created by this current, with

the exception of the direct measurement by

means of a shunt.

Other methods for current measurement are

based on the properties of materials sensi-

tive to magnetic field, like those based on

the magneto-resistive and magneto-optical

principles or those based on the magneto-

diode, magneto-transistor and superconduc-

tors components, etc… [2 - 3].

Comparison Between the Presented

Methods

Table I presents a comparison between dif-

ferent methods of current measurement

described above using some parameters

that determine their main characteristics and

usual applications.

Flux-gate transducers

These transducers have similar physical

structure to Hall transformers. They are

based on the detection of the saturation

state of a magnetic circuit. The ferromagnet-

ic material used presents high permeability

and is immersed in the magnetic field to

measure. This system is appropriate in a

large range of DC and AC current measure-

ment with high accuracy, until maximum fre-

quencies around 100 kHz.

The “Flux-gate” term makes reference to the

principle of operation on which some trans-

ducers are based for the measurement of

current with isolation. In this type of trans-

ducers the magnetic field generated by the

current to measure is detected by means of

a sensor.

In a similar way to the transducers based on

the Hall-effect, the usually called standard

Flux-gate transducers use a toroidal magnet-

ic circuit which includes an air gap with the

field measuring element and a secondary

winding. The main difference between the

transducers Hall and standard Flux-gates

consists on the element to measure the field

that crosses the magnetic circuit, as shows

Figure 1. Hall cells and saturable inductors

are used respectively.

The current transducer proposed in this work

is based on non-standard Flux-gate trans-

ducer. The non-standard transducer devel-

oped uses its own toroidal core as field

detector, and does not include any gap in

the magnetic path. An auxiliary winding is

added to the core and that results in a core-

wounded set, which is used as a saturable

inductor flow detector.

In order to detect a null field in the magnetic

circuit, the secondary winding is excited with

the necessary current. In this circumstance,

the transducer works with zero field condi-

tion, as shown in Figure 2. This condition

verifies that the current imposed, by the sec-

ondary winding, is directly proportional to the

primary current to be measured (IP).

The relationship between the primary and

secondary current is (1), being NS the num-

ber of turns of the secondary winding.

(1)

The detection of the zero flux condition in

the magnetic path of the transducer is based

on the change of the inductance value of the

saturable inductor formed by the ferromag-

netic core and the auxiliary winding. In

absence of current to be measured (IP), the

net flux through the saturable inductor core

is zero.

Under these conditions, if a squared voltage

waveform is applied to the auxiliary winding

(NA), the current waveform in auxiliary wind-

ing will be as shown Figure: 3.

The effect of the current to be measured (IP)

on the auxiliary winding current (NA), when a

square voltage waveform is applied, leads to

an average current value different from zero,

as shows Figure 4.

The average value obtained and its sign will

depend on the specific value and direction of

the current IP.

Flux-gate transducer designed

The designed transducer operates in a

closed-loop, according to the general

scheme shown in Fig. 2. The null average

value condition in the current by the auxiliary

winding (NA) is used to determine the condi-

tion of zero flux in the core. The basic oper-

ating principle of the designed transducer is

in Figure 4.

SSP INI ⋅=

S E N S O R S


Figure 1: Structure of a Flux-gate transduc-er: a) standard and b) without gap in themagnetic path

Figure: 2 Basic principle of behaviour ofFlux-gate transducers

Figure 3: Voltage waveforms of excitationand current by the auxiliary winding underzero flux conditions

Figure 4: Voltage waveforms of excitationand current by the auxiliary winding undernon zero flux conditions

Table1: Comparison of methods for current measurement

Parameter Shunt Current transformer

Hall transformer

Rogowskitransformer

Flux-gate transformer

AC/DC measure AC/DC AC AC/DC AC AC/DCBand Width Low Low Middle Middle HighIsolation No Yes Yes Yes YesLinearity High High Middle High Very High Precision Middle Middle Middle Middle Very HighOffset Yes No Yes No NoHigh current Bad Middle Middle Good Very Good Saturation effect No Yes Yes No NoTemperature dependence

Middle Low High Very Low Low

Power Consumption High Low Low Low MiddleSize Very Low Low Low Middle Middle

A disadvantage presented by this structure is

the possible injection of noise on the primary

current measure (IP). This noise comes from

the auxiliary current (IA), and can be cou-

pled in the primary current due to the trans-

former effect in the magnetic core of the

transducer. The solution usually adopted to

avoid this phenomenon is the use of a sec-

ond core with a new auxiliary winding. These

two cores with their auxiliary windings must

be identical under ideal conditions [4].

Now the secondary winding (NS) in which

the compensation current of flux in the trans-

ducer is applied will be common to both aux-

iliary cores.

The purpose of this second auxiliary core

(also a second saturable inductor) is to com-

pensate the injected noise in the primary

current by the first saturable inductor. If the

second auxiliary core (NA2) is excited with

an equal current but in reverse direction to

the current used for exciting the first auxiliary

core (NA1), the currents induced on the pri-

mary current conductor (IP) will be equal

and in opposite direction, cancelling its

effect.

The block diagram that represents the

designed measurement system is shown in

Figure 6.

Signal Generator for the Excitation of

Auxiliary Windings

It is based on a comparator circuit with hys-

teresis (or Schmitt trigger). This circuit will

change the value of its output voltage when

the circulating current on the main winding

excitation (IA) exceeds a threshold value.

The magnetic component of measure is

included in the oscillator circuit, and the

electrical characteristics of this component

will influence the frequency of oscillation of

the squared signal generator circuit.

For the transducer built, this frequency is

around 300Hz.

Symmetry Detector of the Auxiliary

Current (IA)

In absence of primary current (IP) the aver-

age value of the current of excitation (IA) is

zero. The effect produced by the existence

of a primary current is the appearance of an

average value different from zero and sign

dependent of the sense of of this current.

For the automatic adjustment of the value of

the secondary current winding (IS), the use

of a PI controller is proposed, in order to

ensure that the primary current excitation

winding has zero mean value.

This controller cannot guarantee the proper

functioning of the measurement system at

the start-up process if a primary current (IP)

even of moderate value is already circulat-

ing, because under these conditions the two

inductors will be saturated.

A primary current through the measurement

system in non zero flux conditions, produce

a high frequency current (some tens of kHz)

in the main excitation winding (IA) and non

zero average value, with independent sign of

the primary current circulating sense (IP).

To overcome this drawback, an additional

controller is included which ensures that the

zero flux condition is reached regardless the

value that the primary current (IP) could take

at the start-up time.

The operation of this controller is based on

the property mentioned previously, where the

frequency of the current of the main excita-

tion winding (IA) is high frequency when the

system is not balanced and low frequency

when the system is operating in the vicinity

of the point of zero flux. The presence of this

additional controller increases the robust-

ness against possible situations, as sporadic

transients, ensuring the accomplishment of

the equilibrium conditions.

As Figure 6 shows, this controller includes a

triangular low-frequency oscillator, a frequen-

cy detector for the excitation current (IA) and

an analog switch controlled by the frequency

detector.

While the measurement system does not

operate in zero flux conditions, the input of

the current compensation driver (IS) will be

connected to the triangular low-frequency

signal generator. This waveform guarantees

that, in some moment, a value of the winding

current compensation (IS) next to the neces-

sary condition of zero flux will be reached.

When this happens, the frequency of the

current of the main excitation winding (IA)

decreases. This situation is detected and the

originally proposed PI controller then is con-

nected to the input of the current compensa-

tion driver.

Valid Measure Indicator

The output of the low-frequency detector cir-

cuit is connected to the indicator of valid

measure. This indicator is only activated

when it detects that the current of the pri-

mary winding excitation is of low frequency,

effect that will occur when the system works

in zero flux conditions.

An LED indicator and a relay are the output

elements to indicate the condition of zero

flux valid measure.

Driver to Generate the Compensation Cur-

rent

This circuit is used to generate the current

that will flow through the secondary winding

compensation (NS).

A class D amplifier has been used for the

implementation. These amplifiers present the

advantage of high efficiency compared to lin-

ear amplifiers, but add harmonics of the

same switching frequency and higher.

Is based on a pulse width modulator (PWM),

which generates a squared voltage wave-

form with a duty cycle proportional to the PI

controller output signal.

The output PWM squared waveform of the

modulator is applied to the compensation

winding (NS) through a current driver imple-

mented with a half-bridge inverter.

The own inductance of the NS winding filters

the current that circulates along it. So, the

output voltage of the system measured in a

shunt resistance connected in series with

this winding is proportional to the primary

current to be measured.

Measure of High Frequency Currents

The system of measure proposed, based on

the Flux-gate principle, is only suitable for

the measurement of current in DC or in AC

at low frequencies. The maximum frequency

for the AC measurement is fixed by the

working frequency of the zero flux detection

system.


S E N S O R S

Figure 5: Principle of operation of the Flux-gate transducer designed

Figure 6: Block diagram of the designedFlux-gate transducer

For the measure of high frequency AC cur-

rents and to obtain a suitable dynamic

behaviour in case of fast variations of cur-

rent, a third core is included. This new core

is embraced only by the compensation wind-

ing (NS) and it works exclusively as a con-

ventional current transformer.

Power Supply

Voltage power supply of the transducer is

obtained from a flyback DC / DC converter.

In this way, two stable output voltages (+12V

positive and the other negative -12V) are

derived from a single input voltage which

can be between 10V and 30V.

Experimental results

Figure 7 shows the final look of the con-

structed prototype. It displays the trans-

former of measurement, the PCB with the

used electronics components and the

designed box to contain the measurement

system.

This prototype has been successfully tested

and here we present some of the results

obtained for four different types of measure-

ments.

In the first two experiments 35 times the

main conductor has been coiled on the

measurement transformer. Hence, the cur-

rent measured by the transducer will be 35

times greater than the real value of the IP.

The IP current is measured in a 3 mV/A

shunt, and the IS current, generated by the

designed transducer, is measured on a 1 Ωresistance. Since 1000 turns for NS have

been used, the output voltage of our trans-

ducer will be of 1 mV/A.

Figure 8 shows the result of a 525A DC cur-

rent measurement performed with the

described shunt (CH3) and with the

designed transducer (CH2).

Figure 9 shows the result of the measure-

ment of a 350 A of amplitude squared cur-

rent and 1 kHz of frequency performed with

the described shunt (CH3), and with the

designed transducer (CH2).

Figure 10: shows the result of the measure-

ment of a sinusoidal current of 400 A ampli-

tude and European network frequency (50

Hz), performed by the designed transducer.

Finally, Fig.11 shows the result of a 100 kHz

sinusoidal current of 133 A amplitude meas-

urement, performed by the described shunt

(CH3), the designed transducer (CH1) and

another industrial Flux-gate transducer

(CH2).

Conclusions

A transducer based on the Flux-gate tech-

nology for the measurement of DC and AC

current has been designed and tested.

The power supply of the transducer and the

driver for generating the compensation cur-

rent (IS) are based on high-efficiency DC/DC

power converters. This choice guarantees

the low consumption of the designed system

compared to the existing solutions in the

market.

The main characteristics of the designed

system are the following ones:

• Maximum peak current: 1000 A

• Primary rated current (IN): 700 A

• Small signal bandwidth (5% of IN):

DC to 100 kHz

• Conversion Ratio: 1:1000

• Supply voltage: from 10 to 30 VDC

In order to obtain a more detailed characteri-

zation of the described transducer, the refer-

ence DCT-700A can be consulted at the

products general datasheet of Group

PREMO S.A. [5]. This datasheet is accessi-

ble online.

Acknowledgment

This work has been partially funded by the

PROFIT program of the Spanish Ministry of

Industry and Energy under the project refer-

ence FIT-330100-2006-20.

References

James E. Lenz. ‘A Review of Magnetic Sen-

sors’. Proceedings of the IEEE. Vol.: 78, Iss:

6, pp. 973 - 989. June 1990.

Erik R. Olson and Robert D. Lorenz. ‘Inte-

grating Giant Magneto-resistive Current and

Thermal Sensor in Power Electronic Mod-

ules’. Eighteenth Annual IEEE Applied

Power Electronics Conference and Exposi-

tion, 2003 (APEC’03). Vol.: 2, pp. 9 - 13.

February 2003.

Emerging Technologies Working Group and

Fiber Optic Sensors Working Group. ‘Optical

Current Transducers for Power Systems: A

Review’. IEEE Transactions on Power Deliv-

ery. Vol.: 9, Iss: 4, pp. 1778 - 1788. October

1994.

T. Sonoda, R. Ueda and K. Koga. ‘An ac and

dc Current Sensor of High Accuracy’. IEEE

Transactions on Industry Applications. Vol.:

28, Iss: 5, pp. 1087 - 1094. September-Octo-

ber 1992.

Group PREMO S.A. ‘II - General Datasheet’.

2007. Online Access: www.grupopremo.com

www.grupopremo.com


S E N S O R S

Figure 7: The designed Flux-gate transducer

Figure 9: Measurement of a 1kHz squaredwaveform current

Figure 10: Measurement of a 50Hz sinu-soidal current

Figure 11: Measurement of a 100kHz sinu-soidal current

Figure 8: Measurement of a DC current

There are many well known circuits that fit certain applications very

well, but if we want to find the best solution for a given application

then we need to understand how the choice of topology may affect

the key parameters of the power supply, which are cost, overall size,

EMC performance and efficiency.

The importance each of these parameters varies between application

and trade-offs made between each of them have a significant effect

on the choice of topology. For example, a solution targeting the low-

est cost may be quite different from one targeting the highest efficien-

cy; counter-intuitively a solution targeting the highest power density

(smallest size) won't necessarily achieve the lowest losses. With the

development of the new TDK-Lambda EFE series, a high density AC-

DC supply aimed at embedded front-end applications, an iterative

design method was used to determine the best possible topology.

The key design criteria set for the development of the EFE300 for

instance were the overall dimensions of 5x3-inch and 1U compatible,

300W continuous power rating with 2m/s airflow and 400W peak

power rating for 10 seconds, all achieved over the whole supply volt-

age range 90-264Vac, and curve B conducted EMC (EN55011,

EN55022). Another important design objective was to design the sup-

ply following the tried and tested TDK-Lambda design rules for com-

ponent deratings, spacings, PCB design rules and so on.

These design rules have been proven successful by our engineers

when designing earlier products and following them rigidly reminds

us not to make compromises simply to achieve a small size. In addi-

tion, they are important in creating a product that can be easily man-

ufactured and is reliable. It is always possible to squeeze more com-

ponents into a small space to achieve a “high density” power supply,

but components that are mechanically stressed or over-heated due to

insufficient space being allowed for them will lead to reductions in

overall reliability.

In order to choose the most appropriate topology we need to consid-

er the attributes of possible solutions, shown in Table 1, by adopting

a simple scoring process. Each topology is evaluated in two stages;

firstly for switching and efficiency characteristics, shown in Table 2,

and then for circuit complexity, EMC performance and other relevant

factors of the target application, shown in Table 3.

Each attribute is ranked, from “1” meaning bad through to “5” good,

and the results of both stages are weighted together.

For the topologies considered, Table 2 shows the scoring for the

switching- and efficiency-related characteristics. In general, a topolo-

gy with soft switching and low circulating current will be preferred.

The key issues for the attributes that are scored are:

Circulating VA: The amount of energy circulating within the topology

that is not contributing directly to powering the load. For higher output

voltages, this criterion is less of a concern due to the lower second-

ary-side currents involved.



Choosing The Right TopologyDesign rules have been proven successful

Whatever the final application, power supply users want reasonably priced products thatare small and efficient, yet have excellent EMC performance. The article explains how the

choice of power supply topology can greatly affect these key parameters.

By Andrew Skinner, Advanced Development Manager, TDK-Lambda

Table 1: Possible topologies

“NV” topologyZero-voltage switching variable frequency modified LLC with self-driven synchronous rectifiers. TDK-Lambda patented.

Half-bridge LLC resonant converterZero voltage switching variable frequency converter with activelydriven synchronous rectifiers (self drive is not possible)

Full-bridge Current Doubler Zero voltage switching pulse-width modulation controlled converter with current-doubler rectification.

Half-bridge Current DoublerHard switched half-bridge pulse-width modulation controlledconverter with current-doubler rectification.

ZVZC switching DC-DC transformer plus pre-regulator.Zero voltage and zero current switching resonant DC:DC “transformer” with buck pre-regulator (zero current or boundary mode controlled)

ZCS Resonant Converter Zero current switching , variable frequency resonant converter

Quasi-resonant converter Flyback converter operated with valley switching and activelydriven synchronous rectifier

Table 2: Switching and efficiency characteristics

Topology

Primary switching Secondary switching Circulating VA Efficiency

Turn-on Turn-off Turn-on Turn-off Low outputvoltage

High output voltage Light load Full load

NV topologyself-driven synchronous rectifier

ZVS ZVS ZVS High di/dt 4 3 2 4

Half-bridge LLC synchronous rectifier ZVS ZVS ZVS ZCS 3 5 3 5

Full-bridgecurrent doublersynchronous rectifier

ZVS ZVS/ hard ZVS High di/dt 5 3 2 5

Half-bridge current doublersynchronous rectifier

ZCS/hard ZVS ZVS High di/dt 4 3 3 5

ZVZCSResonant dc transformer plus pre-regulator

ZVS ZVS/ ZCS ZVS ZCS 2 4 2 4

ZCSResonant converter -fixed on-time variable frequency

ZCS ZVS ZVS ZCS 3 4 4 3

Quasi-resonantflyback synchronous rectifier with diode emulation

ZCS ZVS ZVS ZCS 1 3 2 4

Efficiency: Topologies with continuous output current and actively

controlled synchronous rectifiers will be preferred, although generally

this will lead to a lower circuit complexity score. With the appropriate

selection of components and switching frequency, most circuits can

be made highly efficient; this score is more a measure of the design

effort required to achieve high efficiency.

The key attributes relating to the circuit complexity, EMC perform-

ance and other application relevant factors of the topologies is shown

in Table 3. Let’s take a look at the key issues for each.

Multiple outputs: A current-driven circuit without an output inductor is

preferable since this simplifies the mechanical design.

Semi-regulated outputs: Where several outputs (that track one anoth-

er with reasonable accuracy) are required a current driven design

with a low secondary-side di/dt is preferred.

Size: Generally this is dependent on parts count within the power cir-

cuit for low power applications, and efficiency and even loss distribu-

tion, within components, at higher power.

Complexity: A topology that naturally limits current, does not place

stringent timing requirements on the controller and has self-driven

synchronous rectifiers will result in a better score for the power cir-

cuit. A topology that has only low-side drive requirements and

requires only a simple controller will score better for control circuit

complexity.

Complexity is also a measure of cost, generally a topology that is

complex and has a higher parts count will have a higher labour cost

associated with its manufacture. The component costs will also be

expected to be higher for a couple of reasons. Firstly, complex

topologies tend to be less popular and hence controllers for them sell

in lower volume, use a larger die size or require a larger package

with more pins. The second reason, especially at lower power rat-

ings, is that the topology generally requires more devices and will

tend to use relatively small die thereby increasing the relative cost of

the device packaging.

EMC: Topologies with zero-voltage switching (ZVS) on the primary

side will have a better score since this often results in lower conduct-

ed EMC.

Wide adjustment range: Topologies that have zero-voltage switching

often utilise the transformer magnetising current to assist in this. If

the output voltage needs to vary over a wide range, then the mag-

netising current will also vary resulting in variable EMC, efficiency

and component stress. Most soft-switching topologies therefore oper-

ate with a reduced output voltage range compared to hard-switching

pulse-width modulated topologies.

The scores are combined with weighting where the most important

factors for a high density product (size and efficiency) are more heav-

ily weighted than complexity (digital control makes the use of circuits

with complex control algorithms, for example, an acceptable design

choice). RFI is also given high weighting as curve B performance is a

design objective. After applying these weightings, we arrive at the

scores in Table 4. There are four topologies that have similar scores.

The low ripple current in the output filter of the NV topology make it

the preferred choice at the power level and size of interest. In a 5x3-

inch footprint, the number of output filter capacitors is limited due to

PCB real estate constraints and can lead to electrolytic capacitors

operating with high ripple current, which will result in more self-heat-

ing and reduced life. As the achievable operating frequency with the

NV topology is relatively high, a few ceramic capacitors are used

instead, resulting in a compact output filter design with enhanced life.

The industrial markets addressed by TDK-Lambda often require

power supplies that have characteristics modified to suit the end

application, such as non-standard voltages, modified loop-response,

modified signals, etc. By utilising the power of digital control, these

requirements are met more easily and, at the same time, the con-

cerns associated with the more complex control algorithm of a reso-

nant converter are alleviated since with digital control any control law

can be implemented. The EFE series was therefore designed with an

8-bit microcontroller to control the resonant converter and to manage

housekeeping functions.

Although there are similarly rated products available using LLC and

DC-DC transformer with pre-regulator, the high reliability design rules

used at TDK-Lambda don’t allow the small component spacings

needed to fit these topologies into a 5x3-inch format.

Choosing the right topology is vital to the success of the product and

requires detailed knowledge of all the available choices. The correct

choice results in a product with optimum cost, performance and relia-

bility characteristics. Especially for high density power supplies, such

as TDK-Lambda’s EFE series, squeezing an unsuitable topology into

the available space can seriously damage your wealth!

www.emea.tdk-lambda.com



Table 3: Key attributes relating to the circuit complexity, EMC performance and other application relevant factors of the topologies

Topology

Multipleoutputs

Semiregulated outputs

Size ComplexityEMC

Wide adjustrange

Low power

High power

Powercircuit Control

NV topology self-driven synchronous rectifier

5 4 5 3 4 1 5 2

Half-bridge LLC synchronous rectifier

5 5 4 5 4 1 5 2

Full-bridge current doubler synchronous rectifier

2 3 1 5 3 2 5 2

half-bridge current doubler synchronous rectifier

2 3 2 5 2 4 3 5

ZVZCSResonant dc transformer + pre-regulator

5 4 4 4 4 4 5 3

ZCS Resonant converter -fixed on-time variable frequency

5 4 4 2 5 3 4 2

Quasi-resonant flyback synchronous rectifier with diode emulation

5 5 5 1 5 5 4 3

Table 4: Weighted scores for TDK-Lambda EFE300

Topology Weighted score Comments

NV topology self-driven synchronousrectifier 0.89 Continuous output current

Half-bridge LLC synchronous rectifier 0.86 High output filter ripple current and requires active synchronous rectifier gate-drive

Full-bridge current doubler synchronous rectifier 0.64

half-bridge current doubler synchronous rectifier 0.63

ZVZCS Resonant dc transformer +pre-regulator 0.85 High output filter ripple current

ZCS Resonant converter -fixed on-time variable frequency 0.75

Quasi-resonant flyback synchronous rectifier with diode emulation 0.9 Very high output filter ripple current


This article presents an investigation in the algorithms for sensorless

detection of rotor angular position of Permanent Magnet Synchro-

nous Motors (PMSM) and the actual implementation STMicroelec-

tronics has made in its Field Oriented Control (FOC) firmware library

developed for its 32-bit Cortex-M3 microcontroller family, the STM32.

Three phase AC motors (induction and synchronous motors) histori-

cally owe their greatest success in adjustable speed application to

the advent of vector control drives. In particular, Field Oriented Con-

trol (FOC) has guaranteed the highest reachable performances, but

its scope of employment has always been in costly drives mainly

used in the automation and robotics field.

In fact, it requires three essential components, in addition to the con-

verter/inverter electronic stage: intense computational power, accu-

rate sensors for current, and rotor speed/position measurement.

For these reasons, in the last decade, low cost applications (white

goods, HVAC, industrial, pumps) have appointed induction motors

and V/F controls as best compromise for cost containment and target

performance.

This scenario has rapidly changed.

The always stringent requirement of energy efficiency has been com-

plemented, and complicated, by an almost worldwide commitment to

environmental sustainability.

PMSM sinusoidal motors have consolidated – because of advance-

ments in magnet chemistry and for their reduced copper content - as

viable and robust as induction motors.

Powerful 32-bit microcontrollers are now offered as a suitable choice

in the same cost area of 8-bits, throwing open the doors to implement

more advanced control methods, such as FOC.

Some of these microcontroller families, such as the STM32, feature

fast and precise ADCs and advanced PWM timers designed specifi-

cally for motor control, to the extent that the last two cost barriers –

current and speed sensors – have now faded. Current feedback can

now be achieved using inexpensive shunt resistors, while

speed/position sensors have been replaced by mathematical algo-

rithms that bring additional benefits such as improved reliability and

reduced circuit complexity and size.

Because of this, low-cost motor control drives can finally take advan-

tage of the intrinsic properties of FOC, i.e. closed loop current control

(and hence stringent over-current protection, which in turn means a

more focused choice of power devices), best efficiency and dynamics

(even during transients), and quiet operations.

This article presents an investigation in the algorithms for sensorless

detection of rotor angular position of Permanent Magnet Synchro-

nous Motors (PMSM) and the actual implementation STMicroelec-

tronics has made in its Field Oriented Control (FOC) firmware library.

Two methods will be shown in details, as representatives of the two

categories to which they belong: a flux estimator, and a closed-loop

Luenberger’s state observer. They both use the mathematical model

of the machine, while the second one also exploits current feedback.

The aim is to compare them, on the basis of computational effort,

performances, and robustness to parameter variations.

PMSM equations

With reference to the figure, the motor voltage and flux-linkage equa-

tions of a PMSM (isotropic magnetic structure) are generally

expressed as:

M O T I O N C O N T R O L

Comparison of Sensorless Algorithms for PMSM Rotor

Position DetectionPermanent Magnet Synchronous Motors (PMSM)

and the actual implementation

It’s no news that richer performance vector control drives for AC motors could be beneficial, in terms of dynamics and efficiency as well as for every aspect an ideal control

should have. The good news is that the time has come to make wide use of these drives,running low-cost applications with first grade quality.

Stello Matteo Billé, Dino Costanzo, Antonio Cucuccio, STMicroelectronicsAlfio Consoli, Mario Cacciato, Giuseppe Scarcella, Giacomo Scelba, University of Catania

Figure 1: The motor voltage and flux-linkage

41www.bodospower.com July 2009 Bodo´s Power Systems®www.bodospower.com July 2009 Bodo´s Power Systems®

where :

rs is the stator phase winding resistance

Lls s the stator phase winding leakage inductance

Lms is the stator phase winding magnetizing inductance

θr is the rotor electrical angle

Φm is the flux linkage due to permanent magnets

The complexity of these equations is apparent, as the three stator

flux linkages are mutually coupled, and what is more, as they are

dependent on the rotor position, which is time-varying and a function

of the electromagnetic and load torques.

The reference frame theory simplifies the PMSM motor equations, by

making a change of variables that refers the stator quantities abc

(spatially displaced by 120°) to qd components, directed along axes

each 90° apart, rotating at an arbitrary speed ω.

Open-loop flux estimator equations

In particular, if the qd reference frame is stationary (the so-called

Clarke transformation on the αβ frame, ω=0) we’ll get to:

where Ls is the synchronous inductance, Ls = Lls + 3Lms/2,

Let’s define the back-EMFs (Electro-Motive Forces) as:

Substituting the flux linkages equations in the voltage equations and

solving:

These equations give us the possibility of an open-loop estimation of

the rotor flux that goes through known motor parameters and meas-

ured terminal voltage and currents. As can be seen, rotor angular

position information is held directly and can be extrapolated by

means of an arctangent function, recursive algorithm, or PLL (Phase

Locked Loop).

Going into time-discrete domain, it gives:

and whose block diagram is depicted below:

The observer

To understand how a state observer works and why it can be consid-

ered a closed loop approach; let’s start from the definition of ‘observ-

ability.’

In control theory, a system is said to be ‘observable’ if it is possible to

fully reconstruct the system state starting from its output measure-

ments. The ‘state observer’ (or simply the ‘observer’) is then the sys-

tem that provides the estimation of the observed system internal

state (X) given its input (U) and output (Y) measurements.

The state observer thus allows the reconstruction of the internal state

of a system (on condition that it is observable) without having direct

access of it but simply starting from the knowledge of system inputs

and outputs.

As shown in the above figure, the observer is composed of two

blocks. The first block is constituted by a model of the plant whose

internal state we want to know. Due to unavoidable inaccuracies on

plant model and to parameters’ deviations or uncertainties, the states

would be destined to diverge from real state X if we computed it

by simply applying input U to our plant model. On the contrary, this

can be avoided by ‘closing the loop’ - that is, by feeding back the

error between the measured and observed outputs.

In fact, multiplying this error by the observer gain K and reporting it

as input to our plant reproduction allows a continuous adjustment of

the plant model guaranteeing the coherency between X and . X̂

X̂

X̂

( )

( ) )()()()(

)()()()(

1

1

1

1

kiLThirhvk

kiLThirhvk

ss

k

hsPM

ss

k

hsPM

ββββ

αααα

λ

λ

−⋅−=

−⋅−=

∑

∑−

=

−

=

( )( ) ββββ

αααα

θλ

θλ

iLdtirv

iLdtirv

ssrmPM

ssrmPM

−−=Φ=

−−=Φ=

∫∫

cos

sin

rrmmr

rrmmr

dtde

dtde

θωθ

θωθ

β

α

sin)(cos

cos)(sin

Φ−=Φ

=

Φ=Φ

=

⎩⎨⎧

Φ⋅+=Φ⋅+=

⎪⎪⎩

⎪⎪⎨

⎧

+=

+=

mrs

mrs

s

s

iLiL

dtd

irv

dtdirv

θλθλ

λ

λ

ββ

αα

βββ

ααα

cos

sin;

m

r

r

r

abc

mlmm

mml

m

mmml

abc

abcabcsabc

s

ss

ss

s

ss

s

ss

ss

s

s

ss

i

LLLL

LLL

L

LLLL

dtd

irv

Φ

⎥⎥⎥⎥⎥⎥⎥

⎦

⎤

⎢⎢⎢⎢⎢⎢⎢

⎣

⎡

⎟⎠⎞

⎜⎝⎛ +

⎟⎠⎞

⎜⎝⎛ −+

⎥⎥⎥⎥⎥⎥⎥

⎦

⎤

⎢⎢⎢⎢⎢⎢⎢

⎣

⎡

+−−

−+−

−−+

=

+=

3

2sin

3

2sin

sin

22

22

22

πθ

πθ

θ

λ

λ


Figure 2: PLL (Phase Locked Loop) block diagram

Figure 3: The state observer

For all these reasons, a state observer can be considered a closed

loop system.

We can now apply these concepts to PMSM equations in order to get

an estimation of its internal state starting from its input and from the

measurement of its output.

Let’s consider PMSM motor equations:

In order to make this system linear, we introduce two new state vari-

ables:

Supposing now the mechanical quantities slowly changing versus the

electrical ones, we can write that:

This is, under the position x = [iα iβ eα eβ ]t, u = [vα vβ]t, y = [iα iβ]t,

the canonical ISO representation of a linear time-invariant system:

It is possible to demonstrate that the PMSM, so represented, is an

‘observable’ system; then starting from the measurement of its cur-

rents iα iβ and knowing the applied voltages vα vβ, it is possible to

reconstruct the B-emfs values eα eβ:

The feedback given by the error between estimated and measured

currents allows adjusting the motor equation, strongly decreasing the

sensitivity to motor parameters’ uncertainties and inaccuracies.

In order to have a clear idea of the computational complexity of this

approach, let’s write the observer equations:

Going into time-discrete domain, it gives:

Comparative Flux estimator vs Observer

In order to compare the performances of the flux estimator with ones

of the state observer, two aspects have been taken into considera-

tion: the computational complexity and the robustness to motor

parameters’ uncertainties and inaccuracies.

⎪⎪⎪⎪

⎩

⎪⎪⎪⎪

⎨

⎧

−−+=+

+−+=+

+−−+−=+

+−−+−=+

TkepkikiTKkeke

TkepkikiTKkeke

kvLTke

LTkikiTKki

LTrkiki

kvLTke

LTkikiTKki

LTrkiki

r

r

sss

s

sss

s

)(ˆ))()(ˆ()(ˆ)1(ˆ

)(ˆ))()(ˆ()(ˆ)1(ˆ

)()(ˆ))()(ˆ()(ˆ)(ˆ)1(ˆ

)()(ˆ))()(ˆ()(ˆ)(ˆ)1(ˆ

2

2

1

1

αββββ

βαααα

βββββββ

ααααααα

ω

ω

⎪⎪⎪⎪⎪

⎩

⎪⎪⎪⎪⎪

⎨

⎧

−+−=

−+=

−++−−=

−++−−=

)ˆ(ˆˆ

)ˆ(ˆˆ

)ˆ(ˆˆˆ

)ˆ(ˆˆˆ

2

2

1

1

ββαβ

ααβα

ββββββ

αααααα

ω

ω

iiKepdted

iiKepdted

iiKLv

Le

Lir

dtid

iiKLv

Le

Lir

dtid

r

r

sss

s

sss

s

⎩⎨⎧

=+=)()(

)()()(

tCxtytButAxtx&

⎪⎪⎪⎪⎪

⎩

⎪⎪⎪⎪⎪

⎨

⎧

−=

=

+−−=

+−−=

αβ

βα

ββββ

αααα

ω

ω

epdt

de

epdt

deLv

Le

Lir

dtdi

Lv

Le

Lir

dtdi

r

r

sss

s

sss

s

)sin(

)cos(

tppetppe

rrm

rrm

ωωωω

β

α

Φ−=Φ=

⎪⎪⎪

⎩

⎪⎪⎪

⎨

⎧

=

+Φ

+−=

+Φ

−−=

pdt

dLv

tppLL

irdtdi

Lvtpp

LLir

dtdi

rr

srr

s

m

s

s

srr

s

m

s

s

ωθ

ωω

ωω

βββ

ααα

)sin(

)cos(


Figure 4: Feedback given by the error between estimated and meas-ured currents

Figure 5: The block diagram of the observer equations


To evaluate the computational complexity of the two algorithms, the

number of mathematical operations which compose the two schemes

has been taken into account:

As reported in the table, it is possible to see that the number of oper-

ations required by the proposed state observer algorithm is about

double of those required by the VI flux estimator.

However, it has to be pointed out that such an advantage of the VI

flux estimator can not be completely exploited in terms of a smaller

Ts as both the rotor position sensor-less detection algorithms are

often executed with the same sampling rate of the vector control (i.e.

with the same or with an integer sub-multiple of PWM frequency).

Now, let’s evaluate robustness of both of the algorithms to motor

parameters’ uncertainties. Different simulations have been carried out

to measure the error on rotor position angle introduced by a poor

understanding of motor parameters. The figure 6 shows to this pur-

pose the error on rotor position angle when the stator resistance uti-

lized by the algorithm is the double the real one:

The graph in Figure 6 shows a clear and strong sensitivity of VI flux

estimator to stator resistance deviation especially at low speed while

the closed loop approach utilized by the state observer algorithm

allows a full compensation of the stator resistance uncertainty.

On the contrary, as shown in Figure 7, both algorithms are pretty

sensitive to stator inductance uncertainty even if the error introduced

by the state observer is still a bit lower (5% at low speed):

Conclusions

Due to its performance in terms of robustness to motor parameters’

deviation (e.g. stator resistance), the state observer described in this

article had been chosen for implementation on the STM32 microcon-

troller and included in the STM32 FOC PMSM firmware library

The STM32 takes advantage of the powerful CortexTM-M3 computa-

tional capabilities.

In fact, the highly efficient 3-stage pipeline with branch speculation,

the single cycle 32bit multiply, and the hardware divide instructions

allows keeping, in spite of the number of mathematic operations, the

overall state observer routine execution time low - around 3.5μs

(CPU running at 72MHz), thus limiting the CPU load contribution of

the sensor-less algorithm to just 3.5% at 10 kHz PWM frequency.

Moreover, because of the high density of the Thumb2 instruction set,

the code size of the overall state observer routine is quite reduced.

www.st.com


Figure 6; The error on rotor position angle

Figure 7: Both algorithms are pretty sensitive to stator inductance

Mul/Div Add/Sub Total

Flux estimator 6 6 12

State Observer 10 14 24

High Junction Tj: 150C°

17mm height package

High power cycling!

Transfer mold package

Metal Base Plate

SanRex® Semiconductors

New! SanRex Thyristor & Diode Modules Generation!

the"TECHNO-BLOCK´S"

Sansha Electric Japan & SanRex Europe GmbH / Germany introducing:

Thyristor + Thyristor modules

70A up to 110A

up to 1800V

Thyristor + Diode modules

70A up to 110A

up to 1800V

Diode + Diode modules

70A up to 110A

up to 1800V

please contact us!!

more information's: www.sanrex.com

please contact us!!

e-mail: [email protected] GmbH, Dessauerstr. 6, 80992 München /Tel: 089 311 20 34 /Fax: 089 316 16 36

Digital Power Workshop based on TI´s F28x family.

For more information and your free drill hole stencil please visit

www.biricha.com


STM32 FOC PMSM FW library v2.0

State observer execution time 3.5μs

State observer code size 0.5kB


N E W P R O D U C T S

Mitsubishi Electric introduces a new version

Dual In-line Package Power Factor Correc-

tion (DIPPFCTM) developed for high power

air conditioner and general inverter use.

In the DIPPFCTM series (PS5178x) low

thermal resistance was realized by using an

insulation sheet structure with high heat dis-

sipation transfer capability. As a result, the

thermal resistance was improved by about

35% compared with the present large

DIPPFCTM packaging technology. Because

of low thermal resistance, package size of

the new Mini DIPPFCTM is reduced to

approximately 70% compared with the con-

ventional Large DIPPFCTM and the input

amperage rating is expanded up to 30Arms

under its standard application conditions.

Further extension of the current capability to

above 30Arms will be possible in future by

the development and continuous improve-

ment of thermal interface material properties

and lower power device loss.

The internal circuitry of Mini DIPPFCTM

comprises two IGBT chips which are

designed for high speed switching with a

trench gate structure CSTBTTM and four

diode chips in which high-side diodes are

designed as fast recovery type and the low-

side diodes are designed as low forward

voltage drop types. Moreover, a LVIC is

designed and implemented with necessary

functions such as IGBT drive, control power

supply under voltage (UV) lockout circuit. In

contrast to the conventional PFC circuit

topology using a classical boost structure, in

the new Mini DIPPFCTM, rectifier function

and boost operation have merged: The high-

side diode of the diode bridge hold the func-

tion of boost diode concurrently, and IGBT is

added in parallel with the low-side diode of

the diode bridge.

The result is the new Mini DIPPFCTM series

developed by optimized power chips togeth-

er with the innovative dissipation insulation

sheet.

www.mitsubishichips.com

A Novel Transfer Molding PFC

Everlight Electronics Co. Ltd. (TSE:2393)

announces the introduction of single channel

and dual channel 8-pin SOP phototransistor

optocoupler families offering the best avail-

able combination of key specifications

sought after by designers: low-profile (3.63

mm) package, high isolation voltage (3750

Vrms), minimum creepage distance (5 mm),

wide operating temperature range (-55 °C to

+110 °C), multiple current-transfer-ratio

(CTR) bins and high breakdown voltage (80

V). The single channel EL2XX series is com-

prised of 10 devices while the dual channel

ELD2XX series is comprised of 6 devices.

They are all well suited for use in DC-DC

converters, battery chargers, general-pur-

pose switching circuits and programmable

controllers. Compared with conventional

SOP optocouplers, the devices offer impor-

tant advantages, including: Smaller form-

factor (3.63 mm max. package height and

1.27 mm lead pitch) to accommodate

designs with limited board real estate; High-

er temperature operation (110 °C vs. 100 °C)

to improve system reliability; Selectable CTR

ranges characterized at low LED currents to

increase design flexibility; Higher isolation

voltage (3750 Vrms vs. 2500 Vrms) to

improve insulation characteristics and * Pb-

free and RoHS compliant to meet green

environmental initiatives.

www.everlight.com

8-Pin SOP Optocouplers Offer Best Combination of Features

Fairchild Semiconductor addresses a critical

need in the high brightness (HB) light emit-

ting diodes (LED) market with its primary

side regulation (PSR) pulse-width modula-

tion (PWM) controllers that simplify design,

reduce board space and provide important

performance advantages. The FSEZ1016A

is an EZSWITCH™ that integrates a PSR

PWM controller with a power MOSFET and

the FAN100 is a PSR PWM controller.

Through this integration, these controllers

achieve the most accurate constant current

(CC) through their built-in proprietary TRUE-

CURRENT™ technology and tight constant

voltage (CV) without using secondary-side

feedback circuitry. By tightening the constant

current over a wide voltage range, the same

circuit can accommodate different numbers

of LED units in a string, increasing design

flexibility, accelerating time-to-market and

stretching the lifetime of HB LEDs. With this

high level of integration, these PSR PWM

controllers conserve board space, accommo-

dating the form factor of lamp cases that

continue to diminish in size.

The FSEZ1016A and FAN100 feature a pro-

prietary green-mode function that provides

off-time modulation to linearly decrease the

PWM frequency under light-load conditions.

They also minimize power consumption

(standby power at no load condition <0.15W)

by reducing the secondary-side feedback cir-

cuitry and components.

www.fairchild.com

Primary Side Regulation PWM Controllers



Avago Technologies announced that it has developed a new ultra-low

power optocoupler technology that will pave the way for a new gener-

ation of optical isolators that can operate as much as 90 percent less

power than standard optocouplers available today. The total power

consumption of this new innovative optocoupler design is below 2mA

compared to 15mA for a standard optocoupler and 4 to 5 mA for

magnetic isolators. These new ultra-low power optocouplers target

designers of communication interfaces (RS485, CANBus, and I2C),

microprocessor system interfaces, and digital isolation for A/D, D/A

conversion applications. Avago is a leading supplier of analog inter-

face components for communications, industrial and consumer appli-

cations.

Avago’s innovative ultra-low power

optocoupler design features an opti-

cally coupled gate that combines a

high efficiency light emitting diode

(LED) and an integrated high gain photo detector enabling designers

to interface the optocoupler input directly from a microcontroller out-

put – avoiding the use of buffers to drive the LED. Moreover, these

next-generation optocouplers support both 3.3V and 5V supply volt-

ages and provides reliable system performance in industrial tempera-

tures ranging from –40 to +105 degrees C.

www.avagotech.com/optocouplers

Ultra-Low Power Optocoupler Technology

Ideal for embedded computing, storage, tele-

com, datacom and networking, the ZL2008

Requires up to 50% fewer components and

half the PCB space of competitive solutions

Intersil has introduced the ZL2008, a high-

performance synchronous step-down DC-DC

converter with pin-strap compensation and

current sharing. Taking advantage of Zilker’s

patented Digital-DC™ technology, the

ZL2008 is designed for digital power supply

module and system designers who demand

easy-to-use board-level power supply config-

uration to keep ahead of rapidly changing

market requirements.

Key features and benefits: Easy-to-use pin-

strap compensation and current sharing.

The compensation and transient response of

the ZL2008 can be optimized for load cur-

rent and output capacitance by adjusting

resistor pin-straps. Current sharing of up to

eight devices in parallel with individual phase

enable/disable pins is easily configurable.

Pin-strap power management configuration.

Advanced power management features such

as digital soft-start delay and ramp,

sequencing, tracking and margining are fast

and easy to implement. Power supply relia-

bility and availability can be improved

through real-time monitoring using the

I2C/SMBus interface with the PMBus proto-

col. www.intersil.com

Space-saving Digital Power Management IC

Toshiba Electronics Europe has launched a

new range of power MOSFETs that is opti-

mized for motors used in fans, pumps and

other automotive motion control applications.

The new MOSFETs combine industry-lead-

ing on-resistance and input capacitance rat-

ings with a package design that offers better

thermal dissipation and power cycling capa-

bilities than previous automotive MOSFETs.

Available with maximum voltage (VDSS) and

current (ID) ratings of 60V and 150A, Toshi-

ba’s new MOSFETs are based on the com-

pany’s latest U-MOS trench semiconductor

technology. This technology contributes to

typical RDS(ON) specifications as low as

1.7m? and typical input capacitances (Ciss)

down to just 4500pF. As a result, the devices

offer the industry’s smallest RDS(ON)* gate

charge (Qg) ‘figure of merit’, which ensures

optimum switching speed and efficiency.

All of the new MOSFETs are supplied in

Toshiba’s TO220SM(W) package. This uses

copper connectors and a wide source termi-

nal to drive down RDS(ON) and package

inductance, reduce thermal resistance, and

ensure high current carrying capacity. The

package is qualified to AEC-Q101 at a chan-

nel temperature of 175ºC. A thickness of just

3.7mm means that it is 21% thinner than

existing TO-220SM package technology.

www.toshiba-components.com

Power MOSFETs for Automotive Motion Control

Aware that thermal management is an

important part of environmental care, and

that anything which doesn’t require the use

of electricity in order to maintain acceptable

temperatures, is likely to be welcomed by

design engineers, Ohmite have launched the

first of a range of heatsinks which not only

meet these requirements, but also save time

and money.

Specifically designed for use with TO-220

and TO-247 packages, including Ohmite’s

own TAH20, TBH25, TCH35, TEH70, TK20

and TN15 power resistors, the heatsinks fea-

ture an integrated clip for securing the com-

ponent to the heatsink without the need of a

screw.

Pressure is directed on to the center of the

heat dissipating device, maximising the effi-

cient transfer of heat and avoiding the can-

tilever effect which can result from over

torqueing the screw in conventional designs.

The torsion spring clip also has solderable

feet to secure the assembly to the PCB.

www.ohmite.com

Heatsink Design Enhances Thermal Management



These devices prevent damages caused by

transient overvoltages in industrial electrical

equipment and installations.

These damages can be disruptive, dissipa-

tive or destructive whatever their origin:

power or equipment disturbances, switching

on and off, lightning strikes, utility grid

switching.

The core of Surge Trap® is a TPMOV®:

Thermally Protected Metal Oxide Varistor.

TPMOV® is a patented technology devel-

oped by Ferraz Shawmut. It leads to fail-safe

surge protective devices needing no fuse for

overcurrent protection.

Surge Trap® are: Easy to install, they are

DIN-rail mountable, easy to retrofit: when

using the Pluggable model the user has only

to replace the plug unit without removing the

base. Pluggable is the premium offering in

the Surge Trap® line when Modular is an

economic alternative,

Global: with UL and IEC models and for pho-

tovoltaic applications as well, communica-

tive: a front visual indicator communicates

the status of the TPMOV®. Remote signal-

ing is an option via an auxiliary microswitch.

Surge Trap® is a cost-effective solution

against overvoltage transients requiring no

fuse holder and no additional wiring. It pro-

vides substantial cost savings and reduced

installation time as well.

With Pluggable and Modular models Surge

Trap® is a flexible high-tech protection solu-

tion.

www.ferrazshawmut.com

Fail-Safe Surge Protective Devices

LEM has introduced the ITL 4000-S current

transducer for non-invasive measurement of

currents up to 4000ARMS in conductors of

up to 268mm diameter. The new transducer

allows the isolated measurement of AC, DC

and pulsed currents, up to three times the

nominal value for peak measurement at fre-

quencies up to 50kHz (+/-1dB).

Using closed-loop Fluxgate technology, high-

ly accurate measurements of +/-0.1% of IPN

are achieved over the operating temperature

range from -40°C to +70°C. This high level

of accuracy also allows the measurement of

small DC currents in the presence of large

AC components, which is particularly useful

in applications such as transformer protec-

tion. For example, it is possible to monitor

+/-10A DC over a 4000ARMS AC current

with an uncertainty of +/-1A over an operat-

ing temperature range from -25°C to +50°C.

The technology also offers very good offset

and gain thermal drift performance.

The large aperture of the ITL 4000-S makes

it particularly suitable for measurements on

high-voltage DC systems, which use large-

diameter cables. It features high insulation

for working voltages up to 1.5kVRMS in

accordance with the EN 50178 standard.

www.lem.com

Current Transducer Accurately Measures up to 4000A

Since the first announcement of their colla-

boration Fuji is now coming up with MiniSKi-

iP-PIM-Modules from 8 to 100A and a blok-

king voltage of 1200V.

At the same time Fuji has started the mass-

production of the newest IGBT-generation

(V-series) applying FS-Trench-Technologies

and providing lower total-losses and impro-

ved EMI-characteristics at the same time.

V-series IGBTs will be used for the complete

range of Fuji Mini-SKiiP-Modules.

www.Semikron.com

www.fujielectric.de

Fuji to team-up with Semikron for MiniSKiiP®Spring-contact Power Modules

In today’s world and for the future environ-

mentally friendly technologies is a necessity!

Consumer and manufacturers have turned

their attention towards energy saving elec-

tronic devices.

Various semiconductor manufacturers

already offer simple ICs with which competi-

tive SMPS can be designed. Würth Elektron-

ik has developed two transformer series,

which are designed and manufactured to the

requirements of the leading semiconductor

manufacturers STMicroelectronics and

Power Integrations. The offline transformer

WE- UNIT has an input voltage of 85 – 265

VAC and an isolation voltage of 4 kVAC. The

transformers are especially designed for uni-

versal input as well as for offline-switch

mode power supply.

An additional requirement to decrease the

energy consumption will be released by the

law. One of these requirements results in the

disappearance of the linear regulators in the

near future. They will be replaced by SMPS.

The aim of manufacturing SMPS’ is the

development of power supply for the world-

wide universal input. The advantages are

obvious: Efficiencies of 80% and more, less

weight and smaller size than linear regula-

tors as well as a low stand by-power con-

sumption.

www.we-online.com

Transformer for Energy Saving Electronic Devices

C O N T E N T S

SynQor announces the addition of a new

product family to its portfolio of Hi-Rel dc/dc

converters, the MQFL-28E series. Incorpo-

rating SynQor’s field proven high-efficiency

synchronous rectifier technology, this

advancement results in the only wide range

input dc/dc converters developed specifically

for the Military/Aerospace industry.

The MQFL-28E family handles up to 120W

while meeting the long-term over-voltage

surges in the input voltage specified by MIL

STD 704(A-F), RTCA/DO-160E, and DEF

STAN 61-5. The MQFL-28E converters

accept continuous input voltages of 16-70 V

while permitting broader transient input volt-

ages of 16-80V for 1 second.

The MQFL-28E series is available in eleven

standard single output voltages including

1.5V, 1.8V, 2.5V, 3.3V, 5V, 6V, 7.5V, 9V, 12V,

15V and 28V. Dual output converters are

also available with output voltages of +/-5V,

+/-12V and +/-15V with the capability of pro-

viding up to 80% power from either output.

These feature-rich MilQor Hi-Rel MQFL-28E

converters operate at efficiencies up to 91%

and are designed to operate from -55°C to

+125°C with multiple screening options for

stringent environmental requirements.

www.synqor.com

DC/DC Converters & Filters for Military Applications

The 5th IET International Conference on

Power Electronics, Machines and Drives

PEMD 201019-21 April 2010 | Thistle Hotel | Brighton | UK

www.theiet.org/pemd

Call for Papers

18 September 2009 Abstract Submission

27 November 2009 Notification of Acceptance

29 January 2010 Submission of Final Papers

19-21 April 2010 Date of Conference

Key Deadlines

Join a stellar list of international engineers from industry, research and

academia to discuss, debate and learn about recent developments and

future trends in this important and fast changing area.

In 2010 the conference is expanding its focus to embrace the challenges

and solutions of the applications and systems in which power

electronics, motor and drive technologies play a critical part.

Attendees at PEMD 2010, established as a major forum to showcase the

latest advances in power technology, will gain valuable insights into the

technology roadmaps of the materials and components that are integral

to driving innovation.

For a full list of topics and to submit

your paper, please visit the web site

Conference Themes:

� More/All Electric Transport

� Generation, Transmission and Distribution

� Machines and Drives

� Power Electronics

� Renewable Energy Systems

Supported by: Exhibitors: Media Partners:

IXYS Corporation

(NASDAQ: IXYS)

introduces new 170V-

300V GigaMOSTM

Power MOSFETs.

These power MOS-

FETs provide high cur-

rent capability (up to

260A), eliminating the

need for multiple components when parallel-

ing lower current MOSFET devices in high

power applications. The resultant effect is a

reduction in part count, as well as the num-

ber of required drive components, improving

over-all system reliability and simplicity.

These power MOSFETs are optimized for

superior switching performance in a broad

range of high power switching applications.

GigaMOSTM Power MOSFETs incorporate

IXYS’ Trench Technology to achieve low

Rds(on) and gate charge (Qg), while main-

taining superior switching performance and

ruggedness. Power switching capability is

further enhanced by IXYS’ proven HiPer-

FETTM process yielding a fast intrinsic recti-

fier which provides low reverse recovery

charge (Qrr) and excellent commutating

dV/dt ratings. Additional features include a

175 degree Centigrade operating tempera-

ture and avalanche capabilities. These com-

bined product attributes coupled with high

current ratings, make for an ideal device for

high current power switching applications.

The high current capability of these devices

make them suitable for electric and hybrid

car and carts and other high power battery

powered electrical equipment and tools.

http://www.ixys.com

GigaMOSTM Power MOSFETs



APEC 2010 21

Bicker Elektonik 25

CT-Concepts 3+C3

Danfoss 15

epe 33

Intersil 7

IR C4

ITPR 17

IXYS 31

LEM 1

PEMD 2010 47

Powersem 9

Sanrex 43

Semicon 23

Semikron C2

SPS/ICP/DRIVES 13

Würth Elektronik 19

ADVERTISING INDEX

We believe that solar power represents a

future for renewable energy. PV inverters

become more and more compact exposing

sensors to magnetic disturbance. In order to

offer a more efficient sensor for this applica-

tion, we have optimised the ESM range in

terms of magnetic immunity and dynamic

response.

Thanks to a wide range, from 500A to 2000A

and the possibility to customize the sensor in

function of your needs, the ESM sensor is

our high performance range for inverters.

ESM sensors have been developed in accor-

dance with the EN50178 industrial standards

and complies the EN61000-6-2 and

EN61000-6-4 standards regarding electro-

magnetic compatibility.

For all these good reasons, world’s solar

inverter manufacturers place their trust in the

performance, reliability and compliance of

ABB’s sensors.

ABB takes protection of the environment

very seriously. It is a priority for all ABB com-

panies and not least for us at ABB’s Sensors

products line, we are proud of our ISO

14001 certification.

www.abb.com

Sensors Improve the Performance of Inverters

TEWS TECHNOLOGIES announced the

TPMC317, a conduction cooled single-width

32-bit PMC module which offers six inde-

pendent channels operating as either a stan-

dard SSI interface controller, a SSI ‘Listen

only’ device, an incremental encoder, or a

general purpose counter.

The standard SSI interface controller pro-

vides a clock burst output to the absolute

encoder and receives the returned positional

data. The SSI interface controller operates

with a programmable clock rate from 1μs to

15μs and programmable data word length

from 1-bit to 32-bit.

In ‘Listen only’ Mode, the channel listens to

an existing SSI interface to observe its data

transfer using both the SSI clock and data

as inputs. The channel also has a program-

mable data word length from 1-bit to 32-bit,

and the SSI clock rate of the observed SSI

interface can be in the range of 1μs to 15μs.

In both modes the data word can be encod-

ed in Binary- or in Gray code and with odd,

even or no parity.

The 32-bit incremental encoder counter is a

preloadable up-and-down counter. The

counter is programmable for single, double

and quadruple analysis of the encoder sig-

nals. In conjunction with the isolated 24V

digital inputs it provides the possibility of

automatic preload of the counter whenever

the motion system passes a reference posi-

tion.

www.tews.com

6 Channel SSI Incremental Encoder Counter for Motion Control Applications

Tyco Electronics has announced the addition

of a 10A version of its Corcom GG series

general-purpose and HG series medical fil-

tered power-entry modules. A 5-inch (127

mm) wire lead option has also been intro-

duced for the HG medical modules to aid in

module installation. Previously, the lines

were offered in ratings of 1, 3, and 6 amps.

The GG series of power entry modules com-

bines the functions of a general-purpose RFI

filter with an IEC power cord connector and

single or dual metric fuse holder. The HG

series is the medical version of the GG

series with reduced line-to-ground capaci-

tance to meet UL 2601 patient care require-

ments. Both series are compact - they are

Tyco Electronics’ smallest filtered power-

entry modules with metric fuse holders.

The GG and HG series of power-entry mod-

ules are available with current ratings up to

10A at 250 VAC, 50/60 Hz. With the addition

of the lead wire option to the HG series, both

the GG and HG series are available with

either industry-standard .250-inch (6.35 mm)

tab terminals or 5-inch lead wires for load-

side terminations.

These modules are UL recognized, CSA cer-

tified, and VDE approved. Both GG and HG

series power-entry modules find wide use in

communications, computer and consumer

electronics, industrial, commercial, instru-

mentation and medical equipment.

www.tycoelectronics.com

Expanded Line of Power-Entry Modules

SAMPLES AVAILABLE!

CT-Concept Technologie AG, Renferstrasse 15, CH-2504 Biel, Switzerland, Phone +41-32-344 47 47 www.IGBT-Driver.com

High Frequency

Artists!

Features350kHz max. switching frequency

±1ns jitter

+15V/-10V gate voltage

20W output power

60A gate drive current

80ns delay time

3.3V to 15V logic compatible

Integrated DC/DC converter

Power supply monitoring

Electrical isolation for 1700V IGBTs

Short-circuit protection

Fast failure feedback

Superior EMC

The 1SC2060 is a new, powerful member of the CONCEPT

driver core family.The introduction of planar transformer tech-

nology for gate drivers allows a leap forward in power den-

sity, noise immunity and reliability. Equipped with the latest

SCALE-2 chipset, this gate driver supports switching frequen-

cies up to 350kHz with best-in-class efficiency. It is suited

for high-power IGBTs and MOSFETs with blocking voltages up

to 1700V. Let this artist perform in your high-frequency or

high-power applications.

1SC2060 Gate Driver

Part Number Package VOFFSET VOUT

IO+ & IO- (typical)

tON & tOFF

(typical)

AUIRS2123S SOIC8 600V 10V - 20V 500mA 140 ns & 140 ns

AUIRS2124S SOIC8 600V 10V - 20V 500mA 140 ns & 140 ns

The AUIRS212xS family of 600V, single

channel high-side driver ICs for low-,

mid-, and high-voltage automotive

applications features exceptional

negative Vs immunity to deliver the

ruggedness and reliability essential for

harsh environments and automotive

under-the-hood applications.

Features

• Designed and characterized to be

tolerant to repetitive Vs transient

voltage

• Fully operational up to 600V

• Tolerant to large dV/ dt

• Under voltage lockout

• Lead-free, RoHS compliant

• Automotive qualified per AEC-Q100

t

VS Undershoot

VS -COM

-VS

VBUS

Greater protectionagainst a “negative Vs” event

t

Rugged, ReliableAutomotive-Qualified 600V ICs

THE POWER MANAGEMENT LEADER

For more information call +33 (0) 1 64 86 49 53 or +49 (0) 6102 884 311or visit us at www.irf.com

10388AD_AUIR2123_BODOS_v1.indd 1 28/01/2009 16:40

Electronics in Motion and Conversion July 2009 · Electronics in Motion and Conversion July 2009....

Documents

Transcript of Electronics in Motion and Conversion July 2009 · Electronics in Motion and Conversion July 2009....