Electronics- lectures for Mechanical Engineering

part 6

Dr. Bogusław Boratyński

Faculty of Microsystems Electronics and Photonics,

Wroclaw University of Technology,

2011

From the course syllabus

Basic literature & figure sources:

G. Rizzoni, Fundamentals of Electrical Engineering, McGraw-Hill

R.F. Pierret, Semiconductor Device Fundamentals, Addison-Wesley Publ.,

B.G. Streetman, Solid State Electronic Devices, Prentice-Hall,

J. Millman, Microelectronics, McGraw-Hill

Additional literature:

W. Marciniak, Przyrządy półprzewodnikowe i układy scalone, WNT,

A. Świt, J. Pułtorak, Przyrządy półprzewodnikowe, WNT,

B.G. Streetman, Przyrządy półprzewodnikowe, WNT

Digital integrated circuits

Chapter 6. Thyristors.

DC and AC power switching

AC switching devices:

Thyristor, TRIAC, DIAC

DC switches:

IGBT,

PUT, UJT

MOSFET or bipolar transistor current switch

Input control signal UI = UBE or I1=IB

Result: rise of output current IC =Iload

U0

UI

UCCload

IC

IB

Input control signal UG = UGS

Result: rise of output current iD = iload

UDD , UCC - DC supply

Thyristor – switch - dc operation

Source: J. Millman, Microelectronics, McGraw-Hill

DC biasing circuit: UGK >0, UAK >0 DC I-V characteristics

pulse of IG to switch-on (to trigger)

RL

A

K

G

UGK

IGUAK

blocking

conducting

reverse

Thyristor

SCR – Silicon Controlled Rectifier

Thyristor – operation principle

Source: J. Millman, Microelectronics, McGraw-Hill

p-n-p-n structure,

3 p-n junctions in series

Thyristor

SCR – Silicon Controlled Rectifier

”Diode” current controlled

by the gate current pulse

blocking

conducting

reverse

switching

Triggering methods:

1. Pulse of the gate current IG

2. Rise of VAK > VBF

3. Illumination – Light triggered thyristors

Main current – IAK = Iload [A] [kA]

Control current pulse – IG [mA]

Thyristor – circuit application - ac current switch

G

A K

pow er line

230V

LOAD

lighting

system

gate contol

circuit

Basic application system example:

control of light intensity / light dimmer

(heating systems, electrical motors)

Uinput

IAK

UAK

ωt

ωt

ωt

IG pulse

current & voltage waveforms

DIAC

DIODE

SCR

Iload

Thyristor – circuit application - ac current switch

G

A K

pow er line

230V

LOAD

lighting

system

gate contol

circuit

Basic application system example:

control of light intensity / light dimmer

(heating systems, electrical motors)

current & voltage waveforms

G

A K

pow er line

230V

LOAD

lighting

system

gate contol

circuit

Uinput

IAK

UAK

ωt

ωt

ωt

IG pulse

Iload

TRIAC – operation principle

TRIAC – bidirectional thyristor - symmetrical I-V characteristic

(equivalent of two thyristors connected antiparallel) IG pulse turns-on the triac

A1

A2

G

IG pulse

IG pulse

conducting

conducting

blocking

blocking

Application in low and medium power circuits

TRIAC – operation principle - ac current switch

TRIAC – ac operation

A1

A2

G

IG pulse

Uinput

IAK

UAK

ωt

ωt

ωt

IG pulse

Iload

DIAC – operation principle

Source J. Millman, Microelectronics, McGraw-Hill

DIAC – two terminal switching device - symmetrical I-V characteristic

switching – voltage rise Vth= 40V ÷ 60V

A2VthVth

IGBT switching device

- low UCE in on-state

- very high switching voltages [kV]

IGBT Insulated Gate Bipolar Transistor

- takes advantage of MOSFET current-less input and BJT high switching current capability

Source:

- symbol

- equivalent circuit

IGBT switching device

IGBT Insulated Gate Bipolar Transistor

- application circuit

Source: Wikipedia

=

uC – microcontroller, triggering cct.

PUT unijunction transistor

PUT Programmable Unijunction Transistor

Switching voltage Vp adjustable by external resistance voltage divider and supply VBB

A

K

G

UJT - Unijunction Transistor