F. Arteche , C.Esteban , (ITA) I.Vila (IFCA)

F. Arteche, C.Esteban, (ITA)I.Vila(IFCA)

Electronics integration studies for CMS tracker upgrade

2 de 33 CMS / ATLAS Power working groupGeneva, 31 March 2010

OUTLINE• 1. Introduction• 2.R&D project for SLHC:

– Working Packages• 3. WP1: Power network impedance characterization

– System description– Noise emission at system level

• Output impedance• Input impedance • Granularity

• 4. WP4: Power network impedance characterization• 5.Future work• 6. Conclusions


1. Introduction• Main characteristics of the DC-DC converter powering scheme:

– Several noise sources close to FEE-Sensor• DC-DC power converter, MT & HV line & Structure

– High magnetic field inside tracker volume• No optimal DC-DC power converter design

– High switching frequency • Radiation (Near-field and Far-field)

– New FEE design • Sensitive to sensor & power line connection (LF & HF)

• A large R&D effort is planned and taking place to develop a DC-DC switching converter to operate under high magnetic field with low electromagnetic emissions– GREAT effort form Cern & Aachen

• But it is important to have a R&D plan on EMC issues to conduct studies on the tracker detector at the system level• To ensure the correct integration of SLHC tracker at system level


2. R&D project for SLHC• EMC immunity studies for CMS tracker upgrade - 9.04

– IFCA & ITA – Approved by CMS MB on 20th of November• Long & detailed review process (Tracker & CMS upgrade MB )

– Proposal sent – 3 June• Proposal was welcomed because covers a critical integration

issue for the detector - Good comments from reviewers• First stage of the EMC strategy • The main goal of the project is:

– To define preliminary rules to ensure the integration of main components (Detector, FEE, Power network and DC-DC )

– To define design strategies that allow increasing the immunity of the Detector-FEE unit.

• It is divided in two parts:– Noise coupling mechanisms– New high immunity systems to EM noise


2.1 R&D project for SLHC: Working Packages • WP 1: Power network impedance characterization

– The aim of WP1 is to define and characterize the impedances connected to the DC-DC power converters• It defines the noise (conducted and radiated) levels emitted by the

DC-DC power converters AT SYSTEM LEVEL• Characterization of the electromagnetic environment

– Impedances ( FEE & Power Bus)– Multiple units

• ITA will conduct this WP (Open )• WP 2: Noise propagation effects in power network

– The aim of WP2 is to define the key points that allow designing the power network to minimize the effects of noise currents generated by DC-DC coveters.• PCB or Twisted pair cables

– ITA & IFCA will conduct this WP• Very close collaboration with FERMILAB- M.Johnson


2.2 R&D project for SLHC: Working Packages• WP 3: Noise immunity test in FEE prototypes

– The aim WP3 is to define the FEE immunity on prototypes: Impact of integration strategies in the overall design.• Conducted & radiated test (ITA facilities).

– ITA & IFCA will conduct this WP• Prototype development (several possibilities)

• WP 4: Validation of EM immune OFS for temperature, magnetic field and strain: Effect on overall EM noise– The purpose of WP4 seeks out the implementation of OFS to

substitutes previous measuring systems based on cooper cables and increase the immunity of tracker system.• Different methods for attaching the fibres to carbon composites

supports • Architectures for sensor distribution network • EMC factor measurement

– Noise emissions and immunity with conventional electrical technologies versus Optical Fiber Sensors.

– IFCA will conduct this WP


3. WP1: Power network impedance characterization• The first stage of the integration studies• It will help to define preliminary rules to ensure the integration

of main components– Power Network design strategies– Detector - FEE – PS connection– Chip design – DC-DC power converter

• It is very important to define and characterize the impedances connected to the DC-DC power converters– It defines the noise (conducted and radiated) levels emitted by

the DC-DC power converters at system level• Filters degradation

• This characterization will be focused on integration issues at system level and not on DC-DC converter design issues.– It is complementary to the work developed by other groups..

8 de 19

3.1 WP1: PN impedance characterization: System• There are several layout proposal for system layout –Prop. 1

Susanne Kyre, Dean WhiteFirst results very encouraging

G. Hall´s talk DEC 09

9 de 33

3.1 WP1: PN impedance characterization: System• There are several layout proposal for system layout . Prop 2

M. Jonhson´s TalkCMS upgrade WS 2009

DC-DC

3.1 WP1: PN impedance characterization: System


• All proposals are different but in terms of impedances have common points• Input &Output

• Input – Low impedance in DM

• Large amount of capacitors connected in the PN– Ej: Old Tracker : several hundreds uf

– Low impedance in CM• Possible grounding connection is under analysis but ..

– Detector or negative line has to be grounded due to safety reasons & performance

• At high frequency “stray capacitance “starts to play an important role



ZBUSDC BUS

DC

DC

DC

DC

DC

DC

DC

DC

• Output – Low impedance in DM mode

• Decoupling capacitors– Each DC-DC supplies to several chips

– CM impedance will be defined by stray capacitances • Cooling blocks close to the DC-DC• Frame support is made of Carbon Fiber

– Similar to copper above 500 kHz.



• Pspice model has been develop to study the impedance effect in noise emissions at system level – Frequency domain – Time domain.

• DM & CM models has been studied – Today DM• Model based on DC-DC converters models developed by

CERN & K. Aachen– Noise studies– DC-DC converter ( 10 V-2.5V / 1 to 5 A)


3.2 WP1: PN impedance characterization: Noise Emissions at system level

• The DM output emissions from DC-DC are mainly defined by:– Inductor– Pi – filter

• However the load impedance plays an important role in the noise emissions– Load has been characterized by a current source

with a capacitor plus a resistance in parallel.• A frequency characterization of filter performance

respect several impedances has been studied (real vs normalized impedances)– 10mΩ, 50Ω, 100Ω


3.2 WP1: PN impedance characterization: Noise Emissions at system level : Output impedance

• Filter performance– IL > 80 dB– HF increases due to

filter inductance



Frequency

100KHz 300KHz 1.0MHz 3.0MHz 10MHz 30MHz 100MHz20*LOG10(I(R42))

-120

-80

-40

-0

20

Z=10m Ohms

Z=150 Ohms

Z=50 Ohms

• The output DM noise emission depends strongly on the load impedance (Iout=3A).– Expected impedance bellow 0.1 ohms – Possible noise emissions >100mA Pkk



10-2

10-1

100

101

102

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

ZLoad [ ]

Ipp

[A]

4 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 5

x 10-3

-0.4

-0.3

-0.2

-0.1

0

0.1

0.2

0.3

0.4

Time [s]

Iout

[A]

ZL= 10 m

ZL= 1

ZL= 10

ZL= 100

• Spectrum profile is very similar but shifted between 40 and 80 dB.



105

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108

-100

-80

-60

-40

-20

0

20

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100

120

Frequency [Hz]

Iout

[dB

A

]

ZLoad=10 m

ZLoad=50

• It is expected to connect the DC-DC to FEE via short cables

• The output DM noise emissions has been evaluated for 3 cables of different length– 10 cm , 0.5m and 1m– Iout=3A ; Zout=10mΩ

• Reference cable:– L=0.5uH/m (from old TK)

• Noise emissions– Max – 120 mA. pp– Min – few mA. pp



4 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 5

x 10-3

-0.2

-0.15

-0.1

-0.05

0

0.05

0.1

0.15

0.2

Time [s]

I out

put n

oise

[A]

Lg = 0.01 mLg = 0.5 mLg = 1 m

• Spectra profile is very similar but shifted around 30 dB



105

106

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108

-80

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-20

0

20

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80

100

Frequency [Hz]

Iout

[dB

A

]

Lg = 0.01 mLg = 0.5 mLg = 1 m

• The DM input emissions from DC-DC are mainly defined by:– Pi – filter

• But, again, the load impedance plays an important role in the noise emissions

• This impedance will be very low due to the large amount of Capacitor connected to the power network– Old tracker – More the 100 µf (more than 30 capacitors)

• Frequency characterization of filter performance respect several impedances is similar to the output– Filter performance degradation is expected– Input impedance may vary between 1mΩ - 1Ω


3.2 WP1: PN impedance characterization: Noise Emissions at system level : Input impedance

• The DM input noise emission depends strongly on input impedance. – Expected Zin bellow 0.1 ohms – Possible noise – >80mA Pkk

• Zin <10 mΩ → Iinput >300 mA.



4 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 5

x 10-3

0

0.2

0.4

0.6

0.8

1

1.2

Time [s]

Iin [A

]

Zin=1 m

Zin=1

10-3

10-2

10-1

100

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

Zin [ ]

Ipp

in [A

]

• Spectrum profile is very similar but shifted around 40 dB.



105

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108

-60

-40

-20

0

20

40

60

80

100

120

Frequency [Hz]

Iin [d

BA

]

Zin = 1m

Zin = 1

• The granularity of the detector also may have an impact in the noise emission level .

• The detector granularity defines:– Current consumption per DC-DC converter– Number of DC-DC converters connected to the same bus

• DM Noise emissions for two different scenario have been analyzed – Output current

• 1 to 5 A– DC-DC converters connected to the same bus

• 1 to 4 DC-DC converters– As a reference

• Input impedance & output impedance – 10 mΩ23 de 33 CMS / ATLAS Power working group

Geneva, 31 March 2010

3.2 WP1: PN impedance characterization: Noise Emissions at system level : Granularity

• DM Input & output emissions of DC-DC converters has been analyzed – Three cases: 1 A, 3 A and 5 A– Zin=Zout=10 mΩ

• Input emissions – Noise increases

• Iout = 1 A – Noise : 20mA• Iout = 5 A – Noise : 400mA

• Output emissions – Constant



4 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 5

x 10-3

0

0.5

1

1.5

2

2.5

Time [s]

Iin [A

]

I = 1 AI = 3 AI = 5 A

4 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 5

x 10-3

-0.4

-0.3

-0.2

-0.1

0

0.1

0.2

0.3

0.4

Time [s]

Iout

[A]

Iout=1 AIout=3 AIout=5 A

Input

Output

• The spectrum content in DM at the input is similar but it is also shifted around 10 dB – Difference between 1 A and 5 A


3.2 WP1: PN impedance characterization: Noise Emissions at system level :Granularity

105

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-20

0

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Frequency [Hz]

Iin [d

B A

]

Iout=5 AIout=1 A

• The noise emissions at the power network level has been analyzed – 4 DC-DC converter connected in parallel– Synchronized switching frequency



4 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 5

x 10-3

0

0.5

1

1.5

2

2.5

3

3.5

4

Time [s]

I [A

]

Iin -1 DCDCIpn - 4 DC-DC

DC

DC

DC

DC

DC

DC

DC

DC

• The spectrum content in DM at power network increases with the number of DC-Dc connected.– Difference between 1 DC-DC and 4 DC-DC A (10 dB)

• Similar scenario has been already observed in old tracker



105

106

107

108

-40

-20

0

20

40

60

80

100

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Frequency [Hz]

I [dB

A]

4 DC-DC1 DC-DC

• This lead to high noise emission level at power network level – 4 DC-DC / 5 A → 1.6 A at 1 MHz !!!!!!



105

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107

108

0

20

40

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100

120

140

Frequency [Hz]

Ibus

[dB

A]


4. WP 4: Validation of EM immune OFS for temperature, magnetic field and strain: High immunity system

• New tracker system will generate a large amount of noise inside the tracker volume • Easier coupling path • Filtering is more complex• High noise at power network level

• The study or design of new systems insensitive to EM noise to measure temperature, strain or magnetic field will increase the robustness of FEE to EM noise

• The use of optical fibre sensors (OFS) to be used as temperature and strain probes will increase the immunity of tracker system.• They are very well known in aerospace and aeronautics

• This type of sensors is• Not sensitive to EM fields, HV and transients.• Light – weight, miniaturized and flexible• Non-interfering , low-loss, long-range signal transmission


4. WP 4: Validation of EM immune OFS for temperature, magnetic field and strain: High immunity system• Fibre Bragg Grating (FBG ) optical transducer is the most

common transducer to measure strain and temperature– A light is sent via the optical fibber to the transducer and the

diffracted wavelength is measured – Diffracted wavelength depends on FBG geometry, that is affected by

stress and temperature.

Stress

Temp


4. WP 4: Validation of EM immune OFS for temperature, magnetic field and strain: High immunity system• The FBG sensors allows:

– Multiplexing capability – (Sensor Networks)– Embedding in composite material –(Smart structures)– High and low Temperatures ( 4 k – 900 ºC).– Durable to high strain– It is necessary only one fibre to read out strain & temperature

• WP1: Impedance effects– Analyzed CM noise emissions– System test for integration issues under development

• Measure CM & DM emissions respect several impedances and loads

• WP4: Validation of EM immune OFS – Different methods for attaching the fibres to carbon

composites supports – Architectures for sensor distribution network – EMC factor measurement– Noise emissions and immunity with conventional

electrical technologies versus Optical Fibre Sensors.


5. Future work

• ITA & IFCA has recently started a new project focused on integration issues

• R& D project divided in 4 WP • WP1 & WP4 has started • WP1 focused on impedance effects on noise emissions

– First results focused on DM noise– Strong dependence of DM noise emissions respect

• Input & output Impedance • Granularity

• WP4 focused on development of high immunity systems– Substitute the Temp , strain and magnetic monitoring

lines for other based on optical fiber.


6. Conclusions

34 de 33 CMS / ATLAS Power working groupParis- France, 23 September 2009

BACKUP SLIDES

Time

4.423200ms 4.423600ms 4.424000ms 4.424400ms 4.424800ms 4.425200ms 4.425600ms 4.426000ms 4.426400ms4.422844msI(L1)

0A

4.00A

-1.87A

7.87A

Time

4.423200ms 4.423600ms 4.424000ms 4.424400ms 4.424800ms 4.425200ms 4.425600ms 4.426000ms 4.426400ms4.422844msI(R11)

0A

4.00A

-1.87A

7.87A

• But why the noise does not increases at the output ?

• The output current has the same shape – Only they are shifted a

certain DC value defined by current consumption

– AC shape it is defined by duty cycle and converter parameters

• However , the input current has different shape– Spectra content is different



Input

Output

F. Arteche , C.Esteban , (ITA) I.Vila (IFCA)

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