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Rutherford Appleton LaboratoryParticle Physics Department

Serial Powering Scheme

Peter W PhillipsSTFC Rutherford Appleton Laboratory

On behalf of RAL group and collaborators

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Rutherford Appleton LaboratoryParticle Physics Department

Motivations

• Fewer Cables• Fewer Connections• Increased Efficiency• Reduced Material

Concerns• noise/electrical

performance– In fact SP systems are

clean:• local regulation helps• chain current constant,

therefore no IR drops

• Failure in the chain – loss of many modules

• …

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Rutherford Appleton LaboratoryParticle Physics Department

SPPCB - 2006 -111 mm x 83 mm

SSPPCB - 2006/7 -38 mm x 9 mm

Hybrid

SSPPCB

ABCD3TV2

Evolution of Serial Powering CircuitryEvolution of Serial Powering Circuitry

SPPCB - 2006 -150mm x 150mm

AG Analog power AV DG Digital pwr DVData Cmd Clk

4

1350

1400

1450

1500

1550

1600

755 663 159 628 662 006

Module #

<EN

C>

Independent powering Serial Powering

Noise vs injected noise frequency

600.00

610.00

620.00

630.00

640.00

650.00

660.00

1 MHz 5 MHz 10 MHz 30 MHz 40 MHz 50 MHz

Frequency

Out

put n

oise

(EN

C)

SP with current mod.

Voltage noise injection through capacitor

610.00

612.00

614.00

616.00

618.00

620.00

100 kHz 1MHz 10 MHz 30 MHz 40 MHz 50 MHz 70 MHz 120 MHz

Frequency

Noi

se E

NC

Tests with SCT modules or 4 chip hybrids

ENC of IP vs. SP

ENC with injection of external voltage pulse into power line ( 1V pp through 15 pF)

ENC with current modulation of 20 mA

SCT module test set-up

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Rutherford Appleton LaboratoryParticle Physics Department

Interface PCB Cooling hoseswith connector

Module 0

Module 1

Hybrid 2

Module 3

Module 4

Module 5

Picture of the 6-module stave on a bonding fixture.

Module 2 is a bare hybrid without sensor for better comparison with single-hybrid data. The interface PCB at the end of the stave (top of the picture) carries a connector. All other stave electrical connections are made through wire-bonds. The cooling hoses (inlet and outlet) are at the top end of the stave.

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Rutherford Appleton LaboratoryParticle Physics Department

HV from storage capacitors & LVDS power from bench supply

0

200

400

600

800

1000

1200

1400

1600

1800

2000

0 512 1024 1536 2048 2560 3072

Channel number

ENC

ENC 5

ENC 4

ENC 3

ENC 2

ENC 1

ENC 0

1000

1100

1200

1300

1400

1500

1600

1700

0 128 256 384 512

Channel number

ENC

ENC 5 av = 988.5

ENC 4 av = 1139.0

ENC 3 av = 1155.8

ENC 2 av = 618.3

ENC 1 av = 1156.1

ENC 0 av = 1185.9

30

35

40

45

50

55

60

65

70

0 512 1024 1536 2048 2560 3072

Channel number

GA

IN

GAIN 5

GAIN 4

GAIN 3

GAIN 2

GAIN 1

GAIN 0

30

35

40

45

50

55

60

65

70

0 128 256 384 512

Channel number

GA

IN

GAIN 5 av = 50.2

GAIN 4 av = 46.0

GAIN 3 av = 49.4

GAIN 2 av = 54.5

GAIN 1 av = 50.3

GAIN 0 av = 57.9

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Rutherford Appleton LaboratoryParticle Physics Department

• Low output impedance crucial to achieve good ‘grounding’ and reduce picked up noise• Dynamically each sensor is grounded to current source

• Option of using single HV supply for several sensors

No difference in performance is seen with the 6 module stave

Single HV line Separate HV lines for each sensor

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Rutherford Appleton LaboratoryParticle Physics Department

Module with 3cm detectorThree 6-chip hybrids operated as a serial chain

Next step: 30 module stave with commercial SP electronics

Data/clock/command Linear regulator ST SR AC-coupling

Work in Progress:Being built at LBNL

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Rutherford Appleton LaboratoryParticle Physics Department

10 + 10 modules back-to-back 10 cm * 10cm sensors 40 ABC-Next chips/module Custom SP circuitry

Next Year: Short Strip “Supermodule”

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Rutherford Appleton LaboratoryParticle Physics DepartmentSP Architecture Choices

a) External shunt regulator + external power transistor

External commercial SR+ ST, used for RAL studies with SCT modules.

With custom electronics could be part of one chip.

This is good engineering, but implies a high-current device; limited expertise in HEP IC community.

Constant current source

ROIC ROIC ROIC ROIC

Module 1

Module n

Voltage chain

5 V

2.5 V

0 V

We will test this with SPI chip

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Rutherford Appleton LaboratoryParticle Physics Department

b) Shunt regulator + transistor in each ROIC

Integrated (custom) SR and transistor designed by Bonn worked well for pixels.

Many power supplies in parallel; Addresses high-current limitation and provides protection. Difficulty is matching and switch-on behaviour of shunt transistors. Must avoid hot spots that kill one shunt transistor after the other.

We will test this with ABC_Next (and SPi LVDS buffers)

SP Architecture Choices

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Rutherford Appleton LaboratoryParticle Physics Department

c) External shunt regulator + integrated parallel power transistors

New attractive idea. Addresses high-current limitation. Conceptually simple. Need to understand how well distributed feed-back works.

Will test this with SPi (for Shunt Regulator and buffers) and ABC_Next (for Shunt Transistor)

SP Architecture Choices

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Rutherford Appleton LaboratoryParticle Physics Department

Expected benefit of custom SP circuitry

Dynamic impedance: reduced by one or two orders of magnitude!

Measurement (G Villani): Prototype with commercial components

Simulation (M Newcomer): External Shunt Regulator and Integrated Shunt Transistors

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Rutherford Appleton LaboratoryParticle Physics Department

• 30 module ABCD stave• Evaluation of custom circuitry

– ABC_Next and SPi• 20 module ABC-Next “Supermodule”

• Design protection schemes• G&S evaluation of SP systems

– important but not expected to be a concern• Design of constant-current source (Prague (JS) + RAL)

Hybrid

Outlook