GLAST LAT Project Tower Power Supply Review Sept 22, 2003

Gunther Haller Part 2, Version 4 1

GLAST Large Area Telescope:GLAST Large Area Telescope:

Electronics, Data Acquisition & Flight Software TEM Power SupplyPart 2

Gunther HallerStanford Linear Accelerator CenterManager, Electronics, DAQ & FSWLAT Chief Electronics Engineer

haller@slac.stanford.edu(650) 926-4257

Gamma-ray Large Gamma-ray Large Area Space Area Space TelescopeTelescope

GLAST LAT Project Tower Power Supply Review Sept 22, 2003

Gunther Haller Part 2, Version 4 2

TeamTeam

• High-Voltage– Dieter Freytag (SLAC)– Original assist by Art Ruitberg (GSFC)

• Low Voltage– Dave Nelson (SLAC)– Assist by Dieter Freytag, Joszef Ludvig (SLAC)

• Combined Board– Dave Nelson (SLAC)– Mark Freytag, Dieter Freytag (SLAC)

• Layout– HV section: Cathy (SLAC)– Combined Board: Tung Phan (SLAC)

• Assembly/Parts– Lupe Salgado (SLAC)

• Mechanical/Thermal– Dave Nelson, Jobe Noriel, Dave Tarkington (SLAC)

GLAST LAT Project Tower Power Supply Review Sept 22, 2003

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Top-Level BlocksTop-Level Blocks

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Filter SectionFilter Section

Filter28V from PDU

28-V filtered

• Uses standard MIL-461 filter for flight. Board can also be loaded with commercial filter for EGSE versions (to other sub-systems)

• See Schematic “Filter” block

GLAST LAT Project Tower Power Supply Review Sept 22, 2003

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TEM DAQ SectionTEM DAQ Section

Delay28V filtered

3.3V Converter

2.5V Converter

3.3 V TEM DAQ

2.5 V TEM DAQ

• Uses delay circuit to turn-on 3.3V to ACTEL FPGA’s on TEM DAQ after 2.5V core voltage (see ACTEL alert)

• See Schematic “DAQ” block

GLAST LAT Project Tower Power Supply Review Sept 22, 2003

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CAL SectionCAL Section

28V filtered3.3V Converter

3.3V Converter

3.3 V CAL analogFilter

3.3 V CAL digitalFilter

Switch

28V switched

CAL enable

HV Converter

30V-100V

Cal set voltage (0-2V)

• HV starts at 30V• HV and LV are switched on/off together (no independent HV switch)• PC-board designed so linear regulator can be added in case noise is not low enough

– Either International Rectifier low-drop linear regulator– Regulator with single NPN

• Baseline is without linear regulator because– Higher efficiency– Omnirel max output voltage is 3.2V

GLAST LAT Project Tower Power Supply Review Sept 22, 2003

Gunther Haller Part 2, Version 4 7

TKR SectionTKR Section

28V filtered1.5V Converter

1.5 V-A TKR analogFilter

Switch

28V switched

TKR enable

HV Converter30V-150V

TKR set voltage (0-2V)

1.5V Converter1.5 V-B TKR analog

Filter

2.5V Converter2.5 V-A TKR analog

Filter

Filter2.5 V-A TKR dig

2.5V Converter2.5 V-B TKR analog

Filter

Filter2.5 V-B TKR dig

• HV starts at 30V• HV and LV are switched on/off together (no independent HV switch)• PC-board designed so linear regulator can be added in case noise is not low enough

– Either International Rectifier low-drop linear regulator– Regulator with single NPN

• Baseline is without linear regulator because– Higher efficiency– Omnirel min input voltage is 2.9V (high for 1.5V output, loose 50% of power in linear regulator)

GLAST LAT Project Tower Power Supply Review Sept 22, 2003

Gunther Haller Part 2, Version 4 8

Typical Low-Voltage Operating CircuitTypical Low-Voltage Operating Circuit

• For 3.3V and 2.5V: set by resistor ratio according to data-sheet• For 1.5V output:

– Can’t just select resistor divider since internal reference is 2.2V– Solution: sum in current (resistor from external zener diode) at FB node to offset feed-back

voltage

R

Vref

For 1.5V output

GLAST LAT Project Tower Power Supply Review Sept 22, 2003

Gunther Haller Part 2, Version 4 9

High-Voltage DC/DC Converter (Simplified)High-Voltage DC/DC Converter (Simplified)

• For details, see schematic

GLAST LAT Project Tower Power Supply Review Sept 22, 2003

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TEM-PS BoardTEM-PS Board

Maxim High-VoltageConnector to TEM

GLAST LAT Project Tower Power Supply Review Sept 22, 2003

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High-Voltage SuppliesHigh-Voltage Supplies

• SLAC (Dieter)– Circuit Design & Simulations (PSPICE) – PC board circuit debug/circuit modifications– Noise, stability measurements (see example plot)

• GSFC (Art)• Got loaded board from SLAC• Phase margin measurements (see plot)• Consultation

GLAST LAT Project Tower Power Supply Review Sept 22, 2003

Gunther Haller Part 2, Version 4 12

Signal at Coil and at Switching TransistorSignal at Coil and at Switching Transistor

• Courtesy of Dieter Freytag

GLAST LAT Project Tower Power Supply Review Sept 22, 2003

Gunther Haller Part 2, Version 4 13

High Voltage NoiseHigh Voltage Noise

• Courtesy of Dieter Freytag, with RC Filter at output, RMS ~11mV, dominated by 60 Hz-line (need to be remeasured in TPS enclosure)

GLAST LAT Project Tower Power Supply Review Sept 22, 2003

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High-Voltage Amplitude/PhaseHigh-Voltage Amplitude/Phase

• Courtesy of Art Ruitberg

GLAST LAT Project Tower Power Supply Review Sept 22, 2003

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Low-Voltage SuppliesLow-Voltage Supplies

• Mostly Dave Nelson (SLAC)

GLAST LAT Project Tower Power Supply Review Sept 22, 2003

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TKR 1.5V when TKR is turned onTKR 1.5V when TKR is turned on

• 28V powered• TKR 1.5V supply output when TKR supplies are turned-on via TEM DAQ enable signal

GLAST LAT Project Tower Power Supply Review Sept 22, 2003

Gunther Haller Part 2, Version 4 17

CAL 3.3V when 28V is turned onCAL 3.3V when 28V is turned on

• CAL 3.3V analog output when 28V supply is turned on (CAL already enabled)

GLAST LAT Project Tower Power Supply Review Sept 22, 2003

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Step into FeedbackStep into Feedback

• TKR 1.5V response when 200mW step is applied to feed-back• Damped

GLAST LAT Project Tower Power Supply Review Sept 22, 2003

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Step into feedback with 50nFStep into feedback with 50nF

• TKR 1.5V response when 200mW step is applied to feed-back• Better response

GLAST LAT Project Tower Power Supply Review Sept 22, 2003

Gunther Haller Part 2, Version 4 20

Amplitude/Phase of TKR 1.5VAmplitude/Phase of TKR 1.5V

Tracker 1.5 Volt Phase Margin

-30

-20

-10

0

10

20

30

40

50

1.0E+02

1.6E+03

3.1E+03

4.6E+03

6.1E+03

7.6E+03

9.0E+03

1.1E+04

1.2E+04

1.4E+04

1.5E+04

Freq - Hz

Gai

n -

dB

-200

-150

-100

-50

0

50

100

150

200

Ph

ase

- D

egre

e

Gain

Phase

GLAST LAT Project Tower Power Supply Review Sept 22, 2003

Gunther Haller Part 2, Version 4 21

Phase Margin Cal 3.3 Analog

-10

0

10

20

30

40

50

60

701.0E+00

4.1E+01

8.1E+01

1.2E+02

1.6E+02

2.0E+02

2.4E+02

2.8E+02

3.2E+02

3.6E+02

4.0E+02

Freq Hz

Gai

n d

B

-150

-100

-50

0

50

100

150

200

Freq Hz

Ph

ase

Deg

rees

Amplitude/Phase of CAL 3.3VanalogAmplitude/Phase of CAL 3.3Vanalog

• 54 degree phase margin

GLAST LAT Project Tower Power Supply Review Sept 22, 2003

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CAL 3.3V analog Noise SpectrumCAL 3.3V analog Noise Spectrum

Cal 3.3 Analog Noise Spectrum

-0.1

0

0.1

0.2

0.3

0.4

0.50.0E+00

1.0E+05

2.0E+05

3.0E+05

4.0E+05

5.0E+05

6.0E+05

7.0E+05

8.0E+05

9.0E+05

1.0E+06

Freq - Hz

No

ise

- u

V/S

qrt

(Hz)

* Plot is baseline subtracted

• Very good performance

GLAST LAT Project Tower Power Supply Review Sept 22, 2003

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TEM DAQ 3.3V Noise SpectrumTEM DAQ 3.3V Noise Spectrum

TEM 3.3 Volt Noise Spectrum

-20

0

20

40

60

80

100

120

140

160

180

0.0E+00

2.0E+05

4.0E+05

6.0E+05

8.0E+05

1.0E+06

1.2E+06

Freq - Hz

No

ise

- u

V/S

qrt

(Hz)

* Plot is baseline subtracted

• TEM digital has no LC filter on TEM PS

• Still very good performance