Changes since PDR

1
GLAST Large Area Telescope Electronics, Data
Acquisition Flight Software TEM Power
Supply Part 2 Gunther Haller Stanford Linear
Accelerator Center Manager, Electronics, DAQ
FSW LAT Chief Electronics Engineer haller_at_slac.st
anford.edu [phone]
2
Team

• 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)

3
Top-Level Blocks
4
Filter Section
28V from PDU
Filter
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

5
TEM DAQ Section
28V filtered
Delay
3.3V Converter
3.3 V TEM DAQ
2.5V Converter
2.5 V TEM DAQ

• Uses delay circuit to turn-on 3.3V to ACTEL
  FPGAs on TEM DAQ after 2.5V core voltage (see
  ACTEL alert)
• See Schematic DAQ block

6
CAL Section
28V switched
28V filtered
3.3 V CAL analog
3.3V Converter
Filter
Switch
CAL enable
3.3 V CAL digital
Filter
3.3V Converter
30V-100V
HV Converter
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

7
TKR Section
28V switched
28V filtered
1.5 V-A TKR analog
1.5V Converter
Filter
Switch
1.5 V-B TKR analog
TKR enable
1.5V Converter
Filter
2.5 V-A TKR analog
2.5V Converter
Filter
2.5 V-A TKR dig
Filter
2.5 V-B TKR analog
2.5V Converter
Filter
2.5 V-B TKR dig
Filter
HV Converter
TKR set voltage (0-2V)
30V-150V

• 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)

8
Typical Low-Voltage Operating Circuit
Vref
R
For 1.5V output

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

9
High-Voltage DC/DC Converter (Simplified)

• For details, see schematic

10
TEM-PS Board
Connector to TEM

• Maxim

High-Voltage
11
High-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

12
Signal at Coil and at Switching Transistor

• Courtesy of Dieter Freytag

13
High 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)

14
High-Voltage Amplitude/Phase

• Courtesy of Art Ruitberg

15
Low-Voltage Supplies

• Mostly Dave Nelson (SLAC)

16
TKR 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

17
CAL 3.3V when 28V is turned on

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

18
Step into Feedback

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

19
Step into feedback with 50nF

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

20
Amplitude/Phase of TKR 1.5V
21
Amplitude/Phase of CAL 3.3Vanalog

• 54 degree phase margin

22
CAL 3.3V analog Noise Spectrum

• Plot is baseline subtracted
• Very good performance

23
TEM DAQ 3.3V Noise Spectrum

• Plot is baseline subtracted
• TEM digital has no LC filter on TEM PS
• Still very good performance