1. Low Voltage Power Supply & Power Controller Board
Peter Berg
University of California - Berkeley

2. Overview Overview Requirements Specification Design Mass and Power
Test
Schedule
Issues

3. Overview CHANGES SINCE PDR FREQUENCY OF PWM SUPPLIES CHANGED TO 200KHZ
ACCOMODATION FOR MSK INRUSH CURRENT

4. Design Drivers SUPPLY DESIGNED TO RBSP_EFW_LVPS_001
INPUT IS 28 VOLT POWER (22-35 VOLTS NOMINAL)
PRIMARIES ARE CURRENT LIMITED
SUPPLIES SYNCHRONIZED TO 799KHZ
FLOATING SUPLIES RUN AT 399.5KHZ, OTHERS AT KHZ
SUPPLY IS SOFT STARTED TO MINIMIZE TURN-ON STRESSES – INPUT CURRENT CONTROLLED
REGULATION – 1% ON DIRECTLY REGULATED VOLTAGES AND 5% ON AUXILLARY VOLTAGES
ISOLATED SECONDARIES
BEB OUTPUTS INDEPENDENT OF IDPU OUTPUTS
 225V SUPPLY AND FLOATING  15V SUPPLIES FILTERED TO 14μV RMS 10Hz-10KHz, AND 0.4μV RMS 10KHz-100KHz

5. Requirement Body or Section Heading
Requirements ID
Req. Title
Subject
Priority
Requirement Body or Section Heading
Implementation
EFW-61
EFW Power Control
Each EFW IDPU
shall
contain circuitry to open SPB and AXB doors and deploy sensors
Implemented on PCB portion
EFW-62
EFW Low Voltage Conversion
contain circuitry to provide voltages to IDPU boards using the S/C-provided 28Volts
Impemented using PWM converters
EFW-63
EFW Main Power Allocation
Each EFW Suite
not exceed the total power of W from the EFW Main 28V Service
Verified on Flight Unit
EFW-64
EFW Main Power In-Rush
Each IDPU
not exceed ICD values as follows: 10A for 100 usec; 5A for 100us to 1ms 2.5A after 1ms
Implemented using soft start
EFW-65
EFW Main Power Max Voltage
tolerate without damage a maximum input voltage of 40V indefinitely as defined in the ICD
Parts sufficiently derated
EFW-75
EFW IDPU Operational Temp Range
The EFW IDPU
perform as designed from -25 to +55C
Parts chosen are -55 to 125C
EFW-78
EFW IDPU Survival Temp Range
survive without damage from -30 to +60C
EFW-88
EFW IDPU ICD Compliance
comply with the requirements and constraints imposed by all relevant instrument-to-spacecraft interface control documents (ICDs).
Verified by Instrument CPT
EFW-98
EFW Illegal Power States
not be damaged by the application of boom power while the Main power is Off.
By design, verified by test
EFW-99
EFW SPB Deployment Enable
not deploy SPB booms or fire SPB actuators without the SPB and Main power ON.

6. Requirements EFW-100 EFW AXB Deployment Enable The EFW IDPU shall
not deploy AXB booms or fire AXB actuators without the AXB and Main power ON.
By design, verified by test
EFW-101
EFW Boom Pair Redundancy
have separate supplies for each preamp boom axis.
By design
EFW-102
EFW Safing by subsystem
continue to provide EMFISIS with E-Field signals on failure of DCB or DFB
EFW-131
EFW Initial Power On/Reset State
power up in a nominal condition for measuring E-Fields without processor intervention.
EFW-133
EFW Compliance with EM Environment Control Plan
The EFW Suite
comply with the requirements and constraints imposed by the RBSP Electromagnetic Environment Control Plan, APL document no
Verified by Instrument CPT and EMC test
EFW-136
Instrument Compliance with Environmental Design and Test Requirements Document
Each EFW Instrument
comply with the requirements and constraints imposed by the RBSP Environmental Design and Test Requirements Document, APL document no
Verified as per RBSP_EFW_TE_001
EFW-137
EFW Quality Assurance
comply with the RBSP Performance Assurance Implementation Plan, as modified by the Compliance Matrix
Verified as per RBSP_EFW_PA_010

7. Specifications Electro-Mechanical Specifications Connectors ENCLOSURE
KA80.1/127CPFC10TABH
Mate/Demate Cycles >500
Allows use of commercial backplanes for testing
Front Panel 9 Pin Male, 62 Pin Female
ENCLOSURE
Spacing is .75” above, .25” below
Electrically shielded

8. Design

9. Design
Packaging

10. Design

11. Design Design Considerations Grounds Voltage Capabilities
2 Digital
2 Analog
6 Floating
Voltage Capabilities
Worst Case Floating Voltages  240V
Primary to Secondary Isolation >1000V
Current Capabilities
Worst Case Current Req – 2.25A
Pin Capabilities – SDD Series: 5 amps nominal

12. Design
SAMPLE PWM REGULATOR
TO FLOATING SUPPLIES

13. Design
MKS INRUSH MITIGATION
MSK INRUSH MITIGATION TIMER

14. Design
DUAL  FLOATING SUPPLY

15. Floating Supply Testing
Design
Floating Supply Testing

16. Design Power Control Section BYTE 1 MHZ LATCHES CMD CLEARS DECODERS
WITH POWER ON
Power Control Section

17. Design INPUT (FRONT PANEL) POWER SECTION (BACKPLANE)
POWER CONTROL SECTION (FRONT PANEL)

18. Mass & Power Mass Power 824 Grams CBE (BOARD WITH FRONT PANEL)
Shielding Mass held by IDPU Chassis
Growth/Uncertainty Margin is 5%
Power

19. TEST
Sample Tester

20. STATUS WORKING SUPPLY TESTED WITH IDPU TESTED WITH EMFISIS
FLOATER EFFICIENCY 80%
OVERALL EFFICIENCY IS ~50%
VERIFIED 1% REGULATION

21. INRUSH TEST
Inrush Profile

22. SCHEDULE TASK COMPLETION DATE TEST PCB PORTION OF LVPS SEPT 30
NEW ETU LAYOUT RECEIVED
OCT 2
EFFICIENCY
BUILD NEW ETU
OCT 23
SYNC SEQUENCE
OCT 27
LINE REGULATION
OCT 30
LOAD REGULATION
CROSS REGULATION
MSK INRUSH DEFEAT CIRCUIT
RIPPLE MEASUREMENTS
CURRENT TRIP THRESHOLDS
NOV 6
MONITOR GAINS
CONDUCTED EMISSIONS
THERMAL TEST
NOV 13
FLIGHT LAYOUT
NOV 27
BUILD FIRST FLIGHT UNIT
DEC 15
TEST FIRST FLIGHT UNIT
JAN 8

23. PEER REVIEW RFAs TITLE DESCRIPTION RESPONSE Stress Analysis
Ensure stress analysis done on all boards by CDR
Parts chosen at design to accommodate stress margins
PCB Switch Dissipation
Look at thermal dissipation of FET switches on PCB, is heat sinking necessary?
No additional heat sinking is necessary. Two of the higher dissipation FETS have new part numbers and the temp rise of the highest is less than 3°C.
LVPS Thermal Vacuum Test
Check hot and cold operation of LVPS in Thermal Vacuum, in particular sync operation, soft start, in rush times, 1526 startup, floater and 225 supply outputs. Verify at hot that parts do not exceed rated temperatures.
Post CDR on complete ETU
Measure LVPS Efficiency
Measure efficiency of all supplies
Total efficiency of supplies is presently ~ 50%
Measure LVPS Cross Regulation
Verify that cross regulation of supplies meets 5% goal
Will test asap, perhaps on new ETU (post CDR)
LVPS Free-run Frequency
Verify that free run frequency of 1526 does not go above 90% of sync frequency
Currently, set point is 95% of sync frequency.
LVPS Soft start capacitors
Include soft start capacitors in schematics
Will be included where needed
Implement temporary current limiting on IDPU supply
Allow high inrush on the IDPU supply, but safe instrument in case of short
To be implemented with timed increase of overcurrent threshold on new ETU (post CDR).

24. Issues CONSUMPTION NOISE Improve efficiency
Reduce amplitude of tone at 200 kHz