RBSP Radiation Belt Storm Probes RBSP Radiation Belt Storm Probes RBSP/EFW CDR /30-10/1 213 Low Voltage Power Supply & Power Controller Board Peter Berg University of California - Berkeley

RBSP/EFW CDR /30-10/1Berg 214 Overview –Requirements –Specification –Design –Mass and Power –Test –Schedule –Issues

RBSP/EFW CDR /30-10/1Berg 215 Overview CHANGES SINCE PDR –FREQUENCY OF PWM SUPPLIES CHANGED TO 200KHZ –ACCOMODATION FOR MSK INRUSH CURRENT

RBSP/EFW CDR /30-10/1Berg 216 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

RBSP/EFW CDR /30-10/1Berg 217 Requirements IDReq. Title Subject Priority Requirement Body or Section HeadingImplementation EFW-61 EFW Power ControlEach EFW IDPU shallcontain circuitry to open SPB and AXB doors and deploy sensors Implemented on PCB portion EFW-62 EFW Low Voltage ConversionEach EFW IDPU shallcontain circuitry to provide voltages to IDPU boards using the S/C- provided 28Volts Impemented using PWM converters EFW-63EFW Main Power AllocationEach EFW Suite shall not exceed the total power of W from the EFW Main 28V Service Verified on Flight Unit EFW-64EFW Main Power In-RushEach IDPU shall not exceed ICD values as follows: 10A for 100 usec; 5A for 100us to 1ms 2.5A after 1ms Implemented using soft start EFW-65EFW Main Power Max VoltageEach IDPU shall 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 shallperform as designed from -25 to +55C Parts chosen are -55 to 125C EFW-78 EFW IDPU Survival Temp Range The EFW IDPU shallsurvive without damage from -30 to +60C Parts chosen are -55 to 125C EFW-88EFW IDPU ICD ComplianceThe EFW IDPU shall comply with the requirements and constraints imposed by all relevant instrument-to-spacecraft interface control documents (ICDs). Verified by Instrument CPT EFW-98EFW Illegal Power StatesThe EFW IDPU shall not be damaged by the application of boom power while the Main power is Off. By design, verified by test EFW-99EFW SPB Deployment EnableThe EFW IDPU shall not deploy SPB booms or fire SPB actuators without the SPB and Main power ON. By design, verified by test

RBSP/EFW CDR /30-10/1Berg 218 Requirements EFW-100EFW AXB Deployment EnableThe EFW IDPUshall not deploy AXB booms or fire AXB actuators without the AXB and Main power ON. By design, verified by test EFW-101EFW Boom Pair RedundancyThe EFW IDPUshall have separate supplies for each preamp boom axis. By design EFW-102EFW Safing by subsystemThe EFW IDPUshall continue to provide EMFISIS with E- Field signals on failure of DCB or DFB By design EFW-131 EFW Initial Power On/Reset State The EFW IDPUshall power up in a nominal condition for measuring E-Fields without processor intervention. By design EFW-133 EFW Compliance with EM Environment Control Plan The EFW Suiteshall comply with the requirements and constraints imposed by the RBSP Electromagnetic Environment Control Plan, APL document no By design Verified by Instrument CPT and EMC test EFW-136 Instrument Compliance with Environmental Design and Test Requirements Document Each EFW Instrument shall comply with the requirements and constraints imposed by the RBSP Environmental Design and Test Requirements Document, APL document no By design Verified as per RBSP_EFW_TE_001 EFW-137EFW Quality AssuranceThe EFW Suiteshall comply with the RBSP Performance Assurance Implementation Plan, as modified by the Compliance Matrix By design Verified as per RBSP_EFW_PA_010

RBSP/EFW CDR /30-10/1Berg 219 Specifications Electro-Mechanical Specifications –Connectors 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

RBSP/EFW CDR /30-10/1Berg 220 Design

RBSP/EFW CDR /30-10/1Berg 221 Design Packaging

RBSP/EFW CDR /30-10/1Berg 222 Design

RBSP/EFW CDR /30-10/1Berg 223 Design Design Considerations –Grounds 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

RBSP/EFW CDR /30-10/1Berg 224 SAMPLE PWM REGULATOR Design TO FLOATING SUPPLIES

RBSP/EFW CDR /30-10/1Berg 225 Design MKS INRUSH MITIGATION MSK INRUSH MITIGATION TIMER

RBSP/EFW CDR /30-10/1Berg 226 Design DUAL  FLOATING SUPPLY

RBSP/EFW CDR /30-10/1Berg 227 Design Floating Supply Testing

RBSP/EFW CDR /30-10/1Berg 228 Design Power Control Section 1 MHZ BYTE CLEARS DECODERS WITH POWER ON LATCHES CMD

RBSP/EFW CDR /30-10/1Berg 229 Design POWER SECTION (BACKPLANE) POWER CONTROL SECTION (FRONT PANEL) INPUT (FRONT PANEL)

RBSP/EFW CDR /30-10/1Berg 230 Mass & Power Mass –824 Grams CBE (BOARD WITH FRONT PANEL) –Shielding Mass held by IDPU Chassis –Growth/Uncertainty Margin is 5% Power

RBSP/EFW CDR /30-10/1Berg 231 TEST Sample Tester

RBSP/EFW CDR /30-10/1Berg 232 STATUS WORKING SUPPLY TESTED WITH IDPU TESTED WITH EMFISIS FLOATER EFFICIENCY 80% OVERALL EFFICIENCY IS ~50% VERIFIED 1% REGULATION

RBSP/EFW CDR /30-10/1Berg 233 INRUSH TEST Inrush Profile

RBSP/EFW CDR /30-10/1Berg 234 SCHEDULE TASKCOMPLETION DATE TEST PCB PORTION OF LVPSSEPT 30 NEW ETU LAYOUT RECEIVEDOCT 2 EFFICIENCYOCT 2 BUILD NEW ETUOCT 23 SYNC SEQUENCEOCT 27 LINE REGULATIONOCT 30 LOAD REGULATIONOCT 30 CROSS REGULATIONOCT 30 MSK INRUSH DEFEAT CIRCUITOCT 30 RIPPLE MEASUREMENTSOCT 30 CURRENT TRIP THRESHOLDSNOV 6 MONITOR GAINSNOV 6 CONDUCTED EMISSIONSNOV 6 THERMAL TESTNOV 13 FLIGHT LAYOUTNOV 27 BUILD FIRST FLIGHT UNITDEC 15 TEST FIRST FLIGHT UNITJAN 8

RBSP/EFW CDR /30-10/1Berg 235 PEER REVIEW RFAs TITLEDESCRIPTIONRESPONSE Stress AnalysisEnsure stress analysis done on all boards by CDRParts chosen at design to accommodate stress margins PCB Switch DissipationLook 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 TestCheck 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 EfficiencyMeasure efficiency of all suppliesTotal efficiency of supplies is presently ~ 50% Measure LVPS Cross Regulation Verify that cross regulation of supplies meets 5% goalWill test asap, perhaps on new ETU (post CDR) LVPS Free-run FrequencyVerify 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 capacitorsInclude soft start capacitors in schematicsWill 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).

RBSP/EFW CDR /30-10/1Berg 236 Issues CONSUMPTION Improve efficiency NOISE Reduce amplitude of tone at 200 kHz