IDPU Power Control Board PCB Craig Domeny University

IDPU Power Control Board (PCB) Craig Domeny University of California - Berkeley THEMIS IDPU CDR PCB-1 UCB, April 20, 2004

Power Control Board § § § § Overview / Documentation Block Diagram Power Sources Service / Load Classes Circuit Design Actel Power / Thermal Analysis Test THEMIS IDPU CDR PCB-2 UCB, April 20, 2004

Overview / Documentation Electrical Specification • Captured in THM_PCB_001 revision F • Details Power Switching, Housekeeping, and Commanding Requirements • Provides connector specifications and pin-outs Electro-Mechanical • Connectors – – • One VME standard connector 3 x 32 (96 pin) M 55302 (Class 1) Two 15 -pin Sub-D high density connectors on front panel Two 26 -pin Sub-D high density connectors on front panel One 44 -pin Sub-D high density connector on front panel Board – – THEMIS IDPU CDR Board-to-board Spacing is 0. 585” PCB shares board with FGE PCB-3 UCB, April 20, 2004

PCB THEMIS IDPU CDR FGE PCB-4 UCB, April 20, 2004

Functional Block Diagram THEMIS IDPU CDR PCB-5 UCB, April 20, 2004

Power Sources (2): Spacecraft Power Bus (28 V nominal) SPB Motors Axial, SCM, FGM Boom Frangibolts SPB Doors (Nitinol wire) LVPS (Backplane) IDPU Circuits ESA Covers (Nanomuscle) SST Attenuators (Nanomuscle) THEMIS IDPU CDR PCB-6 UCB, April 20, 2004

Service / Load Classes: SPB Motors Nominal; 100 m. A@28 V (Inrush 1 Amp) Axial, SCM, FGM Frangibolts Single; 1. 1 Amp (40 seconds) Redundant; 2. 2 Amps (40 seconds) Instruments Command-enabled (Actel) Current limited +2. 5 VD, +5 VA, -8 VA, +10 VA, -10 VA, +28 VA (+8 VA derived from +10 VA) ON/OFF control to the output service rails (Actel) THEMIS IDPU CDR PCB-7 UCB, April 20, 2004

Service / Load Classes: ESA Covers, SST Attenuators Nanomuscle; 600 m. A, 100 miliseconds SPB Doors 2 Amps, 1 second THEMIS IDPU CDR PCB-8 UCB, April 20, 2004

Circuit Design IDPU Current Limiter / Monitor THEMIS IDPU CDR PCB-9 UCB, April 20, 2004

Circuit Design +10 VA to +8 VA Regulator THEMIS IDPU CDR PCB-10 UCB, April 20, 2004

Actel FPGA • Processes commands from the backplane • Enables/forces IDPU input service sources • Switches IDPU service outputs • Processes analog housekeeping muxes • Forwards SPB turns-counter switches to mux THEMIS IDPU CDR PCB-11 UCB, April 20, 2004

Power / Thermal Analysis Worst-case Offenders (Ambient specified at 55 deg. C) SCM Frangibolts (2. 2 Amps^2) * 0. 35 Ohms = 1. 7 W SPB Doors (2. 0 Amps^2) * 0. 35 Ohms = 1. 4 W Both use IRF 9130… 25 W @ Tc = 25 deg. C Junction rated -55 to 150 deg. C θjc = 5 deg. C/watt PDmax = 150 deg - 55 deg / 5 deg per watt IRF 9130… Pdmax = 19 watts THEMIS IDPU CDR PCB-12 UCB, April 20, 2004

Test Load Board • Plugs into backplane; uses free-wires to front panel connectors • Relies on PCB Actel-based CDI command functionality • Simulates all service-rail output loads • Operator-switched overcurrent tests current limiter • CDI-command forces overcurrent, defeats limiter • Simulates inrush currents and closed-loop actuator functions • Simulates SPB turns-counting switches THEMIS IDPU CDR PCB-13 UCB, April 20, 2004