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AUX_PSU is an extension module (EEM) that provides 3 adjustable DC voltage rails.
Design files (schematics, PCB layouts, BOMs) can be found at AUX_PSU/Releases.
Pasted from the RFC. See the issues for further discussion.
Lab setups rapidly acquire an armada of bench PSUs supplying the same old low voltage DC rails for misc homebrew electronics boxes. Generally these PSUs are bulky, expensive, have much higher current spec than required, and sometimes have knobs on the front that get accidentally knocked with bad consequences.
AUX_PSU is a simple 3U, 4HP card capable of producing common low-current DC voltage rail combinations.
12V - via front panel barrel, rear Molex, and EEM
Voltage rail 1 - selectable between 3.3, 5, 6, 9, 12, 15, 18 and adjustable - 600mA
Voltage rail 2 - selectable between 1.8, 2.5, 3.3, 4, 5, 6, 9, 12 - 800mA
Voltage rail 3 - selectable between -3.3, -5, -6, -9, -12, -15, -18 and adjustable - 600mA
Eight position rotary switches to select voltage on each rail independently.
Rails generated using SMPS followed by LDO.
Specs in line with typical decent bench PSU. Example spec taken from Keysight E3630A as a guide:
Load and line regulation: < 0.01% + 2 mV Ripple and Noise (20 Hz to 20 MHz): < 350 μVrms, < 1.5 mVpp Temperature coefficient per C: < 0.02% + 1 mV Output Drift: Less than 0.1% + 5 mV Transient response time: < 50 μsec following a change in output current from full load to half load for output to recover within 15 mV
Overcurrent indicated by LED. Rail would continue to operate (with no promises on spec) until the thermal limit exceeded. At which point thermal protection LED would come on and the board would shut down.
M8-4 - A compact 4-pin connector - could fit 3 on panel.
Convenient pigtails are available for ~$10. Shielded versions also available for $20.
Overcurrent LED for each rail Thermal protection LED
