What IC/circuit am I looking for to switch power?

[agehall]

I want to construct a small board that allows me to pass 12V at 15A to any of 24 pins, one by one all controlled by an MCU. The idea is to stress test custom built ATX PSU cables before I put them into an actual computer and verify they are making good connection using a thermal camera.

This presented an interesting issue that I realized I don’t know how to solve. I want a single connection to my bench PSU that I can then direct to any of the pins in the test connector. At first I was thinking a simple MOSFET on each pin would do it, but when thinking more about it, I don’t see how this would work.

What else, short of relays, can I use to enable the output on just one pin at the time?

[BillyO]

MOSFETs.

Does your MCU have 24 pins available?

If not you can use three 74LS595.  That way you can use 1 pin on the MCU to dive all 24 MOSFETs.

[Ian.M]

Why would you even want to do that?  Build a jig to zig-zag the circuit through the cable under test so you can apply your high test current to all the wires and contacts simultaneously in series.  Include test points at each end of each wire so you can check the voltage drop, moving the red and black probes on to the next one alternately to match the zig-zag connections.  *IF* you want to include a MCU and automate the test, you could use analog switches to connect the test points to a differential OPAMP buffer feeding the MCU's ADC, to automate the voltage drop testing without a DMM.  You'll probably also want some means of controlling the current through the test jig, and the best option here would be to feed it from a synchronous buck regulator controller with enable pin (so you can shut it off) driving >30A MOSFETs, with its feedback biassed with filtered PWM from the MCU to control its output voltage.  Include a heatsinked low ohm power resistor in the series circuit both as a load for stability and to develop a voltage across it for the ADC to read the current.