#tps65131

We designed this split +12/-12 power supply board based on the TPS65131 (https://www.digikey.com/en/products/detail/texas-instruments/TPS65131RGER/1672464) a few months ago, but it languished while we worked on some other projects. We had an issue where the negative power rail was unstable. Thankfully, we found a thread that suggested slowing down the VNEG feedback loop (https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/628380/tps65131-q1-abnormal-operation-of-tps65131-q1-s-vneg) with a 51k resistor. We hand-soldered that in, and it worked nicely. Then, the other fix was to flip around the trimmers so the turn direction matched the expected behavior. This should be good to book a second prototype, and then it can go into the shop.

- we need -12V to bias the Apple Disk ][ drive control system. It's a combo buck and boost: give it 3~5VDC and give you up to -15V and +15V output. The split supply part is particularly nice because you'll want +-12V or +-15V for analog projects. This standalone power supply breakout has two mini trim pots to help adjust the output voltages on both sides so you can have as little as +/-6V and up to +/-15V. With the 2A internal switches, you'll get a fair amount of current on either rail.