Ask Hackaday: Split Rail Op Amp Power Supply

Water cooler talk at the office usually centers around movies, sports, or life events. Not at Hackaday. We have the oddest conversations and, this week, we are asking for your help. It is no secret that we have a special badge each year for Supercon. Have you ever wondered where those badges come from? Sometimes we do too. We can’t tell you what the badge is going to be for Supercon 2023, but here’s a chance for you to contribute to its design.

What I can tell you is that at least part of the badge is analog. Part, too, is digital. So we were discussing a seemingly simple question: How do we best generate a bipolar power source for the op amps on a badge? Like all design requests, this one is unreasonable. We want:

  • Ideally, we’d like a circuit to give us +/- 9 V to +/- 12 V at moderately low current, say in the tens of milliamps. Actual values TBD.
  • Low noise: analog circuitry, remember?
  • Lightweight: it is going on a badge
  • Battery operated: the badge thing again
  • Cheap: we only have a couple bucks in the budget for power
  • Available in quantity: we’ll need ~600 of these

Many of us immediately went with the “two 9V battery solution.” That’s certainly cheap and easy, but it seems heavy and fiddly for a badge. A DC-to-DC converter is probably the right way to go, but those may not be cheap or have low noise — we haven’t started down this path yet. We could do a single-sided boost and create a mid-rail virtual ground?

The Ask

We want to know your favorite trick for this! Nothing is too crazy to be out of bounds, and we know you can’t get your entire wish list, but we’d like to get as much of it as possible. We will also entertain the expensive, heavy, and noisy solutions just because we could use a good laugh. So if you were thinking of suggesting a dynamotor, go right ahead. (And take pictures!)

As long as you’re doing bipolar power design, you might as well enter it in the op amp contest, which is running right now. If you need some simulation practice with op amps, we can help there, too.



Ask Hackaday: Split Rail Op Amp Power Supply
Source: Manila Flash Report

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