My favorite way of generating a negative rail using more modern components, the inverting sync buck configuration, is especially maddening. The circuit's input, the positive voltage, is the regulator's VCC: so far, so good. The output, the negative voltage, is the regulator's VEE... which sounds fine until you remember these are single supply regulators and so that's their "ground". It's the regulator output that's the mind-bending one: it gets tied to ground! A switching node output, grounded, just does not look right.

It actually makes a lot of sense once you draw it out. The startup is the truly confusing bit, but fortunately it's only unstable for your brain. These guys are actually pretty robust if you can find a part that withstands the full voltage stress (|Vin| + |Vout|), which isn't too hard these days. Highly recommended for a production-quality negative rail generator. Just don't try and do it with a regular buck; synchronous controllers only need apply.

Also works with non-synchronous buck converters, Maxim has an app note here with a schematic: https://www.maximintegrated.com/en/design/technical-document...

Turns out you're right, I was working from app notes which were trying to sell sync bucks. (Not that that's hard to do, sync bucks are awesome.) I do think there are a few pathological startup cases that get easier when the output can sink current, but while those cases are easier to get into with bipolar rails, they still ought to be quite rare.

Just want to say both of these responses are awesome. Sent off a kicad file to OSHPark for a dual +/- 15V supply using the same circuit twice. Will see how it works out :-)

Earth ground, signal ground, digital ground, virtual ground…

Buffered ground.