Remember any intermediary steps will have their own power losses, and efficiency percentages cascade. Two 90% stages in series still results in a 19% power loss, and if you 20V into 5V you still have the problem of trying to get reasonable efficiency out of an 8% duty cycle switcher. I'd be more likely to take 20V down directly with a half-bridge forward converter and custom wound transformer especially if it was a one-off. That's how a lot of your good active-PFC supplies handle bucking 350+VDC down to 12VDC at a hundred or more amps.
Good advice, I just hate hand winding transformers/inductors. But yeah, losses in stages multiply versus being additive.
The eleven projects can largely be subdivided into a few project families with a decent amount of overlap. Eventually I'll be fully excised from the assembly line and can focus more on R&D. That's the dream anyway.
My ardent hope is for your emancipation from the tedium of manufacturing (which pays the bills).
You hinted in a previous post about a new miner project that doesn't rely on BM hash chips. Per chance w/ a chip that's not made in the Pacific Rim? This is something I'd be VERY interested in. And in whatever impotent capacity willing to contribute to.
In the interim if you're not gonna' do a second run of the F I'd be interested in buying some of your leftover PCB's hanging around. Not for resale just for my personal consumption.
As always, a pleasure.
Pup