An experiment from nearly four years ago. Surprised I kept it. Steps down 16-42V down to 12V at a rather abysmal efficiency.
Wanted to power a 12V COB LED using a 10S lithium-ion battery.
Uses the 555 to generate ON pulses that are transmitted through a discrete MOSFET driver stage.
No-name electrolytic output caps means no loop compensation is needed.

I have no clue what inductance value the inductor is; it was ripped out from the output stage of an audio amplifier from 2008.

Power MOSFETs are ones from 2012 and have pretty bad dynamic and static characteristics. It's a complementary P-Channel N-Channel stage.

I tried driving the MOSFETs synchronously and they got really hot because there is no DCM on this circuit, so there were massive recirculation currents.

So the N-channel MOSFET is basically just used for its body diode. The original diodes were some 1N4007s, which switch abysmally slow and as such get hot.