DC-DC conversion w/ isolation

AlbertHall said:

If you haven't done this sort of thing before then don't. The transformer is the most tricky part. It would need to be a custom component.

Click to expand...

Why's that exactly? - I've re-purposed easy to obtain transformers on a number of occasions.

Like the pocket xenon disco strobe built around an Amiga SMPSU transformer.

These days; various scrap set top boxes can be picked up for next to nothing - anything with mains in, will have an SMPSU inside. The chopper transformer can be put back to front in a blocking oscillator style inverter. Typically; about 300V is dead easy, but you can regulate lower.

My strobe ran from a 4.8V Ni-Cd pack and used the highest available transformer ratio, but there's usually a 12V secondary if you need to take it down a notch.

These days; most have a chip - more often than not, the chip has UVLO, so it will probably be easier to go discrete bipolar for the chopper. Most chips run from locally derived Vcc, the winding that supplies that can usually be pressed into service as the BO feedback winding.

Its very instructive to strip/study/trace an old discrete bipolar blocking oscillator style SMPSU.