Gee, I'm kind of disappointed. Doesn't really drive the transformer all that well (as Legg mentioned), no way to adjust voltage, and still a thousand transistors (well, maybe a hundred in an average op-amp / comparator / driver, and you can't see them, but still).
I already solved this problem for cheaper than the bricks and with higher efficiency. Finding the magnetics is the hardest part, but I've found some very cheap and common parts that will easily deliver a few watts with moderate (open loop) regulation, with minimal capacitance, and they hi-pot at a whopping 14kV, not bad for a teeny PC mount transformer rated for
2.5kV peak. I'd provide my circuit, but it counts as proprietary information by now.
The only downside is the limited ratios. Want 12V output from a 5V circuit? Too bad, you need a boost to get the primary voltage up to ~13V. On the upside, at least you can put the boost (or buck or whatever you end up using) inside the feedback loop (if you regulate the whole thing).
Tim
--
Deep Friar: a very philosophical monk.
Website: http://webpages.charter.net/dawill/tmoranwms
"John Larkin" wrote in
message news:dk24b7hs2qoimekeurpq3v0s0mnnoaode1@4ax.com...
> This
>
> http://www.panoramio.com/photo/61564837
>
> might work for powering a thing I'm doing. I can use a standard cheap
> Coiltronix dual-coil inductor as the transformer. The complementary
> emitter followers will have no shoot-through and can have controllably
> slow switching edges, since they will just follow the base drive.
>
> Anybody got ideas for the base driver device? Ideally it would be
> self-oscillating, set with some R-C; have a moderate slew rate; swing
> to the rails. I'm thinking roughly 150 KHz maybe, a few watts output.
>
> Maybe an LM8261 opamp? I'd have to see if it winds up when it rails.
> It might not.
>
> Some sort of fet gate driver would be OK, but few go to 24 volts.
>
> Something discrete maybe, like a 2N7002 to 24-, and maybe a
> bootstrapped pullup?
>
>
> John
>
>
>
>