Re: 200V at 10mA

On 22/08/2024 2:39 am, Edward Rawde wrote:

Is there an off the shelf part I can use for the transformer in this?
 It's based on a design someone else posted in this group a long time ago (maybe 10 years ago by now).
I can't remember the name of that individual.

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There's a more elegant solution to that problem that was discussed here a few yeas ago.
sci-hub.do/10.1109/tpel.2007.909192
Abramovitz, A., & Smedley, K. (2007). A Resonant DC–DC Transformer With Zero Current Ripple. IEEE Transactions on Power Electronics, 22(6), 2344–2351. doi:10.1109/tpel.2007.909192
It's essentially the Baxandall class-D oscillator with two extra windings on the feed inductor. The paper talks about integrating all the windings on single - carefully gapped - I-E core, but using two cores gives you an easily designed way of getting to the same advantage.
At the time I posted an LTSpice simulation that made the point. The output wasn't entirely ripple-free, in that there were switching transients which would have had to have been filtered out, but that needed a much smaller R,L and C values than you'd have need to get rid of the switching frequency components.
It won't be attractive if you have a pathological fear of transformers or an aversion to winding them yourself a or finding a nearby transformer winding shop to wind a few of them for you.
For volume production you'd use printed windings, but thye need a specialist supplier too.
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Bill Sloman, Sydney