Re: 200V at 10mA

"Bill Sloman" <bill.sloman@ieee.org> wrote in message news:vae8ql$1o845$1@dont-email.me...

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?
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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.
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sci-hub.do/10.1109/tpel.2007.909192
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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
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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.
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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.
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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.
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For volume production you'd use printed windings, but thye need a specialist supplier too.

Thanks I'll have a look.
I haven't done much for the past two days due to a touch of Covid.

I have no fear of transformers or winding them myself but I'd have to admit that some of the work I could do 40 years ago might be
best avoided now.

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--
Bill Sloman, Sydney