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Subject: Re: Problems with MOSFET drivers
Date: Mon, 18 Nov 2002 01:08:05 -0000
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"Mike Poulton" wrote in message
> On 16 Nov 2002, "markp" said:
> > Have you seen this?
> > http://www.richieburnett.co.uk/sstate.html
> Yes. His power switching circuit looks nice, but he doesn't actually
> have the schematic for it up there. The schematic on the site does not
> correspond to the circuit he is using in the final version. He doesn't
> have any sort of active tuning, either. There is some degree of
> frequency adjustment based on the input voltage, but that is open-loop.
> I'd really like to provide some type of closed-loop frequency control.
You could use a microcontroller to form a closed loop. Get it resonating at
roughly the right frequency by stimulating from the CPU using one of its
high speed timers. Use a comparitor to create a digital zero-crossing
detector on the feedback winding, and detect the phase difference between
that and what you're driving it with (all you need is a too slow or too fast
comparison). Fine adjust the output frequency, and repeat. Bingo! This does
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