KT4FY says:
>My impression from the original post was that this would be an open
loop
>switching supply. A typical low loss forward converter would give
>reasonable (5 to 10 %) performance without the grief of closing the loop.
Maybe I'm wrong, but if it isn't running closed loop, I figure it looks like
a linear PSU from the point of view of output impedance at 'high' (> a few
Hz) frequencies. It will then need lots of capacitance across the output
(just as a linear supply does) to keep the regulation reasonable under
syllabic conditions. It would be a bit better than a 50 or 60 Hz supply
because of the higher frequency giving charge to the reservoir capacitor
more often, but I figure would still need a fair amount of output capacity.
If it's closed loop with a loop bandwidth of say 5kHz, then you could get
away with minimal capacity on the output - you'd basically just need enough
to give a pole in the response adequate to keep the switching frequency
ripple down. A simulation of output impedance against frequency would be
useful.
What, RZP advocating simulation!!! Whatever next - he'll be using a
calculator!
73
Peter G3RZP
> ----------
> From: Steve Iezzi[SMTP:siezzi@aeronix.com]
> Sent: 01 February 1999 18:26
> To: amps@contesting.com
> Subject: RE: [AMPS] HV Switching Supply
>
>
> >
> > I presume (possibly incorrectly) that it isn't going to have lots of
> capacity in the
> > >output like a linear supply. If so, then the feedback loop bandwidth
> needs to
> > >extend to several kHz if problems are to be avoided.
> > >
> > >73
> > >Peter G3RZP
> > >
>
> My impression from the original post was that this would be an open loop
> switching supply. A typical low loss forward converter would give
> reasonable (5 to 10 %) performance without the grief of closing the loop.
>
> Steve KT4FY
>
>
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