You don't need to use digital feedback at "digitally controlled power
supplies".
The processor sets the voltage digitally to the DAC and that information
is used equivalent to the potentiometer in a regular analog feedback
system. The op-amp compares the DAC output to the analog power output
and correct it as necessary using analog feedback. The ADC side is used
exactly as you are using, just to display and check periodically the
accuracy of the system, when some auto-recalibration can happens.
Wagner

> I haven't seen any designs for digitally controlled supplies. Are you
> taking about using an A/D converter and D/A converter to comprise the
> feedback loop,or simply using a digital pot to adjust the analog feedback?
> If you mean the former, I wonder how good the transient response would be?
>
> I hope to put the schematic and photos of it on my web page soon, but I am
> currently very busy with several simultaneous projects.
>
> Sean
>
> At 12:22 AM 6/30/99 -0300, you wrote:
> >        Does anyones have a good idea on how to make a digital controled
> power supply (a good one), I've already see the example on National's LM317
> datasheet, but I'm looking for something better.
> >        Thanks all for your answers.
> >
> >        Mauricio Jancic
> >        VARIMAK S.A.
> >
> |
> | Sean Breheny
> | Amateur Radio Callsign: KA3YXM
> | Electrical Engineering Student
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