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Thread: Info on PWM PSUs and PID with PICs?
www.piclist.com/techref/microchip/ios.htm?key=PID
face picon face BY : email (remove spam text)(Olin Lathrop)



Philip Pemberton wrote:
> Specs are (at the moment):
>   Vin: 12V
>   Vout: 6V

So why the objection to a Schottky diode?  This sounds like an ideal
application for Schottky.  At these voltages the lower diode drop will make
a noticeable difference in efficiency.  Most of your power loss is probably
in the diode.

>   Topology: Buck (step-down)
>   L: 47uH (actually measured at 43uH)
>   F: 32kHz
>   Filter cap: 47uF jellybean electrolytic (also tried a 1000uF
>     low-ESR).

This cap is probably way inadequate.  Often the limiting factor is not the
bulk capacitance or ESR, but the maximum rippple current the cap can handle.

> Transient response is pretty
> dire though.

As expected if you are still sticking to your PID or linear control scheme.


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