Dave Dilatush wrote:

> >It would be nice to be
> >able to use one of those tiny 2.5mH inductors, the
> >resistor sized green ones that are available for
> >20c each etc.
>
> They should work OK, provided they don't have too high a series
> resistance (I'll check this out, too) and they don't saturate at the
> currents involved.

If you found 2kHz with the other circuit,
it should be possible to decrease the inductor
down to 0.1mH or maybe much less than that,
with the tiny RF inductors the wire size is
larger with the lesser values, and increasing
the speed should help with saturation issues.

A lot of PIC projects only need a few mA, and
a nice alternative to a 7805 regulator chip
or resistor/zener would be great for 9v battery
operated PIC gizmos.


> >9v to 5v, 0 to 10mA
> >9v to 5v, 0 to 25mA
> >12v to 5v, 0 to 10mA
> >12v to 5v, 0 to 30mA.
>
> I can give us a starting point on that; I might get at it this evening
> after I get home from work.

I'm excited to see what you come up with.
It's also pretty interesting that no piclister
seems to have done this before?? We're always
seeing posts about sleep mode and battery
operated PIC stuff, and these SMPS circuits
should be nicely compatible with sleeping
PICs, giving the best of both worlds.

> One thing people should keep in mind about ALL of the switching
> regulators we've talked about in this thread: they're going to have
> output voltage tolerances which are pretty wide. These are NOT
> precision devices.

Ha ha! Neither are batteries! ;o)
-Roman

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads