Olin Lathrop wrote...

>Since everyone is throwing their circuits out there, I've decided to =
give in
>and throw out mine too.  This circuit is a piece of a personal project I=
 am
>currently working on and it was designed before this thread started.
>However, it hasn't been built yet, which is why I didn't want to let it =
out
>earlier.

[snip]

I think the feedback sense is reversed from what it should be: as is,
this circuit will latch up with Q1 either on or off, and stay there.

By deleting R2, connecting +5VREF to the (-) opamp input, and
connecting the junction of R5 and R6 to the (+) opamp input and R4,
the regulator works fine (at least in SPICE).  With 20V in and 10V out
at one amp, efficiency looks to be about 80%.  Output ripple should be
about 850 mVp-p at this load, with an oscillation frequency of 6
kilohertz.  With input voltage reduced to 13 volts, efficiency goes up
to nearly 90%.

Dave

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