Hi Harry,

"Harry Dellamano" wrote in message
...
I see your gate output bottoming at -.85V so the substrate is forward biased
and changing your clock period. Get a Schotkey diode and clamp to ground at
the gate output. May help.

Aha! Thanks, Harry, that's definitely improved the situation a lot.
Open-loop, I can still get it to misbehave at the extremes of the error
voltage, but it doesn't go through "working - not working - working - not
working..." as the error voltage increases like it did without the diode.
This makes the entire thing work except for a few corner cases, right as
you're pushing 80% duty cycle (where it still "stutters"). Even open-loop the
duty cycle gets very jittery and non-linear with respect to error voltage
right around 65% duty cycle, so tomorrow I'll go ahead and wind another
transformer based on a 60% maximum D.C. as you suggested -- the LT1950 seems
to be trying to tell me it would prefer that, no?

---Joel