Roman Black wrote...

[snip]

>Please argue, I appreciate anyone who has made SMPS's for
>25 years, as I know that you learned X things in those
>years and I learned Y things in those years and it sure
>beats arguing the football scores... :o)

Roman, this circuit is like one of those "Roach Motel" thingies:
energy can check into that inductor, but it can't check out.  Under no
circumstances does ANY of the energy stored in the inductor EVER find
its way to the output circuit.  Nary so much as a picojoule.

Going back over my previous post, I don't see how I could clarify my
explanation any; it seems pretty straightforward.

As a thought experiment you could try the following: assume the
inductor and the diode across it are both perfect, so that when Q1 is
off, the inductor current doesn't decay at all.  In other words,
whatever current was flowing through the inductor at the end of the
last pulse, is still flowing through it at the beginning of the next.
And each pulse will increment that current by V * dT / L, where V is
the voltage across the inductor and dT is the duration of Q1's ON
time.  Thus each pulse delivers a bigger and bigger shot of current
into the output capacitor than the one before, which recharges the
output capacitor back to the threshold level faster and faster, and
the pulses get steadily more brief- and intense- as time goes by.

Ask yourself, what is there to limit this pernicious process?

No, don't tell me.  Rather than perpetuate this debate and getting all
vehement about it or anything, why not let's agree wholeheartedly with
one another (heft a pint with me, here) that regardless of what either
of us says, the circuit itself will be the final judge.

You've proposed it, now it's time to build and test it.  I look
forward to seeing your results.

Dave

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