Re: dumper circuit

I'll have an isolated class-D amplifier powered by a dc/dc converter
from my big 48 volt supply. Simple push-pull, transformer, rectifier,
making maybe isolated 46.
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In one situation, the class-D amp can push current uphill into the
isolated supply, and we need to dump it. This circuit acts sort of
like a 25-watt zener diode.
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https://www.dropbox.com/scl/fi/98n07mnf3qokvbewuv1oy/Dumper_1.jpg?rlkey=poiep8hzhz33qecswdj50sdne&raw=1
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It didn't work in simulation. It was driving me to despair. No amount
of chocolate would help.
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The problem was of course that the Spice initial condition simulation
perfectly biased everything, balanced the pencil on its point.
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So how can the initial conditions sim ignore the positive feedback?