Hello Jim,
Yes, and that is a fairly little understood subject among engineers. A
saturated core behaves almost as if it wasn't there.
Most of the switchers I designed have a current mode loop which will
prevent such catastrophes. But I have seen designs without it that were
uncomfortably close to CCM. From there to kablouie it can be as little
as a few milliseconds. The resulting fireworks are usually quite impressive.
Regards, Joerg
"kablouie" reminds of another fun event in my life...
One of the first off-line switchers I was designing (for
OmniComp/GenRad, ~1978) was of great interest to marketing, because it
would significantly decrease the weight of their portable tester
concept, called the PSP (Portable Service Processor).
So all these marketing clowns come trooping into my laboratory when
they got wind that I was testing it.
So they crowd around my workbench.
I warn them that it's not been powered up before and they should stand
back.
They ignore me.
I plug it in.
KABLOUIE!
Flame blew out of the (ferrite) transformer, then it burned back along
the line cord, back toward the receptacle, in a way reminiscent of the
way you see bomb fuses burn, before the breaker finally let go.
After the marketing types regained their skin color, they accused me
of setting the whole thing up to scare them ;-)
...Jim Thompson