Whateverr you
do, don't disable the overcurrent trip circuit. Doing tha=
t
is a sure way to gets bits of (expensive) chopper
transistor distribute=
d
round the room and the magic smoke escaping from
all sorts of component=
s.
Please don't ask how I found that out (OK, I
was young and foolish!).
I was involved with designing a 4 quadrant switcher supply once. Before
I located the input to an OpAmp being inverted, I popped a number of
transistors. I suspect that I could have done the debugging in a safer
way but it was hard to convince my self that there was a design error tha=
t
I'd made my self. Sometimes one just has to burn ones fingers a little
to except reality.
Of course. I was once told 'The designer who never blew a chip up is a
bad designer. He never designed anything'
And while I'll go along with that, it's clearly sensible not to damage
components unecessarily. Hence my comment. Disabling the overcurrent
trip will not do any good at all, and may do a lot of damage.
For the record, the time I did it was in a DEC H754 -15V regulator brick
(which is, of course, a switcher). I had it on dummy load, so I knew it
wasn't really being asked to supply too much current, but there was no
output. I lifted the collector lead of the current sense transistor and
switched on. BAD MISTAKE!. The crowbar was firing (incorrectly, the
zenner diode had failed), so there genuinely was an overcurrent
situation. The result was that 4 of 5 transistors fialed (some were blown
aapart), the current sense resisitor burnt out (I think it actually
glowed) and the fuse blew.
-tony