On 20 Jul 2011 at 22:31, Tony Duell wrote:
Actually, in my experience, a crowbar circuit is often
used on a PSU
with electronic overcurrent protection, and said protectiuon should
operate if the crowbar fires due to an overvotlage. However, there's a
second line of overcurrent protection (e.g. a fuse) that will operate
if the electronic protection doesn;t (e.g. becasue the PSU control
circuitry is totally malfunctioning).
I've got a couple of linear supplies that use just that design--an
SCR crowbar driven by a comparator following a LM723 regulator stage--
the 723 has overcurrent protection, so it all hangs together.
(and there is a fuse on the primary of the transformer as well)
--Chuck