Quote:
Originally Posted by Diabolical Artificer
... I'm also wondering if there's a better protection circuit, I've used this circuit quite a few times and the mosfet's dies pretty easily if there's too much current draw ...
|
I think protection can be hard to implement simply, particularly if you want to protect against very sudden over-current, as in a flash-over inside a downstream valve. You have to worry about charge stored in capacitances which can hold the gate voltage at a high level while either the drain or source goes out of range.
I have a rule of thumb concerning audio amps/pre-amps which turn up here for repair. If there is a MOSFET HV regulator in them and if the kit actually has any fault at all then the fault will include a blown MOSFET HV regulator. So far the rule has proved very reliable indeed. Much, much more reliable than solid-state devices trying to deal with badly-behaved thermionic ones.
EDIT: You could look up 'Maida Regulator' as an introduction to the world of solid-state HV regulation.
Cheers,
GJ