Current limit for HV Power Supply

[Ioannis]

Will do that and report back.

The final circuit will be pretty much as the above posted, though it needs a lot of refinement before it gets on a shiny pcb. Mainly for safety of the circuit and users.

Thanks,
Ioannis

[amgen]

alternate place for I limit circuit.....

[Ioannis]

I have such an option for the PWM and the PIC to stop operating in case of a SC.

But this takes time and the Pass transistor will be burned in the mean time. That is why I have to place the PNP transistor too on +V line too.

I found that the NPN indeed does have the B-C junction working as a diode blocking the Mosfet.

Also that the PNP transistor was defect...!

Soon will test for the PNP to see how it goes. On another test circuit it was promising as expected.

Ioannis

[pedja089]

That solution sound very familiar to me
I have done same thing on 42V Communication PSU. I used ADC in interrupt in background to monitor V and I, it was fast enough to not cause damage. Anyway I added hardware current limit, and it works for years without problem.