OK I have a low current <10ma drain LTC6090 opamp circuit with a max working voltage of 140V DC.

It's supplied by a battery that varies from 96V upto 150V under heavy charging.

I want to design a simple voltage regulator that will limit any voltages over 130V to 130V for my opamp circuit.

I looked at simple 130V zener types but they seem to waste a lot of power when it starts to conduct and require a fairly big wattage resistor in front of the load which causes a voltage drop.

I don't want a crowbar circuit to short it out just something to limit the voltage to 130V..

I have 400V P Channel Mosfets available along with 130V zener diodes etc.

Thoughts

 

Why not just insert a zener in series with supply to OpAmp
circuit ?

Supply >> Zener >> OpAmp Circuit

No passive R to throw away power, just power consumed by Zener and current thru it.


Regards, Dana.