Hi guys

I want to add a 50V over voltage protection in my constant current load, my current design is a 50W constant current load with 5A max capability.

what would be a good low cost design? thanks

 

Use an op amp comparator and pot it down to to say 10 volts using a resistor divider, then feed the output to Mosfet switch, or use a thyristor and zener as a crowbar.

Can you post your circuit for better advice.