Hello,
I am trying to design a test system for HTRB of power semiconductors. The system will have a High Voltage Power Supply (f.i. 2kV) which will be connected in series to several Power Semiconductors (Devices Under Test) in parallel whose leakage needs to be measured. Each one of the Power Semiconductors will have a protection switch in series (3.3kV SiC MOSFET) and a measurement circuit (logarithmic amplifier measuring the range of 1nA to 10mA). I need a protection circuit to assure that in case of breakdown of the Devices Under Test, the measurement circuitry (AD8304 + ADC, etc...) does not see the 2kV or >10mA. A series current limiting resistor at the output of the HVPS will not do the job as the DUTs need to see the 2kV @10mA in worst case. I am not sure if I can solely rely on the protection switches as I think I will need at least 10us to switch them open.
Do you have any idea on how to limit the current in case of failure to 10mA and assure the AD8304 does not see the 2kV?
Thanks,
Javier