Series MOSFETs for HV switching

MarcW

Hello,

We design high voltage, low current DC power supplies for X-ray industry and others.

I would like to take 2 of our units , a +9kVDC supply and a -9kVDC supply, and use MOSFET switching to create a +/-9kV square wave, 400hZ, 5mA.

As I know of no FET that will block the full 18kV differential, I would need several FETs connected in series.

Do you have any reference designs or suggestions for using FETs in series for blocking high voltage?

Thanks, Marc