Electronic – How to use N-channel MOSFET as high side switch (non-buck switching)

drivermosfetswitches

I have an application with some constraints for which it feels difficult to find a solution.

  1. load current more than 10A, so N channel MOSFET is preferred;

  2. working voltage is a bit high, between 50-80V;

  3. logic switch control signal, no driving capability while expecting very fast response;

  4. due to some reason, high side switching is required. That is, the MOSFET will be between power source and load. The load is non-inductive like one in buck converter.

I have searched the web for high-side MOSFET driver, but all are with buck type of application, coming with external capacitor connected to source of MOSFET to get ground rail to be charged. Which I don't think it works in my application where no ground rail exists after switch-on.

I found few drivers with charge pump built-in, but below 36V.

I know a workaround that uses a battery and connects the negative of the battery to source of MOSFET, but this is not a solution as I have no way to charge the battery and so it has to be replaced regularly.

Best Answer

If the application permits, you can use an isolated power supply (12V or 15V) to create the gate driver voltage, then use an optocoupler to turn MOSFET ON or off.

You could use a photovoltaic MOSFET driver (usually used for SSR) For example the VOM1271: VOM1271

Use a automotive high side switch (it contains MOSFET and driver protection features and diagnosis), search Infineon and ST, but honestly it might be difficult to find one that works at 80V Another example: smart high side switches

Related Topic