circuit for switching high current mosphet?

hi im looking for a simple circuit for switching a high current mosphet there are just so many out there,
can someone please reccomend me one thanks want to use it as a switch to turn on off a motor

this is the mosphet i have, here


Just as important.
What are you switching?
Can you connect the gnd of the controller to the gnd of the circuit you are switching or do they need to be isolated from each other?
What model Arduino are you going to use?

Thanks.. Tom.. :slight_smile:

hi tom
im just going to use a simple push switch, i want to switch high side 42v, and its a dc motor to 80 amps
i know hot to switch a low voltage mosphet but a high current one i dont

i want to switch high side 42v

With an N-channel MOSFET? Why?

or low side? dont want to use a contactor or relay as it needs to be in a smsll space

Do use it as a low side switch, and provide excellent heat sinking for the MOSFET.


Use a MOSFET gate driver chip to drive a MOSFET gate, the clue is in the name. There are 1000's available.

The MIC4422 is a low side driver available in DIP and SMT, capable of several amps if you need it. Use 10µF ceramic decoupling on the driver, which needs to be powered from 6 to 12V given the specs of that MOSFET.

If you want to switch high-side you'll need a more specialized gate driver with a charge-pump.

60V MOSFET with 42V load is a bit close to the edge.

Remember switching an inductive load requires a free-wheel diode with a pulse current rating for the full load current.

Bit worried by choice of a surface mount MOSFET - you'll need an aluminium cored PCB to heatsink that.
Screw terminal package might be more appropriate (ISO-TOP for instance).

thanks very much

Use 10µF ceramic decoupling on the driver,

That's some really serious decoupling :slight_smile: But unless OP wants to use PWM on this motor, is a gate driver really needed? Or is it mostly to be able to use 12V easily for the gate?

For packing agreed SMD doesn't sound appropriate for this kind of loads, too hard to get the heat out of. The MOSFET linked to lists 1.4mΩ on resistance, which is really good, but at 80A it still dissipates almost 9W. I'm sure it can be done or the parts wouldn't be made, a larger THT package that can be screwed onto a big heat sink makes a lot more sense. I know you want to place it in a small space but somehow you have to deal with the heat.

Also curious as to what kind of flyback diode such a motor would require!

A PCB technology that is good at moving heat is needed, and/or lots of moving cool air.

The rule of thumb for a diode is that it should have at least the voltage rating and current rating of whatever is being supplied to the motor when the motor is being driven.