P-Mosfet for high voltage switching

Hello guys

I am trying to make the Arduino Nano BLE to control power of my motor ESC.
The idea is to only allow motor to be operated when Arduino sees a Bluetooth tag and providing the enable signal.
The supply voltage is 60-82V DC.
The only available option is using P-Channel mosfet (I'd love to go with N-Channel, but in this case we'll have to deal with 300A instead of 30mA of a current due to a common ground)
So here is the circuit I've built.
pchwnpn.jpg


Both NPN and P-Mosfet are ok with the voltage.
Max current for the FET is 2A (waaaay more then needed, load current is only 30ma)
Previously I tried BSS92 Mosfet. It was working for some time but then blew up :frowning:
It should not be caused by the current, so I added a flyback diode (1N4004) in the new version.
And any way replaced the mosfet with more powerful one.
Now it's just does not work.
Maybe there's something wrong with my understanding of the schema or maybe resistor nominals are wrong (I chose 43K resistor to minimize the current flowing through the resistor and NPN to avoid overheating)

pchwnpn.jpg

MTP2P50EG

VGS max is +-20v, you are using 82v ! :o

So am I right that can't just ground it's gate?
And I need to provide it with voltage which is 20V lower than supply voltage?
If yes- I guess voltage devider would do the trick?
With additional resistor between NPN's collector and FET's Gate

You need something to limit VGS to ~10v

A 10-12v zener or a voltage divider to limit VGS is a must !

Would that work?
pchwnpn (4).png
In this case divider results in 73.5 volts on the gate
Which gives 8.5 Vgs

pchwnpn (4).png

(5k x 82v) ÷ 48k ≈ 8v

6.8k would give VGS ≈ -11V


Edit:

An emitter follower would also be an option.

Ok, great
Thanks alot, Larryd
I'll replace the fet, add the resistor and get back with results

Could you please post some simple schematics of emitter follower solution?
And zener would be also useful (i found some examples, but not sure if it's correct in my case)

kaws:
Ok, great
Thanks alot, Larryd
I'll replace the fet, add the resistor and get back with results

Definitely use a zener too. High voltage circuits with MOSFETs are so easy to blow up if you don't have
gate protection.

I went along with this solution


Thanks again to larryd and MarkT for suggesting it
So far so good, everything works, nothing is really heating up.
I assume it's a success :slight_smile:

That looks like the hand of experience.

kaws:
Thanks again to larryd and MarkT for suggesting it
So far so good, everything works, nothing is really heating up.
I assume it's a success :slight_smile:

Glad its working. Neat looking module BTW.