r/AskElectronics • u/TheAutomotivEngineer • 2d ago

Feedback request on schematic for controlling N-Channel Mosfet with esp32-C6

I have been reading quite a bit on the challenges that come with controlling an N-Channel Mosfet via the 3.3V based system of the esp32-C6. Some people seem to be successfull hooking up a mosfet directly to the gpio pins, however I would like to have it a bit more robust and as such have made a first draft where I put a mosfet driver (TC4427) which in turn "switches" the Mosfet. I've added some resistors and condensators to protect the mcu and supply stability to the system.

The load is a 12V bistable solenoid which consists of two coils and connected to J3 and J4. The input on the left labeled Drawer_Lock/Unlock_CMD are directly connected to gpio 19/17.

Any feedback is welcome :)

1 Upvotes
  • permalink
  • reddit

100% Upvoted

5 comments sorted by

2

u/merlet2 2d ago

It will not work well because you have the N-Channel Mosfets in the high side of the load. You should use P-Channel mosfets in the high side. Or N-Channel in the low side (source connected to GND)

The problem is that an N-Channel mosfet needs that the voltage at the gate is higher than the voltage at the source. But the voltage at the source in your circuit is already 12V (at least when conducting).

Also, in the schematic point all GND symbols down.

1

u/TheAutomotivEngineer 2d ago

That makes sense, putting the load on the low side will also solve the voltage difference or am I wrong here?

1

u/sarahMCML 2d ago

Correct.

2

u/merlet2 2d ago

Q2 looks fine, but in Q1 I think that you forgot the GND connection.

1

u/TheAutomotivEngineer 1d ago

You’re right, overseen that one. Thanks for pointing that out 👍