microcontroller - Power N-Channel Mosfet as a Switch

I just want to use a BJT transistor to act as a interface between a microcontroller and a MOSFET. I need to turn on and off an N-Channel MOSFET for controlling a much higher current on high voltage. A power N-channel mosfet, as far as I know, requires at least 10V Gate to Source voltage to achieve the minimum On resistance. I have 12V on my board so I decided to use that 12V for turning the MOSFET on. The schematic is shown below.It seems that this BJT won't switch on that way?

How can I use NPN Transistor to turn on and off the MOSFET without inverting the signal?

Thanks!

Answer

Impossible. You have to use one more PNP transistor for that. You cannot turn N-MOSFET only by NPN transistor without inverting input signal.

This is modified circuit that should work.

^{simulate this circuit – Schematic created using CircuitLab}

When the input signal is 0V: Q2 is off, base of Q1 is pulled high, so Q1 is off. And M1 is pulled low, so mosfet is off.

When the input signal is 5V: Q2 is on, base of Q1 is pulled low, so Q1 is on. And M1 is pulled high, so mosfet is on.

Problem with your original circuit is that Q31 can be on only when emitter has lower voltage than base. But when you send 5V to input, Q31 is open and emitter is pulled to 12V and so turns Q31 off. Your circuit cannot work.