I have a N-Channel MOSFET gate connected to a Teensy 3.6 analog pwm pin with the intention of setting the duty cycle on the output of the pin to control the switching of the MOSFET. For reference this is 500 Hz I believe although it is irrelevant.
I have noticed that while the MOSFET works as expected and has low resistance (micro-ohms) when the load voltage (6V) is off as soon as the power supply (12V stepped down to 6V using a buck converter) is turned on the resistance shoots up to its off state. The load is a only 4 ohm resistive heater.
The 5V input to the gate is from a level shifter connecting the pin of the Teensy to the MOSFET's gate. There is a 10K Ohm resistor in parallel between ground and the gate and the voltage to the heater is 6V.
I am new to electronics and any help would be much appreciated.