# power mosfet with stm32

I started this circuit with stm32. But it doesn't work properly. When I set zero to all four pins and I don't want any movement, the voltage of 3 volts is at the two ends of the motor again. Or if I want the motor to turn in the right direction The MOSFETs become extremely hot and the motor does not move. What could be the problem? Is the amount of resistance appropriate? I use a 3 volts DC motor.

• Four pins? I only see two STM32 output pins. – skvery Apr 1 at 20:52
• Please specify what the other two pins do. What motor are you using? – sgt_johnny Apr 1 at 20:59
• My "small motor" is as big as my pinkie finger. I know guys whose "small motor" is as big as my whole car. What size is your small motor? Can you edit your question with motor specifications, like voltage and stall torque, or even the manufacturer's part number? – TimWescott Apr 1 at 21:08
• Well a pin from the top of the bridge with a pin from the bottom diagonally connected to rotate the motor in the left and right directions.....I use a 3 volts DC motor. – Mojtaba Miraki Apr 1 at 21:12
• "3 volts DC motor" doesn't tell the whole story. Details matter. How big is it? Did it come with specifications? – TimWescott Apr 1 at 21:15

Your NMOSFETs achieves their rated $$\R_{dson}\$$ at 4V but your STM32 output pins only apply 3.3V. Your PMOS gates achieve their rated $$\R_{dson}\$$ at 10V but you are only applying 5V to it.
Pay ZERO attention to $$\V_{gsth}\$$ when trying to use a MOSFET as a switch. $$\V_{gsth}\$$ is when the MOSFET just barely starts to turn on. Do you want the MOSFET to barely turn on? Or do you want to achieve the rated $$\R_{dson}\$$? In that case, use at least the $$\V_{gs}\$$ specified in the datasheet to obtain the rated $$\R_{dson}\$$.