The MOSFET does not turn off by a turn-off signal. How do I solve this problem?

We will explain the case of N-ch MOSFETs.
Confirm whether the control signal voltage V_drive is close to the GND or not.
When the voltage is not close to the GND, the output impedance of the gate drive circuit may be high. Consider lowering output impedance.
Confirm whether the gate-source voltage V_GS is the same as the control signal or not. If it is not, insert a pull-down resistor R_pull between gate and source to ensure the gate-source voltage V_GS to the GND level.
Please select R_pull that does not affect the gate driving performance.

For MOSFET’s drive, please refer to “MOSFET Gate Drive Circuit:Power MOSFET Application Notes.”