If we directly drive mosfet gate via microcontroller, it means we are driving capacitive load via low impedance source. It is directly correlated to (EMC) Electromagnetic Compatibility We should consider using series resistor for these reasons:
- Limit inrush current into gate capacitance
- Control dV/dt to control switching speed
- Very fast switch means overshoot/ringing, EMI issues.
- Dampen gate ringing Signal Integrity
- gate drive loops contain parasitic LC, which can oscillate at high freq.