Hi there,
I am having some problem with N-channel low side switching.I am trying to control a 12V 30 amps brushed DC motor using PWM.I am using IRL3705 as the FET and IRS4427 as the Low side gate driver.The switching frequency is 32Khz.The gate resistor has a value of 4.7 ohm. I have STTH6004W as the flywheel diode and a electrolytic 100uf DC link capacitor with a metalized polyester film capacitor of 0.1uf in parallel to it.The problem is that I am 100% voltage spikes at the drain of the FET.What could be the reason ??

 

Please, if you can, put the graphics of the signals, at gate, Drain, and Vcc.

Thanks

 

Try a small cap across the motor, like 10nF.