HI everyone. I have been trying to simulate a full bridge inverter using CPM2-1700-0045B mosfet with the driver with the ADuM4121 gate driver. I was able to decrease the postive voltage spike in drain by increasing the gate resistance but there still exist significant spike in the negative side as you can see in the waveform. I have a switching frequency of 2KHz. There is a difference in the PWM waveform for input and output of the driver(in attached figure). I can see a turn on delay for the gate pulse in the output of the gate driver. My Vth is 3V for the mosfet and my gate pulse amplitude(peak) is15V. I fear my mosfets are turning on before my gate pulse reaches 15V i.e mosfet is turning on during the rising edge of my gate pulse I am not sure how to confirm this.
Also my gate current through the Ron(in figure) which is my gate resistance is 25.6mA which I don't think is sufficient to drive my mosfet gate that has a total gate charge of 188nC and rise time of 20ns which gives me a required gate current to be(Qtot/Trise ) if I am right(I fail to calculate the total gate current required) I have used
Ig=Ciss*V(15 volts gate voltage*switching freq) assuming total gate capacitance to be Ciss from datasheet.
Also I have been pointed out that my gate driver is slow and is causing the negative drain current spike(of peak mag 1.6A) and I know this is not good for the mosfet and I would really appreciate if anyone could help understand this problems and point me to the direction of solving these problems.
Thank you.
Also my gate current through the Ron(in figure) which is my gate resistance is 25.6mA which I don't think is sufficient to drive my mosfet gate that has a total gate charge of 188nC and rise time of 20ns which gives me a required gate current to be(Qtot/Trise ) if I am right(I fail to calculate the total gate current required) I have used
Ig=Ciss*V(15 volts gate voltage*switching freq) assuming total gate capacitance to be Ciss from datasheet.
Also I have been pointed out that my gate driver is slow and is causing the negative drain current spike(of peak mag 1.6A) and I know this is not good for the mosfet and I would really appreciate if anyone could help understand this problems and point me to the direction of solving these problems.
Thank you.
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