Calculating the MOSFET gate resistor for an H-bridge driver
This was answered on another forum.
I had misread the total gate charge as 10nC. In reality, it is 45nC. The Gxx is also 15V (Sx+15V from the motor driver's datasheet). Hence the required Ig to turn on the MOSFET is 45nC/58nS = ~776mA. Hence Rg = 15V/776mA = 19.3ohms. However, as pointed in the answer on the other forum, rise time need not be that high. Hence assuming the rise time to be 1% of the switching frequency, we get t(transition) to be 500nS. Recalculating for Ig,
Ig = 45nC/500nS = 90mA, and, Rg = 15V/90mA = ~167ohms