I'm designing a DC motor driver using Allegro's A3941K driver. The block schematic shows a gate resistor for the MOSFETs. The A3941 gate structures are as below,
GHx voltage would be a maximum of 18V? Knowing the current that should flow into the gate would help me calculate the value of the resistance. I found this app note from Microchip on Driving Power MOSFETs in High-Current, Switch Mode Regulators. Using the equations from there and the data from the MOSFET datasheet, I calculate the Ig = Qg/t(rise time) = 10nC/58nS = ~172mA. Hence, the gate resistor Rg = 18/172mA = ~105ohms. Is this the correct line of thinking?
The switching frequency is 20KHz and the MOSFET used is BSC100N06LS3.