What I want to do: pwm controll 24v light sources from my arduino nano v3 board(328p).
Since I also have sensors connected to the 328p I am running it on 3.3v. Since the 328p can only output 6 pwm channels I want to use an extension board with a pca9685 so I get 16 pwm channels. since the pca9685 can only output 25mA I want the pca9685 to controll mosfets.
Now I have landed on the FQP30N06L mosfet.(I might change to IPD220N06L3 mosfets since they have lower Rds and Qg and a built inn drain-source diode)
My problem: How do I calculate the gate resistor?
I want to have it as small as possible so the mosfet switch as fast as possible and at the same time big enough to keep the current under 25mA so I don't overload the pca9685.
Is it as simple as ohms law R=U/I wich gives me 3.3v/25mA=132ohm? Or is there something else to consider?