I'm using a PWM IC to control some LEDs, and it uses an Open Drain setup. So I run 5V to the LED (through the appropriate resistor) then connect the LED ground to the PWM terminal.
I have one led that uses 100mA, which I believe is too much for the PWM IC. So I thought I would use a MOSFET, but I don't understand them enough to make this work.
The gate of the MOSFET is what the PWM IC would control to change the brightness, but the MOSFET requires a voltage to the Gate to close, and the PWM IC would only connect it to Gnd as an open drain.
I'm guessing I'm just wrong to use an N-type MOSFET for this setup, but I don't know what I should be using.
The schematic doesn't show, but the PWM is open drain, so just a connection to gnd. The other LEDs being used are all drawing less than 40mA current, so they go directly to the PWM IC
Parts: PWM IC - PCA9685 MOSFET - MMBF170L LED - IR333-A
Thanks for helping a clueless hobbyist. -Seth