I've been struggling for a few weeks now trying to add a PWM option to my CW laser diode driver design which works OK.
When adding a MOSFET or BJT to PWM the output, I'm getting voltage spikes and noise. This is bad for the driver since the laser diode is a very sensitive and expensive component.
I tried three options to PWM the signal, option 1 (MOSFET ATTACHED TO V3 analog input) works the best, but still not good enough.
Currents are 0-250mA, 1kHz - 10kHz operation.
The PWM signal is currently supplied by an industrial function generator to avoid any problems related to MCU low power pins.
Do you have any idea how to wire the switch correctly for best noise performance?
Am I doing something wrong?
