LED Dimming Circuit

Hello all,

For battery-powered (18650) flashlight dimmer circuit–would it be sufficient to use a simple arduino PWM signal to regulate the brightness of the LED (1 Watt - max 3amp)? Is there any need to add a a purpose made LED driver IC?

Thanks in advance!


If there is just an enable pin on the driver circuit that doesn't draw power from the Arduino then yes there is no necessary circuit needed. If the led is going to draw the current from Arduino then no( you need a driver or transistor) and moreover it is necessary to have a common ground between control an external circuit.


High current LEDs need a constant current driver. You can't just use a series resistor like you can with a normal 5mm led. Look for a constant current driver module with a pwm control input. I think Sparkfun sell some.

There is only a few thenths of a volt between a 1watt white LED and a 3.7volt battery. That might require a special flashlight CC circuit. The Sparkfun Femto/Picobuck drivers need AFAIK 8volt minimum. Leo..