I have searched, but cant find an answer for my specific setup. I have a Xl4015 switching contant current source for my 10w LED set at 1000mA. I would like to add a pwm dimming circuit to switch a mosfet on the led ground. I am using an arduino to create the pwm signal that connects to the mosfet gate. It does dimm, but I do not have an oscilloscope and cant tell if there are any voltage or current spikes each time the led turns on and off.

Will pwm cause any current spikes in this case? Or could it damage the xl4015 circuit?

up vote 0 down vote accepted

The XL Semi XL4015 5A 180KHz 36V Buck DC to DC Converter does not have a PWM (or Enable) control input.

enter image description here

It is very common to add an external MOSFET to a converter chip with an internal MOSFET. You should be fine.

You would add your MOSFET to the output of the SW pin.

enter image description here

I think it would be easier to build this Diode Inc AL8862 circuit than to retrofit the above circuit. The CTRL pin is your PWM input.

enter image description here

  • Thanks. I have been looking into using a different controller chip with a pwm pin. But that will be in the future. Since I already have these cc controllers. – liquidzorch Sep 14 at 17:39

Your Answer


By clicking "Post Your Answer", you acknowledge that you have read our updated terms of service, privacy policy and cookie policy, and that your continued use of the website is subject to these policies.

Not the answer you're looking for? Browse other questions tagged or ask your own question.