Filtering PWM to create a DC voltage.

Well I can tell you that PWM control of LED’s without using a dedicated LED driver is very possible.

During my experimenting I have had all the issues and when it comes to using pwm to control a mosfet (although it does work without any additional circuitry if you use a logic level MOSFET) it can also work when using standard power mosfets. Its called low pass filtering.

I successfully used a 10k resistor and 0.1uF Cap between my PWM signal and the MOSFET and this seemed to solve all issues as it basically convert the digital PWM  signal into an analogue voltage. Verified on Scope. :-)

This filter basically acts a simple digital to analogue convertor.

Using the above basic circuit you can output between 0 and 5 volts on a MCU such as the arduino using the PWM output (Between 0 and 255) 255 being theoretical 5V.

 

Hope this helps those playing with Pulse Width Modulation.

Next I will write up a blog post explaining Pulse Width Modulation and what it can do for you.