Imported from GitHub: Duckle29/PWM-to-fan · commit a7b9fc4 · license MIT

Description

A small board for controlling two DC fans from an open-drain inverted PWM output.

README

PWM-to-fan

This is a small board intended to take an open-drain inverted PWM output, and convert it to constant current from 0-200mA for a fan. This is because many fans do not run well with their main supply PWMed. The reason to go for Constant current, is to limit the heat wasted in the transistor.

The board was made for use with the Duet 3D printer controllers, but will work for any open-drain inverted PWM outputs.

Many thanks to N2 who came up with the circuit.