Closed Loop PWM PC Fan Controller – Video Tutorial

Below is video tutorial about closed loop PWM PC fan controller. Unlike the other controller, in this circuit the potentiometer would not directly changes the duty cycle instead it set an RPM reference value.

On the first state is to read the potentiometer value and to translate it to RPM value using Analog Digital Converter then it read the current fan speed. After comparing this, it decide to increase or decrease the duty cycle. For further information, watch the video.