I'm trying to build a fan controller based on Arduino. It will be (at least I hope so) possible to either control with pure PWM or voltage regulator based on buck converter. Now what I'm trying to do is:
build a circuit that will allow me to choose, if I want to power the fan with full 12V (for PWM fans) or buck converter output (for 3-pin fans).
Selection should be possible with Arduino digital output (either LOW or HIGH). I to google some solutions and tried to simulate some circuits based on diodes or transistors, but it wouldn't work as I envisioned. I lack knowledge to fully design what I want. I would like to get i either:
- sample circuit (if possible simple and cheap)
- phrases to google (I'm not native english speaker and maybe I'm not looking for the right thing)
- some insight if my "vision" is achievable and makes sense
EDIT. According to "pure PWM" or "12 V".
4-pin fans use 12V supply all the time with additional cable to control via PWM. 3-pin fans on the other hands should be controlled by varying input voltage.
This is conceptual image of what I'm trying to do:
Input voltage to buck converter is 12V.
Thank you for tag suggest!