PCB Heaven

General Category => Your projects => Topic started by: zc0rp on February 04, 2015, 15:33:00 PM

Title: 3 wire fan controller
Post by: zc0rp on February 04, 2015, 15:33:00 PM
Hi all, I've got a problem with the 3 wire circuit... everything works but...
the max voltage on load is about 7v instead of 12v. i'm using a 12v 5a powersupply.
it's for operating 4 fans on one controller, the fans are max 0.5 amps.
can anyone help me out please? thanks in advance.

i've used this tut:
http://pcbheaven.com/circuitpages/High_Frequency_PWM_Fan_Controller/
Title: Re: 3 wire fan controller
Post by: kam on February 06, 2015, 22:16:55 PM
Hello zc0rp. Typical mistake on this circuit are the PWM diodes. You do not get all 100% duty cycle.
Title: Re: 3 wire fan controller
Post by: zc0rp on February 09, 2015, 13:52:20 PM
can you tell me how to fix this? i'm a complete n00b... just that you know ;)
Title: Re: 3 wire fan controller
Post by: kam on February 10, 2015, 21:23:20 PM
well, actually I can only tell you that you have most likely make a mistake by copying the schematic on the breadboard. I can't tell what you have done wrong. But most common mistake is that you have connect the diodes wrong.