Hi There,
do u guys have DIY your own Fan Controller before?
It's a linear type or a more complicated PWM type.
anyone have the Circuit pls share it here as i'm planning to build
one for my Delta120mm Fan.

i already had 2 linear fan speed controller so that i plan to own a PWM type.
pls share if u have.

Ask allngap.
He knows this kind of things.

i usually use a function generator for this. But there are circuits for it, but the signalling for the PWM is very specific, 25 khz @1mA draw @ 5.0 volts absolute signalling level. Might have to custom build an oscillator.

There are so many designs you could use here. You could you a traditional oscillator with MOSFET combo, you could use a basic Signetics 555 timer with it's supply power trimmed to 5 volts. Tons of ways lah. Connectors? Well Molex KK .12 pitch leads should work fine here. Duty cycle range, from what i've seen in the data sheet for control should hit atleast 90 percent with a minimum of 30, and a drop to zero signal state from there.

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Added on April 3, 2007, 12:04 pmAnyways here's the data sheet for the sawtooth variable PWM signal supply. http://focus.ti.com/lit/ds/symlink/uc2638.pdf and here's a basic tutorial on PWM, http://www.cpemma.co.uk/pwm.html . A one chip solution for pin 4's needs, is pretty nice amitrite? Anyways if i got the ideals properly....

Pin 1 : 12 volts
Pin 2 : Gnd
Pin 3 : Tachometer (freq / 2 for speed)
Pin 4 : PWM control input

PWM control attributes : Control Signal and not a driver, i'm assuming that the MOSFET is within the fan itself and pin 4 only drives the signalling and control, while power is still derived from pins 1 and 2.

Steps.

1. DB is set to the appropriate 5v signalling level.
2. Current isn't an issue here since by Intel specs the thing can only source 1ma at MAX, the IC's maximum is 40 with SC protection.
3. Calculate a good CT that hits 25khz, don't worry, the IC does 400khz easily so a fan is nothing fancy.
4. PVSET is slaved to a variable resistor (calculate this in relationship to logic level), to determine the dutycycle.
5. Output is then connected to pin 4

This post has been edited by empire23: Apr 3 2007, 12:05 PM

thanks dude empire23 for the link.
i had all the component ready for the circuit.
wait for my final work

actually theres a topic in Case Mod sub forum....
Link

That's just a basic fan controller with a transistor to achieve the effect of variable external duty cycle.

A PWM fan has a MOSFET built internally, the signal is supplied from Pin 4 and it essentially turns the MOSFET on in pulses depending on the duty cycle. So i guess it's comparitively different design.

Is it this?

http://www.ocforums.com/showthread.php?t=438125



I thought of building one myself.

But didn't make it because I couldn't find half of the electronics

This post has been edited by theodore_kh: Apr 5 2007, 01:27 AM

Shouldn't this topic be in the Hardmodding section?

Moved to HardModding.

sorry, i think it belongs here. alot of si fus (bombman. allngap )

the most problematic thing about PWM controller circuit is the switching ON/OFF noise on the fan itself.....it is so annoying not that it is loud

go low frequency and you will hear a low "woshh" sound....

go high frequency and it will sound like mosquito flying pass your ear.....

either way 5/12V or voltage regulators are the best option for me.......

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Added on April 9, 2007, 11:12 pmas for me, i would either hunt for a good fan which can take varying voltages with minimal motor noise or comes with the fan speed control feature.....

so far, i've tested that only SUNON 92mm has got the nicest range all the way from low voltage to 5k rpm, i mean that the step rpm is smallest that i've ever tested

anyway as i said earlier, PWM is a good controller assuming that you can take the buzzing sound from the motor itself.....if you cant then i suggest that you dont waste your time on it......

This post has been edited by AllnGap: Apr 9 2007, 11:12 PM

iinm, also not easy to find pwm suitable fans, those real heavy duty ball bearing fans will make alot of noise, and the leds will keep blinking unless set the controller to full

A question here...

What is the difference between a PWM fan controller and an ordinary fan controller?

Set the operating frequency to above 20kHz, then it will be out of human audio range (your dog might go crazy though).

PWM basically switches the fan on and off many times a second, so if you want the fan to go faster you adjust so that the time its on is longer compared to the time that its off. Advantage of PWM is that you can use it to drive a power transistor enabling high power devices to be PWM controlled-basically limited only by how much current your transistors can handle (MOSFETs can be used in parallel so theoretically there isn't a limit). Main disadvantage is that fan speed monitoring might get screwed up.