PWM to Analog converter circuit

Interesting stuff! :cool:

Wouldn't that do the fans aswell? Or would a IRFZ44NPbF be better to do all?

This is were it starts to lose me, as I know there's a LOT of variables to specing the correct mosfet in a particular circuit :confused:


Managed to do a sketch as to output a pwm signal same as a motherboard does(well hacked others really;) ),
then added a pot so be able to adjust the duty cycle. Then output the RPM and Duty % to the serial monitor

Was very proud of myself. :D

No idea why, have a cpu fan on it on my desk just spinning :o . was tinkering. I can post on here if you want it to test your circuits if its usefull to you! Although going on what you seem to have/ access to, kinda like bringing a knife to a gun battle :p
 
Saw this when it first popped up, and will read more thoroughly when I have time, but it's a good, simple idea! For anyone wanting to play at designing their own, Microcap is a free and very capable simulation package. I'd have a look at designing one myself, but all my time is tied up in simulating my final year project!!
 
pete910 said:
Interesting stuff! :cool:

Wouldn't that do the fans aswell? Or would a IRFZ44NPbF be better to do all?

This is were it starts to lose me, as I know there's a LOT of variables to specing the correct mosfet in a particular circuit :confused:
Click to expand...

It would power anything you wish to connect to it but you'd have to lose all tach feedback on the fans. The hall sensor on the fan body needs to have a voltage at all times to operate accurately. PWM fans have this sorted in electronics but 3 pinners and Molex powered pumps do not. The pump will work fine on PWM but the 3 pin fans are much better off on DC volts, hence the converter.

The IRFZ44NPbF should work fine as it is also a logic level and can source enough current. The circuit is not complex enough to worry about speccing a fet that has certain properties. All it needs is to be able to source the current, switch fast enough and be logic level. I only chose IRL510 because I used one before and it did the job. I've no idea what a lot of the specs of fets actually mean and how they matter in circuits.

Managed to do a sketch as to output a pwm signal same as a motherboard does(well hacked others really;) ),
then added a pot so be able to adjust the duty cycle. Then output the RPM and Duty % to the serial monitor

Was very proud of myself. :D

No idea why, have a cpu fan on it on my desk just spinning :o . was tinkering. I can post on here if you want it to test your circuits if its usefull to you! Although going on what you seem to have/ access to, kinda like bringing a knife to a gun battle :p
Click to expand...

My equipment has taken me two or three years to accumulate and is still way short of what it could be, or I'd like it to be. I'm only a very basic hobbyist and tend to learn what I need for a certain project. I do have quite a selection of components though but typically never the right ones for projects I decide to do. ;)

I've only recently begun playing around with Arduino and find it almost like cheating, after working with simple ICs and passives all this time. It's so easy to just throw in a bit of code and do things that would take dozens, if not hundreds of ICs to accomplish. I must admit being quite happy with myself when I managed getting a scavenged LCD panel to display anything I wanted.

You got me thinking about something now. I'm thinking of building a fan controller and wonder about having a PWM duty cycle modifier through Arduino software, where the incoming PWM cycle is checked and multiplied by a factor determined by an external device eg Potentiometer, thermistor or even photo diode. This might be useful if say the duty cycle at idle drops your pump/fan/LEDs too low.

I use a 555 timer built 25kHz PWM box to verify my own PWM circuits. I could have used one of my Arduino boards to do it but I built the circuit before I started Arduino.
 
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Not sure what's going on in that video. Seems to be showing near max voltage throughout. I did hear a squeak somewhere along the line but the fan in shot didn't seem to deviate.

The video quality is even worse than my videos ;)
 
Tealc said:
Not sure what's going on in that video. Seems to be showing near max voltage throughout. I did hear a squeak somewhere along the line but the fan in shot didn't seem to deviate.

The video quality is even worse than my videos ;)
Click to expand...

LOL roxikmode on!!

In this video PWM with 100% duty cicle OUT 12,24 V MAX with IN 11,80V of mother board (need more amper and my circuit go to 20V)
in the video my circuit pilot with 11,80 of mother board connector 4pin fan
4 fan Corsair AF140 quiet edition in overvolt with duty cicle 100%.
squeak if you hear is the low amper of mother board 4pin connector!
 
darkphoinix said:
LOL roxikmode on!!

In this video PWM with 100% duty cicle OUT 12,24 V MAX with IN 11,80V of mother board (need more amper and my circuit go to 20V)
in the video my circuit pilot with 11,80 of mother board connector 4pin fan
4 fan Corsair AF140 quiet edition in overvolt with duty cicle 100%.
squeak if you hear is the low amper of mother board 4pin connector!
Click to expand...

So you've created a DC-DC buck boost converter, or utilised an off the shelf part?

I'm not really sure why you would need to overvolt a fan. Running them too much above their designed voltage would wear them out much faster, I'd have thought.

Perhaps you could do a video where you describe in more detail what you are doing. Use speech bubbles if your english isn't that great.

I did look at a DC-DC converter as a method to do what I wanted and I think I posted some info early on in the thread about my experiments but I found that the components are closely matched to the current you are drawing and the voltage you are providing. I felt like I would lose the ability to control fans ranging from 0.05A up to 1A neatly. Sure if I were designing it for one or two of my own fans and I knew the current draw curve then it would have been ok I suppose.

But still a buck converter would be more ideal in this situation, especially one where someone wanted to control a load of fans and maybe a pump or two.
 
I have 3x 3pin XSPC 120mm 1650RPM fans connected to my radiator.

Do you sell a cable that allows me to run all 3 fans to a fan header on my motherboard but allowing PWM control?

Kind Regards
 
smsmasters said:
I have 3x 3pin XSPC 120mm 1650RPM fans connected to my radiator.

Do you sell a cable that allows me to run all 3 fans to a fan header on my motherboard but allowing PWM control?

Kind Regards
Click to expand...

I usually fit 3 fan spots to my converters anyway so this would be the nearest thing to a standard build for me. It would work just fine off any PWM enabled header.

Drop me a message in Trust if you'd like me to build one for you.

:)
 
smsmasters said:
I have 3x 3pin XSPC 120mm 1650RPM fans connected to my radiator.

Do you sell a cable that allows me to run all 3 fans to a fan header on my motherboard but allowing PWM control?

Kind Regards
Click to expand...

Ready for dropout? 1000rpm! auauhahuauhuahuhauah :D
i have problem with english more english people have problems with electronic!

http://en.wikipedia.org/wiki/Dropout_voltage

P.s. is very professional Pass-Through Hole board!
 
darkphoinix said:
Ready for dropout? 1000rpm! auauhahuauhuahuhauah :D
i have problem with english more english people have problems with electronic!

http://en.wikipedia.org/wiki/Dropout_voltage

P.s. is very professional Pass-Through Hole board!
Click to expand...

Ok so now we've pretty much discovered your board doesn't work and you've no comeback for that so you trash-talk a member's version, one of which many other members have and rate highly.

If you want to get into mud-slinging. You're Italian and I've owned a Fiat, you've some nerve commenting on other's abilities when it comes to electronics.
 
I've put the two boards together for smsmasters and pob9. Just need the black heatshrink put on and these are good to go.

two-boards1_zps262331e1.jpg


With 4 standard fans attached you can expect fan stall speed-95% fan speed.

I use stripboard because it's cheap and at these sort of frequencies it doesn't make any difference to the function of the circuit. My Oscilloscope agrees with me.

I've not really had professionally made boards priced up but expect that at maybe 20 boards per year they'd be quite expensive and certainly above that which I or anyone else would like to pay for. You need to have thousands made to make it cost effective.
 
Tealc said:
I've put the two boards together for smsmasters and pob9. Just need the black heatshrink put on and these are good to go.

two-boards1_zps262331e1.jpg


With 4 standard fans attached you can expect fan stall speed-95% fan speed.

I use stripboard because it's cheap and at these sort of frequencies it doesn't make any difference to the function of the circuit. My Oscilloscope agrees with me.

I've not really had professionally made boards priced up but expect that at maybe 20 boards per year they'd be quite expensive and certainly above that which I or anyone else would like to pay for. You need to have thousands made to make it cost effective.
Click to expand...

Thank you very much, looking forward to receiving it. :)
 
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