2 Speed Fan Controller

[smartx21]

For those who don't like large heatsinks, this fan controller is a good choice.
It is well explained here: Two Speed Temperature Fan PWM Controller - Electronic Circuit Schematics
I slightly changed the circuit to use dual sensors and dual fans, and to be fed from a 24VDC input.
I need support to draw a decent PCB layout! Is alex mm around?
Cheers,
Max.

 

[AndrewT]

Hi,
a suggestion for a little improvement.

Can you insert a timer to allow the opamp to kick start the fan motor with full voltage?
When the timer expires, the NTC determines whether slow speed or full speed is required.

 

[smartx21]

Also no speed at all....
I see, you mean something like...

 

[smartx21]

I've inserted a diode in series with opamp output, and then a capacitor from +12V.
It works fine, thanks. It is good to cleanup dirt!
I've also inserted two LEDs, between T3 and T4 collectors and +12V, in order to monitor controller's state. Yellow for mid speed, and red for full speed. So, during power-on, red LED is lit!
Thanks!
Regards,
Max.

 

[smartx21]

Refined version

 

[AndrewT]

Clever modifications !
Thanks.

 

[alex mm]

Yes Max I'm here....

but not with empty hands I hope you like it .
Alex.

 

[smartx21]

Very nice!
Are you Merlin, the magician?
Thank you very much!

 

[smartx21]

Here (http://www.diyaudio.com/forums/soli...ur-solid-state-pics-here-166.html#post2397421) you can see some pics of the amp where this fan controller has been inserted in.
Regards,
Max.

 

[nigelwright7557]

I designed my own little SMPS with a pot to control the speed.
I used a PIC micro with a PID technique.
It required very few components.

 

[smartx21]

I designed my own little SMPS with a pot to control the speed.
I used a PIC micro with a PID technique.
It required very few components.

Class D, PIC... I see you are very skilled.
As you can see, counter-clockwise I only make use of quite simple stuff.
Due to knowledge limitations, of course. But there is way to learn. It would be nice to see your schematics and builds.
Regards,
Max.

 

[nigelwright7557]

Class D, PIC... I see you are very skilled.
As you can see, counter-clockwise I only make use of quite simple stuff.
Due to knowledge limitations, of course. But there is way to learn. It would be nice to see your schematics and builds.
Regards,
Max.

The schematics are very basic. Just a PIC driving a MOSFET with the output voltage potentially divided back into a PIC analogue port A2D converter.
The clever bit is the software in the PIC doing the SMPS.
I worked for a PIC consultancy for 13 years so know my way around the PICs.

If you can get away with a 555 timer then great.

 

[smartx21]

My brother, who is an EE in Texas, USA, has presented me with a PIC programmer and a thick book to read. I just neeeeed to start.
As a very good computer programmer in the past, maybe I can climb this mountain...

 

[nigelwright7557]

My brother, who is an EE in Texas, USA, has presented me with a PIC programmer and a thick book to read. I just neeeeed to start.
As a very good computer programmer in the past, maybe I can climb this mountain...

I was originally a Z80 assembly programmer.
I was a bit horrified at the PICs when I first started using them after the Z80. However the PICs are cheap and have loads of options for interfacing.

I have a wealth of old PIC projects to draw on if I need to. Its easier than starting from scratch.

 

[jotha]

PCB

but not with empty hands I hope you like it .
Alex.

Hi alex mm in pcb of smartx21 is used 2 FAN, could be included in your drawing of pcb the second fan?


Congratulations

Hi Smartx21 here too...

Jotha

 

[AndrewT]

Another late thought.
Fan off or fan slow due to low temp heatsink/device: all temperature warning lights OFF.
Fan fast: flashing bright RED LED !
Heatsink overtemp switch on: Power off and latched.

 

[irvynejay]

but not with empty hands I hope you like it .
Alex.

can you pls share pcb copper side i want to try build this one..TY

 

[chlorofille]

very nice fan controller. I would use this in my next amplifier project.

 

[alex mm]

PCB and TOP

...... Bottom view in black and white , top side ,and all
Alex.

 

[chlorofille]

Hey Alex,

Thanks!!

Hi alex mm in pcb of smartx21 is used 2 FAN, could be included in your drawing of pcb the second fan?


Jotha

I am confused as well.
So will I need 2 boards for 2 fans ?
Or can I just parallel 2 fans and connect them together ?

I am thinking of using this controller for a 100W amp, in which both channels are mounted on a single heatsink.