DIY Fan Speed Control

[Bryan]

For those handy in basic electronics there is a IC available that can be used to automatically vary the speed of a fan. Similar to what the Ice Cap fan does.

MIC502 Fan Management IC

Information and dataheet in PDF format at
http://www.synergysemi.com/product-info/products/mic502.html

[Delphinus]

Nifty -- any idea of the cost by any chance?? Thanks!

[stephane]

have you made it Brian ?

Very interest to put it in my new canopy.
How many fan it could drive? I have four 13 mili amps fan in my new canopy could one unit run all?

I have made electronic circuit when I was in scool and I tink I could do it again even if it seem 2 million years ago

but we need the circuit shema to burns the copper
plate and I have no clue how do do this whith those sheet, any help here?

[Bryan]

Delphinus:

I haven't built one yet so I can't give you a price per chip. But I have noticed it's not a very common IC and could be hard to find.

Stephane:

No, I haven't built one yet. Upon closer examination it appears this chip is designed for computer power supply fans. Here is a quote from the PDF file. Looks like the max fan current is dependent upon the tranistor. the recommended transisitor can handle 400ma. As for the PCB the circuit is so simple you could build it on solderable breadboard. If interested you can pop over to www.canada.digikey.com (http://www.canada.digikey.com) for mail order electronic parts.

I think someone on this board is a electrical engineer. If they are listening any thoughts on this IC.

>>Transistor and Base-Drive Resistor Selection
The OUT motor-drive output, pin 7, is intended for driving a medium-power device, such as an NPN transistor. A rather ubiquitous transistor, the 2N2222A, is capable of switching. It is also available as the PN2222A in a plastic TO-92 package. Since 400mA is about the maximum current for most popular computer power supply fans (with
many drawing substantially less current) and since the MIC502 provides a minimum of 10mA output current, the PN2222A, with its minimum β of 40, is the chosen motor-drive transistor.<<

[StirCrazy]

www.canada.digikey.com (http://www.canada.digikey.com)

is that the right address Bryan? it doesent seem to work.

Steve

[Bryan]

Try http://canada.digikey.com/

Originally posted by StirCrazy:
www.canada.digikey.com (http://www.canada.digikey.com)

is that the right address Bryan? it doesent seem to work.

Steve<font size="2" face="Verdana, Helvetica, sans-serif">

[Bryan]

Here is a link to a site that has experimented with the MIC502.

http://www.bit-tech.net/article/51/

[Bryan]

Just to add to my last reply. Here is a link to a site that has experimented with this chip. They used a transistor that can power fans up to 60 watts.

http://www.bit-tech.net/article/51/

Originally posted by stephane:

Very interest to put it in my new canopy.
How many fan it could drive? I have four 13 mili amps fan in my new canopy could one unit run all?

<font size="2" face="Verdana, Helvetica, sans-serif">

[reefburnaby]

Hi,

Neat circuit -- probably hard to find at a good price. You can do the same thing with a 555 timer and some auxiliary circuits.

As for building this pupppy, your best bet is to get a veroboard (Radio shack 276-168) and proto on that board. Its quite cheap and easy to use. Another way to proto is to use a breadboard - also available at RS.

Just in case you didn't know, this thing controls DC motors.

- Victor.

[ 01 April 2002, 20:27: Message edited by: reefburnaby ]

[reefburnaby]

Hi,

As for the 2N2222/PN2222A thingy...I think I(ce) of 400mA is pushing it. Usually, you'll need a aluminum heat sink cap for the 2N2222 to achieve its maximum rating (which happens to be 500mA).
Switching motors (reactive loads) is fairly rough on the electronic switches. It is best to overdesign these circuits. 2N2222/PN2222A are designed to supply 500mA - I would try to keep it below 250mA.

Most bipolar transistors have a beta of 40 or higher.

- Victor.

[ 01 April 2002, 20:59: Message edited by: reefburnaby ]