ECE Majors Unite! Building a TC649 PWM-Temp Fan Cntrlr - Overclock.net

**Burn** · 2 Weeks Ago

http://ww1.microchip.com/downloads/e...Doc/21449c.pdf

I have two IC's on order, one as a DIP package and the other as a MSOP package. Going to try prototyping it on a breadboard and then I may PCB it if I have the willpower to do so

Anyway, an example circuit can be found on page 9 of the PDF, anyone have any insight into the best way to go about it?

**radodrill** · 2 Weeks Ago

The datasheet looks very similar to that of the MIC502 chip. I built a fan controller for RAD-GT using a MIC502 based on a circuit I found on bit-tech; here is my worklog entry on making the fan controller.

**Burn** · 2 Weeks Ago

What PCB did you use? That looks like a really nice size

**radodrill** · 2 Weeks Ago

Quote:

Originally Posted by Burn

What PCB did you use? That looks like a really nice size

That was Jameco Part # 263222; it's a 3 1/4" x 3 11/16" proto board with solder pads for each hole. I must say it was a tight fit cramming all 8 fan control channels onto the board.

cathode · 2 Weeks Ago

You could design the PCB with something like Kicad and have it manufactured for you by a company that does such things, for a small fee.

**Burn** · 2 Weeks Ago

I'm too cheap to do it that way

I'm just going to do it breadboard style, it's only 7 or 8 bucks. We actually have a fairly large ECE shop on campus so once I get the TC649 I probably will head down there to get breadboard, caps and resistors. Still need to find the right transistor or MOSFET capable of handling enough current though :\

**Burn** · 2 Weeks Ago

Quote:

Originally Posted by Burn

I'm too cheap to do it that way

I'm just going to do it breadboard style, it's only 7 or 8 bucks. We actually have a fairly large ECE shop on campus so once I get the TC649 I probably will head down there to get breadboard, caps and resistors. Still need to find the right transistor or MOSFET capable of handling enough current though :\

Need some help buying a thermistor- it says it should provide 100k ohms resistance at 25C but it doesn't specify anything otherwise. On digi-key, they have a bunch of b-values. What are these and are they important for my application?

**radodrill** · 2 Weeks Ago

Quote:

Originally Posted by Burn

Need some help buying a thermistor- it says it should provide 100k ohms resistance at 25C but it doesn't specify anything otherwise. On digi-key, they have a bunch of b-values. What are these and are they important for my application?

They really should be listing a reference resistance, reference temp, as well as a B-value; knowing those 3 values you can find the temp with a measured resistance and vice verse using the thermistor B-parameter equation.

**Burn** · 1 Week Ago

Quote:

Originally Posted by radodrill

They really should be listing a reference resistance, reference temp, as well as a B-value; knowing those 3 values you can find the temp with a measured resistance and vice verse using the thermistor B-parameter equation.

I really am lost on the whole thermistor choice- could you find me one that does 100k ohms on digi-key that is a bead-type? That would help out so much

IC arrived today, looks cool

**radodrill** · 1 Week Ago

Quote:

Originally Posted by Burn

I really am lost on the whole thermistor choice- could you find me one that does 100k ohms on digi-key that is a bead-type? That would help out so much

I'll certainly take a look; but is there any specific reason why you want to buy it at Digi-Key? I usually purchase electronics parts from other locations since they have better website designs that make it easier to find stuff.

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ECE Majors Unite! Building a TC649 PWM-Temp Fan Cntrlr

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