H-Bridge Question

Hey fella's, hoping someone here can lend me some good knowledge on whether or not this H-bridge will work for my nefarious plans! It features PWM and forward/reverse control.

Single motor controller - 14A 6V-16V
http://www.robotshop.com/ca/productinfo.aspx?pc=RB-Pol-21&lang=en-US

I need to control a peltier which is max rated at 15.4vdc @ 15a. I will be running it at 12Vdc off of a good PC psu and I'm not even sure that it will draw a full 15a running at 12v. Anyway, I'm not even sure if I can use an H-Bridge, or this type of H-Bridge to do this. I want to use PWM to control the temperature. The peltier is mounted to a large copper heat sink, and the temperature changes will be very minimal so I know the peltier will be fine, but can this H-Bridge control my peltier using PWM and forward/reverse current control for heat/cool switching of the peltier?

Thanks for the help!

Yes, that H-drive looks to be a good match for your peltier. And your peltier will draw less current if driven by 12vdc instead of it's max rated 15A @ 15.4 vdc, probably around 12amps. Pololu makes pretty nice quality stuff, I would have no problems recommending their stuff.

Lefty

You may be able to use a logic level MOSFET if you do not need to reverse the current flow direction in your device.

zoomkat:
You may be able to use a logic level MOSFET if you do not need to reverse the current flow direction in your device.

Well he did post that he needs/wants to be able to switch between heating and cooling so a simple mosfet switch wouldn't meet the requirement.

but can this H-Bridge control my peltier using PWM and forward/reverse current control for heat/cool switching of the peltier?

Thanks so much Retro! I'm really glad that that H-Bridge will work as it's very reasonably priced and I'm glad to hear you recommending that company. One other question, hopefully someone can answer this easily enough... I am running a DHT-11 temp/RH sensor and I'm also using an LM34... I tend to get a lot of erroneous readings from my sensors... I also have a CO2 sensor which is setup using I2C, and that gives me steady readings all the time... But the DHT-11 is setup to a digital pin and LM34 is setup to an analog pin and occasionally the DHT11 gives out an odd reading like it'll go from 75F steady to like... 83F and then back to 75F... The LM34 is much worse in this regard. The readings can really fluctuate all over the place with-in a few degree's but it's rarely stable. Is this a matter of wire shielding or something else? I've tried pull-up resistors with out much success.

Thanks!

Oh, the LM34 is wired using some standard 4-conductor telephone wire.

I've seen conflicting information on the web as to whether a peltier PWM drive needs a low-pass LC filter for best performance.

If PWM is used a high frequency seems to be important to avoid thermo-mechanical stress failure.