Still waiting for those damn MOSFETS.

In the meanwhile. Could someone possibly help me locate a driver suitable for a peltier?

I can shop on farnell.co.uk and uk.rs-online.com

Basically I want something that takes a logic PWM (500Hz) wave and turns it into a voltage that can drive my peltier (15V 9A max)

I was thinking something like this:
http://focus.ti.com/lit/ds/symlink/drv8402.pdf

Would that work or are there better alternatives?

 

Ok I've found the source of the problem now but I have no idea what's going on...

As soon as I plug in the negative pole of the source (to the S of the MOSFET) the mosfet opens. I.e when the source is fully connected (and off!) the MOSFET opens.

Any idea why this might be happening?

 

By source, do you mean the 13.8V source in your previous diagram?

What is the Vin set to at this point? Can you measure it?

 

As someone has asked before, can you take a picture of the connections to the MOSFET? Label which connection is which...

You also mentioned in a previous post that when the PWM is off the circuit was on. Are you forcing the gate to GND so the part stays off?

 

As someone has asked before, can you take a picture of the connections to the MOSFET? Label which connection is which...

You also mentioned in a previous post that when the PWM is off the circuit was on. Are you forcing the gate to GND so the part stays off?

You're right. I'm an idiot Left my inductor and capacitor from the previous circuit intact and they were charging the gate.

It works completely fine now with only the mosfet and the peltier...

Only recommendation I would make for others as wayneh said is to get a current rating far far above what you're running at!!

Thanks for all the help guys. It looks fairly stable so I probably won't need the low pass filter.