View Single Post
Old 08-20-2011, 07:39 PM   #74 (permalink)
George Tyler
EcoModding Lurker
 
Join Date: Jan 2011
Location: Hamilton, New Zealand
Posts: 74
Thanks: 1
Thanked 3 Times in 3 Posts
Quote:
Originally Posted by ConnClark View Post
I am. I had to have some diodes though. FETs won't work very well on their own. They can act like a diode for start up but they have a limit on the amount of current you can pass through them. I still need some diodes in parallel to the FETs. Also the diodes will serve as a back up if the FETs get fried.
The diodes can be used, they used to be slow on old FETs but the newer ones are fast too, and can usually handle similar currents, that fet you are using has a diode current peak rating of 400A, continuos of 89A at 25 deg C, not sure what it is at 100 C. It would still do it. Also, the FETs will die short curcuit, though it could fuse the bonding wire I suppose. there may be better FETs for this puspose, I also don't like driving them with an opamp for a number of resons. a driver IC would do a much better job, and you could use a comparitor instead of a opamp.
  Reply With Quote