Electronics > Projects, Designs, and Technical Stuff
My constant current load - 90W , 3A 30V
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Harvs:
Without an insulator and using Arctic Silver thermal paste, I had 60W per TO220 mosfet being transferred into a CPU cooler (120W total), not getting above about 60 degrees C.  But that's with a heatpipe cooler, I couldn't get close to that result with a standard alu heatsink.

When paralleling mosfets I used two control loops.  Tied the drains together to the input, then had separate load sense resistors and op-amps. If you just hook them together like you have, then you're going to struggle to get equal current sharing.  Sense resistors and op amps are cheap... ;)
Spikee:
I prefer one big TO-264 package n channel mosfet. I saw some high power ones from IXYS at farnell at a reasonable price.
I do not mind paying around 5-9 euro for one of those mosfets. The bigger packaging also is nicer to solder to.

Now i need to find one that is suited for my application.

Gate drive voltage : 0 -> 12V
Voltage rating: from 75V and up
Current rating: 10A and up
Watt rating: 100W and up

blackdog:
Hi Spikee

Buy 5 a 10 of these Fets:
http://www.dickbest.nl/index.php?_a=viewProd&productId=2164

Select the fet's, see picture


Kind regarts,
Blackdog
Harvs:

--- Quote from: Spikee on November 29, 2012, 10:35:00 am ---I prefer one big TO-264 package n channel mosfet. I saw some high power ones from IXYS at farnell at a reasonable price.
I do not mind paying around 5-9 euro for one of those mosfets. The bigger packaging also is nicer to solder to.

Now i need to find one that is suited for my application.

Gate drive voltage : 0 -> 12V
Voltage rating: from 75V and up
Current rating: 10A and up
Watt rating: 100W and up



--- End quote ---

None of that is particularly difficult.  The cheapest TO-264 mosfet on digikey, IXFK230N20T, could easily do it.

With the junction to case and typical case to heatsink figures you're only looking at a 24 degree difference at 100W from junction to heatsink with a 175 degree max temp.  Your difficulty will just be to keep the localized heating in your heatsink under control.  That's where heatpipes are king.
Spikee:
I can't get the IXFK230N20T at farnell so that would be a bit of a problem.
To prevent localized heating multiple fets would be the best solution.
I have ordered the fets blackdog suggested and i will use his method to match a pair of them.

They will arrive tomorrow or saturday . I will test them on sunday / monday .
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