| 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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