IRF9540N
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johnuready
- Posts: 1
- Joined: Mon Nov 16, 2015 5:50 pm
IRF9540N
Newbie here. Getting back to electronics after a few years. I'm looking at building a device where 4 mosfets sink max 80w each. I'm trying to work out what heat sink I will require to take 4 devices? Anybody help?
Re: IRF9540N
You are sinking 320W in total - the short answer is a large one!
The longer answer is to check out the thermal dissipation of available heatsinks. This will be given as so many degrees C per watt. You will need to work out the max temp that the mosfets will stand, allow a generous margin of safety. Multiply the watts to be dissipated (I suspect you will need one large heatsink per device) by the heat sink's dissipation, and this will give the rise in temp. Check the max temperature rise is within the spec for the mosfets.
Don't forget to bolt the mosfets with heat conducting grease (usually looks like white toothpaste) between the device and the metal. It would also be a very good idea to arrange a temperature sensor on each sink to cut out in the event that things get too hot. A couple of fans (such as you see in computers) of adequate size would not be a bad idea also. Err on the side of caution!
Hope this helps.
The longer answer is to check out the thermal dissipation of available heatsinks. This will be given as so many degrees C per watt. You will need to work out the max temp that the mosfets will stand, allow a generous margin of safety. Multiply the watts to be dissipated (I suspect you will need one large heatsink per device) by the heat sink's dissipation, and this will give the rise in temp. Check the max temperature rise is within the spec for the mosfets.
Don't forget to bolt the mosfets with heat conducting grease (usually looks like white toothpaste) between the device and the metal. It would also be a very good idea to arrange a temperature sensor on each sink to cut out in the event that things get too hot. A couple of fans (such as you see in computers) of adequate size would not be a bad idea also. Err on the side of caution!
Hope this helps.