Heat sink temperature for 10 watt led load
- Thread starter Bronx68
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srfreddy
Enlightened
Depends on the heat transfer of the mounting method.
The led is mounted on a mcpcb board with thermal paste. The junction to slug is 1.8 deg C per watt and the slug to mcpcb is 2 deg C per watt. So between these 2 interfaces the led junction should be about 38 deg C higher than the heat sink. Since the Tj rating of the led is 125 deg C I should be able to get away with a heat sink with a thermal resistance of about 7 deg C / watt. I would like to have quite a bit of head room to extend the led life. What kind of safety margin is everyone using for long led life?
srfreddy
Enlightened
The heatsink has to be dissipating heat. The junction between the star and heatsink will have to be perfectly flat for the numbers to work, so you should have some headroom and lap both surfaces with sandpaper... But I don't know how hot the heatsink should be... don't forget that the whole heatsink isn't the same temperature.
