How much °C can a LED withstand without taking any damage or...

The_bad_Frag

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Mar 13, 2011
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233
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Germany
So my qustion is how much heat can a LED (XM-L) take in continuous use? I'm planing a flashlight with temperature control and I need a range (like 50-60°) for the controller to program. I read the datasheet but didn't found anything good...:shakehead


Pls help!:candle:
 

andersonEE

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Feb 27, 2009
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Erie, PA
It is not as simple as what specific temperature can the LED take. Cree uses 145 degrees C as a "worst case" allowable junction temperature in their XLAMP Thermal Management App Note. However, you would not get a very long life from the LED at that temp and it would only be putting out about 75% relative luminous flux. Personally, I would shoot for 75 degrees Celsius junction Temperature or less.
 

MikeAusC

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Jul 8, 2010
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995
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Sydney, Australia
You can't measure the Junction Temperature, but you can measure the base temperature, and knowing the thermal resistance between Junction and base from the datasheet, and the power to the LED, you can work out the Junction temperature.
 
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