Study on the Junction Temperature Measurement of GaN Based LED Using Resistance Temperature Coefficient

The relationship between the resistance and the temperature of a GaN based light emitting diode(LED) has been investigated under different driving current.It was found that the resistance decreased proportionally with an increase in the temperature.The resistance-temperature coefficient has been obtained by linearly fitting resistance and temperature.The coefficient values keep almost constantly in a wide driving current range.Using this characteristic,the junction temperatures of LED under any working current(within the current range in which the coefficient values almost constantly) can be detected by determining the resistance-temperature coefficient under a specific current.