Latest Article——Junction temperature measurement of alternating current light-emitting-diode by threshold voltage method
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Abstract
Junction temperature of alternating current light-emitting-diode (AC-LED) has a significant effect on its stable light output and lifetime. The threshold voltage measurement is employed to characterize the junction temperature of AC-LED, due to its excellent merits in high efficiency and accuracy. The threshold voltage is measured when the driving current of an AC-LED rises to a reference on-set value from the zero-crossing node. Based on multiple measurements of threshold voltage at different temperatures, a linear relationship was uncovered between the threshold voltage and the junction temperature of AC-LED with the correlating factor of temperature sensitive parameter (TSP). Thereby, we can calculate the junction temperature with the TSP and threshold voltage once the AC-LED stays at thermal equilibrium state. The accuracy of the proposed junction temperature measurement technique was found to be±3.2°C for the reference current of 1 mA. It is concluded that the method of threshold voltage is accurate and simple to implement, making it highly suitable for measuring the junction temperature of AC-LED in industry.
Keywords optoelectronics junction temperature measurement threshold voltage method alternating current light-emitting-diode (AC-LED) |
Corresponding Authors: Ran YAO |
Just Accepted Date: 17 September 2015 Online First Date: 26 October 2015 |