Analysis of Pulse-Driven LED Junction Temperature and its Reliability

LEDs need to be strobed at some higher pulsed current whenever high light output for a short duration is necessary. It is known the higher pulse current induces the more localized current crowding with overheating and leads to the thermal runaway, and eventually can result in the early catastrophic damage. In this paper, the LED light output depreciation and the junction temperature rise are investigated to evaluate its reliability under the pulse width modulation (PWM) driven mode with different currents, duties and frequencies.