LED Driver Design and Thermal Management

Abstract

The lighting industry has been ushered to a new lighting revolution with the advent of light emitting diode (LED). During the last decade, research work carried out extensively in material science has completely eradicated the optical shortcomings in LEDs by and large. However, one important aspect still remains a challenge for engineers worldwide—LED thermal management. It has been well established by now that LEDs are prone to degradation in terms of light output with a rise in junction temperature. This paper investigates the aspect of thermal issues pertaining to (a) LED solder point temperature and (b) ambient temperature for 5 mm high-brightness LEDs. 5 mm high-brightness LEDs are selected. The LEDs are subjected to stress environmental conditions and the light output with change in solder point temperature is evaluated. Further, a driver circuit design using LM3464 IC is proposed to arrest the change in light output with solder point temperature. A plot suggesting a correlation is derived to suggest the change in light output with change in solder point temperature. Finally, it also explores the heat dissipation in the solder pad of the LED. The software tool for execution of the plots is carried out using Origin 7 and driver design along with the thermal distribution of the heat sink, with the aid of WEBENCH design tool and Heat Sink Calculator, respectively.