Parametric Compact Thermal Modeling of Power LEDs

Abstract

Light-emitting diodes are nowadays the most dynamically developing type of light sources. Considering that temperature is the main factor affecting electrical and lighting parameters of these devices, thermal models are essential subcomponents of multidomain models commonly used for simulation of their operation. The authors investigated white power light-emitting diodes soldered to metal core PCBs. The tested devices were placed in a light-tight box on a cold plate and their cooling curves were registered for different diode current and cold plate temperature values. These data allowed the computation of optical and real heating power values and consequently the generation of compact thermal models in the form of Foster and Cauer RC ladders. This rendered possible also the analysis of the influence of the considered factors on compact model element values and their parametrization. Consequently, the resulting models yield accurate estimates of device junction temperature in virtually any realistic operating conditions and they could be easily included in multidomain compact models.