Heat Dissipation Analysis of High-Power, Multi-Chip LED Bulbs

摘要

To ensure the reliability of high-power light-emitting diode (LED) bulbs, temperature management is very important, including reduction of the junction temperature on the LED chip and enhancing outward thermal dissipation. Simulation can be an effective tool for predicting the temperature distribution over all bulbs, which enables a quantitative analysis. In this study, we investigated a high-power LED bulb consisting of 21 LED packages with a single LED chip for each. We experimentally measured the temperature at the surface of the LED bulb using a thermocouple, and a finite volume method (FVM) simulation was conducted for the same position to confirm the accuracy of the prediction model. In addition, thermal equilibrium models based on heat transfer equations are proposed for quantitative analyses using calculations based on the models. Using this method, we explain the effect of the lens on the surface temperatures of the LED bulb and predict the junction temperature. By comparing the analysis of the heat dissipation characteristics from the calculations to the thermal equilibrium models, we determined the accuracy of the FVM simulation in this study for the variation in thermal conductivity of the heat sink. Based on the reliability of the FVM simulation, we investigated the effects of the surface emissivity of the heat sink and heat convection conditions.