Thermal performance of heatsink and thermoelectric cooler packaging designs in LED

Abstract

Active heat dissipation method plays a vital role in thermal management of high power light emitting diode (LED) packaging. As a new cooling device, thermoelectric cooler (TEC) is applied in electronic packaging, for which the extensively applied devices are the heatsink and the fan by now. In order to evaluate the cooling performance of the heatsink and TEC, three different cooling models for light emitting diode (LED) packaging, which include the heatsink model, the heatsink and fan model and the TEC, heatsink and fan model, are established and their thermal performance of packaging are investigated in present study. Junction temperatures of the chip are measured by experimental measurement method, the thermal resistances of TEC, thermal interface material (TIM) and heatsink are analyzed by thermal resistance network method in the situation of different chip power, different TEC input current and different wind speed caused by the fan. The optimal input currents of TEC in different conditions are analyzed. Based on the cooling performance of the different models, the critical chip power is 35 W between the TEC method and the heatsink method at the same time the junction temperature is 40 °C. For optimizing the TEC, it's necessary to reduce the thermal resistance of TEC as same as improve its cooling capacity because the thermal resistance of TEC plays a major role in the total resistance of LED package.