Comparison of the Thermal Performance of the Multichip LED Packages

Single chip, 4-chip, and 16-chip light emitting diode (LED) packages were prepared to compare the thermal performance of the LED packages. Vertical type, GaN blue LED chips with alumina submount were used, and thermal transient analysis was conducted to investigate the thermal characteristics of the LED packages. Temperature sensitive parameter value was measured and the junction temperature was predicted. Thermal resistance between the p-n junction and the ambient was obtained from the structure function with the junction temperature evolution during the cooling period of LED. Junction temperature and thermal resistance were investigated with the change of input current level and compared for 1-chip, 4-chip, and 16-chip LED packages. The results showed that the junction temperature and the thermal resistance are strongly related to the number of the chips and the chip arrangement.