Comparison on the Thermo-Optical Performance of LEDs with MCPCB and FR4PCB under Various Drive Currents and Ambient Temperatures

Abstract

Proper heat management is necessary for better performance of the LEDs. In the present study, the thermo-optical properties of the LED with different type of PCBs were analyzed. The measurement was done with two different testing conditions to identify the effect of increasing drive current at constant ambient temperature and increasing ambient temperature at constant drive current on the the LEDs with different PCBs. In both the conditions, the thermal behaviors of the LED are affected much due to different type of boards. As the drive current increases, the junction temperature and RthJA of the LED with MCPCB reduces around 3.7K/W and 15.3K/W compare with the LED with FR4. The change in magnitude of chromaticity coordinates of LED with FR4PCB and MCPCB calculated as 0.154 and 0.132 respectively. At a lower ambient temperature, the LEDs with FR4 and MCPCB record the RthJA as 71.2K/W and 50.6K/W respectively. However, these values were lowered around 15% at higher ambient temperatures for both the LEDs. As ambient temperature increases, the shift in chromaticity coordinates for the LEDs with MCPCB and FR4 was obtained as 0.0163 and 0.0165. The influence of the different type of PCB’s performance on LEDs was observed in the increasing drive current condition rather than the increasing ambient temperatures.