Evaluation of thermal transient characterization methodologies for high-power LED applications

In the past, thermal characterization methodologies for LED packages have mainly been derived from already existing solutions of the microelectronics industry. Within this paper, several issues regarding the determination of the junction-to-case thermal resistance R_thJC for LED packages are addressed. The new JESD51-14 standard is taken into consideration and especially the so called "point of separation" of the underlying dual-interface method is investigated. Experiments and finite element simulations were carried out in order to investigate the environmental influences on this crucial point. The investigations reveal that the point of separation changes depending on the thermal boundary condition at the case of the LED module, viz the quality of the package attach.