2 September 2008 Thermal characterization of single-die and multi-die high power light-emitting diodes
Author Affiliations +
The forward voltage Uf for single-die high-power light-emitting diodes (LEDs) driven at currents within a specific current interval is proportional to the diode junction temperature T . This correlation can be used to determine junction temperatures in lots of practical applications. However, multi-die high-power LED modules with multiple series or parallel connections of diode chips are believed to have a much greater potential to be used in general lighting than single-die packages. The current-voltage characteristics of a variety of multi-die LEDs, ranging from two to a few hundred dies, are recorded at different ambient temperatures. The results are used to model the forward voltage as a function of a generalized junction temperature. In multi-die LED modules these models allow analogous junction temperature determination as in single-die packages. The influence of drive current and drive mode (DC or PWM) on junction temperature is examined and compared for both single-die and multi-die packages. Apparently, junction temperature only significantly increases when a certain current level is exceeded, depending on the internal series resistance of the complete LED package. Moreover, combining Uf (T) models for single-die and multi-die LEDs allows for the characterization of thermal interactions between different dies of multi-die packages, whether they are switched on or not. The junction temperature of separate LED dies in multi-die modules can then be predicted and used for further diode characterization.
© (2008) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
A. Keppens, A. Keppens, D. De Smeyter, D. De Smeyter, W. R. Ryckaert, W. R. Ryckaert, G. Deconinck, G. Deconinck, P. Hanselaer, P. Hanselaer, "Thermal characterization of single-die and multi-die high power light-emitting diodes", Proc. SPIE 7058, Eighth International Conference on Solid State Lighting, 70580H (2 September 2008); doi: 10.1117/12.794836; https://doi.org/10.1117/12.794836

Back to Top