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Proceedings Paper

Thermal characterization of single-die and multi-die high power light-emitting diodes
Author(s): A. Keppens; D. De Smeyter; W. R. Ryckaert; G. Deconinck; P. Hanselaer
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Paper Abstract

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.

Paper Details

Date Published: 2 September 2008
PDF: 12 pages
Proc. SPIE 7058, Eighth International Conference on Solid State Lighting, 70580H (2 September 2008); doi: 10.1117/12.794836
Show Author Affiliations
A. Keppens, Univ. College Kaho St.-Lieven (Belgium)
K. U. Leuven (Belgium)
D. De Smeyter, Univ. College Kaho St.-Lieven (Belgium)
W. R. Ryckaert, Univ. College Kaho St.-Lieven (Belgium)
K. U. Leuven (Belgium)
G. Deconinck, K. U. Leuven (Belgium)
P. Hanselaer, Univ. College Kaho St.-Lieven (Belgium)
K. U. Leuven (Belgium)

Published in SPIE Proceedings Vol. 7058:
Eighth International Conference on Solid State Lighting
Ian T. Ferguson; Tsunemasa Taguchi; Ian E. Ashdown; Seong-Ju Park, Editor(s)

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