Study on the temperature-dependent thermal resistance matrix of a multi-chip LED-matrix

Abstract

The solid lighting industry comply with costumer's requirements of high light output and a higher grade of functionality, especially in the automotive sector. The integration of multiple LED-chips on one illuminant has the advantage of weight and size reduction. However, multiple LED-chips lead to increased power density; to get rid of their produced heat, an energy strategy is necessary. The key term is Thermal Management, to understand the thermal behavior of a LED lighting system. In this paper, the investigation of the thermal interdependencies of a 4-chip-matrix was presented. The thermal characterization was done by thermal transient measurements of each chip and their structure functions, followed by the study of its thermal resistance (Rth) matrix. The Rth-matrix represented the thermal properties of each LED-chip and its interdependency. As supplement of the thermal characterization, thermal simulations were carried out. Moreover, the Rth-matrix was used to analyze the LED-matrix in terms of their temperature dependency. The heat path investigation via Rth-matrix showed different behaviors of the 4-chip-matrix by using different heat sink temperatures. The method was used as an evaluation tool for thermal management of LED-matrix systems.