Thermal analysis of LED lamp with LTCCCOB package

The purpose of this paper is to investigate the thermal behaviors of high power LED packages to enhance the thermal performances of low temperature cofired ceramic chip on board (LTCCCOB) package. Thermal analysis demonstrated an improved LTCCCOB package design that is comparable to a metal lead frame package with low thermal resistance. The LED device developed in this study is a LTCC package mounted directly on the metal PCB. A numerical simulation was performed to investigate the thermal characteristics of the LED module using the finite volume method, which is embedded in commercial software (Fluent V.6.3). Thermal resistance and temperature measurement validate the simulated results. The effect of the thickness of the die attach material on the thermal resistance was dominant due to low thermal conductivity, and the junction temperature decreased significantly with slight increases in thermal conductivity, especially when the value was less than 5 W/mK. The results reveal that the thermal resistance of MCPCB is about 49 per cent58 per cent of the junction to board thermal resistance. The thermal model results showed good agreement with experimental results. The developed model overcomes the large thermal resistance of a conventional LTCC package for high power LED module. The extensive results have demonstrated an improved thermal design, optimal dimensions of each component and boundary conditions for high power LTCCCOB type package.