Thermal characterization of a printed circuit board with thermal vias for the application of high brightness light-emitting diodes

Abstract

The power of state-of-art LED has been substantially raised for the continuous demand of high lumen output. Limited by the overall efficiency, at least 70% of the total input power would be transformed into heat. As a result, thermal management gained more and more attention. For the sake of reducing the material cost and also further improving the thermal performance, the FR-4 printed circuit board (PCB) cooperating with thermal via as the alternative of metal core PCB (MC-PCB) is attracting more and more attentions. In this study, the LED devices using thermal via for heat dissipation were fabricated and characterized. By means of the transient thermal characterization, the thermal performances of these devices were estimated. Firstly, the thermal resistance of the LED component was achieved through the dual thermal interface method by surface mounting the components with two types of soldering materials of different thermal conductivities. Then, the junction temperatures and the structure function of every sample were measured and the corresponding thermal resistances of their PCBs were obtained. Through the comparison among all the samples, it can be observed that the FR-4 PCB with fully filled thermal via showed a prominent thermal performance better than the MC-PCB.