Thermal Design of a LED Multi-chip Module for Automotive Headlights

In this paper, a LED multi-chip module with a heat pipe was designed for automotive headlights, which took advantages of the relative air flow during vehicle travelling for forced convection to keep the junction temperature of LED chips below 60 degrees C. The Structure is compact enough to be suitable for placement in a small space for automotive lighting. The influence of paraments on the junction temperature of LED chips, such as the distance of LED arrangement and dimensions of both DBC substrates and sinks, has also been discussed by numerical simulation using ANSYS software. Then, the structure of the module was optimized. The junction temperature was measured using the forward voltage method, under the condition of both natural convection and forced convection. It was analyzed that the factors having an effect on thermal performance of the module. Furthermore, taking the condition of natural air convection during vehicle stopping into account, a temperature control system was designed for this module.