Understanding Thermal Interface Conditions of Chip-on-Board LED Light Sources

Thermal management of electronics devices is crucial for (lifetime) performance and reliability. As LED-based light sources are rapidly gaining market share, so is the need to understand their thermal behaviour. This paper analyses thermal interface conditions of a chip-on-board LED light source mounted onto a forced convection heat sink. A stepwise strategy is developed to characterize the heat sink and construct an experimentally validated computational model through which the actual efficiency and power (heat) losses of the light source are determined. Using this reference model, a high-resolution model is developed. Both ideal and poor interface conditions are simulated, and the observational quality of the chip's case temperature measurement point is discussed. Results show that only monitoring the temperature here cannot guarantee that overheating is avoided unless additional design margin or chip assembly validation is considered. Finally, the high-resolution model is also used to analyse the impact of production process variability.