Thermal Analysis of Power Module Packaging Using Power-System-in-Inductor (PSI2) Technology

This paper presents a thermal analysis of the power-system-in-inductor (PSI²) packaging for power modules. PSI² uses magnetic material as both the power module packaging and magnetic inductor core to increase inductor winding size and thermal conductivity of the package. Two identical buck power modules are designed using the new PSI² package and traditional plastic packaging. A thermal equivalent circuit (TEC) model is developed to estimate case and junction temperatures based on estimated loss data. FEA simulation is used to validate the TEC and predict the experimental results. Experimentation is conducted at constant load and loss to compare thermal performance of PSI² to conventional plastic epoxy packaging using identical buck power modules. In experimental testing, constant loss experimentation reveals an 8.6 C surface temperature decrease for the PSI² package. Therefore, approximately 33% of the PSI² temperature decrease is attributed to improved package thermal performance.