Self-consistent compact electrical and thermal modeling of power devices including package and heat-sink

This paper shows a hybrid approach to electro-thermal modeling of power device assemblies that aims at bridging the gap between compact models amenable to insertion into circuit simulators and physical models (such as finite-element ones) of the three-dimensional heat flow in the system. We self-consistently couple a standard analytical description of the temperature-dependent electrical behavior of a power MOSFET with a lumped-element thermal network representing the die - package - heat-sink assembly and convective boundary conditions. This lumped-element network is built by partitioning the system into elementary building blocks and assigning to the thermal resistances values determined by the geometrical dimensions and material thermal conductivities. The results of the lumped-element model are shown to be in good agreement with measurements and three-dimensional finite-element simulations.