Efficient modelling approach for transient coupled electro-thermal simulation on the example of a D2PAK application

This contribution derives an efficient approach to model a coupled electro-thermal design problem for transient system simulation, using an analogue simulator, like SPICE. It introduces the electrical and thermal modelling procedures and the coupling of both models. The electrical model is based on the fundamental equations of semiconductor physics. Using the respective physical parameters the model can easily be adapted to an existing component. The thermal model is based on a modified Foster model, extracted from transient FEM simulation results using thermal unit step responses. During the coupled transient simulation the electrical behaviour of each electrical component will be influenced on its self-heating and the coupled heating of active components in vicinity. The approach can also be applied to other coupled problems in MEMS, where a thermal coupling is important. The method will be demonstrated on the example of a D2PAK application, assembled on a PCB, using four MOSFET transistors.