A Cross-Scale Electrothermal Co-Simulation Approach for Power MOSFETs at Device-Package-Heatsink-Board Levels

This paper proposes a cross-scale simulation approach for evaluating the steady-state electrothermal performance of power MOSFETs at the device-package-heatsink-board (DPHB) level. A co-simulation framework is designed by employing the iterative process of power loss and chip temperature to bridge the device and package-heatsink-board (PHB) level simulators. As a result, the cross-scale electrothermal coupling effect within multilevel settings is considered. Correspondingly, variation values in chip temperature and temperature-dependent drain current can be obtained at various voltage biases, level settings, and DPHB structural parameters, incorporating cross-level physical insights. The simulation results are compared with existing methods, and their features and limitations are discussed. Additionally, this paper also derives an empirical equation from the co-simulations to characterize the relationship between the drain current and the chip temperature under different operations exactly. A commercial MOSFET with TO-220F packaging is implemented in experiments to extract the chip temperature and drain current in electrothermal equilibrium. The method comparisons and fair agreement among simulations, equations, and measurements presents the proposed approach as generalized and powerful for describing variations in chip temperature and drain current considering from micrometer devices to millimeter packages-heatsinks-PCB boards, thus providing effective support for DPHB-level co-design.