Fast extraction of dynamic thermal impedance for multi-chip power modules

A novel method for the extraction of the dynamic thermal impedance models of multi-chip power modules is presented. The method described is a fast, accurate approach based on the GMRES algorithm that extracts dynamic thermal impedance expressions without the need for curve fitting to finite-element or experimental data. The method is applied to an example half-bridge multi-chip power module. It is shown that dynamic thermal impedance can be constructed using the dominant eigenvalues of the finite-difference matrices and these eigenvalues can be obtained from a reduced order system model available from GMRES. The models generated are compared against finite element data and a traditional curve fit models produced from the FEM results.