This paper presents an approach to the analysis of transient thermal states in electronic circuits using
an analytical solution of the heat equation. Fully three-dimensional analytical time dependent
solutions are determined for multilayered structures with the help of Green`s functions (GFs). The
GFs required for the solution are found using a Galerkin-based integral method. The entire solution
method is illustrated in detail using a practical example, where the results of transient thermal
simulations of a real hybrid power module are compared with infrared measurements.