Modeling the Temperature Dependence of TDDB in Galvanic Isolators Based on Polymeric Dielectrics

We present an analytical model to reproduce the non-monotonic temperature dependence of Time-Dependent Dielectric Breakdown (TDDB) in galvanic isolators based on polymeric dielectrics. The model is based on the concurrent action of two competing mechanisms involved in the TDDB dynamics, namely the worsening of the polymer dielectric strength due to moisture and the outdiffusion of water molecules during the electrical stress phase. By catching the most relevant features of the temperature dependence of TDDB in a simple yet effective way, the model represents a valuable tool to support the design of galvanic isolators based on polymeric dielectrics.