Thermal parameter estimation using recursive identification

A method that converts a semiconductor transient thermal impedance curve (TTIC) into an equivalent thermal R-C network model is presented. Thermal resistance (R) and thermal capacitance (C) parameters of the model are identified using manufacturer´s data and offline recursive least square (RLS) techniques. Relevant estimation theory concepts and the formulation of an appropriate model for the identification process are given. Model synthesis is illustrated using an isolated base power transistor module. The application of time decoupled theory for high order thermal models is outlined. Simulation of junction temperature responses using model and manufacturer TTICs are compared. Identified parameter validity is further confirmed by parameter calculation obtained from module physical dimensions.<>