A correction of measured power MOSFET´s normalized temperature response because of a case temperature rise

A method of power MOSFET´s normalized temperature response (transient thermal impedance) measurement and correction is presented. During the normalized temperature response measurement it is practically impossible to maintain the constant case temperature required by a definition of normalized temperature response. The method introduced enables a correction of the measurement error caused by the case temperature rise. It is based on finding the semiconductor device thermal system model parameters and identifying the point on the thermal model which belongs to the semiconductor device´s case. Measurements of power MOSFET´s normalized temperature response are made with the help of a computer controlled electrical method, with the semiconductor device mounted on a real heatsink. A software package developed enables: (i) graphical representation of temperature responses, (ii) identification of semiconductor device thermal system parameters and (iii) correction of the measurement error caused by the semiconductor device´s case temperature rise.