Important properties of transient thermal impedance for MOS-gated power semiconductors

Important properties of transient thermal impedance (TTI) for MOS-gated power semiconductors are investigated on the basis of measurement results. An electrical method of transient thermal impedance measurement was used with different temperature sensitive electrical parameters (TSEPs). A wide variety of measurements on MOSFET and IGBT samples was performed, to be able to answer the questions about TTI existence conditions. Different types of temperature responses were used, as well as different power dissipation levels and conditions. Finally, a TEMPFET test, with simulation and measurement of overtemperature protection reaction time, shows that TTI of MOS-gated components, if properly measured, can be successfully used for simulative estimation of a semiconductor´s operating temperature.