Thermal Impedance Extraction Technique for Power MOSFETs

This paper investigates proposals for advances in thermal characterisation techniques of power MOSFET packages. The basic contributions are focused on improving the performance of existing and well-known methods for thermal impedance extraction so as to allow for modelling the high thermal dynamic range of the power device. It means to effectively extend the transient thermal impedance curve to shorter pulse widths. To make this possible, a measurement technique is proposed that aims at overcoming two basic limitations of conventional techniques: the bandwidth response of the temperature sensing means and the accuracy of the power pulses injected into the device for heating up. Experimental results show the effectiveness of the method to measure transient thermal curves of short power pulses and derive corresponding parameters of a lumped model.