Zth-Scope: Thermal Impedance Measurement System for Power Semiconductors with Variable Sample Time

This paper presents a novel device for measuring the transient thermal impedance of power semiconductors, called the zth-scope. Containing a high-speed Analog-to-Digital Converter and also being responsible for controlling auxiliary switches via fibre-optics, it facilitates such a measurement noticeably, compared to usual setups. It also features a touch display for showing measurement data and controlling measurements easily. A detailed overview of the system design process is given and also an example measurement of a high-power semiconductor module is presented and discussed.