On-State Voltage Sensing of Fast-Switching Power Transistors: Evaluation, Challenges, and Advanced Design Considerations

The fast and accurate sensing of the on-state voltage is a vital part of power semiconductor device characterization. While there are many different approaches and circuits in the literature, the results are often difficult to compare, obstructing the evaluation process. To allow a conclusive comparison with other circuits, a comprehensive evaluation approach to assess and compare on-state voltage measurement circuits is proposed. Additionally, two custom clamping circuits are proposed and evaluated with the developed benchmarking scheme. The circuits reach 3-dB frequencies of 56.7 MHz and 250.9 MHz and average reaction times of 41.1 ns and 23.1 ns, respectively, and can be used for the characterization of 1200 V power devices.