Robust Gate Driving Vectors to Load Current and Temperature Variations for Digital Gate Drivers

Abstract

A digital gate driver is effective to solve the trade-off between the switching loss and the current/voltage overshoot of power transistors. A load current and temperature dependent optimization of the gate driving vectors for the digital gate drivers, however, is required [13], because an optimum vector at a particular load current and temperature does not often work at different conditions. When sensors for the load current and/or temperature are not available, the digital gate drivers are not useful under load current and temperature variations. To solve the problem, robust gate driving vectors to load current and temperature variations for the digital gate drivers are proposed. To compare a conventional single-step gate drive and the proposed robust gate driving vectors, the switching loss and the current/voltage overshoot in turn-on/off state of IGBT are measured by using a 6-bit programmable digital gate driver IC across nine conditions including different load currents (20 A, 50 A, and 80 A) and temperatures (25 °C, 75 °C, and 125 °C). The performance of the switching loss and the current/voltage overshoot of the proposed robust vectors is improved by 2% to 11 % and 16 % to 29 % across the nine conditions in turn-on/off state, respectively, which indicates that the proposed robust vectors requiring no current and temperature sensors are a useful method for the digital gate drivers.