Active Gate Driver Combining Current Source and Active Gate Resistors to Reduce Turn-on Switching Loss and Surge Voltage

Active gate drivers (AGDs) improve the trade-off between switching losses and surges by actively manipulating switching transitions. However, conventional AGDs have limitations to achieve enough high-speed driving. This is because most of them change their switching transitions with a few gate resistors and a fixed supply voltage for the gate driver. In this paper, a novel AGD that combines a current source and active gate resistors is proposed. The proposed circuit further reduces turn-on losses with current source compared to those of conventional AGD. The proposed circuit also introduces the comparable turn-off switching loss reduction as conventional AGD with active gate resistors. Double-pulse tests confirmed that the proposed circuit reduces turn-on switching loss by maximum 32.4 % compared to a conventional gate driver and maximum 4.82 % compared to conventional AGD.

I. Introduction

Downsizing and higher efficiency of the power conversion circuits are required in many applications. There is a growing trend to replace conventional Silicon (Si) power semiconductors with wide bandgap semiconductors[1]. In inverters used to drive motors, Si-insulated gate bipolar transistor (IGBT) with high withstand voltage have been widely used, though they have the disadvantage of slow switching speed. By replacing Si-IGBT with Silicon-Carbide (SiC) -metal-oxide-semiconductor field effect transistor (MOSFET), faster switching speed and low conduction loss can be achieved [2]. The faster the switching speed lead to the lower the switching loss, though the higher surge voltage of the switching device occurs.