Abstract
Traditionally, gate control of IGBTs could be a way to reduce switching losses and voltage overshoots by means of adding passive components such as snubbers in the circuits. While they are easy to implement and effective, additional part count and power losses make them less attractive. Previous studies focus on methods of changeable driving speed during switching process, with open-loop or close-loop controls, in order to lower di/dt and dv/dt. However, in some cases, the complexity of the control methodology makes them hard to implement for practical uses. The objective of this study is to design a gate driver circuit for insulated gate bipolar transistors (IGBTs) with functions such as two-level turn-on to reduce peak reverse recovery current when turning on the device, two-level turn-off to limit over-voltage when the device is turned off, and under-voltage lock out protection. Based on several requirements to achieve optimal switching performance for IGBTs under hard-switching conditions, principles and operations of the two-level gate control are explained. The improvements of current overshoot at turn-on, voltage overshoot at turn-off, and switching energy losses are measured and discussed. The proposed IC is realized using a foundry’s HV 0.25μm BCD technology. The die area of the IGBT gate driver IC is 2mm × 2mm. Both the simulation and experimental results show good agreement with the theoretical analysis.