Active gate control in half-bridge inverters using programmable gate driver ICs to improve both surge voltage and switching loss

The requirements for peripheral circuits of power converters are becoming restrictive due to the enhancement of Si power devices and the practical use of SiC and GaN devices. In the design of recent converters with high-speed switching, we must consider the stray inductances and capacitances in the device package and the gate drive circuit in addition to those in the main circuit of the power converter. In these situations, the gate driving technique is a key technology to enhance the high-speed switching ability of power devices, as there are design limitations to reduce the stray inductances and capacitances. So far, several active gate control methods have been proposed. However, most conventional active gate drivers are configured using analog circuits such as transistors and diodes. Thus, it is difficult to reconfigure their control parameters to fit the stray inductances and capacitances after the implementation of power converter and gate circuits. As a solution to these problems, we have proposed a programmable gate driver IC, which is a digitally controlled circuit. This gate driver IC can control the gate current at 63 separate levels, operated by programmable full-digital 12-bit and the clock signals. In this study, an active gate current control based on the load current in a half-bridge inverter with two programmable gate driver ICs is demonstrated. It is verified that the proposed active gate control can effectively improve the trade-off relationship between the surge voltage and switching loss of the PWM half-bridge inverter circuit.