Driving Control of GaN Devices for Transient Response Improvement of Voltage Regulator

Abstract

With the continuous development of microprocessors, more stringent voltage regulation requirements have been put forward for the voltage regulators (VR) in the transient process. This letter proposes a driving control method for gallium nitride (GaN) devices to improve the transient response of the VR. When the GaN device conducts reverse, its source-drain voltage can be controlled by its gate voltage. During load step-down transient, the reverse conduction voltage of the GaN device is naturally applied across the inductor, which can be utilized to speed up the change rate of the inductor current. As a result, the overshoot of the output voltage can be reduced during load step-down transient. The proposed method does not need to modify the power circuit, and is easy to implement. Finally, the effectiveness of the proposed method is verified by experiments. The results show that the output voltage overshoot is reduced by 55%, and the transition time is shortened by 80% using the proposed method. The results also show that with the same overvoltage, using the proposed method can reduce the output capacitance by 57% and the transition time by 77%, thereby increasing the power density of the VR circuit and saving costs.