Monolithic Design of 48 V GaN DC-DC Buck Converter with Pulse-Triggered Level Shifter

This paper presents the design of a fully integrated gallium nitride (GaN) half-bridge DC-DC buck converter. The circuit employs a high-frequency half-bridge driver for enhancement-mode GaN-on-Si HEMTs, featuring a stable output scheme that utilizes instant sensing and feedback in accordance with load fluctuations. A self-bootstrap gate driver is designed to enable the implementation of rail-to-rail gate drive control voltages, facilitating the design of circuits with rapid switching speeds and minimal on-resistance. A pulse-triggered level-shifting circuit is proposed to achieve sub-nanosecond propagation delays and reduce power consumption. In addition, a closed-loop pulse-width modulation (PWM) control module is successfully realized without external control. The proposed integrated GaN buck converter could achieve a stable 48 V to 24 V conversion at 1MHz, indicating a high integration level of GaN power converters.