A GaN Driver for a Bi-Directional Buck/Boost Converter With Three-Level V $_GS$ Protection and Optimal-Point Tracking Dead-Time Control

This paper presents a gate driver for a GaN-based half-bridge structure operating in a buck converter with input voltage >40 V or a boost converter with output voltage >30 V. Two 500 pF on-chip capacitors are utilized to construct three-level gate drivers, providing a near- $V_{{DD}}$ negative voltage for gate of the rectifier switch to eliminate the induced pulse on the gate from the high dv/dt slew rate of $V_{X}$ when the main switch is turned on. The dead time controller tunes the delay of the gate signal of the rectifier switch by sensing the slope of $V_{X}$ , thus the near-optimal zero-voltage switching can be achieved with deviation <3 ns. The GaN driver is implemented with a 0.18-mu m BCD process. The efficiencies can be improved by 8.33% and 6.87% at light load in a buck and a boost converter due to the dead-time control. The peak efficiencies of 20 V-12 V and 12 V-18 V conversions are 86.37% and 84.39%, respectively.

Automated summary

This paper presents a gate driver for a GaN-based half-bridge structure operating in a buck converter with input voltage >40 V or a boost converter with output voltage >30 V. The gate driver utilizes two 500 pF on-chip capacitors to construct three-level gate drivers, providing a near-$V_{{DD}}$ negative voltage for the rectifier switch gate to eliminate induced pulses on the gate. The dead time controller adjusts the gate signal delay of the rectifier switch based on the slope of $V_{X}$, achieving near-optimal zero-voltage switching with <3 ns deviation. The GaN driver is manufactured using a 0.18-μm BCD process. The efficiencies of the buck and boost converters are improved by 8.33% and 6.87% at light load, respectively, due to the dead-time control. The peak efficiencies of the 20 V-12 V and 12 V-18 V conversions are 86.37% and 84.39%, respectively.