A High-Speed Dual-NMOSFETs Output Stage Buffer with Charge-Transferring Bootstrap Circuit for GaN-Based DToF LiDAR Application

In GaN-based direct time-of-flight LiDAR system, a dual-NMOSFETs output stage buffer with charge-transferring bootstrap (CTB) circuit is proposed to enhance driving capability and transmission speed of GaN driver by voltage boosting of CTB circuit. A LDMOS-less high-voltage level shifter is also provided to ensure high speed of proposed buffer. The buffer has been fabricated in a $0.18\mu \mathrm{m}$ BCD process as part of a GaN driver. Experimental results show that the GaN driver with proposed buffer operates at 50MHz pulse repetition frequency (PRF) with 1.4ns on-time, where the rise/fall time of output pulse are 323ps/333ps and turn on/off delay are 2.41ns/2.56ns. The GaN driver with proposed buffer has stronger driving capability and higher transmission speed than a GaN driver with the same peak source & sink currents.