A Monolithic GaN Laser Diode Driver with Steep-Edge Driving Current for LiDAR Transmitters Using a 3× Self-Circulating Charge Pump

Direct time-of-flight (dToF) light detection and ranging (LiDAR) is widely used for real-time, long-range 3D sensing. It requires narrow optical pulses with high peak power to achieve high detection resolution and long range, imposing high demands on the laser diode driver (LDD) in the LiDAR transmitter. Monolithic GaN integration is well-suited for LDD design, as it minimizes gate-drive loop parasitics and offers devices with superior figures of merit (FOMs). However, conventional GaN-based gate drivers suffer from limited driving capability due to the lack of suitable p-type devices. This article presents an FET-controlled LDD based on a 0.25-μm GaN-on Silicon process. A 3× self-circulating charge pump (3× SCCP) and zero-voltage-drop fast-charging (ZVFC) switches strengthen the pre-driver, enabling high-speed switching of the GaN control switch. Experimental results show that the proposed LDD achieves a 10 A peak driving current with fast edge transitions of 434 ps (rise) and 252 ps (fall). Dead time insertion and an on-chip filtering capacitor suppress shoot-through current in the final stage of the pre-driver. The LDD exhibits an average power loss of 420 mW at 10 MHz and achieves a peak efficiency of 92.44%.