An Automotive LiDAR SoC for 240 × 192-Pixel 225-m-Range Imaging With a 40-Channel 0.0036-mm2 Voltage/Time Dual-Data-Converter-Based AFE

Abstract

This article presents a 40-channel high-resolution automotive LiDAR system-on-chip (SoC), which utilizes the world's first dual-data converter (DDC). The proposed DDC consolidates the functions of ADC and TDC into a single circuitry and achieves acquisition of both high-precision time and voltage data from the input, realizing a 5× smaller analog front-end (AFE) area than prior arts. Such innovations lead us to a 40channel AFE integration of the SoC without silicon cost increase, which characterizes our LiDAR system with 2× higher pixel resolution. To enhance the ADC's signal-to-noise and distortion ratio (SNDR) without sacrificing the area efficiency, a calibrationfree and variation-tolerant voltage-controlled oscillator (VCO)based ADC with a multiphase pulse density modulator (MP-PDM)-based feedback is proposed. Our proof-of-concept LiDAR system achieves a measurement range of 225 m at 70-klx direct sunlight, with a resolution of 240 × 192 pixels at 10 frames per second (FPS). To quantitatively measure the effect of the resolution improvement of our LiDAR, we evaluate the LiDAR's detection accuracy of small targets 75 m away. Due to the 2× higher vertical pixel resolution, our LiDAR can detect targets with 2× smaller height. The 3-D point cloud of the LiDAR captured outdoor in the wild is presented.