A 100×80 CMOS Flash LiDAR Sensor with 0.0011mm2 In-Pixel Histogramming TDC Based on Analog Counter and Self-Calibrated Single-Slope ADC

This paper presents a CMOS flash LiDAR sensor with an in-pixel histogramming TDC occupying the smallest size of 1110μm2 based on dual analog counters. The proposed analog counter replaced with histogram memories achieves 3,300-fold power reduction compared with the conventional digital counter. The analog counters and a timing generator in each pixel are reconfigured to a single-slope ADC (SS-ADC) with a self-referenced ramp mitigating nonuniformities of counters. The prototype LiDAR sensor fabricated in a 0.11µm CMOS process demonstrates a 2.3cm depth resolution at a 7.5m distance. An analog counter only consumes 8nW for in-pixel histogramming operation.