A 64 × 64 SPAD Flash LIDAR Sensor Using a Triple Integration Timing Technique With 1.95 mm Depth Resolution

Abstract

This paper presents a 64×64 dual mode flash LIDAR sensor that utilizes a triple integration timing technique. The sensor, fabricated in 130 nm HV CMOS, is capable of operating in both a direct time-of-flight (ToF) mode where the timestamp of the first arriving photon is recorded per-pixel, as well as a photon counting mode where the number of photons is recorded over a time interval. The timing technique utilizes both a time-to-digital converter (TDC) and a time-to-amplitude converter (TAC) with a counter measuring global clock cycles and the triple integration interpolator (TII) measuring between clock cycles. The TII uses an analog integration with an additional two reference integrations allowing the time measurement to be resistant to PVT variation and in turn, allowing the circuit to be miniaturized without causing a large timing non-uniformity across the array. Utilizing the TII, the sensor achieves a state-of-the-art timing performance, with a resolution of 13 ps (1.95 mm depth resolution), a maximum range of 220 μs (32 km), a single-shot jitter of 233 ps, and a differential non-linearity (DNL) of 6 ps (0.47 LSB). The sensor captures at a maximum frame rate of 8,300 fps and consumes 733 mW during operation. Experimental scenarios demonstrating the operation of the sensor are also provided.