A 30-frames/s, 252 x 144 SPAD Flash LiDAR With 1728 Dual-Clock 48.8-ps TDCs, and Pixel-Wise Integrated Histogramming
A 30-frames/s, 252 x 144 SPAD Flash LiDAR With 1728 Dual-Clock 48.8-ps TDCs, and Pixel-Wise Integrated Histogramming
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DOI：
10.1109/jssc.2018.2883720
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发表时间：
2019-04-01
影响因子：
5.4
通讯作者：
Charbon, Edoardo
中科院分区：
文献类型：
--
作者：
Zhang, Chao;Lindner, Scott;Charbon, Edoardo
一个252 x 144单光子雪崩二极管（SPAD）像素传感器，称为Ocelot，被报道用于光探测和测距（激光雷达）。该传感器采用180纳米CMOS技术制造，具有1728个12位时间-数字转换器（tdc），分辨率为48.8 ps （LSB）。半列中的每126个像素通过碰撞检测总线连接到6个tdc，从而实现了资源的有效共享，因此填充系数为28%，像素间距为28.5 μ m。基于双时钟架构的列并行tdc的DNL为+0.48/-0.48 LSB， INL为+0.89/-1.67 LSB；它们以可扩展的菊花链方法动态重新分配，每半柱每个照明周期最多可以检测五个光子。该传感器可以工作在时间相关单光子计数（TCSPC）和单光子计数（SPC）模式下，同时在传感器的工作中包含峰值检测（PD）和部分直方图（PH）。PD和PH模式是通过基于3.32 mb sram的PH读出（PHR）方案提供14.9比1的压缩，首次实现完整阵列的集成直方图实现的。遥测测量高达50米达到8.8厘米的精度和1.4毫米（西格玛）的最坏情况的精度。演示了基于Ocelot的使用直接飞行时间（dTOF）的闪光激光雷达，采用平均功率为2 mW，峰值功率为0.5 W的超低功率激光器，以30帧/s的帧速率实现短距离深度成像。
A 252 x 144 single-photon avalanche diode (SPAD) pixel sensor, called Ocelot, is reported for light detection and ranging (LiDAR). The sensor, fabricated in the 180-nm CMOS technology, features 1728 12-bit time-to-digital converters (TDCs) with 48.8-ps resolution (LSB). Each 126 pixels in a half-column are connected to six TDCs through a collision detection bus, which enables effective sharing of resources, and consequently a fill factor of 28% with a pixel pitch of 28.5 mu m. The column-parallel TDCs, based on dual-clock architecture, exhibit a DNL of +0.48/-0.48 LSB and an INL of +0.89/-1.67 LSB; they are dynamically reallocated in a scalable daisy chain approach that enables a maximum of five photon detections per illumination cycle per half-column. The sensor can operate in time-correlated single-photon counting (TCSPC) and single-photon counting (SPC) modes, while peak detection (PD) and partial histogramming (PH) are included in the operation of the sensor. The PD and PH modes are enabled by the first implementation of integrated histogramming for a full array via 3.32-Mb SRAM-based PH readout (PHR) scheme providing a 14.9-to-1 compression. Telemetry measurements up to 50 m achieve an accuracy of 8.8 cm and worst-case precision of 1.4 mm (sigma). A flash LiDAR using direct time of flight (dTOF) and based on Ocelot is demonstrated, achieving depth imaging at short distances with a frame rate of 30 frames/s, employing an ultra-low power laser with an average power of 2 mW and peak power of 0.5 W.