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A 30-frames/s, $252\times144$ SPAD Flash LiDAR With 1728 Dual-Clock 48.8-ps TDCs, and Pixel-Wise Integrated Histogramming


Zhang, Chao; Lindner, Scott; Antolovic, Ivan Michel; Mata Pavia, Juan; Wolf, Martin; Charbon, Edoardo (2019). A 30-frames/s, $252\times144$ SPAD Flash LiDAR With 1728 Dual-Clock 48.8-ps TDCs, and Pixel-Wise Integrated Histogramming. IEEE Journal of Solid State Circuits, 54(4):1137-1151.

Abstract

A 252 × 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 μm. The columnparallel 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 timecorrelated 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 SRAMbased 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 (σ). 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.

Abstract

A 252 × 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 μm. The columnparallel 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 timecorrelated 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 SRAMbased 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 (σ). 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.

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Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:04 Faculty of Medicine > University Hospital Zurich > Clinic for Neonatology
Dewey Decimal Classification:610 Medicine & health
Scopus Subject Areas:Physical Sciences > Electrical and Electronic Engineering
Uncontrolled Keywords:Electrical and Electronic Engineering
Language:English
Date:1 April 2019
Deposited On:07 Feb 2020 09:09
Last Modified:29 Jul 2020 13:37
Publisher:Institute of Electrical and Electronics Engineers
ISSN:0018-9200
OA Status:Closed
Publisher DOI:https://doi.org/10.1109/jssc.2018.2883720
Official URL:https://ieeexplore.ieee.org/document/8595429
Project Information:
  • : FunderFP7
  • : Grant ID312807
  • : Project TitleTHOR - INNOVATIVE THERMAL MANAGEMENT CONCEPTS FOR THERMAL PROTECTION OF FUTURE SPACE VEHICLES

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