A CMOS SPAD Imager with Collision Detection and 128 Dynamically Reallocating TDCs for Single-Photon Counting and 3D Time-of-Flight Imaging
Per-pixel time-to-digital converter (TDC) architectures have been exploited by single-photon avalanche diode (SPAD) sensors to achieve high photon throughput, but at the expense of fill factor, pixel pitch and readout efficiency. In contrast, TDC sharing architecture usually features high fill facto...
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| Format: | Article |
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MDPI AG
2018-11-01
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| Series: | Sensors |
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| Online Access: | https://www.mdpi.com/1424-8220/18/11/4016 |
| _version_ | 1818473390070038528 |
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| author | Chao Zhang Scott Lindner Ivan Michel Antolovic Martin Wolf Edoardo Charbon |
| author_facet | Chao Zhang Scott Lindner Ivan Michel Antolovic Martin Wolf Edoardo Charbon |
| author_sort | Chao Zhang |
| collection | DOAJ |
| description | Per-pixel time-to-digital converter (TDC) architectures have been exploited by single-photon avalanche diode (SPAD) sensors to achieve high photon throughput, but at the expense of fill factor, pixel pitch and readout efficiency. In contrast, TDC sharing architecture usually features high fill factor at small pixel pitch and energy efficient event-driven readout. While the photon throughput is not necessarily lower than that of per-pixel TDC architectures, since the throughput is not only decided by the TDC number but also the readout bandwidth. In this paper, a SPAD sensor with 32 × 32 pixels fabricated with a 180 nm CMOS image sensor technology is presented, where dynamically reallocating TDCs were implemented to achieve the same photon throughput as that of per-pixel TDCs. Each 4 TDCs are shared by 32 pixels via a collision detection bus, which enables a fill factor of 28% with a pixel pitch of 28.5 μm. The TDCs were characterized, obtaining the peak-to-peak differential and integral non-linearity of −0.07/+0.08 LSB and −0.38/+0.75 LSB, respectively. The sensor was demonstrated in a scanning light-detection-and-ranging (LiDAR) system equipped with an ultra-low power laser, achieving depth imaging up to 10 m at 6 frames/s with a resolution of 64 × 64 with 50 lux background light. |
| first_indexed | 2024-04-14T04:23:21Z |
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| institution | Directory Open Access Journal |
| issn | 1424-8220 |
| language | English |
| last_indexed | 2024-04-14T04:23:21Z |
| publishDate | 2018-11-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Sensors |
| spelling | doaj.art-d1d29a0003164df8afc884e04943b4b42022-12-22T02:12:25ZengMDPI AGSensors1424-82202018-11-011811401610.3390/s18114016s18114016A CMOS SPAD Imager with Collision Detection and 128 Dynamically Reallocating TDCs for Single-Photon Counting and 3D Time-of-Flight ImagingChao Zhang0Scott Lindner1Ivan Michel Antolovic2Martin Wolf3Edoardo Charbon4Quantum and Computer Engineering, Delft University of Technology, Mekelweg 4, 2628CD Delft, The NetherlandsBiomedical Optics Research Laboratory, University of Zurich, Rämistrasse 71, 8006 Zürich, SwitzerlandAdvanced Quantum Architecture Laboratory, École Polytechnique Fédérale de Lausanne (EPFL), Route Cantonale, 1015 Lausanne, SwitzerlandBiomedical Optics Research Laboratory, University of Zurich, Rämistrasse 71, 8006 Zürich, SwitzerlandAdvanced Quantum Architecture Laboratory, École Polytechnique Fédérale de Lausanne (EPFL), Route Cantonale, 1015 Lausanne, SwitzerlandPer-pixel time-to-digital converter (TDC) architectures have been exploited by single-photon avalanche diode (SPAD) sensors to achieve high photon throughput, but at the expense of fill factor, pixel pitch and readout efficiency. In contrast, TDC sharing architecture usually features high fill factor at small pixel pitch and energy efficient event-driven readout. While the photon throughput is not necessarily lower than that of per-pixel TDC architectures, since the throughput is not only decided by the TDC number but also the readout bandwidth. In this paper, a SPAD sensor with 32 × 32 pixels fabricated with a 180 nm CMOS image sensor technology is presented, where dynamically reallocating TDCs were implemented to achieve the same photon throughput as that of per-pixel TDCs. Each 4 TDCs are shared by 32 pixels via a collision detection bus, which enables a fill factor of 28% with a pixel pitch of 28.5 μm. The TDCs were characterized, obtaining the peak-to-peak differential and integral non-linearity of −0.07/+0.08 LSB and −0.38/+0.75 LSB, respectively. The sensor was demonstrated in a scanning light-detection-and-ranging (LiDAR) system equipped with an ultra-low power laser, achieving depth imaging up to 10 m at 6 frames/s with a resolution of 64 × 64 with 50 lux background light.https://www.mdpi.com/1424-8220/18/11/4016single-photon avalanche diodeSPADtime-of-flightdynamic reallocationtime-to-digital convertercollision detection busimage sensorlight detection and rangingLiDAR |
| spellingShingle | Chao Zhang Scott Lindner Ivan Michel Antolovic Martin Wolf Edoardo Charbon A CMOS SPAD Imager with Collision Detection and 128 Dynamically Reallocating TDCs for Single-Photon Counting and 3D Time-of-Flight Imaging Sensors single-photon avalanche diode SPAD time-of-flight dynamic reallocation time-to-digital converter collision detection bus image sensor light detection and ranging LiDAR |
| title | A CMOS SPAD Imager with Collision Detection and 128 Dynamically Reallocating TDCs for Single-Photon Counting and 3D Time-of-Flight Imaging |
| title_full | A CMOS SPAD Imager with Collision Detection and 128 Dynamically Reallocating TDCs for Single-Photon Counting and 3D Time-of-Flight Imaging |
| title_fullStr | A CMOS SPAD Imager with Collision Detection and 128 Dynamically Reallocating TDCs for Single-Photon Counting and 3D Time-of-Flight Imaging |
| title_full_unstemmed | A CMOS SPAD Imager with Collision Detection and 128 Dynamically Reallocating TDCs for Single-Photon Counting and 3D Time-of-Flight Imaging |
| title_short | A CMOS SPAD Imager with Collision Detection and 128 Dynamically Reallocating TDCs for Single-Photon Counting and 3D Time-of-Flight Imaging |
| title_sort | cmos spad imager with collision detection and 128 dynamically reallocating tdcs for single photon counting and 3d time of flight imaging |
| topic | single-photon avalanche diode SPAD time-of-flight dynamic reallocation time-to-digital converter collision detection bus image sensor light detection and ranging LiDAR |
| url | https://www.mdpi.com/1424-8220/18/11/4016 |
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