256 x 8 SPAD Array With 256 Column TDCs for a Line Profiling Laser Radar

A receiver circuit for pulsed time-of-flight line profiling laser radar has been designed in 0.35μm CMOS technology. The receiver consists of a line detector array with 256×8 SPADs with a pitch of 41.6μm. The diameter of the SPAD’s active area is 25.6μm, which gives a fill factor of 0.35. Each column has 8 SPADs and a TDC with a range and resolution of 640 ns and 20 ps, respectively. The TDCs are based on the Nutt interpolation method where cyclic converters are utilized as fine converters. A compact demonstrator system has been built with a horizontal FOV of about 37°, which gives a column-wise angular resolution of about 0.15°. This solid-state system uses a pulsed laser diode with cylindrical transmitter optics to illuminate the full FOV of the receiver with a single laser pulse. The system can measure distances up to 30 m @ 28 fps with an accuracy and precision of few millimeters in typical indoor lighting conditions. Outdoors, in direct sunlight conditions, the measurement range is decreased to 5 m. Outdoor range, however, can be increased if frame rate is lowered and more laser shots are accumulated per frame.

Authors:
Keränen Pekka, Kostamovaara Juha

Publication type:
A1 Journal article – refereed

Place of publication:

Keywords:
light detection and ranging (LiDAR), single-photon avalanche diode (SPAD), time-of-flight (TOF), Time-to-digital converter (TDC)

Published:

Full citation:
P. Keränen and J. Kostamovaara, “$256times8$ SPAD Array With 256 Column TDCs for a Line Profiling Laser Radar,” in IEEE Transactions on Circuits and Systems I: Regular Papers, vol. 66, no. 11, pp. 4122-4133, Nov. 2019. doi: 10.1109/TCSI.2019.2923263

DOI:
https://doi.org/10.1109/TCSI.2019.2923263

Read the publication here:
http://urn.fi/urn:nbn:fi-fe2019120946167