US 12,074,242 B2
Anode sensing circuit for single photon avalanche diodes
Mohammed Al-Rawhani, Glasgow (GB); Neale Dutton, Edinburgh (GB); John Kevin Moore, Edinburgh (GB); Bruce Rae, Edinburgh (GB); and Elisa Lacombe, Edinburgh (GB)
Assigned to STMicroelectronics (Research & Development) Limited, Marlow (GB)
Filed by STMicroelectronics (Research & Development) Limited, Marlow (GB)
Filed on May 2, 2022, as Appl. No. 17/734,738.
Application 17/734,738 is a division of application No. 16/718,762, filed on Dec. 18, 2019, granted, now 11,349,042.
Prior Publication US 2022/0271184 A1, Aug. 25, 2022
This patent is subject to a terminal disclaimer.
Int. Cl. H01L 31/107 (2006.01); H01L 27/146 (2006.01); H04N 25/705 (2023.01); H04N 25/75 (2023.01)
CPC H01L 31/107 (2013.01) [H01L 27/14612 (2013.01); H01L 27/14643 (2013.01); H04N 25/705 (2023.01); H04N 25/75 (2023.01)] 15 Claims
OG exemplary drawing
 
1. An array of pixels, each pixel comprising:
a single photon avalanche diode (SPAD);
a transistor circuit comprising:
a clamp transistor configured to clamp an anode voltage of the SPAD to be no more than a threshold clamped anode voltage; and
a quenching element coupled in series with the clamp transistor and configured to quench the anode voltage of the SPAD when the SPAD is struck by an incoming photon; and
readout circuitry coupled to receive the clamped anode voltage from the transistor circuit and configured to generate a pixel output therefrom, wherein the threshold clamped anode voltage is below a maximum voltage rating of transistors forming the readout circuitry.