US 12,192,644 B2
Pulse-width modulation pixel sensor
Nikolai E. Bock, San Jose, CA (US); Andrew Kenneth John McMahon, San Carlos, CA (US); Dario Clocchiatti, Los Gatos, CA (US); Emanuele Mandelli, Mountain View, CA (US); Gennady A. Manokhin, Cupertino, CA (US); and Robert H. Mullis, Santa Cruz, CA (US)
Assigned to Apple Inc., Cupertino, CA (US)
Filed by Apple Inc., Cupertino, CA (US)
Filed on Jul. 14, 2022, as Appl. No. 17/865,128.
Claims priority of provisional application 63/227,202, filed on Jul. 29, 2021.
Prior Publication US 2023/0044950 A1, Feb. 9, 2023
Int. Cl. H04N 5/04 (2006.01); G04F 10/00 (2006.01); H01L 27/146 (2006.01); H04N 23/71 (2023.01); H04N 23/73 (2023.01); G11C 11/419 (2006.01)
CPC H04N 23/73 (2023.01) [G04F 10/005 (2013.01); H04N 5/04 (2013.01); H04N 23/71 (2023.01); G11C 11/419 (2013.01); H01L 27/14634 (2013.01)] 7 Claims
OG exemplary drawing
 
1. A method of operation of a pulse-width modulation (PWM) image sensor, the method comprising:
during a detection period, receiving a number of photons at a PWM pixel of the PWM image sensor;
converting the number of photons into a photocurrent as the number of photons is received;
accumulating a number of electrons at a sense node during the detection period, the number of electrons accumulated in response to the sense node receiving the photocurrent;
during and in synchronization with the detection period, incrementing a count non-linearly, each value of the count synchronized with a non-linear time reference; and
when the accumulated number of electrons reaches a threshold number of electrons, latching a value of the count in a memory of a time-to-digital converter (TDC) circuit.