US 11,906,353 B2
Digital pixel with extended dynamic range
Xinqiao Liu, Medina, WA (US); Song Chen, Redmond, WA (US); Andrew Samuel Berkovich, Bellevue, WA (US); and Wei Gao, Bothell, WA (US)
Assigned to Meta Platforms Technologies, LLC, Menlo Park, CA (US)
Filed by Meta Platforms Technologies, LLC, Menlo Park, CA (US)
Filed on Jun. 7, 2019, as Appl. No. 16/435,451.
Claims priority of provisional application 62/683,550, filed on Jun. 11, 2018.
Prior Publication US 2019/0376845 A1, Dec. 12, 2019
Int. Cl. G01J 1/44 (2006.01)
CPC G01J 1/44 (2013.01) [G01J 2001/446 (2013.01)] 24 Claims
OG exemplary drawing
 
1. An apparatus comprising:
a photodiode;
a charge storage unit; and
a processing circuits configured to:
transfer overflow charge from the photodiode to the charge storage unit to develop a first voltage;
compare the first voltage against a first ramping threshold voltage to generate a first decision;
generate, based on the first decision, a first digital value;
transfer residual charge from the photodiode to the charge storage unit to develop a second voltage;
compare the second voltage against a static threshold voltage to determine whether the photodiode saturates to generate a second decision, wherein the static threshold voltage is based on a quantity of the residual charge equal to a saturation capacity of the photodiode;
compare the second voltage against a second ramping threshold voltage to generate a third decision;
generate, based on the third decision, a second digital value; and
output, based on the second decision, one of the first digital value or the second digital value to represent an intensity of light received by the photodiode.