CPC G01J 1/44 (2013.01) [G01J 2001/446 (2013.01)] | 24 Claims |
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.
|