Patent ID: 9185314
Filing Date: 2015-11-10
Classification: H01L,H04N

Abstract:
1. A circuit in an image sensing system, the circuit comprising: a charge-to-voltage converter to convert a charge to a voltage, wherein the charge represents an intensity of energy incident on a pixel in an image sensor in the image sensing system, the charge-to-voltage converter being coupled to receive the charge on an input terminal of the charge-to-voltage converter, the charge-to-voltage converter designed to amplify the charge to generate the voltage on an output terminal; a first switch coupled between the input terminal and a first reference voltage, wherein the first switch is configured to be closed and the input terminal reset if a magnitude of the voltage of the output terminal exceeds a first threshold voltage, the first switch being open and the input terminal not being reset otherwise, a first comparator coupled to receive the voltage and the first threshold voltage, the first comparator to generate a first result representing a comparison of the voltage with the first threshold voltage; a first memory element to store the first result, wherein the first result indicates whether the magnitude of the voltage exceeds the magnitude of the first threshold voltage, wherein the charge-to-voltage converter is an operational amplifier (OPAMP) comprising an output terminal and a pair of input terminals, wherein a capacitor is coupled between the output terminal and a first one of the pair of input terminals, wherein the second one of the pair of input terminals is coupled to a second reference voltage; a second comparator coupled to receive the voltage and a second threshold voltage, the second comparator to generate a second result representing a comparison of the voltage with the second threshold voltage; a second memory element to store the second result; and an OR gate to generate a logical-OR result of the first result and the second result, wherein a first logic value of the logical-OR result causes the first switch to be closed.