Pixel for global shutter operation

摘要

A pixel for use in an image sensor comprises a photo-sensitive element 11, an input node 12 and a transfer gate TG connected between the photo-sensitive element and the input node that controls the transfer of charge to the input node. A first amplifier 20 has an input connected to the input node 12. A reset switch RS is connected between the input node and an output of the first amplifier for resetting the input node to a predetermined voltage. A feedback capacitance Cfb (that can be either a parasitic capacitance or a capacitive element) is positioned between the input node and the output of the first amplifier. A first sample stage connected to an output node of the first amplifier is selectively operable to sample and store a value of the input node. A second sample stage is connected in cascade with the first sample stage and is selectively operable to sample and store a value of the input node. An output stage comprising a second amplifier outputs a signal from the first sample stage and the second sample stage.