Patent ID: 9204074
Filing Date: 2015-12-01
Classification: H01L,H04N

Abstract:
1. A pixel circuit, comprising: a plurality of pixel units, each one of the pixel units comprising: an individual photosensor; an individual readout circuit, coupled to a supply voltage and the photosensor and comprising a floating diffusion node for storing data of the photosensor and an output node for outputting data of the floating diffusion node, wherein the readout circuit comprises: a first switch, controlled by a reset signal and coupled between the supply voltage and the floating diffusion node; a MOS transistor, controlled by a voltage level of the floating diffusion node and a drain node coupled to the supply voltage; a second switch, controlled by a select signal and coupled between a source node of the MOS transistor and an output node; and a third switch, controlled by a read signal and coupled between the floating diffusion node and the photosensor; and an individual switch circuit, coupled between the photosensor and a tail node, wherein the tail node is coupled to the floating diffusion node of another pixel unit, wherein the switch circuit comprises: a fourth switch, controlled by a first control signal and coupled between the photosensor and a first node, wherein a virtual capacitor is formed in the first node; and a fifth switch, controlled by a second control signal and coupled between the first node and the tail node, wherein a conversion gain through the third switch to the output node is higher than that through the fourth switch and the fifth switch to the output node of the other pixel unit.