Multi-cell pixel array for high dynamic range image sensors

A method for generating an output signal based on light incident on a pixel in which the pixel is comprised of an array of a plurality of photodiodes, the method comprising:

• receiving, at an output circuitry and from a floating diffusion node, image charge photogenerated by each of first photodiodes included in a set of first photodiodes of the array of the plurality of photodiodes, the array of photodiodes which includes a plurality of rows of photodiodes and a plurality of columns of photodiodes, the plurality of photodiodes which includes the set of first photodiodes that has a first surface area, the plurality of photodiodes which includes at least one second photodiode that has a second surface area that is smaller than the first surface area, wherein the first surface area of the first set of photodiodes is arranged symmetrically around the second surface area of the at least one second photodiode along at least a first axis of symmetry and a second axis of symmetry, wherein said each of the first photodiodes in the set of first photodiodes is electrically coupled to the output circuitry;
• selectively closing an electrical switch to electrically couple the at least one second photodiode with the output circuitry, and when the electrical switch is selectively closed, receiving, at the output circuitry and from the floating diffusion node, image charge photogenerated by the at least one second photodiode;
• selectively closing one or more dual floating diffusion (DFD) switches to electrically couple the set of first photodiodes to low conversion gain circuitry, wherein the pixel is in a high conversion gain state when the one or more DFD switches are open and wherein the pixel is in a low conversion gain state when the one or more DFD switches are closed, and wherein the low conversion gain circuitry is coupled between the set of first photodiodes and the floating diffusion node;
• collecting at least some of the image charge photogenerated by light incident on the at least one second photodiode using a lateral overflow integration capacitor coupled between the at least one second photodiode and the floating diffusion node;
• and
• generating the output signal based upon the image charge received at the output circuitry.

A high dynamic range imaging system, comprising:

• an array of pixels, wherein each pixel in the array of pixels includes:
• an array of a plurality of photodiodes, the array of photodiodes which includes a plurality of rows of photodiodes and a plurality of columns of photodiodes, the plurality of photodiodes which includes a set of first photodiodes that has a first surface area and at least one second photodiode that has a second surface area that is smaller than the first surface area, wherein the first surface area of the first set of photodiodes is arranged symmetrically around the second surface area of the at least one second photodiode along at least a first axis of symmetry and a second axis of symmetry;
• a floating diffusion node selectively coupled to receive image charge from the first set of photodiodes or the at least one second photodiode;
• output circuitry that is electrically coupled to the floating diffusion node;
• a switch that is selectively, operably closed to electrically couple the floating diffusion node to the at least one second photodiode;
• one or more dual floating diffusion (DFD) switches to electrically couple the set of first photodiodes to low conversion gain circuitry, wherein the pixel is in a high conversion gain state when the one or more DFD switches are open, wherein the pixel is in a low conversion gain state when the one or more DFD switches are closed, and wherein the low conversion gain circuitry is coupled between the set of first photodiodes and the floating diffusion node;
• and
• a lateral overflow integration capacitor coupled between the at least one second photodiode and the floating diffusion node;
• control circuitry which is electrically coupled to the array of pixels to control operation of the array of pixels;
• and
• readout circuitry which is electrically coupled to the array of pixels to receive output signals from the array of pixels, the readout circuitry which converts the received output signals to image data.

A method for generating an output signal based on light incident on a pixel in which the pixel is comprised of an array of a plurality of photodiodes, the method comprising:

• generating image charge photogenerated by each of first photodiodes included in a set of first photodiodes of the array of the plurality of photodiodes, the array of photodiodes which includes a plurality of rows of photodiodes and a plurality of columns of photodiodes, the plurality of photodiodes which includes the set of first photodiodes that has a first surface area;
• generating image charge photogenerated by at least one second photodiode that is included within the plurality of photodiodes, the at least one second photodiode which has a second surface area that is smaller than the first surface area, wherein the first surface area of the first set of photodiodes is arranged symmetrically around the second surface area of the at least one second photodiode along at least a first axis of symmetry and a second axis of symmetry;
• selectively closing one or more dual floating diffusion (DFD) switches to electrically couple the set of first photodiodes to low conversion gain circuitry, wherein the pixel is in a high conversion gain state when the one or more DFD switches are open and wherein the pixel is in a low conversion gain state when the one or more DFD switches are closed, wherein the low conversion gain circuitry is coupled between the set of first photodiodes and the floating diffusion node;
• collecting at least some of the image charge photogenerated by light incident on the at least one second photodiode using a lateral overflow integration capacitor coupled between the at least one second photodiode and the floating diffusion node;
• and
• receiving the image charge from at least one of the set of first photodiodes and the at least one second photodiode at the output circuitry;
• and
• generating the output signal based upon the image charge received at the output circuitry.