Solid state image sensing device for analog-averaging and sub-sampling of image signals at a variable sub-sampling rate and method of driving the same

An image sensing device comprising:

• a plurality of averaging correlated double sampling (CDS) circuits each connected to one column of a pixel array, and
• a plurality of switches configured to establish connections between averaging CDS circuits corresponding to columns having the same color pixels in a each row of the pixel array,
• wherein each averaging CDS circuit is configured to average a plurality of image signals received from pixels having the same color, and to average a plurality of reset signals received from pixels having the same color pixel, and to generate a comparison signal based on the average of the image signals, and the average of the reset signals, and
• wherein each of the plurality of averaging CDS circuits comprises:
• a first switch configured to transfer the reset signals and image signals when turned ON;
• a reset signal averaging unit configured to average the reset signals received through the first switch;
• and
• an image signal averaging unit configured to average the image signals received through the first switch.

An image sensing device comprising:

• a plurality of averaging correlated double sampling (CDS) circuits each connected to one column pixel array, and
• a plurality of switches configured to establish connections between averaging in CDS circuits corresponding to columns having the same color pixels in a each row of the pixel array,
• wherein each averaging CDS circuit is configured to average a plurality of image signals received from pixels having the same color, and to average a plurality of reset signals received from pixels having the same color pixel, and to generate a comparison signal based on the average of the image signals, and the average of the reset signals,
• wherein the plurality of switches comprises:
• odd-column row-averaging switches connecting a number n of odd-numbered averaging CDS circuits;
• and
• even-column row-averaging switches connecting a number n of even-numbered averaging CDS circuits equal to the number n.

A method of driving an image sensing device comprising a two-dimensional array of pixels arranged in rows and columns, the method comprising:

• receiving n reset signals at a time from n selected rows of the pixels in a sub-sampling mode wherein n is based on the sub-sampling rate;
• averaging a first n reset signals received from pixels in a first selected column by separately accumulating each of the first n received reset signals, and then combining the first n received reset signals;
• averaging a second n reset signals received from pixels in a second selected column by separately accumulating each of the second n received reset signals, and then combining the second n received reset signals;
• averaging the first and second received reset signals together by combining the first and second combined reset signals together;
• receiving n image signals at a time from n selected rows of the pixels in a sub-sampling mode wherein n is based on the sub-sampling rate;
• averaging a first n received image signals by separately accumulating each of the first n received image signals and then combining the first n received image signals;
• averaging a second n received image signals by separately accumulating each of the first n received image signals and combining the second n received image signals;
• averaging the first and second n received image signals together by combining the first and second combined image signals together;
• generating a comparison signal in response to a difference between the average of the reset signals and the average of the image signals.