Light sensor

A light sensor comprising:

• an array of pixels arranged in rows and in columns;
• and
• a control circuit coupled to the array of pixels;
• wherein each pixel comprises a photodiode, a sense node coupled to the photodiode, an initialization transistor connected to the sense node wherein each pixel, and a transfer gate coupling the sense node of the pixel to the photodiode of the pixel;
• wherein N successive pixels of a column or of a row are associated, N being an integer greater than or equal to 2;
• wherein the initialization transistor of a first one of the N pixels arranged at one end of the association of the N pixels is connected between the sense node of the first one of the pixels and a node of application of an initialization potential;
• wherein for each two successive pixels among the N pixels, the initialization transistor of one of the two pixels that is the most distant from the end is connected between the sense nodes of the two pixels;
• and
• wherein the control circuit is configured to:
• implement phases of initialization of the sense nodes of the N pixels, and, for each phase of initialization of the sense node of each of the N pixels, to keep in a conductive state simultaneously the initialization transistors coupling the sense node to the node of application of the initialization potential;
• in a first operating mode where the N pixels are distributed in groups of successive pixels among the N pixels, and for each group, to keep in the conductive state the initialization transistor connected between the sense nodes of each two successive pixels of the group;
• in the first operating mode further comprising, for each group first phases of transfer of photogenerated charges to the sense nodes of the pixels in the group, and for each group, to keep in a non-conductive state each initialization transistor connected between the sense node of a pixel of the group and the sense node of a pixel of another one of the groups or the node of application of the initialization potential, during each first phase of transfer of photogenerated charges to the sense nodes of the pixels of the group;
• for each group and simultaneously for each pixel of the group, to control a plurality of successive switchings to the conductive state of the transfer gate of the pixel at each first charge transfer phase to the sense nodes of the pixels of the group.

A method of operating a light sensor that comprises an array of pixels arranged in rows and in columns and a control circuit coupled to the array of pixels, wherein each pixel comprises a photodiode, a sense node coupled to the photodiode, an initialization transistor connected to the sense node wherein each pixel, and a transfer gate coupling the sense node of the pixel to the photodiode of the pixel. wherein N successive pixels of a column or of a row are associated, N being an integer greater than or equal to 2, wherein the initialization transistor of a first one of the N pixels arranged at one end of the association of the N pixels is connected between the sense node of the first one of the pixels and a node of application of an initialization potential, and wherein for each two successive pixels among the N pixels, the initialization transistor of one of the two pixels that is the most distant from the end is connected between the sense nodes of the two pixels, the method comprising:

• implementing phases of initialization of the sense nodes of the N pixels, and, for each phase of initialization of the sense node of each of the N pixels, keeping in a conductive state simultaneously the initialization transistors coupling the sense node to the node of application of the initialization potential;
• in a first operating mode where the N pixels are distributed in groups of successive pixels among the N pixels, and for each group,
• keeping in the conductive state the initialization transistor connected between the sense nodes of each two successive pixels of the group;
• and
• for each group first phases of transfer of photogenerated charges to the sense nodes of the pixels in the group, and for each group, keeping in a non-conductive state each initialization transistor connected between the sense node of a pixel of the group and the sense node of a pixel of another one of the groups or the node of application of the initialization potential, during each first phase of transfer of photogenerated charges to the sense nodes of the pixels of the group;
• and
• in a second operating mode that comprises second phases of transfer of photogenerated charges to the sense nodes of the N pixels, for each of the N pixels
• keeping in the non-conductive state each initialization transistor connected to the sense node of the pixel during each second phase of charge transfer to the sense node of the pixel;
• and
• controlling a single switching to the conductive state of a transfer gate of the pixel at each second phase of charge transfer to the sense node of the pixel, or controlling a plurality of switchings to the conductive state of the transfer gate of the pixel at each second phase of charge transfer to the sense node of the pixel.