Systems and methods for providing shiftable column circuitry of imager pixel arrays
View Patent ↗This is generally directed to systems and methods for providing shiftable column circuitry for a pixel array of an imaging system. Columns of a pixel array can be switchably coupled (e.g., through multiplexers) to their default column circuitry as well as coupled to one or more instances of a neighboring column's column circuitry. In response to an instance of default column circuitry being identified as defective, its corresponding column may “shift” and choose to couple to the neighboring column circuitry. Similarly, all following columns may also shift and couple to a neighboring column circuitry. In some embodiments, the defective column circuitry can be identified during wafer testing and identifying information (e.g., an address) of the defective column circuitry stored in memory. The identifying information may then be accessed from memory and, during an image signal readout phase, used to suitably shift the columns to avoid the defective column circuitry.
1. An imaging system comprising:
a pixel array including a plurality of pixel cells arranged in a plurality of columns;
a plurality of column circuitry including a plurality of default column circuitry, wherein each column of the plurality of columns is associated with a different default column circuitry of the plurality of default column circuitry; and
a plurality of multiplexers, wherein each multiplexer is operable to switchably couple a different column of the plurality of columns to one of:
the default column circuitry associated with that different column; and
shift the different column in a first direction to at least one other column circuitry of the plurality of column circuitry that is physically adjacent to that different column, and to shift in the first direction away from the different column any column of the plurality of columns that follow the different column.
2. The imaging system of claim 1 , wherein:
the plurality of column circuitry further includes at least one instance of alternative column circuitry; and
at least one multiplexer of the plurality of multiplexers switchably couples the different column to the at least one instance of alternative column circuitry.
3. The imaging system of claim 2 , wherein the different column switchably coupled to that at least one alternative column circuitry is positioned near an end of a row of the pixel array.
4. The imaging system of claim 2 , wherein the at least one instance of alternative column circuitry comprises between four and eight instances of alternative column circuitry.
5. The imaging system of claim 1 further including a memory operable to store identifying information of at least one defective instance of default column circuitry.
6. The imaging system of claim 5 further including a control circuit operable to access the identifying information; and to instruct, based on the identifying information, a multiplexer switchably coupled to the at least one defective instance and any following multiplexers to couple to the at least one other column circuitry.
7. The imaging system of claim 1 further including one or more alternate column circuitry wherein the plurality of multiplexers are operably coupled to shift in the first direction one of the columns that follow the different column to one of the one or more alternate column circuitry.
8. The imaging system of claim 5 , wherein the memory comprises at least one of a non-volatile memory, a register, and a memory in analog.
9. The imaging system of claim 5 , wherein the identifying information comprises an address of the at least one defective instance of default column circuitry.