Methods and apparatus for an image sensor
Various embodiments of the present technology provide a method and apparatus for an image sensor. In various embodiments, the apparatus provides a driver circuit connected to a plurality of electrically distinct pixel groups to provide the pixel groups with a control signal. A delay measurement circuit is connected to the driver circuit and at least one of the pixel groups to measure a time delay of the control signal. A row control circuit is connected to the delay measurement circuit to receive the measured time delay and, in turn, deliver, via the driver circuit, the control signal to all pixel groups in a single row substantially simultaneously.
1. An image sensor, comprising:
a pixel array comprising a plurality of rows, wherein a first row comprises a first pixel group and a second pixel group, wherein the first pixel group has first and second opposing ends, and wherein the second pixel group has first and second opposing ends;
a first row driver circuit connected to the first end of the first pixel group;
a second row driver circuit connected to the second end of the second pixel group;
a first delay measurement circuit that has a first input connected directly to the first row driver circuit and a second input connected directly to a first node that is interposed between the first end of the first pixel group and the first row driver circuit; and
a second delay measurement circuit that has a first input connected directly to the second row driver circuit and a second input connected directly to a second node that is interposed between the second end of the second pixel group and the second row driver circuit.
2. The image sensor defined in claim 1 , further comprising a third delay measurement circuit that has a first input connected directly to the first end of the second pixel group and a second input connected directly to the second end of the first pixel group.
3. The image sensor defined in claim 2 , wherein the first delay measurement circuit is configured to:
measure a first time delay between a transmission of a first control signal from the first row driver circuit and a receipt of the first control signal at the first node; and
transmit the measured first time delay to a row control circuit.
4. The image sensor defined in claim 3 , wherein the second delay measurement circuit is configured to:
measure a second time delay between a transmission of a second control signal from the second row driver and a receipt of the second control signal at the second node; and
transmit the measured second time delay to the row control circuit.
5. The image sensor defined in claim 2 , wherein:
the pixel array is formed on a first die; and
the first row driver circuit and the second row driver circuit are formed on a second die.
6. The image sensor defined in claim 5 , wherein the first row driver circuit is situated directly below the first pixel group and wherein the second row driver is situated directly below the second pixel group.
7. The image sensor defined in claim 6 , wherein the first, second, and third delay measurement circuits are formed on the second die.
8. The image sensor defined in claim 5 , wherein the first and second delay measurement circuits are formed on the second die.
9. The image sensor defined in claim 1 , wherein the first row has a total number of pixels and wherein the first and second pixel groups each include, within the first row, more than one pixel but less than the total number of pixels.
10. The image sensor defined in claim 1 , wherein the first row driver circuit is also connected to the first end of the second pixel group and wherein the second row driver circuit is also connected to the second end of the first pixel group.
11. The image sensor defined in claim 1 , wherein the second end of the first pixel group is interposed between the first end of the first pixel group and the second pixel group and wherein the first end of the second pixel group is interposed between the second end of the second pixel group and the first pixel group.
12. An image sensor, comprising:
a pixel array comprising a plurality of rows, wherein a first row comprises a first pixel group and a second pixel group, wherein the first pixel group has first and second opposing ends, and wherein the second pixel group has first and second opposing ends;
a first row driver circuit connected to the first end of the first pixel group;
a second row driver circuit connected to the second end of the second pixel group; and
a delay measurement circuit connected to the first end of the second pixel group and the second end of the first pixel group, wherein the delay measurement circuit is configured to measure a time delay between the first end of the second pixel group receiving a first control signal from the first row driver circuit and the second end of the first pixel group receiving a second control signal from the second row driver circuit.
13. An image sensor, comprising:
a pixel array comprising a plurality of rows, wherein a first row comprises a first pixel group and a second pixel group, wherein the first pixel group has a first center point, and wherein the second pixel group has a second center point;
one or more row driver circuits connected directly to only the first center point and the second center point, wherein the one or more row driver circuits comprises a first row driver circuit connected directly to only the first center point; and
a first delay measurement circuit connected to the first row driver circuit and the first pixel group.
14. The image sensor defined in claim 13 , wherein the one or more row driver circuits is configured to deliver a control signal to both the first center point and the second center point.
15. The image sensor defined in claim 13 , wherein the first row has a total number of pixels and wherein the first and second pixel groups each include, within the first row, more than one pixel but less than the total number of pixels.
16. The image sensor defined in claim 13 , wherein:
the pixel array is formed on a first die;
the one or more row driver circuits is formed on a second die; and
the first and second dies are coupled to form a vertical stack.
17. The image sensor defined in claim 13 , wherein the one or more row driver circuits comprises:
a second row driver circuit connected directly to only the second center point.
18. The image sensor defined in claim 17 , further comprising:
a second delay measurement circuit connected to the second row driver circuit and the second pixel group.
19. The image sensor defined in claim 18 , wherein the one or more row driver circuits includes logic circuitry responsive to a system clock signal and a time delay signal from the first delay measurement circuit or the second delay measurement circuit.
20. The image sensor defined in claim 13 , wherein the one or more row driver circuits includes logic circuitry responsive to a system clock signal and a time delay signal from the first delay measurement circuit.