Photoelectric conversion device, imaging system, and movable body

1. A photoelectric conversion device comprising:

a plurality of pixels which are disposed in a plurality of columns;

a plurality of holding circuits which are disposed so as to correspond to the columns in which the plurality of pixels are disposed and hold digital signals corresponding to outputs of the pixels;

a first signal transfer unit group having a plurality of signal transfer units which transfer digital signals from a first holding circuit group which is part of the plurality of holding circuits and has two or more of the holding circuits;

a second signal transfer unit group having a plurality of signal transfer units which transfer digital signals from a second holding circuit group which is another part of the plurality of holding circuits and has two or more of the holding circuits; and

a plurality of common output lines which include a first common output line to which digital signals are transferred from the first signal transfer unit group and a second common output line to which digital signals are transferred from the second signal transfer unit group, wherein

each of the plurality of signal transfer units is capable of transiting to a first state and a second state in which current consumption is less than current consumption in the first state, and,

in a predetermined period, a number of the signal transfer units in the second state increases in the first signal transfer unit group and a number of the signal transfer units in the second state decreases in the second signal transfer unit group.

2. The photoelectric conversion device according to claim 1 , wherein the first signal transfer unit group and the second signal transfer unit group transfer digital signals in mutually opposite directions.

3. The photoelectric conversion device according to claim 1 , wherein, in the predetermined period, a number of the signal transfer units in the first state and a number of the signal transfer units in the second state in all of the signal transfer units included in the first signal transfer unit group and the second signal transfer unit group are constant.

4. The photoelectric conversion device according to claim 1 , further comprising:

a plurality of block output lines each of which is provided so as to correspond to a block including two or more of the holding circuits, and to which digital signals held in two or more of the holding circuits included in each of the blocks are output, wherein

two or more of the block output lines which are part of the plurality of block output lines are connected to the first signal transfer unit group, and

two or more of the block output lines which are another part of the plurality of block output lines are connected to the second signal transfer unit group.

5. The photoelectric conversion device according to claim 4 , further comprising:

a buffer circuit which is provided between the corresponding block output line and one of the plurality of common output lines and performs buffering on a digital signal from the block output line.

6. The photoelectric conversion device according to claim 1 , further comprising:

a horizontal scan circuit which controls an output of each of the plurality of holding circuits, wherein

the horizontal scan circuit 1) controls outputs of the first holding circuit group such that digital signals are transferred to the first common output line in an order in which the columns of the holding circuits in the first holding circuit group are arranged, and 2) controls outputs of the second holding circuit group such that digital signals are transferred to the second common output line in an order in which the columns of the holding circuits in the second holding circuit group are arranged.

7. The photoelectric conversion device according to claim 1 , wherein, in the second state, input of a reference clock to the signal transfer unit is stopped.

8. The photoelectric conversion device according to claim 1 , wherein, in the second state, a reset signal is input to the signal transfer unit.

9. The photoelectric conversion device according to claim 1 , wherein, in the second state, an input of the signal transfer unit is fixed to a reference potential.

10. The photoelectric conversion device according to claim 1 , wherein the signal transfer unit is a synchronization delay circuit which synchronizes a digital signal input from the holding circuit to a clock.

11. The photoelectric conversion device according to claim 1 , wherein

each of the plurality of holding circuits outputs a differential signal including a normal signal and an inverted signal to the signal transfer unit as a digital signal, and

the signal transfer unit determines a digital signal to be transferred by comparing the normal signal with the inverted signal.

12. The photoelectric conversion device according to claim 1 , wherein

each of the plurality of holding circuits holds a reference signal which is a digital signal of a pixel in a reset state and an effective signal which is a digital signal of a pixel in a non-reset state, and

the reference signal and the effective signal held by one holding circuit are transferred to, among the plurality of common output lines, a same common output line.

13. The photoelectric conversion device according to claim 1 , wherein

a color filter of one color is provided in each of the plurality of pixels, and

digital signals of the pixels in which the color filters of different colors are provided are respectively transferred to, among the plurality of common output lines, the common output lines which are different from each other.

14. The photoelectric conversion device according to claim 1 , wherein digital signals held in the holding circuit in an odd-numbered column and digital signals held in the holding circuit in an even-numbered column are transferred to, among the plurality of common output lines, the common output lines which are different from each other.

15. The photoelectric conversion device according to claim 1 , further comprising:

a third signal transfer unit group and a fourth signal transfer unit group which are different from the first signal transfer unit group and the second signal transfer unit group, wherein

each of the third signal transfer unit group and the fourth signal transfer unit group has a plurality of the signal transfer units which are different from each other, and,

in a predetermined period, a number of the signal transfer units in the first state increases in the third signal transfer unit group and a number of the signal transfer units in the first state decreases in the fourth signal transfer unit group.

16. The photoelectric conversion device according to claim 1 , further comprising:

a plurality of signal processing circuits which perform processing on digital signals, wherein

the plurality of common output lines are connected to the signal processing circuits which are different from each other.

17. An imaging system comprising:

the photoelectric conversion device according to claim 1 ; and

a processing device which processes a signal output from the photoelectric conversion device.

18. A movable body comprising:

the photoelectric conversion device according to claim 1 ;

a moving device;

a processing device which acquires information from a signal output from the photoelectric conversion device; and

a control device which controls the moving device based on the information.