Image capturing apparatus, control method thereof, and storage medium

1 . An image capturing apparatus comprising:

a pixel portion in which a plurality of pixels each including a plurality of photoelectric conversion elements are arranged in a matrix;

at least three sample-hold circuits that are arranged with respect to pixel signals output from one pixel;

a voltage-current conversion portion configured to output a difference between two sample-hold circuits, out of the at least three sample-hold circuits, as a current signal;

a first and a second AD converters configured to convert an output signal of the voltage-current conversion portion to a digital signal; and

at least one processor or circuit configured to function as:

a control unit configured to perform control such that a first pixel signal obtained from the pixel is held in one sample-hold circuit, out of the at least three sample-hold circuits and a second pixel signal obtained from the pixel become held in another sample-hold circuit, out of the at least three sample-hold circuits, and in a period in which the first pixel signal is AD converted by the first AD converter, an operation is started in which the second pixel signal is AD converted by the second AD converter.

2 . The image capturing apparatus according to claim 1 , wherein the control unit causes the at least three sample-hold circuits to hold a reset signal of the pixel.

3 . The image capturing apparatus according to claim 1 , wherein the first pixel signal is a signal based on charges of at least one photoelectric conversion element of one of the pixels, and the second pixel signal is a signal based on charges of a plurality of photoelectric conversion elements of the one pixel.

4 . The image capturing apparatus according to claim 1 , wherein the control unit performs control such that, after the AD conversion of the first pixel signal is ended, and the second pixel signal is sample-held, an operation is stared in which a sample-hold circuit that held the first pixel signal is caused to hold a third pixel signal.

5 . The image capturing apparatus according to claim 1 , wherein the AD converter includes a delta-sigma type AD converter.

6 . An image capturing apparatus comprising:

a pixel portion in which a plurality of pixels each including a plurality of photoelectric conversion elements are arranged in a matrix;

at least three sample-hold circuits that are arranged with respect to pixel signals output from one pixel;

a voltage-current conversion portion configured to output a difference between two sample-hold circuits, out of the at least three sample-hold circuits, as a current signal;

a first and a second AD converters configured to convert an output signal of the voltage-current conversion portion to a digital signal; and

at least one processor or circuit configured to function as:

a control unit configured to perform control such that a first pixel signal obtained from the pixel is held in one sample-hold circuit, out of the at least three sample-hold circuits and a second pixel signal obtained from the pixel become held in another sample-hold circuit, out of the at least three sample-hold circuits, and in a period in which the first pixel signal is AD converted by the first AD converter, an operation is started in which the first pixel signal is AD converted by the second AD converter,

wherein the first pixel signal is a signal based on charges of at least one photoelectric conversion element of one of the pixels, and the second pixel signal is a signal based on charges of another conversion element of the one pixel.

7 . A method of controlling an image capturing apparatus including: a pixel portion in which a plurality of pixels each including a plurality of photoelectric conversion elements are arranged in a matrix; at least three sample-hold circuits that are arranged with respect to pixel signals output from one pixel; a voltage-current conversion portion configured to output a difference between two sample-hold circuits, out of the at least three sample-hold circuits, as a current signal; and a first and a second AD converters configured to convert an output signal of the voltage-current conversion portion to a digital signal, the method comprising:

performing control such that a first pixel signal obtained from the pixel is held in one sample-hold circuit, out of the at least three sample-hold circuits and a second pixel signal obtained from the pixel become held in another sample-hold circuit, out of the at least three sample-hold circuits, and in a period in which the first pixel signal is AD converted by the first AD converter, an operation is started in which the second pixel signal is AD converted by the second AD converter.

8 . A method of controlling an image capturing apparatus including: a pixel portion in which a plurality of pixels each including a plurality of photoelectric conversion elements are arranged in a matrix; at least three sample-hold circuits that are arranged with respect to pixel signals output from one pixel; a voltage-current conversion portion configured to output a difference between two sample-hold circuits, out of the at least three sample-hold circuits, as a current signal; and a first and a second AD converters configured to convert an output signal of the voltage-current conversion portion to a digital signal, the method comprising:

performing control such that a first pixel signal obtained from the pixel is held in one sample-hold circuit, out of the at least three sample-hold circuits, and a second pixel signal obtained from the pixel become held in another sample-hold circuit, out of the at least three sample-hold circuits, and in a period in which the first pixel signal is AD converted by the first AD converter, an operation is started in which the first pixel signal is AD converted by the second AD converter,

wherein the first pixel signal is a signal based on charges of at least one photoelectric conversion element of one of the pixels, and the second pixel signal is a signal based on charges of another conversion element of the one pixel.