Solid-state image capturing element, image capturing apparatus, and method of controlling solid-state image capturing element

An image capturing apparatus, comprising:

• a pixel array section that includes a plurality of pixels,
• wherein each of the plurality of pixels is configured to generate a pixel signal;
• an analog-to-digital converter configured to:
• one of increase or decrease an analog signal based on an analog gain selected from a plurality of analog gains, and
• convert the one of increased or decreased analog signal to a digital signal, wherein
• the analog-to-digital converter includes:
• a comparator configured to compare the analog signal with a specific ramp signal, and output a result of the comparison, and
• a digital signal generation section configured to generate the digital signal based on the result of the comparison,
• the comparator includes:
• a differential amplification circuit configured to amplify a difference between a specific reference voltage and a voltage of a specific node, and output the amplified difference as the result of the comparison,
• a vertical signal line side capacitor between the specific node and an input switching circuit,
• a ramp side capacitor between the specific node and a digital-to-analog converter that generates the specific ramp signal, and
• a switch configured to change a capacitance ratio between the vertical signal line side capacitor and the ramp side capacitor based on a specific control signal, and
• the plurality of analog gains is classified into a plurality of gain domains for which the capacitance ratio is mutually different;
• the input switching circuit configured to input, as the analog signal, one of a test signal having a specific level or the pixel signal to the analog-to-digital converter;
• a correction value calculation section configured to:
• obtain, from the test signal and the digital signal, a correction value to correct an error in the selected analog gain, and
• output the correction value;
• and
• a correction section configured to correct the digital signal based on the outputted correction value.

A method of controlling a solid-state image capturing element, the method comprising:

• one of increasing or decreasing, by an analog-to-digital converter of the solid-state image capturing element, an analog signal based on an analog gain selected from a plurality of analog gains;
• converting, by the analog-to-digital converter, the one of increased or decreased analog signal to a digital signal, wherein
• the analog-to-digital converter includes a comparator and a digital signal generation section, and
• the comparator includes a differential amplification circuit, a vertical signal line side capacitor, a ramp side capacitor, and a switch;
• comparing, by the comparator, the analog signal with a specific ramp signal and outputting a result of the comparison;
• generating, by the digital signal generation section, the digital signal based on the result of the comparison;
• amplifying, by the differential amplification circuit, a difference between a specific reference voltage and a voltage of a specific node, and outputting the amplified difference as the result of the comparison, wherein
• the vertical signal line side capacitor is between the specific node and an input switching circuit of the solid-state image capturing element, and
• the ramp side capacitor is between the specific node and a digital-to-analog converter that generates the specific ramp signal;
• changing, by the switch, a capacitance ratio between the vertical signal line side capacitor and the ramp side capacitor based on a specific control signal,
• wherein the plurality of analog gains is classified into a plurality of gain domains for which the capacitance ratio is mutually different;
• inputting, by the input switching circuit, as the analog signal, one of a test signal having a specific level or a pixel signal to the analog-to-digital converter;
• obtaining, by a correction value calculation section of the solid-state image capturing element, from the test signal and the digital signal, a correction value which is for correcting an error in the selected analog gain;
• outputting, by the correction value calculation section, the correction value;
• and
• correcting, by a correction section of the solid-state image capturing element, the digital signal based on the outputted correction value.