Field of the Invention
One disclosed aspect of the embodiments relates to an image pickup apparatus and an image pickup system using the image pickup apparatus.
Description of the Related Art
An image pickup apparatus including an analog-to-digital (AD) converter provided in association with a column of pixels has been proposed. The AD converter is provided with a comparator configured to compare a pixel signal with a reference signal. Japanese Patent Laid-Open No. 2010-016656 discloses a technology for restricting an amplitude of a control signal for controlling a feedback switch to reduce an offset for each comparator including the feedback switch for calibration.
According to Japanese Patent Laid-Open No. 2010-016656, a signal line of the control signal for controlling the feedback switch is also connected to a feedback switch of a comparator on another column. According to the above-described configuration, when an output of the comparator is inverted, an output of the comparator on the other column may be affected in some cases. That is, crosstalk may occur. When this crosstalk occurs, an error may be caused in a result of the comparator on the other column. The error of the result of the comparator is an error of an AD conversion result, and an image quality is decreased. The above-described crosstalk may occur in a case where not only a line for the feedback switch but also a signal line for controlling an operation of the comparator is provided commonly to a plurality of comparators.