Ad conversion device, ad conversion method, image sensor, and electronic apparatus

An image sensor, comprising:

• a pixel that includes a photoelectric conversion element for performing photoelectric conversion and outputting an electrical signal;
• a reference signal output section that outputs a variable-level reference signal;
• an analog to digital (AD) conversion section that includes a comparator for comparing the electrical signal outputted from the pixel with the reference signal and performing AD conversion of the electrical signal by using a result of a comparison made by the comparator between the electrical signal and the reference signal;
• and
• a controller configured to exercise control in such a manner that a bias current flowing in the comparator to operate the comparator during a certain section of the reference signal including a section where the variable-level reference signal changes is increased from a first current to a second current, the first current being larger than 0 (zero) and the second current being larger than the first current.

An electronic apparatus, comprising:

• an optical system that collects light;
• and
• an image sensor that receives the light and outputs a signal corresponding to an amount of the light received,
• wherein the image sensor includes:
• a pixel that includes a photoelectric conversion element for performing photoelectric conversion and outputting an electrical signal,
• a reference signal output section that outputs a variable-level reference signal,
• an analog to digital (AD) conversion section that includes a comparator for comparing the electrical signal outputted from the pixel with the reference signal and performing AD conversion of the electrical signal by using a result of a comparison made by the comparator between the electrical signal and the reference signal, and
• a controller configured to exercise control in such a manner that a bias current flowing in the comparator to operate the comparator during a certain section of the variable-level reference signal including a section where the reference signal changes is increased from a first current to a second current, the first current being larger than 0 (zero) and the second current being larger than the first current.