Analog-to-digital conversion method, analog-to-digital converter, semiconductor device for detecting distribution of physical quantity, and electronic apparatus

An analog-to-digital converter comprising:

• a comparator that compares a signal corresponding to each of a reference component and a signal component with a reference signal;
• and
• a counter that performs counting in one of a down-count mode and an up-count mode concurrently with the comparison in the comparator and that holds a count value at a time of completion of the comparison in the comparator,
• wherein,
• the counter includes a common counter circuit, and is capable of switching between the up-count mode and the down-count mode, and
• in a case of performing comparison and counting on the signal component, the comparator is not reset, and the reference signal is supplied to the comparator, thereby staffing comparison and counting for the signal component.

A semiconductor device comprising:

• a plurality of unit elements, each of the unit elements including a charge generator that generates a charge corresponding to incident electromagnetic radiation and a unit-signal generator that generates an analog unit signal including a reference component and a signal component;
• a comparator that compares a signal corresponding to each of the reference component and the signal component with a reference signal;
• and
• a counter that performs counting in one of a down-count mode and an up-count mode concurrently with the comparison in the comparator and that holds a count value at a time of completion of the comparison in the comparator,
• wherein,
• in a case of performing comparison and counting on the reference component, the comparator is reset to a predetermined operational reference value for reading the reference component, and the reference signal is then supplied to the comparator, thereby staffing comparison and counting for the reference component.

An electronic apparatus comprising:

• a reference signal generator that generates a reference signal for converting a difference signal component of an analog signal to be processed including a reference component and a signal component into digital data, the difference signal component representing a difference between the reference component and the signal component;
• a comparator that compares a signal corresponding to each of the reference component and the signal component with the reference signal generated by the reference signal generator;
• a counter that performs counting in one of a down-count mode and an up-count mode concurrently with the comparison in the comparator and that holds a count value at a time of completion of the comparison in the comparator;
• and
• a controller that switches a mode of counting in the counter depending on whether the comparator performs the comparison on the reference component or the signal component,
• wherein,
• in a case of performing comparison and counting on the reference component, the comparator is reset to a predetermined operational reference value for reading the reference component, and the reference signal is then supplied to the comparator, thereby starting comparison and counting for the reference component.