Method and apparatus for AD conversion, semiconductor device for detecting distribution of physical quantity, and electronic apparatus

A converter for analog-to-digital converting, into digital data, a difference signal component, representing a difference between a standard component and a signal component, of an analog signal to be processed containing the standard component and the signal component, the converter comprising:

• a comparator for comparing a signal corresponding to each of the standard component and the signal component with a reference signal for generating the digital data;
• a counter for performing a counting operation in one of a down-count mode and an up-count mode in parallel with the comparison operation performed by the comparator and for storing the resulting count at the moment the comparison operation is completed, and
• a controller for switching the count mode of the counter depending on whether the comparator performs the comparison operation on the standard component or the signal component,
• wherein the controller is operable to perform a control process to perform the comparison operation and the counting operation on the standard component in a first step, and to perform the comparison operation and the count process on the signal component in a second step.

A semiconductor device, for detecting a distribution of a physical quantity, including a matrix of unit elements, each unit element including a charge generator for generating a charge corresponding to an input electromagnetic wave, and a unit signal generator for generating an analog unit signal containing a standard component and a signal component, the semiconductor device comprising:

• a comparator for comparing a reference signal for generating digital data of the signal component with each of signals corresponding to the standard component and the signal component;
• a counter for performing a counting operation in one of a down-count mode and an up-count mode in parallel with the comparison operation of the comparator, and storing a count at the moment at the moment the comparator completes the comparison operation, and
• a controller for switching the count mode of the counter depending on whether the comparator performs the comparison operation on the standard component or the signal component,
• wherein the controller is operable to perform a control process to perform the comparison operation and the counting operation on the standard component in a first step, and to perform the comparison operation and the count process on the signal component in a second step.

An electronic apparatus comprising:

• a reference signal generator for generating a reference signal for converting, into digital data, a difference signal component, between a standard component and a signal component, of an analog signal containing the standard component and the signal component;
• a comparator for comparing the reference signal generated by the reference signal with each of signals corresponding to the standard component and the signal component;
• a counter for performing a counting operation in one of a down-count mode and an up-count mode in parallel with the comparison operation of the comparator, and storing a count at the moment the comparator completes the comparison operation;
• a controller for switching the count mode of the counter between the up-count mode and the down-count mode depending on whether the comparator performs the comparison operation on the standard component or the signal component, and
• wherein the controller is operable to perform a control process to perform the comparison operation and the counting operation on the standard component in a first step, and to perform the comparison operation and the count process on the signal component in a second step.