Patent ID: 7623057

Claim:
An analog-to-digital converter, comprising: a plurality of capacitor networks each including a first switch group configured to be connected to an input terminal into which an analog signal is inputted; a capacitor group configured to be connected to the first switch group, and configured to store the analog signal inputted from the input terminal as a charge; a second switch group configured to be connected to the capacitor group, and configured to transfer the charge in the capacitor group; and a plurality of reference voltage selectors configured to be connected to the first switch group and the capacitor group, and each of which selects a predetermined voltage in accordance with the digital value; a sampling unit grounded at one end thereof; a plurality of A/D converters each including: a operational amplifier configured to subtract the predetermined voltage from a voltage generated in the capacitor group in conjunction with the transfer of the charge, and the operational amplifier then configured to set, as an output voltage, a voltage obtained by amplifying the result of the subtraction; and converter configured to be connected to the operational amplifier, and the converter configured to convert the output voltage into a digital value of a predetermined number of bits including a redundancy bit; and a plurality of switch networks each of which connects a corresponding one of the plurality of the capacitor networks to any one of the sampling unit and the plurality of A/D converters in one-to-one correspondence, wherein the switch networks change the connections among the plurality of capacitor networks, the sampling unit and the plurality of A/D converters, at each predetermined time intervals, so that a pipeline operation is performed.