Analog digital converter

Abstract

In one aspect, provided is an A/D converter including: a plurality of capacitor networks each including a first switch group; a capacitor group; a second switch group; and a plurality of reference voltage selectors; a sampling unit grounded at one end thereof; a plurality of A/D converters; and converting means; 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, and in which converter the switch networks change the connections between 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.

1 . An analog-to-digital converter comprising:
 a first switch group configured to be connected to an input terminal, and an analog signal being inputted into the input terminal;   a capacitor group configured to be connected to the first switch group, and the capacitor group stores, as a charge, the analog signal inputted from the input terminal;   a second switch group configured to being connected to the capacitor group, and the second switch group transfers the charge in the capacitor group;   a operational amplifier configured to be connected to the capacitor group and the second switch group, the operational amplifier subtracts a predetermined voltage from a voltage generated in the capacitor group in conjunction with the transfer of the charge, and the operational amplifier then sets, as an output voltage, a voltage obtained by amplifying the result of the subtraction;   converter configured to be connected to the operational amplifier, and the converter converts the output voltage into a digital value of a predetermined number of bits including a redundancy bit; and   a plurality of reference voltage selectors configured to be connected to the first switch group and the capacitor group, and each of the plurality of reference voltage selectors selects the predetermined voltage in accordance with the digital value,   wherein the connecting of the capacitor group to the operational amplifier, and the voltage selection of each reference voltage selector, are performed for a plurality of times.   
   
   
       2 . The analog-to-digital converter according to  claim 1 , the digital value of a predetermined number of bits is a digital value in binary code in accordance with the output voltage. 
   
   
       3 . The analog-to-digital converter according to  claim 1 , in the converter, MDAC calculation operation is held in accordance with the output voltage. 
   
   
       4 . The analog-to-digital converter according to  claim 1 , the predetermined voltage is one of the following voltage, a positive reference voltage +Vref, 0 volt, and a negative reference voltage −Vref. 
   
   
       5 . The analog-to-digital converter according to  claim 1 , further comprising a digital encoding circuit configured to add a plurality of the digital values together, and the digital encoding circuit configured to perform an error correction. 
   
   
       6 . The analog-to-digital converter according to  claim 5 , the error correction is that the digital values are overlaped and added.