| 摘要 |
An arithmetic operation circuit provided in a delta-sigma modulator of a delta-sigma A/D converter includes two reference capacitors which are respectively provided at a positive side input node and a negative side input node of an operational amplifier. When a signal corresponding to an output of the modulator is added or subtracted to or from an input signal, the amount of charge added to the input node of the operational amplifier is made to be always the same regardless of the reference voltage by complementarily switching the connection of the reference capacitors at the positive side input node and the negative side input node, and thereby the potential of the input node of the operational amplifier is made to converge to the common mode potential of the circuit.
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