| 摘要 |
PROBLEM TO BE SOLVED: To provide a cyclic A/D converter capable of improving an S/N ratio.SOLUTION: A residual voltage generating circuit 12 generates a residual voltage obtained by amplifying a difference voltage between a voltage that an input voltage is sample-and-hold processed and a predetermined analog voltage. An input switching circuit 12 inputs any one of an external signal voltage Vin and the voltage Vout outputted from the residual voltage generating circuit 12 into an A/D conversion circuit 2 and the residual voltage generating circuit 12. A control circuit 10 sets an analog voltage in the residual voltage generating circuit 12 to a voltage corresponding to a D/A conversion value of a digital conversion value outputted from the A/D conversion circuit 2, and performs an A/D conversion operation by cycling the external signal voltage Vin through an input switching circuit 13, the A/D conversion circuit 2, and the residual voltage generating circuit 12. At the time of performing, a sample voltage is accumulated by performing a plurality of sample-and-hold processing, and the control circuit allows the residual voltage to be generated by the residual voltage generating circuit 12 based on the voltage as an accumulated result.SELECTED DRAWING: Figure 1 |
