| 摘要 |
PROBLEM TO BE SOLVED: To correct errors resulting from switching noise generated in a comparison circuit and improve conversion accuracy without inviting an increase in area, reduction in conversion rate or increase in consumption current in a successive approximation analog-digital (AD) converter circuit. SOLUTION: In the successive approximation AD converter circuit provided with the comparison circuit including a plurality of amplifier stages cascade-connected via a coupling capacitance for evaluating sizes of input analog voltage and comparison voltage, a capacitance with one terminal connected to an input terminal of a first stage of amplifier stages in the comparison circuit, a sub-DA converter circuit having a switching means capable of switching voltages to be applied to another terminal of the capacitance based on an output from the comparison circuit, and a control circuit which can generate a control signal for the sub-DA converter circuit depending on the output from the comparison circuit to allow the comparison circuit to perform a redundancy comparison as well as can execute an averaging processing of the outputs from the comparison circuit to generate correction signal of a value for a register are provided to allow to execute the redundancy comparison action using a result of a normal AD conversion action as a start value after the AD conversion action. COPYRIGHT: (C)2011,JPO&INPIT
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