| 摘要 |
In an analog-to-digital conversion circuit, the gain of an operational amplification circuit in each of first- to third-stage circuits is two. The reference voltage range of a sub-A/D converter in each of the stages of circuits is set to one-half the reference voltage range of a D/A converter, so that the output voltage range of the D/A converter coincides with the output voltage range of the operational amplification circuit. When the voltage range of the analog input signal is VINp-p, the full-scale range of the sub-A/D converter is switched to VINp-p, and the gain of the operational amplification circuit is one. When the voltage range of the analog input signal is VINp-p/2, the full-scale range of the sub-A/D converter is switched to VINp-p/2, and the gain of the operational amplification circuit is two.
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