conversion range between the upper ADC and the lower ADC. Figure 4(a) shows the state of conversion when a voltage shift of ΔV occurs in the upper and lower conversion ranges in the conventional two-stage A/D conversion. The conventional two-stage A/D transformation has a fixed lower A/D conversion range. In this example, the lower part does not have a value over three or more. When there is a voltage shift of ΔV in the conversion range, a large conversion error occurs at the switching point of the upper ADC, and the DNL deteriorates so much. In contrast, if the subconversion is performed using interpolation as shown in Figure 4(b), the voltage between the top two points is divided evenly so as to the spring coil, and the conversion error is distributed and does