Circuit structure for improving significant bit of 12-bit sectional capacitance SAR ADC (Synthetic Aperture Radar Analog to Digital Converter)

The utility model belongs to the technical field of analog-to-digital converters, and particularly provides a circuit structure for improving the significant bit of a 12-bit sectional capacitor SAR ADC, which comprises a low-bit capacitor bank formed by connecting a plurality of capacitors in parallel and a high-bit capacitor bank formed by connecting a plurality of capacitors in parallel, the capacitance values in the low-bit capacitor bank comprise C, 2C, 4C, 8C, 16C and 32C, and the capacitance values in the high-bit capacitor bank comprise C, 2C, 4C, 8C, 16C and 32C. The capacitance value in the high-bit capacitor bank comprises at least two C, and C is the size of a unit capacitor; capacitors of the low-bit capacitor bank and the high-bit capacitor bank are respectively and independently connected with an input signal vin, and the other end of the low-bit capacitor bank is connected with the other end of the high-bit capacitor bank through a capacitor and then connected with the negative input end of the