Digital self-calibration device and method for successive approximation type analog-to-digital converter

Abstract

The invention belongs to the field of analog integrated circuit design, and discloses a digital self-calibration device and method for a successive approximation type analog-to-digital converter. Thedigital self-calibration device comprises a calibration switch, a comparator, and a logic control unit. The digital self-calibration method comprises the following steps: performing sampling; selecting a first calibration capacitor unit for charge redistribution; logically controlling the lower polar plate of the capacitor to be grounded or the switching between reference voltages, successively approximating the voltage difference brought by charge redistribution of the first calibration capacitor unit, carrying out quantitative calculation through output of the comparator, carrying out calibration calculation according to a quantitative result, enabling an obtained calibration result to serve as a calibration weight value and to be stored in the register for range finding work of the analog-digital converter, and completing calibration of all high-order capacitors repeatedly. According to the method, through multiplexing the calculation circuit, the circuit area is reduced, and high-precision quantification of the analog-to-digital converter is ensured.

Description

technical field [0001] The invention belongs to the field of analog integrated circuit design, and relates to a digital self-calibration device and method of a successive approximation analog-to-digital converter. Background technique [0002] The main factors restricting the performance of successive approximation analog-to-digital converters include comparator offset, noise influence, capacitance parasitic and capacitance mismatch and other factors. Capacitors often experience random mismatches due to manufacturing process variations. When capacitance mismatch occurs in the capacitor array of the SAR, it will affect the overall linearity of the SAR. Calibrating the capacitance array of the successive approximation analog-to-digital converter is an important technique to improve the linearity of the successive-approximation analog-to-digital converter. Calibration can be divided into digital calibration and analog calibration, and digital calibration includes foreground c...

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to overcome the shortcomings of the complex calculation circuit and low precision of the digital front calibration algorithm of the successive approximation analog-to-digital converter in the above-mentioned prior art, and provide a digital self-calibration device of the successive approximation analog-to-digital converter and method

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