High precision analog-to-digital converter and conversion method based on weight calibration

Abstract

The invention provides a weight calibration based high-precision analog-to-digital converter and a conversion method thereof. The analog-to-digital converter comprises a redundant weight capacitor array, a comparator array, a comparator, a control logic circuit, a weight extraction circuit and a weight calibration circuit. The analog-to-digital converter can greatly reduce the unit capacitor number, saves the layout area and power consumption and reduces the design complexity of an analog circuit. In addition, the error measurement precision is not restricted by process conditions, so that utilization of a compensation capacitor array related with capacitor mismatch error calibration and related circuits is avoided. The analog-to-digital converter reduces the number of data point actually required by curve fitting, the calculation amount of curve fitting is greatly reduced through repeated use of a small amount of data, and influences on capacitor error estimation by the frequency of input signals are reduced.

Description

technical field [0001] The invention relates to the field of electronics, in particular to a high-precision analog-to-digital converter based on weight calibration and a conversion method. Background technique [0002] Analog-to-digital converters are electronic components used to convert analog quantities into digital quantities through a certain circuit. Successive approximation (SAR, successive approximation register) analog-to-digital (A / D, Analog to Digital) converters are currently the most popular in the world. A research hotspot. It usually includes a capacitor array, a comparator, a successive approximation register and control logic. Since the number of unit circuits in the SAR type A / D converter is relatively small, and does not include operational amplifiers that consume a large amount of power consumption, very low power consumption can be achieved. Due to the small number of circuit modules, the layout area is also small. These characteristics make the SAR t...

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Problems solved by technology

[0006] (3) The traditional analog method for weight extraction and calibration, on the one hand, due to the need to increase the auxiliary capacitor array and auxiliary control logic circuit, resulting in high complexity of circuit design, on the other hand, the accuracy of weight extraction and calibration Limited by the minimum capacitance value, it is difficult for traditional analog calibration methods to meet the accuracy requirements of high-precision ADCs;

[0007] (4) Some digital calibration methods proposed in recent years also have the problem of high calibration complexity. The calibration accuracy is limited by the accuracy of auxiliary ADC or disturbance signal generation, and it is difficult to apply to high-precision ADCs.

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