A Digital Background Correction Method Based on Least Mean Square Algorithm

Abstract

A digital background correction method based on least mean square algorithm for split SAR ADC. First set up the split SAR ADC, and perform digital background correction based on the least mean square algorithm for the set split SAR ADC; the split SAR ADC includes two ADC modules, and the main DAC capacitor array in each ADC module uses non-binary capacitors At the same time, the weight of the highest capacitor in the main DAC redundant capacitor array is set to the minimum, so that the random switching of the correction DAC capacitor array can effectively correct each capacitor in the main DAC capacitor array, including the capacitor with the largest weight, and improve The linearity and dynamic range of the ADC; the introduction of the random switching method of the correction DAC can effectively solve the problem that the two ADC capacitors are mismatched in the same direction and cause the correction to be invalid; in addition, the main DAC capacitor array introduces redundancy, which can weaken the system during the quantization process. The dynamic error introduced ensures the correctness of each switch and improves the speed of iteration.

Description

technical field [0001] The invention belongs to the technical field of analog integrated circuits, and in particular relates to a digital background correction method based on a least mean square algorithm (LMS), which is used for correcting a capacitance array of a high-precision successive approximation analog-to-digital converter (SAR ADC). Background technique [0002] With the improvement of the precision of the analog-to-digital converter (ADC), the matching precision of the capacitor determines the static and dynamic performance of the ADC in a small-scale process. In addition to a better layout of the capacitor array layout, we also need to correct the capacitor array. The current mainstream correction methods include digital correction and analog correction. Digital correction means that the elimination of capacitor mismatch is completed in the digital domain. The weight of each capacitor corresponds to a digital codeword. This codeword corresponds to the digital w...

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Problems solved by technology

[0025] Aiming at the deficiencies that the above-mentioned traditional digital background correction method based on the split type split ADC cannot be corrected when the mismatch direction is consistent and the highest bit capacitance correction is not performed, the present invention proposes a digital method based on the least mean square algorithm (LMS algorithm). The background calibration method uses a non-binary capacitor array, which can effectively solve the problem of invalid calibration caused by the mismatching direction of the two ADC capacitors; at the same time, the non-binary capacitor array introduces redundancy to ensure the feasibility of digital calibration; finally, The capacitor with the highest weight is specially designed so that it can be effectively corrected

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