24-bit low-distortion Sigma-Delta analog-to-digital converter

Abstract

The invention discloses a 24-bit low-distortion Sigma-Delta analog-to-digital converter, and the converter comprises a first-stage integrator which is used for carrying out the integration of a difference value between an input signal and a feedback signal of the analog-to-digital converter, and obtaining an output signal of the first-stage integrator; a second-stage integrator used for obtaining a second-stage integrator output signal; a Flash quantizer module used for quantizing the analog signal into a digital signal and obtaining a 16-bit thermometer code; a DWA module used for converting the 16-bit thermometer code into a 5-bit binary code and obtaining a digital signal after weighted averaging; a feedback DAC module used for converting the digital signal into an analog feedback signal; and a digital decimation filter module used for carrying out digital filtering and downsampling on the 5-bit binary code and cutting a high-bit 24-bit digital code. A cascade integrator feed-forward structure is adopted, and a direct feed-forward path from input to a quantizer is introduced, so that non-ideal nonlinear factors in the circuit cannot directly act on input signals, and the low-distortion characteristic of the whole system is achieved.

Description

technical field [0001] The invention belongs to the technical field of digital-analog hybrid integrated circuits, and in particular relates to a 24-bit low-distortion Sigma-Delta analog-to-digital converter. Background technique [0002] Digital signal processing technology is developing rapidly in today's world, and the processing accuracy can reach a very high level, but most of the signals in nature are analog signals, which must be processed before they can be converted into digital signals, so the conversion of analog signals to digital signals becomes extremely important. Analog to Digital Converter (ADC, Analog to Digital Converter) is a bridge connecting the analog world and the digital world. The conversion accuracy and conversion speed of the ADC directly affect the efficiency and effect of signal processing. Among various A / D converters, Sigma-Delta A / D converter adopts oversampling technology and noise shaping technology. With its own characteristics of high pre...

AI Technical Summary

Problems solved by technology

However, the traditional Sigma-Delta ADC is affected by the limited gain, limited slew rate and limited output swing of the operational transconductance amplifier in the integrator, so that the output often contains high harmonic components, affecting the final signal-to-noise Distortion ratio (SNDR, Signal to Noise and Distortion Ratio), which reduces the accuracy of the converted data

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