Successive approximation type ADC structure and algorithm

Abstract

The invention discloses a successive approximation type ADC structure and an algorithm. An ADC involved in the successive approximation type ADC structure is a segment capacitor type electric charge redistribution successive approximation type ADC. Main modules include the novel segment capacitor type DAC, a comparator and successive approximation logic, wherein the novel segment capacitor type DAC is the structure core of the successive approximation type ADC structure, and the intersegmental difference to single-end algorithm matched with the segment capacitor type DAC is synthesized into the successive approximation logic. According to the successive approximation type ADC, the segment capacitor type DAC of a differential structure is adopted, the intersegmental difference to single-end technology is utilized, and the effect of obtaining an (N+1)-bit ADC resolution ratio with an N-bit ADC basis structure is achieved; meanwhile, the influence of parasitic capacitance on the linearity of the segment capacitor type DAC is greatly reduced, and the performance of the ADC is improved.

Description

Technical field [0001] The invention belongs to the field of analog-to-digital converters of integrated circuits, and particularly relates to a new type of successive approximation ADC structure and algorithm. Background technique [0002] The successive approximation ADC (Analog to Digital Converter) is an analog-to-digital converter that can provide higher conversion speed and higher resolution. It has the advantages of low power consumption and small area, so it is more widely used. Come more and more widely. [0003] The most widely used successive approximation ADC is the charge redistribution structure. The charge redistribution DAC (Digital to Analog Converter, digital-to-analog converter) is its core circuit, and its basic structure is a capacitor array with binary weights. Generally, when the ADC resolution is greater than 8 bits, a segmented method is used to reduce the area of ​​the capacitor. figure 1 It shows a typical segmented capacitive successive approximation ADC...

AI Technical Summary

Problems solved by technology

The ADC with this structure has an obvious irrational factor. The parasitic capacitance of the upper plate of the segment capacitor Cs will introduce nonlinearity, thereby affecting the performance of the ADC.

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