Successive approximation type analog-to-digital converter and conversion method

Abstract

The invention provides a successive approximation type analog-to-digital converter and a conversion method, and the method comprises the steps: a first digital-to-analog conversion module and a second digital-to-analog conversion module respectively receive a normal-phase input signal and an inverted-phase input signal, and carry out the digital-to-analog conversion; the differential comparison module is used for comparing output signals of the first digital-to-analog conversion module and the second digital-to-analog conversion module and outputting a first comparison result; the first verification comparison module is used for comparing an output signal of the first digital-to-analog conversion module with a common-mode voltage and outputting a second comparison result; the second verification comparison module is used for comparing the output signal of the second digital-to-analog conversion module with the common-mode voltage and outputting a third comparison result; the digital logic control module generates a conversion result and a switch switching signal based on the first comparison result, the second comparison result and the third comparison result. The comparator is allowed to convert when the voltage of the digital-to-analog conversion unit is not completely established, the conversion time is shortened, and the conversion speed is increased; and meanwhile, the random error and the metastable state of a single comparator can be inhibited, and the effect of improving the conversion precision is also achieved.

Description

Technical field [0001] The present invention relates to the field of integrated circuit design, and more particularly to a secondary approximation modulus converter and a conversion method. Background technique [0002] SUCCESSIVE Approximation, SAR) ADC is a very common analog-to-digital converter, especially with the process integration, SAR ADC is ideal for design under deep submicron. Its main architecture group has become DAC, comparator, SAR logic, and DAC is generally capacitive DAC. The degree of manufacturing match determines the accuracy of SAR ADC, and as the process node advances, the degree of matching of unit area can do higher, It is conducive to the increase in SAR ADC accuracy; the comparator is a digital-to-analog mix circuit, and its bandwidth and response speed are easier to improve under small dimensional nodes; SAR logic is a pure digital circuit, which is easy to implement GHz in a low-voltage small size node The frequency, so SAR ADC is a research directio...

AI Technical Summary

Problems solved by technology

Since the DAC weight is from high to low, the time requirements for each weight conversion are inconsistent, and the higher the weight (MSB), the longer it takes to establish

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