Cyclic conversion SAR ADC circuit and SAR ADC method

Abstract

The invention provides a cyclic conversion SAR ADC circuit and an SAR ADC method. The cyclic conversion SAR ADC circuit comprises a first sampling switch, a second sampling switch, a first digital-to-analog conversion unit, a second digital-to-analog conversion unit, a residual signal amplification feedback unit, a comparator and an SAR control logic unit. Compared with a traditional SAR ADC circuit architecture, a cyclic conversion method is used, a low-order SAR ADC is repeatedly used, and the design problem that conversion of a high-precision SAR ADC needs a large number of DAC capacitors and high-precision comparators is solved; and by amplifying a residual signal, the complexity of comparator design is reduced, the high-precision matching requirement is met by reducing the number of capacitors and increasing the area of a unit capacitor through cyclic conversion, and the total area of the capacitors is smaller than that of a traditional SAR ADC circuit architecture.

Description

technical field [0001] The invention relates to the field of integrated circuit design, in particular to a cyclic conversion SAR ADC circuit and a SAR ADC method. Background technique [0002] Successive Approximation (SAR) ADC is a very widely used ADC, especially for some high-speed, high-precision and low-power applications. As the process node advances to the nanometer level, the advantages of SAR ADC are becoming more and more obvious, because its interior is mainly composed of capacitors, comparators and some logic switches, making the area gradually smaller and the accuracy easier to improve, and the power consumption can also be reduced. further compression. [0003] With the development of application requirements, the requirements for signal measurement accuracy are becoming more and more accurate, the requirements for signal conversion speed are getting higher and higher, the speed and accuracy of ADC are also constantly updated, and the chip area is also require...

AI Technical Summary

Problems solved by technology

[0006] In view of the shortcomings of the prior art described above, the purpose of the present invention is to provide a cyclic conversion SAR ADC circuit and a SAR ADC method, which are used to solve the problem that the unit capacitance in the digital-to-analog conversion unit in the prior art increases with the increase of output accuracy by 1 bit capacitance. Doubling the Area and Comparator Noise, Accuracy, and Speed ​​Issues

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