Vcm-based ultra-low power consumption SAR ADC switch switching structure and switch switching method thereof

Abstract

The invention relates to a Vcm-based ultra-low power consumption SAR ADC switch switching structure and a switch switching method thereof. The circuit comprises a first capacitor array, a second capacitor array, a comparator, two change-over switch groups and two sampling switches; capacitor top plates DACP and DACN of the first capacitor array and the second capacitor array are respectively connected with the comparator. The DACP and the DACN are respectively connected with a common mode level Vcm through two sampling switches; bottom plates of capacitors in the first capacitor array and thesecond capacitor array are connected with a reference level Vref, a ground level Vss, the common mode level Vcm and an input level Vip or Vin through a first change-over switch group and a second change-over switch group; the comparator comprises a dynamic preamplifier and a dynamic latch which are connected in sequence, the two input ends of the dynamic preamplifier serve as the in-phase input end and the anti-phase input end of the comparator respectively, and the output end of the dynamic latch serves as the output end of the comparator. Compared with a traditional capacitor array, the highest-order weight capacitor is saved, and compared with a capacitor array switch switching structure for top plate sampling, better ADC precision can be achieved.

Description

technical field [0001] The invention relates to a Vcm-based ultra-low power consumption SAR ADC switching structure and a switching method thereof. Background technique [0002] With the continuous development of science and technology, modern society has also entered the era of the Internet of Things. The era of the Internet of Things is a new era based on the Internet, and the term "Internet of Everything" is also a good description of the basic characteristics of the Internet of Things era. The rapid development of the Internet of Things era has given birth to the rise of many industries, such as the sensor industry, embedded industry, and radio frequency device industry. For the current smart nodes of the Internet of Things, the Internet of Things devices are gradually becoming smaller, which requires devices capable of information conversion-sensors also tend to be miniaturized and intelligent. Therefore, as a bridge connecting smart devices and the natural world, the...

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Problems solved by technology

In order to study how to reduce the switching power consumption of capacitor arrays, countless scholars have conducted research on the basis of this traditional backplane sampling structure over the years, and invented many low-power capacitor array switching schemes, especially the use of top boards. Capacitor array with sampling structure is the representative, and the average switching power consumption of the current mainstream 10-bit capacitor array based on top plate sampling is 255 C 0 V ref 2 However, due to the natural advantage of higher precision in bottom-board sampling compared to top-board sampling, this makes the switch switching scheme based on bottom-board sampling and low-switching power consumption capacitor arrays a hot topic of research.

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