Segmented capacitor array of analog-to-digital converter and switching method

Abstract

The invention discloses a segmented capacitor array of an analog-to-digital converter and a switching method. The segmented capacitor array comprises a low-significant-bit capacitor array and a high-significant-bit capacitor array, wherein the high-significant-bit capacitor array is formed by connecting non-redundant-bit capacitors and redundant-bit capacitors, the non-redundant-bit capacitors are C, 2C, 4C... 2M-2C in sequence, and the redundant-bit capacitors comprise C, C, 2C, 4C... 2M-2C. And the redundant bit capacitors are inserted into the non-redundant bit capacitors in sequence. Through a reasonable redundant bit construction mode, under the condition that the number and the area of unit capacitors in the capacitor array are not increased, the influence of capacitor mismatch in the segmented capacitor array is reduced, and it is guaranteed that redundant bits can provide enough redundant digital code space; meanwhile, the offset calibration of the comparator can be completed by reasonably utilizing redundancy; and a corresponding capacitor array switching method is utilized, so errors are further reduced, and the precision is improved.

Description

Technical field [0001] The present invention relates to the field of electronic circuit technology, and more particularly to a segment capacitance array and a switching method of an analog-to-digital converter. Background technique [0002] With the rapid development of CMOS integrated circuit, SAR ADC (SUCCESSIVE-Approximation-Register Analog-to-Digital Converter, successive approximation register modulus converter) is still ADC research hotspot. In order to reduce its power consumption, the structure of binary weight retention array is used. [0003] For N-bit Saradc, classic binary weight retransmission arrays such as figure 1 Indicated. Depend on figure 1 It can be seen that the number of unit capacitors and the area and the accuracy n are index relationships. In order to alleviate the problem, the prior art proposes a segmented capacitor array such as figure 2 with image 3 Indicated. The mismatch of high-active bit capacitance arrays in the segmented capacitor array will red...

AI Technical Summary

Problems solved by technology

[0004] Embodiments of the present invention provide a segmented capacitor array of an analog-to-digital converter and a switching method, which are used to solve the influence of the capacitance mismatch of the high effective bit capacitor array in the segmented capacitor array in the prior art, and at the same time solve the The influence of error

Images