Successive approximation type analog-digital converter

Abstract

The invention discloses an improved successive approximation type analog-digital converter. The analog-digital converter comprises a capacitance digital-to-analog conversion network, a comparator and a successive approximation logic circuit, wherein the capacitance digital-to-analog conversion network consists of a plurality of switch and capacitor cells, each switch and capacitor cell comprises four capacitors and six switches, the first ends of the first capacitor and the second capacitor are connected to a positive output end, and the first ends of the third capacitor and the fourth capacitor are connected to a negative output end; the second end of the first capacitor is connected to a first potential by the first switch, and the second end of the second capacitor is connected to a second potential by the second switch; the second end of the third capacitor is connected to the first potential by the third switch, and the second end of the fourth capacitor is connected to the second potential by the fourth switch; and the second end of the first capacitor is connected with the second end of the fourth capacitor by the fifth switch, and the second end of the second capacitor is connected with the second end of the third capacitor by the sixth switch. The analog-digital converter disclosed by the invention has the advantage of high conversion rate.

Description

technical field [0001] The invention belongs to the technical field of integrated circuits, and in particular relates to an analog-to-digital converter, in particular to a successive approximation analog-to-digital converter. Background technique [0002] figure 1 A conventional successive approximation analog-to-digital converter is shown, which includes a capacitive digital-to-analog conversion network 101 , a comparator 102 and a successive approximation logic circuit 103 . The capacitive digital-to-analog conversion network 101 is a differential structure with two sides, and each side includes several capacitors. To simplify, figure 1 Only 5 capacitors are shown on each side of the capacitor digital-to-analog conversion network 101, for example, the upper side is C 1n ~C 5n . They are arranged from largest to smallest, C jn = 2C (j+1)n , j=1, 2, 3, C 4n =C 5n ; the lower side is C 1p ~C 5p , C jp = 2C (j+1)p , j=1, 2, 3, C 4p =C 5p . The upper plates of t...

AI Technical Summary

Problems solved by technology

[0005] The technical problem to be solved by the present invention is the slow conversion speed of the traditional successive approximation analog-to-digital converter, and the conversion speed of the successive approximation analog-to-digital converter is improved by a new capacitor digital-to-analog conversion network

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