Voltage comparing circuit

Abstract

A voltage comparing circuit of the invention includes a first and a second capacitor, terminals on one side of which are respectively connected to a positive side voltage of an analog input signal and a negative side voltage of a reference voltage via a first and a second switch and terminals on other side of which are commonly connected, a third and a fourth capacitor terminals on one side of which are respectively connected to a positive side voltage of the reference voltage and a negative side voltage of the analog input signal via a third and a fourth switch and terminals on other side of which are commonly connected, a first and a second inverter respectively connected to a common connection terminal of the first and the second capacitors and a common connection terminal of the third and the fourth capacitors and connected with a fifth and a sixth switch respectively between input and output terminals thereof, a seventh and an eighth switch respectively connected between the input terminal of the first inverter and the output terminal of the second inverter and between the input terminal of the second inverter and the output terminal of the first inverter, and a ninth and a tenth switch respectively connected between the first capacitor and the fourth capacitor and between the second capacitor and the third capacitor.

Description

technical field [0001] The present invention relates to a voltage comparison circuit, and more particularly to a chopper type voltage comparison circuit used in a high-speed A / D converter or the like. Background technique [0002] The inventors of the present application have proposed a chopper type voltage comparison circuit using an inverter in Japanese Patent No. 3105862. The following will refer to Figure 7 to Figure 10 , describing the published voltage comparator circuit. Figure 7 shows a published voltage comparator circuit, while Figures 8A to 8C show respectively Figure 7 The working states of the input sampling mode, amplification mode and lock mode of the medium voltage comparison circuit. also, Figure 9 is a timing diagram showing the operation of each switch in various modes. In these drawings, numerals 101 to 108 denote switches, numerals 110, 111, 114 and 115 denote capacitors, and numerals 112 and 113 denote inverters. Furthermore, the symbol Vip rep...

AI Technical Summary

Problems solved by technology

However, according to the actual inverter, the output amplitude of the inverter is limited, so when the difference between the common-mode voltage of the analog input signal and the common-mode voltage of the reference voltage increases, the output of the inverter saturation, and the difference between the outputs of these inverters is invalid, thus creating a problem in lock mode where the analog input signal cannot be properly determined to be greater or lesser than the reference voltage

Images