Multiplication-type A/D (Analog/Digital) converter capable of correcting limited gain error

A digital-to-analog converter and limited-gain technology, which is applied in the field of high-speed, high-precision, low-power pipeline A/D converters, can solve the problem of low-power multiplying digital-to-analog converters with limited gain errors that are difficult to reduce, operational amplifier DC Gain limitation, equivalent non-ideality of virtual ground, etc., to achieve the effect of reducing DC gain requirements, reducing power consumption, and reducing power consumption

CN102324940BActive Publication Date: 2013-08-07CHONGQING GIGACHIP TECH CO LTD
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Publication Date
2013-08-07

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Abstract

The invention relates to a multiplication-type A / D (Analog / Digital) converter capable of correcting a limited gain error, which comprises an amplifying circuit unit and a limited gain error correcting circuit unit. According to the invention, two compensation capacitors and an amplifier constitute the limited gain error correcting circuit unit, part of output quantity is adjustably compensated into the input end of an operation amplifier, nonzero / virtual earth / is adjusted, and the limited gain error is greatly reduced; after the adoption of the limited gain error correcting circuit unit, the limited gain error of the whole streamlined A / D converter is reduced by one order of magnitude; and in the invention, gain of the amplifier is adjustable, and therefore the limited gain error causedby temperature and process changes is effectively offset. According to the invention, the limited gain error correcting circuit has the characteristics of small limited gain error, low power consumption and high reliability and is suitable for the fields of high-speed, high-precision, low power-consumption streamlined A / D converters.
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Description

technical field

[0001] The invention relates to a multiplication type digital-to-analog converter capable of correcting limited gain errors, and its direct application field is a high-speed, high-precision, low-power consumption pipeline A / D converter. Background technique

[0002] The multiplying digital-to-analog converter is the sub-level core unit of the pipeline A / D converter. figure 1 The basic structure of a fully differential multiplying digital-to-analog converter is given. The advantage of this structure is that it uses the feedback principle to make the gain equal to the sampling capacitor C s with the feedback capacitor C f The ratio improves the accuracy and linearity of the gain. However, the gain error of this structure is too large, and there are two main sources: 1) the sampling capacitor C s with the feedback capacitor C f The accuracy and matching degree of the circuit are limited, so that its ratio cannot be exactly equal to the circuit design value,...

Examples

Embodiment Construction

[0024] The specific implementation manners of the present invention are not limited to the following description, and are now further described in conjunction with the accompanying drawings.

[0025] The circuit diagram of the multiplying digital-to-analog converter of the present invention is as figure 2 shown. Its basic composition includes an amplifying circuit unit and a finite gain error correction circuit unit. Amplifying circuit unit includes: operational amplifier A2, sampling capacitor C s1+ and C s1- , feedback capacitance C f1+ and C f1- , Interconnect switch S s1+ and S s1- , Interconnect switch S r1+ and S r1- , Interconnect switch S f1+ and S f1- . The finite gain error correction circuit unit includes: variable gain amplifier A3, compensation capacitor C cal+ and C cal- , Interconnect switch S 1+ and S 1- , Interconnect switch S 2+ and S 2- .

[0026] figure 2 The specific connection relationship and functional relationship in are the same a...