A two-stage operational amplifier

An operational amplifier and amplifying circuit technology, applied in the field of frequency compensation, can solve the problems of systematic imbalance and limited multiplication factor of structural capacitance, and achieve the effect of improving gain and unity gain bandwidth, saving chip area, and improving the multiplication factor of capacitance

Inactive Publication Date: 2016-07-13
UNIV OF ELECTRONICS SCI & TECH OF CHINA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the capacitance multiplication factor of this structure is limited, and it will introduce a systematic offset for the first stage

Method used

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  • A two-stage operational amplifier
  • A two-stage operational amplifier
  • A two-stage operational amplifier

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Embodiment Construction

[0025] Below in conjunction with accompanying drawing, describe technical scheme of the present invention in detail:

[0026] Such as figure 2 Shown is the topological structure of the two-stage operational amplifier of the present invention, including two transconductance amplification stages and a capacitance multiplication module. The transconductance of the first stage is gm1, the output impedance is R1, and the output capacitance is C1. The transconductance of the second stage is gm2, the output impedance is R2, and the output capacitance is C2. Cm is the compensation capacitance. The capacitance multiplication module is composed of a current-controlled current source X1 and a voltage-controlled current source X2. The transfer current ratio of X1 is k, and the transfer conductance of X2 is gmf. The X1 input terminal resistance is Rt, and the parasitic capacitance is Cp, then the small signal transfer function of the operational amplifier of the present invention is: ...

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Abstract

The invention relates to electronic circuit technology, in particular to the frequency compensation technology of operational amplifiers in analog integrated circuits. A two-stage operational amplifier according to the present invention includes a bias circuit, a first-stage amplifying circuit, and a second-stage amplifying circuit connected in sequence, and is characterized in that the first-stage amplifying circuit includes a capacitance multiplication module, and the The capacitance multiplying module is composed of a current-controlled current source and a voltage-controlled current source. The invention has the beneficial effects of increasing the capacitance multiplication factor, reducing the required compensation capacitance, saving chip area, not requiring an additional bias circuit, improving the gain and unity gain bandwidth of the operational amplifier, and simultaneously reducing systemic imbalance. The invention is particularly applicable to two-stage operational amplifiers.

Description

technical field [0001] The invention relates to electronic circuit technology, in particular to the frequency compensation technology of operational amplifiers in analog integrated circuits. Background technique [0002] Operational amplifiers are the most common and important unit circuits in linear circuits, and are widely used in analog systems and mixed-signal systems. Commonly used operational amplifiers include single-stage operational amplifiers, two-stage operational amplifiers, and three-stage operational amplifiers. Two-stage operational amplifiers are widely used because of their high gain and wide output swing. [0003] In some drive circuits (such as LCD drive and headphone drive), the operational amplifier is required to have high gain, wide bandwidth and other characteristics, and can drive large capacitive loads. Inserting a current snubber in series with the Miller capacitor breaks the feed-forward path formed by the compensation capacitor while increasing...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H03F3/45
Inventor 罗萍廖鹏飞杨云陈伟中甄少伟
Owner UNIV OF ELECTRONICS SCI & TECH OF CHINA
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