Broadband programmable gain amplifier based on operational amplifier

An operational amplifier, programmable gain technology, applied in differential amplifiers, amplifier control, DC-coupled DC amplifiers, etc., can solve problems such as limited bandwidth of programmable gain amplifiers

Inactive Publication Date: 2010-12-15
EAST CHINA NORMAL UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, due to the finite cutoff frequency of the op amp, the bandwidth of the programmable gain amplifier is limited

Method used

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  • Broadband programmable gain amplifier based on operational amplifier
  • Broadband programmable gain amplifier based on operational amplifier
  • Broadband programmable gain amplifier based on operational amplifier

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Embodiment

[0022] refer to figure 2 , the closed-loop programmable gain amplifier designed in the present invention uses a negative feedback structure and has stable performance. Its gain depends on the ratio of the feedback resistance to the input resistance, and the linearity is high. It can realize end-to-end input and output, and the signal dynamic range is large. Most closed-loop programmable gain amplifiers use differential input and output op amps, decoders, input resistors and feedback resistors. The gain of the amplifier can be changed by changing the value of the input resistance and the feedback resistance through numerical control, that is, the gain of the amplifier can be programmed. In order to expand the bandwidth of the programmable gain amplifier, a two-pole-one-zero structure is adopted to extend the cut-off frequency of the operational amplifier to 10MHz, which improves the frequency response characteristics of the programmable gain amplifier. The specific applicat...

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Abstract

The invention discloses a broadband programmable gain amplifier based on an operational amplifier. By designing an operational amplifier with two poles and a zero point and using a zero point compensated secondary pole realized by a feedforward structure, the amplifier expands running bandwidth when ensuring 60dB low-frequency gain and obtains 10MHz cut-off bandwidth and the gain bandwidth product of 4.5GHz. The whole programmable gain amplifier realizes the regulation of 10MHz bandwidth and 50dB gain. The invention has negative feedback structure, stable performance and higher linearity, and the gain depends on the ratio of feedback resistance and input resistance; and the end-to-end input and output can be realized, and a signal dynamic range is wide.

Description

technical field [0001] The invention relates to a programmable gain amplifier, to be precise, to a programmable gain amplifier controlled by a digital signal, and belongs to the technical field of amplifying circuits. Background technique [0002] The analog circuit needs to amplify or attenuate the signal, and this function is realized by a variable gain amplifier (VGA). A variable gain amplifier is an amplifier whose gain can be varied. It is widely used in disk reading drive circuits, magnetic data storage systems, electromagnetic meters, TV tuners, etc., and also plays an important role in the analog front end of transceivers for wireless communications. [0003] With the development of digital-analog hybrid circuits, more and more variable gain amplifiers use digital signals to control gain changes (also known as programmable gain amplifiers). Compared with the analog automatic gain control loop, the numerical control method is easy to realize, has high control precis...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H03G3/20H03F3/45
Inventor 张勇张润曦赖宗声任旭黄飞马聪蒋颖丹何伟徐萍
Owner EAST CHINA NORMAL UNIV
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