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A Digitally Controlled Variable Gain Amplifier

A gain amplifier, digital control technology, applied in the direction of gain control, amplification control, electrical components, etc., can solve the problems of mismatch, difficult to achieve gain control gain step size, etc. Effects of matching questions

Active Publication Date: 2020-12-18
CHENGDU GANIDE TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] Aiming at the above-mentioned deficiencies in the prior art, the digitally controlled variable gain amplifier provided by the present invention solves the problem that the existing numerical control adjustable gain amplifier realizes a wide dynamic range, which is prone to mismatch and difficult to achieve accurate gain step size of gain control The problem

Method used

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  • A Digitally Controlled Variable Gain Amplifier
  • A Digitally Controlled Variable Gain Amplifier
  • A Digitally Controlled Variable Gain Amplifier

Examples

Experimental program
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Embodiment 1

[0043] The present invention is based on the improved Cherry-Hooper amplifier gain unit. In the three-stage VGA circuit, the first and second stages are composed of a variable transconductance amplifier and a constant transimpedance amplifier, and the third stage is composed of a variable transconductance amplifier and a variable transimpedance amplifier. Composition, a high-pass filter is used between the two VGA circuits to eliminate the DC bias voltage generated by each VGA unit to ensure the reliability of the circuit, and the output buffer is used to drive a 100Ω differential load impedance.

[0044] Such as Figure 1-2 As shown, the digitally controlled variable gain amplifier among the present invention includes the first stage VGA circuit, the second stage VGA circuit, the third stage VGA circuit and the output buffer circuit connected in sequence;

[0045]The first input end and the second input end of the first-stage VGA circuit are jointly used as the input end of t...

Embodiment 2

[0064] This embodiment provides the working principles of VGA circuits at all levels in the above embodiment 1:

[0065] Such as image 3 As shown, the transconductances of the five input-pair transistors in the first-stage VGA circuit are g m1 , g m2 , g m2ˊ , g m3 , g m3ˊ , g m2 and g m2ˊ have the same transconductance value, but opposite polarity, when the digital control signal of the numerical control device is input into C 0 When the data selector controls the MOS switch to select the transconductance pair g m2 ; When the digital control signal input C 0 Non-time, through the data selector to control the MOS switch to select the transconductance pair g m2ˊ , g m3 and g m3ˊ Right works and g m2 and g m2ˊ for the same, when the digital control signal input C 1 When the data selector controls the MOS switch to select the transconductance pair g m3 ; When the digital control signal of the numerical control device is input into C 1 Non-time, through the data s...

Embodiment 3

[0069] The digitally controlled variable gain amplifier in this embodiment has a 0.5-dB step size and a constant bandwidth. By using a variable transconductance stage and a variable transimpedance stage, a constant bandwidth exceeding 3.5 GHz is achieved. The subsequent simulation results are as follows Figure 5 As shown; high gain above 60dB, gain range of 30.5dB, precise gain step size of 0.5dB, the maximum step size error between the simulation result and the design value (0.5dB) is less than ±0.15dB, as Image 6 shown.

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Abstract

The invention discloses a digitally controlled variable gain amplifier, which includes a three-stage VGA circuit and an output buffer circuit. The first and second stages of the three-stage VGA circuit are composed of a variable transconductance amplifier and a constant transimpedance amplifier, and the third stage is composed of a variable transconductance amplifier and a constant transimpedance amplifier. Composed of a variable transconductance amplifier and a variable transimpedance amplifier, a high-pass filter is used between the two VGA circuits to eliminate the DC bias voltage generated by each VGA unit to ensure the reliability of the circuit, and the output buffer is used to drive 100Ω differential load impedance. The present invention avoids the mismatch problem caused by too many transistors by simultaneously introducing a variable transconductance stage and a variable transimpedance stage into the third-stage VGA circuit, and simultaneously realizes high gain, precise gain step size and constant bandwidth , has good linearity, which is conducive to the realization of a wide dynamic range system.

Description

technical field [0001] The invention belongs to the technical field of variable gain amplifier design, in particular to a digitally controlled variable gain amplifier. Background technique [0002] Due to the existence of low atmospheric attenuation, the research and design of several millimeter-wave spectral windows, such as 35GHz, 77GHz, 95GHz and 140GHz, have received more and more attention in recent years. Existing applications include 60GHz wireless communication, 77GHz collision avoidance radar and 94GHz imaging, etc. In these applications, the passive millimeter-wave imaging system has the advantages of small size, light weight, and low power consumption; as an important part of the passive wave imaging receiver, the baseband VGA is used to offset the change of the input signal level and maintain The output signal level is stabilized to maximize the dynamic range of the receiver. [0003] The VGA design of mmWave imaging receivers faces many challenges such as wide...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H03G3/30
CPCH03G3/3089
Inventor 苏黎胡柳林郑薇伍莲洪何舒玮廖旭阳陈依军侯杰蒋汶兵边丽菲袁野
Owner CHENGDU GANIDE TECH