Differential Amplifier Feedback for Output Error Compensation

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Solution Overview

Problem

Amplifiers in wireless communication systems, such as transimpedance and inverting amplifiers, suffer from undesired output errors, where the actual output deviates from the desired output, leading to inefficiencies in signal amplification.

Innovation Solution

The amplification systems are designed to reduce output errors by incorporating a feedback path that couples the inverse of the input-referred error signal to the non-inverting input of the amplifier, effectively halving the output error voltage through the use of an inverting buffer or inverting amplifier configuration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional amplifier configurations are used, then the amplification system is simple, but output error voltage is high

Engineering Contradiction:
Improveoutput error voltageVSAvoidamplifier configuration
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies feedback by coupling the inverse of the input-referred error signal back to the non-inverting input of the amplifier through a feedback path. This feedback mechanism continuously monitors and corrects the error signal, reducing the output error voltage while maintaining system functionality.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent utilizes inversion by generating the inverse of the input-referred error signal and feeding it back to the non-inverting input. This inverted error signal counteracts the original error, effectively reducing the output error voltage through destructive interference of the error components.

Inventive Principle:
Principle #13The other way round (Inversion)

2Reliability

If feedback path with inverting buffer is added, then output error is reduced, but device complexity increases

Engineering Contradiction:
Improveamplification accuracyVSAvoidfeedback circuit structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the amplifier system into distinct functional blocks: the main amplifier, the inverting buffer, and the feedback path. This segmentation allows each component to be optimized independently and simplifies the analysis and design of the overall error reduction mechanism.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The inverting buffer serves as an intermediary element that processes the error signal before feeding it back to the non-inverting input. This intermediary component isolates the feedback path from direct coupling to the output, reducing loading effects and improving the precision of error correction.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3491736B1Amplification systems
Publication Date: 2021.05.05 QUALCOMM INC
  • EP3491736B1 patent drawingFigure 1
  • EP3491736B1 patent drawingFigure 2
  • EP3491736B1 patent drawingFigure 3

AI summary

Certain aspects of the present disclosure provide methods and apparatus for implementing an amplification system. The amplification system includes an amplifier comprising differential inputs and an output. The differential inputs include an inverting input and a non-inverting input. The amplification system further includes a feedback path from the output coupled to the inverting input. The feedback path from the output is coupled to at least one of an inverting amplifier or buffer, and the at least one of the inverting amplifier or buffer is further coupled to the non-inverting input.