Multi-Path Amplifier Circuit With Single-Sideband Flicker Noise Rejection

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Solution Overview

Problem

Amplifiers, particularly those using CMOS technology, suffer from offset and flicker noise that corrupt low-frequency signal content, and existing chopper stabilization techniques face challenges in effectively suppressing these noises without increasing power consumption or introducing aliasing issues.

Innovation Solution

The implementation of a multi-path operational amplifier circuit using single-sideband chopper stabilization techniques, which includes a high frequency path and a low frequency path with an image band rejection mechanism, employs quadrature chopping signals to up-convert and down-convert signals, and uses a summing node to combine outputs from both paths, effectively attenuating flicker noise and image band components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If chopper stabilization techniques are used to reduce offset and flicker noise, then noise reduction is improved, but power consumption increases and aliasing issues are introduced

Engineering Contradiction:

Improveoffset and flicker noiseVSAvoidpower consumption

Core Design Contradiction:

Object-affected harmful factorsVSUse of energy by moving object

Solution Approach 1:

The amplifier is divided into multiple parallel paths (first amplifier path, second amplifier path, third amplifier path) with different frequency responses. Each path processes signals differently, allowing noise reduction without requiring high-frequency chopping that would increase power consumption. The segmented architecture enables selective noise filtering while maintaining energy efficiency.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A combiner is introduced as an intermediary element that merges the outputs of the three amplifier paths. The combiner selectively combines signals based on their frequency characteristics, allowing low-frequency noise from one path to be canceled by corresponding signals from other paths, while maintaining overall system power efficiency.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If chopper stabilization techniques are used to reduce offset and flicker noise, then noise reduction is improved, but aliasing issues are introduced

Engineering Contradiction:

Improveoffset and flicker noiseVSAvoidaliasing

Core Design Contradiction:

Object-affected harmful factorsVSObject-generated harmful factors

Solution Approach 1:

The signal processing is segmented into three distinct amplifier paths with different frequency responses. This segmentation allows each path to handle specific frequency ranges differently, preventing the aliasing that occurs in traditional single-path chopper stabilization by distributing the processing load and frequency management across multiple paths.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system uses a composite architecture combining multiple amplifier types (first, second, and third amplifiers) with different frequency characteristics. This composite approach creates a unified system that leverages the strengths of each amplifier type to achieve noise reduction without the aliasing problems that plague single-approach systems.

Inventive Principle:

Principle #40Composite materials

3Object-affected harmful factors

If multi-path amplifier circuitry is used to reduce noise, then noise reduction is improved, but device complexity increases

Engineering Contradiction:

Improveflicker noiseVSAvoidcircuit complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The multiple amplifier paths are designed to perform multiple functions simultaneously: the first, second, and third amplifiers each contribute to both signal amplification and noise cancellation. The combiner serves dual purposes of signal summation and noise rejection. This multi-functionality reduces the need for separate dedicated noise cancellation circuits, thereby limiting the increase in overall device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

4Object-affected harmful factors

If image band rejection mechanism is used, then signal quality is improved, but device complexity increases

Engineering Contradiction:

Improveimage band componentsVSAvoidcircuit complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The image band rejection functionality is merged into the existing multi-path amplifier architecture through the combiner. Rather than adding a separate image rejection circuit, the combiner is designed to simultaneously perform signal combination and image band cancellation by exploiting the phase and frequency relationships between the three amplifier paths. This merging approach achieves image rejection without proportionally increasing device complexity.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS8099073B1Noise reduction in amplifier circuitry using single-sideband chopper stabilization

Publication Date: 2012.01.17 MARVELL ASIA PTE LTD

AI summary

A multi-path amplifier can include a high frequency path, a low frequency path, and a summing node to sum an output from the high frequency path with an output from the low frequency path. The low frequency path can include a flicker noise reduction mechanism including an image band rejection mechanism. The low frequency path can include an in-phase path and a quadrature path.