Variable-Gain Input Amplifier With Attenuator Bypass for Low Noise

Solution Overview

Problem

Existing amplifiers in wireless communication devices face challenges in maintaining desired signal characteristics across a range of gain levels, particularly in high gain modes where noise factor is increased and linearity is compromised due to the use of variable-attenuation elements.

Innovation Solution

A variable-gain signal amplifier with a first attenuation stage having multiple branches with switches and programmable attenuation elements, allowing for a bypass path in high gain mode to prevent noise increase, and tailored attenuation in other modes to enhance linearity, coupled with an amplification stage and a post-amplification attenuation stage to maintain signal quality across various gain levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If variable-attenuation elements are used in the amplifier, then gain control is achieved, but noise factor increases in high gain modes

Engineering Contradiction:

Improvegain controlVSAvoidnoise factor

Core Design Contradiction:

PowerVSObject-affected harmful factors

Solution Approach 1:

The amplifier is divided into multiple independent branches, each with its own variable-attenuation element and switch. This segmentation allows selective activation of attenuation paths based on operating conditions, enabling the system to bypass attenuation elements in high gain modes to avoid noise degradation while maintaining gain control capability in other modes.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The amplifier dynamically switches between different operational configurations using control signals. The switches selectively connect or disconnect variable-attenuation elements based on the desired gain level, allowing the system to adapt its structure in real-time to optimize performance - bypassing attenuators in high gain mode to minimize noise while engaging them in lower gain modes for proper signal level control.

Inventive Principle:

Principle #15Dynamics

2Power

If variable-attenuation elements are used in the amplifier, then gain control is achieved, but linearity is compromised

Engineering Contradiction:

Improvegain controlVSAvoidlinearity

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

The amplifier is divided into multiple independent branches, each with its own variable-attenuation element and switch. This segmentation allows selective activation of attenuation paths based on operating conditions, enabling the system to bypass attenuation elements in high gain modes to avoid noise degradation while maintaining gain control capability in other modes.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system changes operational parameters by switching between different gain modes. The control circuit adjusts the state of switches and variable-attenuation elements based on the required gain level, thereby changing the effective circuit configuration to optimize linearity - bypassing attenuators in high gain mode where linearity is critical while engaging them in lower gain modes where signal level control is needed.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If attenuation is applied to maintain signal characteristics, then signal quality is improved, but noise performance deteriorates in high gain modes

Engineering Contradiction:

Improvesignal qualityVSAvoidnoise performance

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The amplifier dynamically switches between different operational configurations using control signals. The switches selectively connect or disconnect variable-attenuation elements based on the desired gain level, allowing the system to adapt its structure in real-time to optimize performance - bypassing attenuators in high gain mode to minimize noise while engaging them in lower gain modes for proper signal level control.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

Different parts of the amplifier circuit have different functional characteristics optimized for specific operating conditions. The bypass paths provide a low-noise route for high gain operations, while the attenuation paths provide signal level control for lower gain operations. This local optimization of circuit quality for different operating modes resolves the contradiction between signal quality and noise performance.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS10797668B2Multi-input amplifier with variable gain for individual inputs

Publication Date: 2020.10.06 SKYWORKS SOLUTIONS INC

AI summary

Described herein are variable gain amplifiers and multiplexers that embed programmable attenuators into switchable paths to provide variable gain for individual amplifier inputs. The variable gain for an individual input is provided using a amplification stage that is common for each input of the amplifier. A variable attenuation is provided for individual inputs through a combination of a band selection switch and an attenuation selection branch. The attenuation can be tailored for individual inputs and can depend on a gain mode of the amplifier.