Amplifier Circuit Switching Layout for Impedance Matching

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Solution Overview

Problem

Amplifier circuits with amplification and bypass paths suffer from non-linear distortion and impaired impedance matching in both bypass and amplification modes due to off-capacitance issues, leading to degraded gain and distortion characteristics.

Innovation Solution

Incorporating a first series switch and a first shunt switch on the bypass path, along with an inductor and a second shunt switch on the amplification path, which reduces high-frequency signal components and improves impedance matching by canceling out reactance components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a shunt switch is added to the bypass path to improve isolation characteristic, then the isolation characteristic is improved, but off-capacitance occurs at the shunt switch which deteriorates impedance matching

Engineering Contradiction:

Improveisolation characteristicVSAvoidimpedance matching

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

A series switch is introduced as an intermediary component on the bypass path. When the shunt switch is in the off-state, the series switch isolates the off-capacitance of the shunt switch from the bypass path, preventing deterioration of impedance matching while maintaining the isolation function of the shunt switch.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The circuit uses dynamic switching control where the series and shunt switches are coordinated to change states based on operating mode. In bypass mode, the series switch is on and shunt switch is off; in amplification mode, the series switch is off and shunt switch is on. This dynamic configuration optimizes both isolation and impedance matching characteristics.

Inventive Principle:

Principle #15Dynamics

2Adaptability or versatility

If a bypass switch is added to switch between bypass and amplification modes, then mode switching capability is improved, but off-capacitance at the bypass switch deteriorates impedance matching in amplification mode

Engineering Contradiction:

Improvemode switching capabilityVSAvoidimpedance matching

Core Design Contradiction:

Adaptability or versatilityVSEase of operation

Solution Approach 1:

The series switch acts as an intermediary that isolates the off-capacitance of the bypass switch from the amplification path. When the bypass switch is off in amplification mode, the series switch being off also prevents the off-capacitance of the bypass switch from affecting the output impedance matching.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Power

If the amplifier is used for signal amplification, then gain is improved, but non-linear distortion including harmonic and intermodulation distortion increases

Engineering Contradiction:

ImprovegainVSAvoidnon-linear distortion

Core Design Contradiction:

PowerVSObject-generated harmful factors

Solution Approach 1:

The off-capacitances of the switches, which are normally harmful parasitic elements, are utilized as beneficial capacitance components for output impedance matching. By coordinating the switching states, the off-capacitances are positioned to provide the necessary reactive compensation for impedance matching in both bypass and amplification modes.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution effectively reduces non-linear distortion and enhances output impedance matching in both bypass and amplification modes, resulting in improved gain and distortion characteristics.

Implementation Method 1

an inductor coupled on an output side with respect to the amplifier... Since the inductor is provided on the output side with respect to the amplifier, high frequency signal components outputted by the amplifier are reduced

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

The bypass path includes a first series switch coupled in series on the bypass path and a first shunt switch coupled in series between the bypass path and ground

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 3

the inductor and the second shunt switch coupled in series between the inductor and ground are provided on the output side with respect to the amplifier... it is possible to improve output impedance matching in both bypass and amplification modes

Methodology Applied

Scientific EffectImpedance matching through reactance cancellation:

Data Source

PatentUS11309847B2Amplifier circuit

Publication Date: 2022.04.19 MURATA MFG CO LTD

AI summary

An amplifier circuit has an amplification path including an amplifier and a bypass path configured to bypass at least the amplifier. The bypass path includes a switch coupled in series on the bypass path and another switch coupled in series between the bypass path and ground. The amplification path further includes an inductor coupled on an output side with respect to the amplifier and a switch coupled between the inductor and ground on a path between the inductor and the amplifier.