Hybrid Class Amplifier With Harmonic Impedance Switching

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Solution Overview

Problem

Traditional power amplifiers face challenges in combining high efficiency at medium output amplitudes with high maximum output power, as they experience negative interactions between narrow current pulses and high harmonic impedances, leading to efficiency degradation and potential transistor breakdown.

Innovation Solution

A power amplifier is configured to generate impedances at harmonic frequencies, allowing it to operate in class C mode at low output amplitudes and class F or inverse class F mode at high output amplitudes, using a combination of parallel and series resonators to manage harmonic impedances and reduce voltage overshoots.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the amplifier operates in class C mode with narrow current pulses, then efficiency at medium output amplitudes is improved, but voltage overshoots and transistor breakdown risk increase at high output amplitudes

Engineering Contradiction:

Improveamplifier efficiencyVSAvoidtransistor breakdown risk

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The amplifier dynamically switches between class C mode (for medium output amplitudes) and class F or inverse class F mode (for high output amplitudes). This dynamic operation mode allows the amplifier to optimize efficiency at medium levels while preventing voltage overshoots and transistor breakdown at high levels by activating harmonic impedance management only when needed.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The amplifier changes the impedance parameters at harmonic frequencies based on the output amplitude level. At medium amplitudes, the amplifier operates with standard class C characteristics. At high amplitudes, it modifies the harmonic impedance parameters by engaging class F or inverse class F mode, which manages voltage peaks and prevents transistor breakdown while maintaining efficiency.

Inventive Principle:

Principle #35Parameter changes

2Strength

If the amplifier operates in class F or inverse class F mode at high output amplitudes, then voltage overshoots are reduced, but device complexity increases

Engineering Contradiction:

Improvevoltage controlVSAvoidamplifier configuration

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The amplifier uses dynamic switching between different operation modes (class C, class F, and inverse class F) based on the output amplitude level. This dynamic approach allows the system to maintain simple class C operation at medium amplitudes while transitioning to class F or inverse class F mode only when high amplitude operation is required, thus managing voltage overshoots without permanently increasing device complexity.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The amplifier is designed with multi-functionality, capable of operating in multiple modes (class C, class F, and inverse class F) using the same hardware infrastructure. This universal design allows the amplifier to adapt its behavior based on operating conditions without requiring separate dedicated circuits for each mode, thereby controlling device complexity while achieving effective voltage management.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Stability of the object's composition

If traditional linear amplifiers are used, then linearity is maintained, but efficiency and power output are reduced

Engineering Contradiction:

Improvesignal linearityVSAvoidamplifier efficiency

Core Design Contradiction:

Stability of the object's compositionVSUse of energy by moving object

Solution Approach 1:

The amplifier dynamically adapts its operation mode based on the signal characteristics and output amplitude. For medium amplitudes, it operates in class C mode to maximize efficiency. For high amplitudes, it transitions to class F or inverse class F mode to manage voltage peaks. This dynamic adaptation allows the system to achieve high efficiency and power output while maintaining signal integrity through intelligent mode selection rather than relying on traditional linear amplification.

Inventive Principle:

Principle #15Dynamics

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

This configuration achieves higher average efficiency and increased output power compared to traditional amplifiers, while maintaining robustness and avoiding transistor saturation, particularly suitable for multi-carrier radio signals.

Implementation Method 1

Methodology Applied

Scientific EffectResonance: Resonance

Data Source

PatentUS8593225B2Hybrid class amplifier

Publication Date: 2013.11.26 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

A power amplifier is configured to generate impedances at harmonic frequencies such that the power amplifier operates in a class C mode in a low output amplitude range and in a class F or inverse F mode in a high output amplitude range. Related methods of operation are also discussed.