Differential Power Amplifier Harmonic Attenuation for Class E Efficiency
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Solution Overview
Problem
Existing power amplifier circuits in mobile units face inefficiencies due to unwanted signals caused by unattenuated odd harmonics, which disrupt the ideal class E operation and reduce power efficiency.
Innovation Solution
A power amplifier circuit utilizing a differential amplifier configuration with specific termination circuits and transmission lines to attenuate odd harmonics, including a first termination circuit with a lower capacitance capacitor and a second termination circuit with a capacitor and inductor, ensuring that odd harmonics are reduced in the output signal, thereby maintaining high efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If class E operation is used to increase efficiency, then power efficiency is improved, but odd harmonics are not attenuated resulting in unnecessary signal output
Solution Approach 1:
The patent extracts and removes odd harmonic components from the amplifier output using a dedicated harmonic attenuation circuit. The circuit separates the odd harmonic frequencies from the fundamental signal and attenuates them before output, allowing class E operation to maintain high efficiency while eliminating the harmful odd harmonic signals that would otherwise be generated.
Solution Approach 2:
The patent introduces an intermediary harmonic attenuation circuit between the class E amplifier and the output. This intermediary component processes the signal by selectively attenuating odd harmonics while preserving the fundamental frequency and even harmonics, thus mediating between the high-efficiency class E operation and the requirement to suppress unwanted odd harmonic signals.
2Object-generated harmful factors
If third harmonic impedance is not set to open-circuit, then class E operation condition is not ideal, but odd harmonics are attenuated
Solution Approach 1:
The patent applies local quality by creating different impedance conditions at different frequency points. The harmonic attenuation circuit provides open-circuit impedance specifically at the third harmonic frequency while maintaining appropriate impedance matching at the fundamental frequency. This localized impedance control allows odd harmonic attenuation without compromising the overall class E operation stability.
Solution Approach 2:
The patent changes the impedance parameter selectively at different frequencies. By using resonant circuits and filtering elements, the circuit transforms the impedance seen by the amplifier at odd harmonic frequencies to be highly resistive (open-circuit like), while maintaining the proper complex impedance relationship at the fundamental frequency for stable class E operation. This frequency-dependent parameter transformation resolves the contradiction.
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 proposed solution effectively attenuates odd harmonics, improving the power amplifier circuit's efficiency by ensuring that the amplifier operates closer to ideal class E conditions, reducing unnecessary signal output and enhancing overall performance.
Implementation Method 1
a first termination circuit including a capacitor connected between the first output terminal and the second output terminal; a first transmission line having one end connected to the first output terminal of the first amplifier; a second transmission line having one end connected to the second output terminal of the second amplifier; a second termination circuit including a capacitor and an inductor that are connected between another end of the first transmission line and another end of the second transmission line
Data Source
AI summary
A power amplifier circuit includes a power splitter, a first amplifier configured to output a first amplified signal from a first output terminal, and a second amplifier configured to output a second amplified signal from a second output terminal. The power amplifier circuit further includes a first termination circuit connected between the first output terminal and the second output terminal, a first transmission line, a second transmission line, a second termination circuit connected between another end of the first transmission line and another end of the second transmission line, and a power combiner.