Multi-Stage Power Amplifier Harmonic Control for Higher Efficiency
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Solution Overview
Problem
Existing power amplifier circuits in mobile communication devices face challenges in achieving high-efficiency power amplification, particularly when multiple transistors are connected in series, as there is a lack of effective methods for high-efficiency power amplification in such configurations.
Innovation Solution
A power amplifier circuit configuration that includes a first amplifier performing class inverse-F operation and a subsequent amplifier performing class F operation, with harmonic control circuits and matching networks to control even and odd-order harmonics, allowing for high-efficiency power amplification across multiple stages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple transistors are connected in series to meet power level requirements, then the power amplification capability is improved, but the power consumption increases and efficiency decreases
Solution Approach 1:
The power amplifier is divided into multiple transistor stages connected in series, with each stage operating in class F mode. This segmentation allows the total power amplification to be distributed across stages, reducing the temporal overlap between voltage and current waveforms at each transistor and thereby improving overall efficiency while meeting power level requirements
Solution Approach 2:
The invention changes the operating class of each transistor from conventional modes to class F operation, characterized by specific harmonic terminations (odd harmonics shorted, even harmonics open). This parameter change in operating mode reduces the temporal overlap between voltage and current waveforms, significantly improving power efficiency while maintaining the required power amplification capability
2Power
If multiple transistors are connected in series to amplify power, then the power output is improved, but the complexity of harmonic control increases
Solution Approach 1:
The invention extracts and controls specific harmonic components separately: odd-order harmonics are shorted to ground while even-order harmonics are open-circuited at each transistor stage. This selective extraction and control of harmonics simplifies the overall harmonic management in multi-transistor configurations compared to treating all harmonics uniformly
Solution Approach 2:
Instead of attempting to control all harmonic orders equally, the invention focuses on partial action by specifically targeting odd and even harmonic separation with simple short/open terminations. This partial control approach is sufficient to achieve class F operation benefits without requiring complex harmonic control circuits for each stage
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 reduces power consumption by minimizing the temporal overlap of voltage and current waveforms, improving power-added efficiency and gain linearity while maintaining transistor withstand voltage, even across multiple stages of amplification.
Implementation Method 1
The first amplifier performs class inverse-F operation
Implementation Method 2
the second amplifier performs class F operation
Data Source
AI summary
A power amplifier circuit includes a first amplifier that amplifies a first signal, and a second amplifier arranged subsequent to the first amplifier. The second amplifier amplifies a second signal that is based on an output signal of the first amplifier. The first amplifier performs class inverse-F operation, and the second amplifier performs class F operation.