Parallel RF Power Amplifier Switching With Input Inductors
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Solution Overview
Problem
High-frequency power amplifiers face challenges in achieving high efficiency at both high and low output levels due to gain differences between large and small output operations, which is difficult to minimize in existing technologies, especially in portable devices where battery life is a concern and in base stations where miniaturization is required.
Innovation Solution
A high-frequency power amplifier design with multiple power amplifiers arranged in parallel, where inductance elements are inserted in series in the input signal lines, and an input and output matching circuit are used to control the amplifiers such that all are active during high output and some are inactive during low output, minimizing gain differences through strategic switching and matching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If multiple power amplifiers are used and switched according to output level, then efficiency at low output is improved, but gain difference between high and low output operations increases
Solution Approach 1:
The patent changes the impedance parameters of the amplifiers by introducing inductance elements in series with the input signal lines. This parameter change allows the amplifiers to have different input impedances, which enables better matching when amplifiers are switched on and off, thereby reducing gain difference between high and low output operations while maintaining efficiency improvements.
Solution Approach 2:
The inductance elements act as intermediary components between the signal source and the amplifiers. These intermediaries modify the input impedance characteristics, facilitating smoother transitions when amplifiers are switched and reducing the harmful gain differences that would otherwise occur during power level changes.
2Weight of moving object
If amplifier size is reduced for miniaturization, then device size and weight are reduced, but saturation output level decreases
Solution Approach 1:
The patent divides the power amplification function into multiple smaller amplifier units that can be switched on and off. By segmenting the amplification task across multiple smaller devices rather than using one large amplifier, the system achieves miniaturization while maintaining the required saturation output level through coordinated operation of multiple units.
Solution Approach 2:
The patent introduces dynamic switching control that adapts the number of active amplifiers based on the required output level. This dynamic operation allows smaller amplifier units to be combined in different configurations to achieve the required saturation output when needed, while maintaining miniaturization benefits during normal operation.
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 design effectively minimizes gain differences between high and low output operations, allowing for efficient power amplification across varying output levels while reducing the size and weight of the amplifier unit, thus enhancing battery life in portable devices and miniaturizing base station equipment.
Implementation Method 1
an inductance element inserted in series in an input signal line of each power amplifier
Data Source
AI summary
A high-frequency power amplifier comprising: a plurality of power amplifiers arranged in parallel; an inductance element inserted in series in an input signal line of said each power amplifier; an input matching circuit for performing matching of inputs of a parallel connection which connected each series connection of said power amplifier and said inductance element in parallel; an output matching circuit for performing matching of outputs of the parallel connection; and a control unit for controlling said power amplifiers in such a manner that one of said power amplifiers is always brought to an operation condition and the remainder of said power amplifiers are brought to an operation or non-operation condition.