Parallel Power Amplifier Branches Without RF Switching Loss
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Solution Overview
Problem
Conventional power amplifiers face inefficiencies in both low and high power regions, particularly in mobile devices, which limits battery life and requires multiple power modes that increase complexity and production costs.
Innovation Solution
A power amplifier design that divides the main amplification stage into multiple branches with impedance matching circuits and an impedance transformation network, allowing selective activation of branches to optimize efficiency across various power modes without using RF switches, thereby enhancing efficiency in both low and high power regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a conventional class AB power amplifier is used, then the amplifier can operate continuously, but the efficiency is low in low-power regions
Solution Approach 1:
The power amplifier is divided into multiple parallel amplification stages (first amplification stage, second amplification stage, third amplification stage) that can be selectively activated. Each stage has its own impedance matching network, allowing the amplifier to operate efficiently across different power levels by enabling only the necessary stages.
Solution Approach 2:
The amplifier transitions from a static conventional class AB design to a dynamic multi-stage architecture where stages are selectively enabled or disabled based on power requirements. Control circuits dynamically adjust which amplification stages are active, optimizing efficiency for varying power demands.
2Adaptability or versatility
If power amplifiers are designed for different communication standards, then each standard can be optimized, but multiple power amplifier modules are required
Solution Approach 1:
The power amplifier is designed as a universal multi-functional device that can serve multiple communication standards (CDMA, GSM, EDGE, WCDMA) through its parallel amplification stages. By selectively activating different combinations of stages and configuring impedance matching networks, a single amplifier module adapts to various power requirements of different standards.
3Adaptability or versatility
If RF switches are used for mode switching, then power modes can be switched, but performance degradation and production cost increase
Solution Approach 1:
The invention removes RF switches from the signal path by using parallel amplification stages with separate control circuits. Each amplification stage has dedicated control logic that enables or disables the stage without requiring signal switching, thereby eliminating the performance degradation and reliability issues associated with RF switches.
4Use of energy by moving object
If power amplifiers operate at maximum output power, then efficiency is maximized, but battery life is reduced
Solution Approach 1:
The amplifier dynamically changes operational parameters by selectively activating different amplification stages based on power requirements. Instead of always operating at maximum power, the system adjusts the number of active stages to match the actual power demand, maintaining high efficiency while reducing overall power consumption to extend battery life.
Data Source
AI summary
An amplification device includes a series combination of a driver stage, an output terminal matching network, and a secondary amplification stage. The driver stage includes a driver amplifier and an output matching network. The secondary amplification stage includes a parallel combination of an impedance transformation network and a main amplification stage. The main amplification stage includes a plurality of main amplification branches in parallel with each other, and an input matching network in series with the parallel combination. Each main amplification branch includes a main amplifier, and input and output impedance matching networks. A control circuit supplies activation signals to the main amplification branches to selectively turn them on and off. The device has no switches in the path of the signal that is amplified. In at least one operating mode, the control circuit turns on at least two of the main amplification branches at the same time.