Multi-Mode Power Amplifier Termination Control for VSWR Variation
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Solution Overview
Problem
Power amplifiers in radio systems face challenges with efficiency, output power, and linearity due to voltage standing wave ratio (VSWR) variations and beam scanning, particularly in high-performance applications like 5G and 6G wireless communication, where load impedance variations degrade performance.
Innovation Solution
A multi-mode power amplifier circuit that operates in Doherty, segmented, and balanced modes, adjusting termination impedance and power amplifier biasing to adapt to different VSWR ranges and beam positions, using hybrid combiners and adjustable termination impedance circuits to optimize performance across varying load conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional Class B power amplifier is used, then the device complexity is low, but the power added efficiency and linearity degrade under VSWR variations
Solution Approach 1:
The power amplifier is divided into multiple amplifier cores (first power amplifier core and second power amplifier core) that can operate in different modes. Each core can be independently controlled to provide different terminations to the hybrid combiner, enabling the system to adapt to various VSWR conditions through selective activation and configuration of individual segments.
Solution Approach 2:
The amplifier employs dynamic mode switching between Doherty mode, segmented mode, and balanced mode based on detected VSWR conditions. The termination impedance provided by each amplifier core is dynamically adjusted through biasing control, allowing the system to transition between different operational states to maintain optimal performance under varying load conditions.
2Adaptability or versatility
If the termination impedance is fixed, then the device complexity is low, but the adaptability to different VSWR ranges is poor
Solution Approach 1:
Each amplifier core is designed to provide multiple functions by delivering different termination impedances (resistive termination in segmented mode, reactive termination in Doherty mode) to the hybrid combiner. The same hardware infrastructure supports multiple operational modes, making the system universally adaptable to different VSWR ranges without requiring separate dedicated circuits for each mode.
Solution Approach 2:
The termination impedance provided by the amplifier cores is dynamically changed based on VSWR detection. The biasing conditions of the amplifier cores are adjusted to transform the termination characteristics from resistive to reactive or vice versa, enabling the system to adapt to different VSWR ranges by changing the electrical parameters of the termination rather than physically reconfiguring the circuit topology.
3Use of energy by moving object
If Doherty mode is used for high efficiency, then the power added efficiency is improved, but the linearity degrades under certain VSWR conditions
Solution Approach 1:
The system incorporates VSWR detection and mode selection logic that monitors the load conditions and automatically selects the appropriate operational mode (Doherty, segmented, or balanced) to maintain both efficiency and linearity. When VSWR conditions are detected that would degrade Doherty mode linearity, the system provides feedback to switch to segmented mode or balanced mode, ensuring continuous optimal performance.
Solution Approach 2:
The power amplifier employs a composite operational approach that combines characteristics of different amplifier architectures (Doherty, segmented, balanced) within a single system. By integrating multiple operational modes with distinct characteristics into one unified amplifier system, it leverages the high efficiency of Doherty mode when appropriate while utilizing the superior linearity of segmented or balanced modes under different conditions.
Data Source
AI summary
Aspects of this disclosure relate to a multi-mode power amplifier circuit. The power amplifier circuit can include a first power amplifier core, a second power amplifier core, an output combiner, and an adjustable termination impedance circuit connected to a port of the output combiner. The adjustable termination circuit can provide different terminations for different modes of the multi-mode power amplifier circuit. In certain embodiments, the different modes can include a Doherty mode, a segmented mode, and/or a balanced mode. The multi-mode power amplifier circuit can operate in different modes based one or more of load impedance, voltage standing wave ratio variation, or beam angle in certain applications.