Power Amplifier Linearizing Circuit for High-Output RF Linearity
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Solution Overview
Problem
In wireless communication systems, particularly for sub-6 GHz 5G, power amplifiers face challenges in maintaining linearity as channel bandwidth increases, requiring higher output power and improved linearity relative to output power, which existing technologies have not adequately addressed.
Innovation Solution
A power amplifier design incorporating a first and second power transistor with bias circuits and linearizing circuits that couple portions of the input and output RF signals to compensate for voltage drops, enhancing linearity by adjusting the power mode to manage input and output signal power effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the output power of the power amplifier is increased to meet the demands of sub-6 GHz 5G communication, then the channel bandwidth and coverage are improved, but the linearity of the power amplifier deteriorates
Solution Approach 1:
The patent implements a feedback mechanism where a portion of the output RF signal is fed back to the bias circuit through a linearizing circuit. This feedback allows the bias circuit to dynamically adjust the bias current based on the actual output signal conditions, thereby compensating for non-linearities that occur at high output power levels and maintaining linearity across varying power conditions
Solution Approach 2:
The patent dynamically changes the bias current parameter based on the output power level. The bias circuit adjusts the bias current in response to the fed-back output signal, effectively changing the operating parameters of the power amplifier to maintain optimal linearity across different output power conditions, particularly when operating at high power levels required for 5G communication
2Productivity
If the channel bandwidth is increased for higher data rates in 5G communication, then the communication capacity is improved, but the linearity requirements become more stringent and difficult to maintain
Solution Approach 1:
The feedback mechanism continuously monitors the output signal and adjusts the bias current in real-time, ensuring that linearity is maintained across the expanded channel bandwidth. This dynamic adjustment allows the power amplifier to handle wider bandwidth signals without compromising linearity, thereby supporting higher communication capacities required for 5G
3Device complexity
If a conventional power amplifier design is used without linearizing circuits, then the device complexity is reduced, but the linearity performance at high output power is insufficient
Solution Approach 1:
The patent introduces a linearizing circuit as an intermediary component between the power amplifier and the bias circuit. This intermediary circuit processes the feedback signal and conditions it appropriately before delivering it to the bias circuit, enabling effective linearity correction without requiring a complete redesign of the entire amplifier architecture, thus balancing complexity and performance
Data Source
AI summary
A power amplifier includes a first power transistor configured to amplify an input radio-frequency (RF) signal, and output the amplified input RF signal as an output RF signal; a first transistor including a first terminal configured to provide a first bias current to the first power transistor; and a first linearizing circuit connected between a terminal of the first power transistor from which the output RF signal is output and the first terminal of the first transistor and configured to couple a portion of the output RF signal to the first terminal of the first transistor.