Power Amplifier Gain Control for High-PAPR Linearity
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Solution Overview
Problem
Existing power amplifier modules in wireless communication systems face challenges in achieving both linearity and efficiency due to variations in gain caused by multiple amplification paths and switching losses, which complicates module design and reduces efficiency.
Innovation Solution
A power amplifier module with a first amplifier circuit and a second amplifier circuit, where the second control signal increases the power-supply voltage for the second amplifier as the peak-to-average power ratio of the RF signal increases, and the first control signal compensates for gain variations in the power-supply voltage, allowing for flexible gain control and improved linearity and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple amplification paths are used to improve linearity and efficiency, then performance is improved, but gain variations occur and device complexity increases
Solution Approach 1:
The power amplifier is divided into two separate amplification paths: a first power amplifier for amplifying RF signals and a second power amplifier for amplifying the amplified RF signals. This segmentation allows independent optimization of each path's operating conditions, enabling the system to achieve both linearity and efficiency improvements without requiring complex switching mechanisms between multiple complete amplification chains.
Solution Approach 2:
The patent implements dynamic control of power supply voltages for both amplifiers based on the PAPR characteristics of the input signal. The control unit adjusts the power supply voltage of the first amplifier and the second amplifier independently according to real-time signal conditions, enabling adaptive optimization of linearity and efficiency. This dynamic adjustment eliminates the need for fixed amplification paths and reduces gain variations.
2Use of energy by moving object
If multiple amplification paths are switched to adapt to different signal conditions, then efficiency is improved, but switching losses occur and gain variations increase
Solution Approach 1:
Both the first power amplifier and the second power amplifier operate continuously simultaneously, with the control unit dynamically adjusting their respective power supply voltages based on signal PAPR characteristics. This continuous operation without switching eliminates switching losses entirely, while the dynamic voltage adjustment maintains optimal efficiency across varying signal conditions. The system transitions smoothly between operating modes by continuous voltage modulation rather than discrete switching.
3Reliability
If backoff operation is performed to achieve linearity for high PAPR signals, then linearity is improved, but efficiency decreases
Solution Approach 1:
The patent changes the power supply voltage parameter dynamically based on signal PAPR characteristics. For high PAPR signals, the control unit adjusts the power supply voltage of the first amplifier to maintain linearity while optimizing the second amplifier's voltage to maintain efficiency. For low PAPR signals, the system operates with higher efficiency by adjusting both amplifiers' voltages to reduce backoff. This parameter change approach allows the system to achieve both linearity and efficiency simultaneously under different signal conditions.
Data Source
AI summary
A power amplifier module includes a first amplifier circuit that amplifies a radio frequency signal with a first gain corresponding to a first control signal to generate a first amplified signal; a second amplifier circuit that amplifies the first amplified signal with a second gain corresponding to a second control signal to generate a second amplified signal; and a control unit that generates the first control signal and the second control signal. The second control signal is a control signal for increasing a power-supply voltage for the second amplifier circuit as a peak-to-average power ratio of the radio frequency signal increases. The first control signal is a control signal for controlling the first gain of the first amplifier circuit so that a variation in the second gain involved in a variation in the power-supply voltage for the second amplifier circuit is compensated for.