Balanced RF Power Amplifier for Load-Tolerant Linear Output
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Solution Overview
Problem
Current radio frequency power amplifiers face challenges in supporting the mobile high-power user equipment (HPUE) function, particularly in the Band41 frequency band, due to reduced antenna gain and increased load impedance voltage standing wave ratio (VSWR), which limits linear power output and requires increased power supply voltage or current, leading to inefficiencies and complex implementations.
Innovation Solution
A balanced radio frequency power amplifier is designed with a control unit, 90-degree power splitter, and adjustable 90-degree power combiner, dividing the input signal into equal-amplitude signals with a 90-degree phase difference, and controlling capacitors and resistors to minimize phase and amplitude differences, thereby synthesizing the signals for improved linear power output and reduced sensitivity to load changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the output voltage of the radio frequency power amplifier is increased to improve linear power, then the linear power is improved, but the power added efficiency at backoff power is reduced and the ruggedness requirement on power tube is increased
Solution Approach 1:
The patent divides the power amplifier into two parallel power tubes instead of using one power tube. This segmentation allows the system to achieve higher linear power output while maintaining better power added efficiency at backoff power, as each tube operates in a more optimal range rather than overloading a single tube.
Solution Approach 2:
The patent changes the operational parameters by using two power tubes with different bias settings and impedance transformations. This allows the system to maintain higher power added efficiency at backoff power while achieving the required linear power output, resolving the contradiction between power output and efficiency.
2Power
If the area of the output power tube is increased to improve linear power, then the linear power is improved, but the parasitic parameters become excessively large which deteriorates high-frequency performance
Solution Approach 1:
The patent segments the power amplification function into two separate power tubes rather than using one large power tube. This segmentation avoids the excessively large parasitic parameters that would result from increasing the area of a single power tube, thereby maintaining high-frequency performance while achieving the required linear power output.
3Power
If multiple power amplifiers are connected in parallel to improve linear power, then the linear power is improved, but the output power loss caused by antenna load impedance change cannot be resolved
Solution Approach 1:
The patent changes the impedance parameters at different stages of the power amplifier using impedance transformation networks. This allows the system to maintain low sensitivity to antenna load impedance changes while achieving high linear power output through parallel connection of power tubes, resolving the contradiction between power output and load adaptability.
4Power
If the power supply voltage is instantaneously increased to improve linear power, then the linear power is improved, but the implementation complexity increases and higher bandwidth signal processing becomes difficult
Solution Approach 1:
The patent segments the power amplification into two parallel tubes with different bias settings, eliminating the need for instantaneous power supply voltage increases. This segmentation approach achieves high linear power output with simpler implementation and better bandwidth signal processing capability compared to envelope tracking methods.
Data Source
AI summary
Disclosed in the present invention are a balanced radio frequency power amplifier, a chip and a communication terminal. The radio frequency power amplifier divides, by means of a 90-degree power splitter unit, a radio frequency input signal into two equal-amplitude signals having a phase difference of 90 degrees, the two radio frequency input signals are amplified and then inputted into an adjustable 90 -degree power combiner, and the values of a adjustable capacitor and an adjustable resistor in the adjustable 90-degree power combiner are controlled by means of a control unit, so as to synthesize the two radio frequency input signals into one radio frequency input signal when the phase difference and amplitude difference of the two signals at different frequencies are the smallest, and to input the radio frequency input signal into a circuit of the next stage by means of a specific radio frequency transmission path.