RF Outphasing Amplifier Control With Bias Blending
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Solution Overview
Problem
Existing outphasing techniques for RF power amplifiers require isolating and combining elements that cause degradation in output signal power and low power amplifier efficiency, making them unsuitable for modern portable devices, which need to generate complex RF waveforms with stringent linearity and dynamic range requirements.
Innovation Solution
A blended control approach that combines pure outphasing with bias and amplitude control to generate desired waveforms, reducing branch isolation and phase/amplitude accuracy requirements, allowing for high accuracy and efficiency in RF power transmission without the need for isolating/combining elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If isolating and combining elements are used in outphasing amplification, then linearity is improved, but output signal power is degraded and power amplifier efficiency is reduced
Solution Approach 1:
The patent extracts and eliminates the isolating and combining elements from the outphasing amplification system. By removing these passive components that cause insertion loss and bandwidth limitations, the system achieves both high linearity and high efficiency without the traditional trade-off.
Solution Approach 2:
The patent introduces an intermediary signal processing approach that separates the signal into constant envelope constituents before amplification, then combines them through controlled addition rather than traditional isolating/combining elements. This intermediary processing stage enables linear amplification without the lossy passive components.
2Manufacturing precision
If isolating and combining elements are used in outphasing amplification, then linearity is improved, but device size increases
Solution Approach 1:
The patent removes the large physical isolating and combining elements from the system architecture. By eliminating these bulky passive components, the device size is dramatically reduced while maintaining the linearity benefits through active signal processing instead.
Solution Approach 2:
The patent replaces the mechanical/passive isolating and combining elements with an active electronic control system that uses signal processing and controlled addition. This substitution transitions from a space-consuming passive system to a compact active system.
3Manufacturing precision
If pure outphasing is used to achieve high linearity, then branch isolation requirements increase, but system complexity and manufacturing difficulty increase
Solution Approach 1:
The patent applies partial action by using controlled addition rather than complete isolation between branches. Instead of requiring high branch isolation to prevent interference, the system uses controlled addition with moderate isolation requirements, reducing the complexity while maintaining linearity through the blending control approach.
Solution Approach 2:
The patent changes the operational parameters from requiring high branch isolation to using controlled addition with moderate isolation. By adjusting the isolation requirement parameter and introducing amplitude/phase control parameters, the system achieves linearity with reduced complexity.
Data Source
AI summary
Embodiments of the present invention enable a blended control approach to generate a desired output waveform in an outphasing-based system. Embodiments of blended control according to the present invention combine outphasing with bias and/or amplitude control to yield an accurate, practical, and producible system with substantially comparable performance to that of a theoretical ideal outphasing system, but without the isolation and accuracy requirements of outphasing alone.