Pseudo-Doherty Balanced Amplifier With Separate Drive Signal Control
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Solution Overview
Problem
Radio systems face challenges in achieving high efficiency, output power, and linearity in power amplifiers, particularly in multi-stage power amplifiers where optimizing drive signals for efficient operation is complex.
Innovation Solution
A multi-stage pseudo-Doherty load modulated balanced amplifier (LMBA) circuit with separate drive signals for each component amplifier, utilizing a digital splitter for efficient drive signal creation, and current sensors for wideband efficiency estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If separate drive signals are provided to each component amplifier in a multi-stage power amplifier, then efficiency and output power are improved, but device complexity increases due to the need for multiple drive signal paths and control circuitry
Solution Approach 1:
The power amplifier is divided into multiple independent stages, each with its own drive signal path. The first power amplifier stage and second power amplifier stage are separately driven, allowing independent optimization of each stage's operating point and efficiency characteristics while maintaining overall high output power capability
Solution Approach 2:
The drive signals to each power amplifier stage are dynamically adjusted based on operating conditions. The system transitions between different drive configurations depending on the required output power level, optimizing efficiency across varying power demands rather than operating at a fixed configuration
2Use of energy by moving object
If separate drive signals are provided to each component amplifier, then efficiency at larger back-offs is improved, but ease of operation deteriorates due to complex drive signal coordination requirements
Solution Approach 1:
The system includes automatic drive signal coordination circuitry that self-adjusts the phase and amplitude relationships between multiple drive signals based on real-time operating conditions. This eliminates the need for manual calibration and simplifies operation while maintaining optimal efficiency across different power back-off levels
3Power
If multi-stage amplification is used to achieve high output power, then power output is improved, but efficiency deteriorates due to cumulative losses across multiple stages
Solution Approach 1:
The system dynamically changes operating parameters including drive signal phase relationships, amplitude distributions, and bias conditions across the power amplifier stages. By adjusting these parameters based on the required output power level, the system optimizes the efficiency of each stage to minimize cumulative losses while maintaining high output power capability
Data Source
AI summary
Aspects of this disclosure relate to a multi-stage pseudo-Doherty load modulated balanced amplifier that includes a control stage and balanced stages. The balanced stages can each include a balanced amplifier biased in class C. The balanced stages can each include an output coupler having a port driven by another stage of the multi-stage pseudo-Doherty load modulated balanced amplifier. In certain embodiments, two or more stages of the multi-stage pseudo-Doherty load modulated balanced amplifier are driven by separate drive signals.