Multi-Phase Doherty Power Amplifier Cell Control for Deep Backoff
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Solution Overview
Problem
Conventional power amplifiers suffer from low efficiency and deteriorating performance in high-order broadband modulation signals, particularly in the deep backoff region, which is exacerbated by issues in digital power amplifiers such as inefficiencies in digital rectangular-coordinates and polar-coordinates power amplifiers.
Innovation Solution
A multi-phase-based Doherty power amplifier method that divides the main and auxiliary power amplifiers into working cells, using non-orthogonal vector signals for precise amplitude and phase control, combined with class-G technology to achieve differentiated power output levels, enhancing efficiency and linearity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional power amplifier works in a deep backoff region to support high-order broadband modulation signals, then the data rate and modulation order are improved, but the working efficiency deteriorates to approximately less than 10%
Solution Approach 1:
The power amplifier is divided into multiple working cells (first working cell, second working cell, third working cell, fourth working cell) that can be independently controlled. Each cell contains multiple power amplifier units that can be selectively activated based on the input signal power level, allowing the amplifier to maintain high efficiency across different operating conditions by engaging only the necessary number of cells.
Solution Approach 2:
The system dynamically adjusts the number of active power amplifier units in each working cell based on the input signal power level. Control circuits selectively enable or disable specific units within cells depending on the operating condition, allowing the amplifier to adapt its configuration in real-time to maintain optimal efficiency while supporting high-order modulation signals.
2Power
If existing digital power amplifiers use digital rectangular-coordinates or polar-coordinates architectures to overcome the bottleneck of output power restriction, then the output power control is improved, but the performance such as efficiency and linearity in broadband modulation signals deteriorates
Solution Approach 1:
The power amplifier is divided into multiple working cells (first working cell, second working cell, third working cell, fourth working cell) that can be independently controlled. Each cell contains multiple power amplifier units that can be selectively activated based on the input signal power level, allowing the amplifier to maintain high efficiency across different operating conditions by engaging only the necessary number of cells.
Solution Approach 2:
Different working cells are optimized for different operating conditions. The first and second working cells are configured for lower power levels, while the third and fourth working cells are configured for higher power levels. Each cell has tailored control circuits that apply specific control strategies appropriate for its intended operating range, thereby maintaining high efficiency and linearity across the entire power range.
3Reliability
If the main power amplifier and auxiliary power amplifier are divided into multiple working cells with independent control, then the working efficiency and linearity are improved, but the device complexity increases
Solution Approach 1:
The control circuits for the multiple working cells are integrated into a unified control architecture that receives a single input signal and coordinates all cells simultaneously. The control system merges the control functions for different power levels into a cohesive structure that manages the first, second, third, and fourth working cells through coordinated activation and deactivation based on the overall power requirement.
Solution Approach 2:
Instead of fully activating all power amplifier units across all cells, the system selectively activates only the necessary number of units required for the current power level. This partial action approach maintains high efficiency by avoiding the activation of excess units while still providing the required output power, thereby managing complexity through selective rather than comprehensive activation.
Data Source
AI summary
This application discloses example multi-phase-based Doherty power amplifier control methods and apparatus. An example method includes obtaining a baseband signal and generating two vector signals based on the baseband signal, where the two vector signals each include a phase signal and amplitude signal, and the two vector signals are non-orthogonal signals. Amplitude control signals of a target power amplifier are obtained based on quantization encoding of amplitude signals of the two vector signals, where the target power amplifier includes a main and power amplifier, and the main and auxiliary power amplifier each include a plurality of working cells. Phase control signals of the target power amplifier are obtained based on phase signals of the two vector signals. Based on the phase control signals and the amplitude control signals, a plurality of working cells in the main power amplifier and the auxiliary power amplifier to output power signals are controlled.