Dual-Drive Doherty Power Amplifier for Back-Off Efficiency
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional power amplifiers face limitations in efficiency, output power, and gain due to low breakdown voltages, limited frequency range, poor quality on-chip passives, and high peak-to-average power ratio, leading to reduced average modulation efficiency, especially under power back-off conditions, and existing techniques like Doherty and outphasing amplifiers sacrifice gain, linearity, and peak efficiency.
Innovation Solution
A dual-drive Doherty power amplifier architecture that combines a Doherty load modulation power combining network with main/auxiliary power amplifier cores using a dual-drive configuration, where the dual-drive power amplifier core drives the gate and source terminals out-of-phase, reducing the transistor knee voltage and increasing the output voltage swing, and employs a multi-feed coupling network to enhance linearity and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional power amplifiers operate under power back-off conditions to handle high peak-to-average power ratio signals, then the average modulation efficiency is reduced, but the linearity and reliability are maintained
Solution Approach 1:
The power amplifier is segmented into two parallel amplifiers with different operating characteristics. The first amplifier operates in a linear region to maintain signal fidelity, while the second amplifier operates in a non-linear region to provide additional power capacity. This segmentation allows the system to achieve high average modulation efficiency while maintaining linearity through the combined output of both amplifiers.
2Productivity
If Doherty and outphasing amplifier techniques are used to improve efficiency, then average efficiency increases, but gain and linearity are sacrificed
Solution Approach 1:
Different regions of the amplifier system are assigned different operating qualities. The first amplifier is optimized for linear operation with high gain, while the second amplifier is optimized for high efficiency operation. By locally optimizing each amplifier's operating point according to its specific role in the system, the overall system achieves both high efficiency and maintained linearity without the trade-offs of conventional Doherty or outphasing architectures.
3Loss of energy
If power amplifiers operate at peak power to maximize efficiency, then efficiency is improved, but the ability to handle high peak-to-average power ratio signals is reduced
Solution Approach 1:
The amplifier system dynamically adapts its operating state based on the input signal conditions. The first amplifier dynamically adjusts its contribution to handle the linear portion of the signal, while the second amplifier dynamically engages to provide additional power capacity during peak conditions. This dynamic operation allows the system to maintain high efficiency across varying power levels while effectively handling high peak-to-average power ratio signals.
Data Source
AI summary
Provided is a dual-drive based Doherty amplifier that includes a first power amplifier and a second power amplifier that is in parallel with the first power amplifier. The first power amplifier is configured to receive a first portion of a signal having a first phase, and the second power amplifier is configured to receive a second portion of the signal having a second phase that has a phase difference from the first phase. At least one of the first power amplifier or the second power amplifier includes a dual-drive power amplifier core.