Doherty amplifier circuit
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Traditional high power Doherty amplifiers suffer from narrow operational bandwidth and poor linearity due to impedance transformation networks and signal mismatch between main and peak amplifier stages, limiting their efficiency and frequency range.
Innovation Solution
A scalable amplifier concept using multiple Doherty amplifier cells with controllable input power splitters that modify signal amplitude and phase to optimize efficiency and linearity, allowing for improved power output scaling and reduced space requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If impedance transformation networks are used in traditional high power Doherty amplifiers, then power output capability is improved, but operational bandwidth becomes narrow and linearity deteriorates
Solution Approach 1:
The amplifier is divided into multiple independent Doherty amplifier cells, each capable of operating independently. This segmentation allows each cell to be optimized for specific power levels while collectively providing wide bandwidth operation, resolving the contradiction between power output capability and operational bandwidth.
Solution Approach 2:
The patent employs controllable power splitters that can dynamically adjust signal distribution based on operating conditions. This dynamic control enables the amplifier to maintain optimal performance across different frequency bands and power levels, simultaneously achieving high power output and wide bandwidth.
2Power
If impedance transformation networks are used in traditional high power Doherty amplifiers, then power output capability is improved, but signal linearity becomes poor
Solution Approach 1:
The patent incorporates control circuits that monitor output signals and provide feedback to adjust the operation of power splitters and amplifier stages. This feedback mechanism compensates for nonlinearities introduced by impedance transformation networks, maintaining signal linearity while preserving high power output capability.
Solution Approach 2:
The controllable power splitters can change their splitting ratios and phase characteristics dynamically based on operating conditions. By adjusting these parameters in real-time, the system maintains optimal linearity across different power output levels, resolving the contradiction between power capability and signal linearity.
3Loss of energy
If multiple Doherty amplifier cells are used with controllable power splitters, then power efficiency and linearity are improved, but device complexity increases
Solution Approach 1:
Multiple Doherty amplifier cells are combined in parallel, with their inputs connected to a common input stage and outputs combined at a common output stage. This merging approach allows the system to achieve high power efficiency through coordinated operation of multiple cells while avoiding the need for separate complete amplifier chains, thus managing complexity.
Solution Approach 2:
The controllable power splitters serve multiple functions: signal distribution, phase control, and dynamic power management across different amplifier cells. This multi-functionality reduces the need for separate control mechanisms for each cell, thereby improving power efficiency while limiting the increase in device complexity.
Data Source
AI summary
The present invention relates to an amplifier comprising a plurality of Doherty amplifier cells each Doherty amplifier cell comprising an input and an output respectively connected to an input and an output of the amplifier, a main amplifier stage, a peak amplifier stage and a signal combining circuit configured to combine signals from outputs of the main and peak amplifiers and provide a combined signal to the output of the Doherty amplifier cell. Each cell comprises a controllable splitter having an input (connected to the input of the Doherty amplifier cell. The controllable splitter is configured to receive a splitter control signal and modify an amplitude and phase of a signal at the input of the Doherty amplifier cell in response to the splitter control signal.