Amplifier Linearizer Biasing for RF Efficiency-Linearity Tradeoff
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Power amplifiers face a tradeoff between efficiency and linearity, with high-efficiency amplifiers offering poor linearity and vice versa, limiting their operational range and effectiveness in RF transmission systems.
Innovation Solution
A linearizer device is coupled with the amplifier to provide a non-constant impedance transfer function, compensating for non-linear responses by adjusting the DC bias voltage of transistors, thereby improving overall linearity across a range of input voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If high-efficiency amplifier configurations are used, then power efficiency is improved, but linearity deteriorates
Solution Approach 1:
The amplifier is divided into multiple stages with different functions: a first amplification stage configured for high efficiency and a second amplification stage configured for linearity. This segmentation allows each stage to optimize for its specific purpose while working together to achieve both high efficiency and good linearity in the overall system.
Solution Approach 2:
A third amplification stage is introduced as an intermediary between the first and second stages. This intermediate stage serves as a buffer that isolates the high-efficiency first stage from the linear second stage, allowing both to operate optimally without interfering with each other's performance.
2Manufacturing precision
If linear operation over wide voltage range is achieved, then linearity is improved, but power dissipation increases
Solution Approach 1:
The voltage range is segmented into different operating regions, with the first amplification stage handling high-voltage swings for efficiency and the second stage handling smaller voltage ranges for linearity. This segmentation allows the amplifier to achieve wide voltage range operation without requiring all components to operate linearly across the entire range, thus reducing overall power dissipation.
Solution Approach 2:
The amplifier dynamically switches between different operating modes and configurations depending on the input signal level. During high-power operation, the system prioritizes efficiency; during low-power operation, it prioritizes linearity. This dynamic adaptation allows the amplifier to maintain good linearity across a wide voltage range while minimizing power dissipation at each operating point.
Data Source
AI summary
Some embodiments relate to a device, comprising an amplifier and a linearizer, the linearizer comprising a first transistor, the first transistor comprising a first terminal coupled to an input of the amplifier, a second terminal configured to be coupled to a DC supply voltage, and a control terminal configured to control a current flowing between the first and second terminals and configured to receive a DC bias voltage different from a voltage of the first terminal. Some embodiments relate to a device, comprising an amplifier, comprising an input, an output, and a first set of one or more transistors coupled between the input and the output, and a linearizer, comprising a second set of one or more transistors coupled between a DC supply voltage and the input of the amplifier, wherein the first set of transistors and the second set of transistors have a same topology.