Two-Stage Doherty Power Amplifier Biasing for Wider Back-Off Efficiency
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Solution Overview
Problem
In 5G wireless communication systems, power amplifiers face efficiency reduction and increased power consumption due to high peak-to-average power ratio (PAPR) modulation, limiting the back-off region where efficiency is improved, even with Doherty power amplifiers.
Innovation Solution
A 2-stage Doherty power amplifier with different biases for driver and main stages, and a coupler between stages, enabling phase modulation and maintaining constant phase difference between output currents, which improves power efficiency and reduces power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a power amplifier operates in a back-off region to linearly amplify high PAPR modulation signals, then linearity is improved, but efficiency is reduced and power consumption is increased
Solution Approach 1:
The power amplifier is divided into multiple stages (first stage and second stage), each handling different portions of the signal amplification process. The first stage performs initial amplification while the second stage provides additional gain, allowing the overall system to achieve linear operation in back-off regions without sacrificing efficiency in any single stage.
2Use of energy by moving object
If a Doherty power amplifier is used to improve amplifier efficiency in the back-off region, then efficiency is improved, but the back-off region is limited
Solution Approach 1:
The invention extends the traditional single-stage Doherty architecture into multiple stages, adding a temporal and functional dimension to the amplification process. This multi-stage configuration allows efficiency improvement to be maintained across a broader range of back-off conditions by distributing the amplification function across multiple operational phases.
3Use of energy by moving object
If different biases are applied to power amplifiers in different stages, then power efficiency is enhanced, but device complexity increases
Solution Approach 1:
Different bias conditions are applied to different stages of the power amplifier according to their specific operational requirements. The first stage and second stage each receive optimized bias levels tailored to their respective functions, allowing each component to operate at peak efficiency for its specific role in the overall amplification process.
Data Source
AI summary
A Doherty power amplifier of a wireless communication system is provided. The Doherty power amplifier includes a first stage including a first power amplifier and a second power amplifier. The Doherty power amplifier includes a second stage including a third power amplifier and a fourth power amplifier. The Doherty power amplifier includes a coupler between the first stage and the second stage. The Doherty power amplifier includes a load impedance connected to the second stage. A bias of the first power amplifier is applied differently from a bias of the second power amplifier. A bias of the third power amplifier is applied in the same manner as a bias of the fourth power amplifier.