Shared-Choke Doherty Power Amplifier With Resonant LC Load Network
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Solution Overview
Problem
Doherty amplifiers require greater load impedance and inductance, leading to larger space requirements, making them unsuitable for small electronic devices like cellular phones due to increased inductor size.
Innovation Solution
A power amplifier configuration with a power splitter, two amplifiers, and LC parallel resonant circuits, where the amplifiers share a single choke inductor and LC circuits with resonant frequencies being integer multiples of the signal frequency, reducing inductor size and cross-talk, allowing for a compact high-efficiency design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a Doherty amplifier configuration with two power amplifiers is used, then power-added efficiency is improved, but the inductor size and space requirements increase
Solution Approach 1:
The patent merges the choke inductors of the carrier amplifier and peak amplifier into a single shared choke inductor. This combining of previously separate components reduces the total inductor count and space requirements while maintaining the Doherty amplifier's efficiency benefits through the resonant frequency design of the LC circuits
Solution Approach 2:
The patent introduces LC parallel resonant circuits with resonant frequencies set at integer multiples of the signal frequency. This parameter change in the circuit design allows for reduced inductor values and sizes while preserving the power-added efficiency characteristics of the Doherty configuration
2Use of energy by moving object
If greater inductance of choke inductor is used to support Doherty amplifier operation, then amplifier efficiency is improved, but the device size increases
Solution Approach 1:
The patent changes the operational parameters by introducing resonant frequency design where the LC parallel resonant circuits operate at integer multiples of the signal frequency. This allows the system to achieve high efficiency with reduced inductance values, directly addressing the contradiction between efficiency and device volume
Solution Approach 2:
The patent adds a frequency dimension to the design by utilizing resonant frequencies at integer multiples of the signal frequency. This dimensional approach allows the circuit to achieve high efficiency performance while using smaller inductor values, effectively reducing device volume without sacrificing amplifier efficiency
3Reliability
If additional choke inductors are included for each amplifier path, then amplifier performance is improved, but device complexity and size increase
Solution Approach 1:
The patent combines the previously separate choke inductors into a single shared component that serves both the carrier amplifier and peak amplifier paths. This merging reduces circuit complexity and the number of components while maintaining amplifier performance through the resonant frequency design of the LC circuits
Solution Approach 2:
The shared choke inductor is designed to serve multiple functions simultaneously - it acts as the choke inductor for both the carrier amplifier and peak amplifier paths. This multi-functional design reduces device complexity while preserving the performance benefits of the Doherty configuration
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables a compact, high-efficiency power amplifier by reducing inductor size and eliminating the need for additional choke inductors, maintaining power-added efficiency and gain characteristics comparable to traditional Doherty amplifiers.
Implementation Method 1
the first LC parallel resonant circuit has a resonant frequency that is approximately an integer multiple of a frequency of the first signal, and the second LC parallel resonant circuit has a resonant frequency that is approximately an integer multiple of the frequency of the first signal
Data Source
AI summary
A power amplifier includes a power splitter that splits a first signal into a second signal and a third signal, a first amplifier that amplifies the second signal within an area where the first signal has a power level greater than or equal to a first level and that outputs a fourth signal, a second amplifier that amplifies the third signal within an area where the first signal has a power level greater than or equal to a second level higher than the first level and that outputs a fifth signal, an output unit that outputs an amplified signal of the first signal, a first and a second LC parallel resonant circuit, and a choke inductor having an end to which a power supply voltage is supplied and another end connected to a node of the first and second LC parallel resonant circuits.