Dual-Path Power Amplifier Isolation With Switchable Inductor
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Solution Overview
Problem
Power amplifier circuits with two power amplification paths face significant power loss due to repeated impedance conversion, which is necessary to ensure isolation between the high-gain and low-gain amplification paths.
Innovation Solution
A power amplifier circuit design that includes a first and second path in parallel, with a first amplifier and matching circuit in the first path, and a second amplifier in the second path, utilizing a short-circuit switch to short or open-circuit the inductor in different modes to manage impedance and reduce power loss while maintaining isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If impedance conversion is performed multiple times using matching circuits to ensure isolation between two power amplification paths, then isolation between paths is improved, but power loss increases
Solution Approach 1:
The patent extracts the isolation function from the signal path by using a switching circuit that connects the second amplifier's output to ground when the first amplifier is operating. This removes the need for multiple matching circuits to achieve isolation, as the switching circuit provides direct ground connection to isolate the inactive path, thereby reducing power loss while maintaining isolation between paths.
Solution Approach 2:
The patent introduces a switching circuit as an intermediary element between the second amplifier and ground. This switching circuit acts as a mediator that provides isolation by connecting the inactive amplifier path to ground potential, eliminating the need for complex matching circuit arrangements and reducing associated power losses.
2Adaptability or versatility
If two power amplification paths with different gains are used to switch output levels, then adaptability is improved, but device complexity increases
Solution Approach 1:
The patent makes the switching circuit multi-functional by having it perform both the isolation function (connecting second amplifier to ground) and the signal routing function (selecting which amplifier output reaches the output terminal). This consolidation of functions reduces the number of separate components needed, thereby reducing device complexity while maintaining the ability to switch between different output levels.
Solution Approach 2:
The patent merges the isolation mechanism and the signal switching mechanism into a single switching circuit configuration. Instead of using separate matching circuits for isolation and separate switching elements for signal routing, the invention combines these functions into one integrated switching circuit, simplifying the overall device structure.
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 design effectively reduces power loss and ensures isolation between the high-gain and low-gain amplification paths, improving efficiency and performance by minimizing unnecessary impedance conversions.
Implementation Method 1
The short-circuit switch is placed in a short-circuit position in the first mode to short-circuit the first end and the second end of the first inductor
Implementation Method 2
The short-circuit switch is placed in an open-circuit position in the second mode
Implementation Method 3
the impedance is decreased by using a matching circuit and is then increased by using another matching circuit
Data Source
AI summary
A power amplifier circuit includes a first path and a second path between an input terminal and an output terminal, a first amplifier located in the first path operative in a first mode, a second amplifier located in the second path operative in a second mode, a first matching circuit between the first amplifier and the output terminal in the first path, a first capacitor having a first end connected to the output terminal side of the first matching circuit, and a second end, a first inductor having a first end connected to the second end of the first capacitor and a second end grounded, and a short-circuit switch connected in parallel with the first inductor. The short-circuit switch short-circuits the first and second ends of the first inductor in the first mode and is placed in an open-circuit position in the second mode.