RF Matching Circuit With Unequal Switch Stacks for Impedance Tuning
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Solution Overview
Problem
Conventional matching circuits for RF communications systems face challenges in reducing size and manufacturing cost due to the need for equal numbers of stacked transistors in capacitor branches, leading to impedance mismatch and power loss in RF signal transmission.
Innovation Solution
A matching circuit design that includes a first and second set of switching devices with different numbers of transistors, controlled by a controller to provide variable impedances based on detected electrical properties of the input signal, allowing for reduced transistor count and area while maintaining effective impedance matching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If equal quantities of stacked transistors are used in capacitor branches to effectively isolate unselected branches, then isolation performance is improved, but circuit size and manufacturing cost increase
Solution Approach 1:
The patent applies local quality by using different numbers of stacked transistors in different capacitor branches based on their specific isolation requirements. The first capacitor branch uses a first number of stacked transistors while the second capacitor branch uses a second number of stacked transistors, allowing each branch to have optimized isolation performance for its specific function rather than uniformly using equal quantities across all branches.
2Reliability
If equal quantities of stacked transistors are used in capacitor branches, then isolation performance is improved, but manufacturing cost remains high
Solution Approach 1:
The patent reduces manufacturing cost by optimizing the transistor count in each capacitor branch according to local isolation requirements. By using a first number of stacked transistors in the first branch and a second number in the second branch, the design avoids the waste of using equal quantities throughout, thereby reducing overall manufacturing cost while maintaining necessary isolation performance.
3Adaptability or versatility
If multiple parallel capacitor branches are used to provide multiple impedances, then adaptability is improved, but device complexity increases
Solution Approach 1:
The patent segments the capacitor branches into distinct groups (first capacitor branch with first set of switching devices, second capacitor branch with second set of switching devices) with different transistor quantities. This segmentation allows independent optimization of each branch for specific impedance values, providing adaptability while managing complexity through modular design.
Data Source
AI summary
A matching circuit includes an input terminal, an output terminal, a first impedance component, a first set of switching devices, a second impedance component, a second set of switching devices and a controller. The first impedance component includes a first terminal coupled between the input terminal and the output terminal, and a second terminal. The first set of switching devices is coupled to the second terminal of the first impedance component, the controller and a reference terminal. The second impedance component includes a first terminal coupled between the second terminal of the first impedance component and the first set of switching devices, and a second terminal. The second set of switching devices is coupled to the second terminal of the second impedance component, the controller and the reference terminal. The controller controls the first set of switch devices and the second set of switch devices according to a detection signal.