Impedance Detection Circuit Without Directional Couplers
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Solution Overview
Problem
Existing impedance detection circuits for amplification devices, such as those described in Patent Document 1, require large directional couplers, making them unsuitable for mobile communication terminals and necessitating a solution to prevent circuit upsizing while maintaining impedance detection capabilities.
Innovation Solution
An impedance detection circuit comprising a first detector for detecting a first voltage amplitude, a second detector for detecting a second voltage amplitude, and a phase difference detector, along with an impedance control circuit using transistors and variable phase/gain control circuits to manage impedance, allowing for compact design and impedance detection without directional couplers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If directional couplers are used to detect reflection coefficients for impedance detection, then impedance detection accuracy is improved, but circuit size increases making it unsuitable for mobile communication terminals
Solution Approach 1:
The patent extracts the impedance detection function from the traditional directional coupler structure and implements it using a simplified circuit configuration with detectors and phase difference detection. This removes the bulky directional coupler while retaining the essential impedance detection capability, thereby reducing circuit size while maintaining detection accuracy.
Solution Approach 2:
The patent uses detectors to measure voltage amplitudes and phase differences as proxies for direct impedance measurement. Instead of using complex directional couplers to directly measure reflection coefficients, the system copies the essential measurement information through voltage and phase detection, achieving the same functional result with a more compact implementation.
2Measurement precision
If two directional couplers are used to detect reflection coefficients of both amplification parts, then impedance control precision is improved, but device complexity increases
Solution Approach 1:
The patent merges the impedance detection functions for multiple amplification parts into a unified detection system. Instead of using separate directional couplers for each amplification part, the system uses a combined detection approach with voltage detectors and phase difference detection that can monitor multiple signals simultaneously, thereby reducing circuit complexity while maintaining control precision.
Solution Approach 2:
The detection circuit is designed with multi-functionality to handle impedance detection for multiple amplification parts. The voltage detectors and phase difference detector can process signals from different amplification paths, making the detection system universal and eliminating the need for separate dedicated couplers for each path, thus reducing overall device complexity.
Data Source
AI summary
An impedance detection circuit includes: a first detector that detects a first voltage amplitude at an end of an inverter circuit having the end to which a radio frequency signal is input and having a different end from which a signal is output; a second detector that detects a second voltage amplitude of the different end of the inverter circuit; and a phase difference detector that detects a phase difference between a phase of a voltage across the end of the inverter circuit and a phase of a voltage across the different end of the inverter circuit. An absolute value of a product of diagonal elements of a dependent parameter for the inverter circuit is smaller than an absolute value of a product of off-diagonal elements.