Signal Input Switching Circuit Crosstalk Prevention
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Solution Overview
Problem
In display systems with multiple connected devices, switch circuit crosstalk can lead to malfunctions, where a signal is erroneously detected on a non-selected input terminal, causing incorrect signal switching and display issues.
Innovation Solution
A signal input switching circuit with multiple switch circuits, input control units, and a control unit that selectively enables output from the selected input terminal while disabling inputs from non-selected terminals, using Hot Plug Detect (HPD) signals to manage signal connections and prevent crosstalk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple outside apparatuses are connected to the display device using a switch circuit, then the versatility and adaptability of the display system is improved, but crosstalk occurs in the switch circuit causing signal detection errors and malfunctions
Solution Approach 1:
The patent divides the single switch circuit into multiple independent switch circuits (first switch circuit and second switch circuit), each handling specific input terminals. This segmentation isolates signal paths to prevent crosstalk while maintaining the ability to connect multiple outside apparatuses, thereby resolving the contradiction between versatility and signal detection accuracy.
Solution Approach 2:
The patent introduces an HPD (Hot Plug Detect) control unit as an intermediary between the switch circuits and outside apparatuses. This intermediary manages signal flow by controlling HPD signals to prevent unauthorized or erroneous signal detection on non-selected terminals, thus maintaining reliable signal detection while supporting multiple connected devices.
2Ease of operation
If a switch circuit is used to switch between multiple input terminals, then the ease of operation is improved, but crosstalk causes erroneous signal detection and malfunctions
Solution Approach 1:
The patent segments the signal switching function across multiple independent switch circuits, each dedicated to specific input terminals. This segmentation ensures that switching operations in one circuit do not interfere with others, preventing crosstalk-related detection errors while maintaining easy signal switching capability.
Solution Approach 2:
The patent implements feedback control through HPD control units that monitor and manage signal flow based on the selected input terminal. When a specific terminal is selected, the HPD control unit provides feedback signals to enable only the corresponding switch circuit, ensuring accurate signal detection and preventing malfunctions during switching operations.
3Device complexity
If standard switch circuits are used for signal switching, then the device complexity is reduced, but crosstalk occurs causing detection unit errors
Solution Approach 1:
The patent uses multiple simple switch circuits with segmented functionality rather than a single complex high-capability circuit. Each switch circuit is designed for specific input terminals, reducing individual circuit complexity while collectively providing reliable signal switching without crosstalk, thus maintaining detection unit accuracy.
Solution Approach 2:
The patent introduces HPD control units as intermediaries that manage signal flow between simple switch circuits and the detection unit. These intermediaries prevent crosstalk errors by controlling which signals are permitted to pass through, thereby maintaining detection accuracy without requiring complex switch circuit design.
Data Source
AI summary
A signal input switching circuit, including a switch circuit including a plurality of input terminals to which signals are respectively applied as input from different signal sources, and the switch circuit supplying as output thereof a signal that is applied as input by way of an input terminal selected from among the plurality of input terminals, and input control units provided corresponding to each of the plurality of input terminals belonging to the switch circuit, controlling signal sources that are connected to input terminals that were not selected by the switch circuit to not present signals to the corresponding input terminals.