Input Sensing Circuit With Switching Units for Noise-Stable Hover Detection
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Solution Overview
Problem
Display devices with touch screen panels experience reduced signal-to-noise ratio and deteriorated sensing sensitivity due to interference and noise, particularly when sensing hovering or gesture inputs, which require higher sensitivity.
Innovation Solution
An input sensing device with a binding structure where multiple voltage controlled current sources are connected to one analog front-end circuit, using switching units to stabilize the voltage of mirror output terminals and connect them to reference voltages, thereby reducing interference and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If multiple voltage controlled current sources are connected to one analog front-end circuit in a binding structure, then device complexity is reduced, but interference and noise increase due to floating mirror output terminals
Solution Approach 1:
A switching unit is introduced as an intermediary component between the voltage controlled current source and the analog front-end circuit. The switching unit includes a switching element that connects the mirror output terminal to either the analog front-end circuit or a reference voltage terminal, preventing the floating state that causes interference and noise while maintaining the binding structure's complexity reduction benefits.
2Device complexity
If mirror output terminals are left floating to simplify circuit connection, then device complexity is reduced, but signal-to-noise ratio deteriorates
Solution Approach 1:
The switching element dynamically changes the connection state of the mirror output terminal based on operational requirements. During normal operation, the switching element connects the mirror output terminal to the analog front-end circuit for signal processing. During non-operation or idle states, it connects to the reference voltage terminal to prevent floating, thereby adapting the circuit state to maintain signal-to-noise ratio while keeping the overall structure simple.
3Measurement precision
If switching units are added to stabilize mirror output terminals, then signal-to-noise ratio is improved, but device complexity increases
Solution Approach 1:
The switching unit integrates multiple functions into a single compact component structure. The switching element, control terminal, and reference voltage terminal are combined in a way that adds minimal complexity while effectively stabilizing the mirror output terminal. The switching unit can be implemented using standard semiconductor switching elements that can be integrated alongside existing circuit components, minimizing the overall complexity increase.
Data Source
AI summary
The embodiments relate to an input sensing device, including: a sensing panel allowing a plurality of driving lines and a plurality of sensing lines to be disposed thereon; and a sensing driving circuit configured to sense an input based on input sensing signals output from the plurality of sensing lines, and a display device including the same.