Touch Sensor Driving Device Discharge Circuit Saturation
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Solution Overview
Problem
Large-sized touchscreens face the issue of output voltage exceeding permissible ranges and becoming saturated in touch sensing circuits, making it impossible to accurately detect touch inputs due to increased capacitance values.
Innovation Solution
Incorporating discharge circuits with charge eliminating pulse signals and switches to reduce the voltage swing amplitude and capacitance, preventing saturation by adjusting the output voltage within a predetermined range through multiple charge eliminating pulses and capacitors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If display devices are made larger, then the screen size increases, but the output voltage of touch sensing circuits exceeds permissible ranges and becomes saturated
Solution Approach 1:
The patent applies dynamics by making the integration capacitance adjustable rather than fixed. The touch sensor driving device dynamically changes the integration capacitance value based on the detected capacitance magnitude, allowing the system to adapt to different screen sizes and capacitance ranges while maintaining output voltage within permissible ranges
Solution Approach 2:
The patent changes the parameter of integration capacitance to resolve the contradiction. By varying the integration capacitance value according to the detected capacitance magnitude, the system prevents output voltage saturation while supporting larger screen sizes with higher capacitance values
2Measurement precision
If the capacitance of touch sensors increases, then the sensing capability improves, but the output voltage exceeds permissible ranges and becomes saturated
Solution Approach 1:
The patent changes the integration capacitance parameter in response to detected capacitance magnitude. When higher sensor capacitance is detected, the system adjusts the integration capacitance to maintain output voltage within permissible ranges, preserving both sensing capability and voltage reliability
Solution Approach 2:
The patent implements feedback by detecting the capacitance magnitude and using this information to adjust the integration capacitance. This closed-loop control ensures that the output voltage remains within permissible ranges while maintaining optimal touch sensing performance
3Reliability
If the output voltage swing amplitude is reduced, then saturation is prevented, but the touch sensing sensitivity may be affected
Solution Approach 1:
The patent dynamically adjusts the integration capacitance based on detected capacitance magnitude, which in turn dynamically controls the output voltage swing amplitude. This dynamic adjustment prevents saturation while maintaining sufficient sensitivity for accurate touch detection across different operating conditions
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 solution effectively prevents saturation of output voltage in touch sensing circuits, allowing for accurate touch detection and reducing the size and manufacturing cost of the touch sensor driver by finely adjusting the swing amplitude of touch sensor signals.
Implementation Method 1
the discharge circuit CR comprises a plurality of charge eliminating capacitors Ccr1 to Ccrj connected to a first node N1 in parallel. The electrodes at one side of the charge eliminating capacitors Ccr1 to Ccrj are connected commonly to the first node N1, and the electrodes at the other side of the charge eliminating capacitors Ccr1 to Ccrj are connected respectively to input terminals of charge eliminating pulse signals Vcr1 to Vcrj
Data Source
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AI summary
A touch sensor driving device comprises: a plurality of touch sensing circuits that receive touch sensor sensing signals from touch sensors of a touchscreen through a plurality of receiving channels; and a plurality of discharge circuits (CR) connected between the receiving channels and the touch sensing circuits to receive charge eliminating pulse signals (Vcr1, ..., Vcrj) and reduce the swing amplitude of the touch sensor sensing signals input into the touch sensing circuits.