Capacitive Touch Driving Module Using Opposite Polarity Signals
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Solution Overview
Problem
Conventional capacitive touch panels suffer from reduced sensitivity due to common mode voltage signals, which affect the accuracy of touch detection.
Innovation Solution
A sensing and driving apparatus that outputs reference signals of different polarities to adjacent driving lines, reducing common mode signals and enhancing sensitivity by counteracting positive and negative polarities, thereby improving the detection of touch events.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional capacitive touch panels use single polarity reference signals, then the sensing circuit can detect voltage changes, but the common mode voltage reduces the sensitivity of the sensing circuit
Solution Approach 1:
The patent applies the counterweight principle by driving adjacent driving lines with reference signals of opposite polarities. The common mode voltages generated by these opposite polarity signals counteract each other, reducing the net common mode interference at the sensing lines. This allows the sensing circuit to detect touch-induced voltage changes with higher precision without being overwhelmed by common mode voltage.
Solution Approach 2:
The patent inverts the conventional approach by using opposite polarities for adjacent driving lines instead of the same polarity. This inversion strategy causes the common mode voltages to have opposite signs, enabling them to cancel each other out and improve the signal-to-noise ratio for touch detection.
2Measurement precision
If reference signals of different polarities are applied to adjacent driving lines, then common mode signals are reduced and sensitivity is improved, but the driving module complexity increases
Solution Approach 1:
The patent merges the generation of opposite polarity reference signals into a single driving module that can output multiple polarities simultaneously. By integrating the polarity inversion function within the existing driving module architecture, the patent achieves common mode reduction without requiring separate dedicated circuits for each polarity, thus limiting the increase in device complexity.
Solution Approach 2:
The driving module is designed with multi-functionality to generate and output reference signals of multiple polarities to different driving lines. This universal approach allows a single driving module to handle both positive and negative polarity signals, reducing the need for additional dedicated circuits and minimizing the overall complexity increase.
Data Source
AI summary
A sensing and driving apparatus suitable for a sensing interface is provided. The sensing and driving apparatus includes a driving module and a sensing unit. The driving module outputs a first reference signal and a second reference signal which have different polarities with each other, and respectively transmits the first reference signal and the second reference signal to a first driving line and a second driving line of the sensing interface so as to generate a first sensing signal during a first period. The sensing unit receives the first sensing signal and detects a change of the first signal so as to generate a sensing result. A sensing and driving method, a touch sensing system and a device using the same are also provided herein.