Capacitive Touch Driving Apparatus Reducing High-Frequency Interference
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Solution Overview
Problem
Capacitive touch control systems in electronic devices, such as smartphones, face interference issues due to high-frequency components in driving signals, which affect neighboring communication circuits, leading to performance degradation.
Innovation Solution
A capacitive touch control system with a driving apparatus that includes a signal generating module and an adjusting module, which generates an adjusted signal by controlling the rising or falling edge of the waveform to reduce the high-frequency component, thereby minimizing interference with peripheral circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If square wave driving signals are used in capacitive touch control systems, then the touch control functionality is achieved, but high-frequency components interfere with neighboring communication circuits
Solution Approach 1:
The patent applies parameter changes by modifying the waveform parameters of the driving signal. Specifically, it transforms the traditional square wave signal into a signal with controlled rising and falling edges, adjusting the slope parameters to reduce high-frequency content while maintaining the capacitive coupling effect necessary for touch detection
Solution Approach 2:
The patent introduces an intermediary signal processing stage between the signal source and the electrode. This intermediary module shapes the driving signal by controlling the rising and falling edges, acting as a mediator that prevents high-frequency interference from reaching the communication circuits while preserving the essential signal characteristics for touch control operation
2Area of stationary object
If the distribution range of driving electrodes is increased to cover larger sensing panels, then the sensing area is expanded, but the interference influence range on peripheral circuits increases
Solution Approach 1:
The patent applies parameter changes by modifying the temporal characteristics of the driving signal. By controlling the rising and falling edge slopes, the signal transitions more gradually, reducing the spectral content at high frequencies. This allows larger electrode distributions to be used without proportionally increasing interference, as the modified signal parameters suppress the harmful high-frequency components that would otherwise spread across the panel
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 adjusted signal reduces the high-frequency component, minimizing interference with other circuits and enhancing the performance of communication systems by reducing the affected region.
Implementation Method 1
The adjusting module controls a rising edge or a falling edge of the waveform of the adjusted signal, so that a high-frequency component in the adjusted signal is less than that in the driving signal
Implementation Method 2
When a touch event takes place, capacitance coupling is caused between the driving electrode and the receiving electrode corresponding to the touch point, giving rise to a change in the sensing signal associated with the mutual capacitance
Data Source
AI summary
A driving apparatus for an electrode in a capacitive touch control system is provided. The driving apparatus includes a signal generating module and an adjusting module. The signal generating module generates a driving signal. The adjusting module is connected between the signal generating module and the electrode, and generates an adjusted signal according to the driving signal to replace the driving signal. The adjusting module controls a rising edge or a falling edge of the waveform of the adjusted signal, so that a high-frequency component in the adjusted signal is less than that in the driving signal.