Capacitive Sensing Circuit Alternating Sampling for Noise Suppression
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Solution Overview
Problem
Capacitive sensing and sampling circuits in touch display panels face interference from white noise, leading to reduced signal-to-noise ratios and decreased accuracy in detecting touch object coordinates due to insufficient sampling numbers.
Innovation Solution
A capacitive sensing and sampling circuit that uses a voltage source with multiple voltage levels to drive a capacitive sensing component, allowing first and second sensing output units to alternately sense and sample capacitive signals, thereby increasing the number of samples and suppressing white noise interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sampling number of the touch sensing circuit is increased, then the signal-to-noise ratio is improved, but the sampling time required is increased
Solution Approach 1:
The patent applies periodic action by using multiple sensing output units that alternately sense the capacitive sensing component in a periodic manner. The voltage source sequentially drives the capacitive sensing component with different voltage levels, and each sensing output unit samples during its designated time window. This periodic alternating sensing allows multiple samples to be collected within a compressed time frame, effectively improving the signal-to-noise ratio without proportionally increasing the total sampling time.
2Measurement precision
If multiple sensing output units are used to increase sampling number, then white noise interference is suppressed, but the device complexity is increased
Solution Approach 1:
The patent applies segmentation by dividing the sensing function into multiple sensing output units (first sensing output unit and second sensing output unit), each handling specific sampling tasks. The voltage source is also segmented to provide different voltage levels sequentially. This segmentation allows the system to collect multiple capacitive signals through different pathways, improving white noise suppression by averaging multiple samples while keeping each individual sensing unit relatively simple in structure.
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 increased sampling of capacitive signals improves the signal-to-noise ratio and enhances the accuracy of detecting touch object coordinates by effectively mitigating white noise interference.
Implementation Method 1
a capacitive sensing component Ccom...when the capacitive sensing component is driven by the voltage source with the first voltage level, the first sensing output unit senses a first capacitive signal
Data Source
AI summary
A capacitive sensing and sampling circuit and method thereof are disclosed. The capacitive sensing and sampling circuit has a voltage source, a sensing unit and a detecting circuit. The detecting unit has a first sensing output unit, a second sensing output unit and a sampling unit. The first and second sensing output units are electrically connected to an output of the sensing unit and the sampling unit. Therefore, by increasing the number of alternatively sensing the capacitive sensing component to obtain more capacitive signals, the number of sampling the sensed capacitive signal is relatively increased. Therefore, the white noise interference for the capacitive sensing and sampling circuit is effectively suppressed, so the signal-to-noise ratio is increased and accuracy of detecting coordinates of the touch object is increased.