Capacitance Detection Circuit Noise Avoidance
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Solution Overview
Problem
Existing touch display panels face low touch sensitivity due to interference from driving the display, which cannot be effectively avoided by current capacitance detection schemes, leading to significant noise and reduced signal quality.
Innovation Solution
A capacitance detection method that generates a trigger signal based on real-time sync signals to avoid display driving noise, allowing for synchronized driving and signal detection in noise-free periods, thereby improving the signal-to-noise ratio and touch sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If capacitance detection is performed continuously, then touch detection coverage is improved, but display driving noise increases and touch sensitivity deteriorates
Solution Approach 1:
The patent implements periodic capacitance detection synchronized with display refresh cycles, performing detection only during specific time windows when display driving noise is minimal. This periodic action pattern allows the system to maintain comprehensive touch detection coverage while avoiding continuous detection that would amplify noise interference, thereby resolving the contradiction between detection coverage and noise reduction.
2Measurement precision
If detection frequency is increased to improve touch sensitivity, then response speed is improved, but display driving interference becomes more significant
Solution Approach 1:
The patent performs preliminary synchronization by locking the capacitance detection phase to the display refresh cycle before actual detection begins. This preliminary action establishes an optimal detection timing window in advance, allowing high-frequency detection to be performed only during noise-free periods, thus improving touch sensitivity without amplifying display driving interference.
3Measurement precision
If frequency-hopping detection mechanism is used to optimize touch sensitivity, then detection accuracy is improved, but display driving interference cannot be avoided
Solution Approach 1:
The patent introduces a sync signal as an intermediary between the display driver and capacitance detection circuit. This sync signal mediates the timing relationship, allowing the detection system to synchronize with display refresh cycles and identify optimal detection windows. The intermediary sync mechanism enables both high detection accuracy and effective interference avoidance, overcoming the limitations of frequency-hopping methods.
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
This approach significantly enhances touch sensitivity by minimizing the impact of display driving noise on the sensing wire, allowing for the detection of larger effective signal amounts with improved signal quality.
Implementation Method 1
capacitance sensor...detecting a signal value of the capacitance sensor
Data Source
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AI summary
A capacitance detection method of a touch display panel, a capacitance detection circuit of a touch display panel, a touch chip and an electronic device are provided. The method includes: receiving a real-time sync signal sent from a display panel, and generating a trigger signal in a period in which a display driving noise is avoided based on the real-time sync signal (SI); generating a sync driving signal in the period in which the display driving noise is avoided based on the received trigger signal, to drive a driving electrode of the touch display panel (S2); and detecting a signal value of a capacitance sensor in the touch display panel in the period in which the display driving noise is avoided based on the received trigger signal (S3). This method is little affected by the display driving operation, and improves the signal-to-noise ratio (SNR) of a finally detected effective signal, thus greatly improving the touch sensitivity.