Touch Detection Circuit With Noise-Adaptive Drive and Strobe Timing
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Solution Overview
Problem
Touch detection systems face low sensitivity due to interference from display drive signals and noise in the working environment, which affects the accuracy of touch coordinates and increases errors in calculations.
Innovation Solution
A touch detection method and circuit that synchronizes with a real-time synchronization signal from a touch display panel, acquires the frequency of noise signals, sets the frequency of a coding drive signal to minimize noise interference, and generates a strobe signal to detect signals from the sensing electrode, thereby improving the signal-to-noise ratio and touch sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the touch detection system operates in the working environment with display drive signals, then the touch detection function is available, but the noise interference from display drive signals reduces touch sensitivity
Solution Approach 1:
The patent applies periodic action by using a strobe signal to enable touch detection only during specific time periods when the display drive signal is not active. The strobe signal periodically gates the detection circuit to sample touch signals during noise-free intervals, thereby resolving the contradiction between maintaining touch detection functionality and avoiding display drive noise interference
Solution Approach 2:
The patent implements preliminary action by generating the strobe signal in advance based on the synchronization signal from the display panel. This allows the detection system to preemptively identify and prepare for noise-free detection windows before the actual touch detection occurs, ensuring optimal timing for capturing touch signals without interference
2Measurement precision
If the coding drive signal uses a fixed frequency, then the circuit design is simple, but the noise interference varies with frequency and reduces detection accuracy
Solution Approach 1:
The patent applies dynamics by making the coding drive signal frequency adjustable rather than fixed. The system dynamically selects the frequency of the coding drive signal based on the detected noise characteristics of the display drive signal, allowing optimal frequency selection to minimize interference while maintaining detection accuracy
Solution Approach 2:
The patent implements parameter changes by varying the frequency parameter of the coding drive signal according to the noise spectrum of the display system. By changing the frequency parameter to match conditions of minimal interference, the system improves measurement precision without requiring complete redesign of the signal generation architecture
3Measurement precision
If touch detection is performed continuously, then the response speed is fast, but the detection accuracy decreases due to noise interference during display drive periods
Solution Approach 1:
The patent resolves this contradiction by implementing periodic touch detection synchronized with the display refresh cycle. The strobe signal enables detection during specific periods when noise is minimal, achieving high signal-to-noise ratio while maintaining acceptable response speed through timely sampling at optimal moments
Solution Approach 2:
The patent uses feedback by continuously monitoring the synchronization signal from the display panel to determine the appropriate timing for touch detection. This feedback mechanism allows the system to adaptively adjust detection timing based on the actual display drive cycle, optimizing both precision and response speed
Data Source
AI summary
A touch detection method, a touch detection circuit, a touch chip and an electronic device. The touch detection method includes: receiving a real-time synchronization signal sent by a touch display panel; acquiring a frequency of a noise signal in a working environment of a touch chip; setting a frequency of a coding drive signal based on the frequency of the noise signal, generating the coding drive signal based on the frequency of the coding drive signal, and outputting the coding drive signal to a drive electrode of the touch display panel; generating a strobe signal based on the real-time synchronization signal; and receiving a signal of a sensing electrode of the touch display panel, and outputting a detection result based on the strobe signal and the signal of the sensing electrode.