Touchscreen Capacitance Detection Circuit for Display Noise Peaks
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Capacitive sensors in electronic devices face interference from display screen noise, which affects the accuracy of touch detection by reducing the signal-to-noise ratio and detection sensitivity.
Innovation Solution
A capacitance detection circuit with an amplification circuit and control circuit that adjusts magnification in accordance with noise signal magnitude during specific sub-periods, inversely proportional to noise levels, to prevent saturation and enhance signal quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the magnification of the amplification circuit is increased to improve the signal-to-noise ratio, then the detection sensitivity is improved, but the amplification circuit will saturate during noise peaks
Solution Approach 1:
The patent applies dynamic adjustment of the magnification parameter by controlling the magnification to vary over time based on the noise signal characteristics. The control circuit dynamically adjusts the magnification of the amplification circuit according to the detected noise signal magnitude, using a magnification control expression that incorporates noise signal information to optimize the balance between detection sensitivity and saturation prevention.
Solution Approach 2:
The patent changes the magnification parameter dynamically based on noise conditions. By using a magnification control expression that includes noise signal magnitude and time constants, the system adjusts the amplification factor adaptively - increasing magnification when noise is low to improve sensitivity, and reducing magnification when noise is high to prevent saturation.
2Device complexity
If the magnification is kept constant to simplify the circuit control, then the device complexity is reduced, but the signal-to-noise ratio cannot be optimized during noise peaks
Solution Approach 1:
The patent implements preliminary action by detecting the noise signal characteristics in advance and using them to pre-adjust the magnification before the actual capacitance detection occurs. The control circuit continuously monitors the noise signal and prepares the appropriate magnification level, so when detection is needed, the amplification is already optimized for current noise conditions.
Solution Approach 2:
The patent employs feedback mechanisms where the noise signal is fed back to the control circuit, which then adjusts the magnification accordingly. The magnification control expression incorporates feedback from the noise signal magnitude, creating a closed-loop system that automatically optimizes the signal-to-noise ratio based on real-time noise conditions without requiring complex manual control.
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 solution effectively reduces the influence of display screen noise on capacitance detection, improving the signal-to-noise ratio and detection performance by dynamically adjusting amplification based on noise peaks, ensuring effective operation and better detection accuracy.
Implementation Method 1
Capacitive sensors are widely used in electronic products to implement touch detection. When a conductor, such as a finger, touches and approaches a detection electrode in a touch screen of an electronic device, a capacitance corresponding to the detection electrode changes.
Data Source
AI summary
A capacitance detection circuit, a touch control chip and an electronic device are provided, which could reduce the influence of a display screen noise on capacitance detection. The capacitance detection circuit includes: an amplification circuit, connected to a detection capacitance in a touch screen, and configured to amplify a capacitance signal of the detection capacitance and convert the capacitance signal into a voltage signal, the voltage signal configured to determine the detection capacitance; and a control circuit, connected to the amplification circuit, and configured to control a magnification of the amplification circuit, where a period in which a noise peak of a noise signal of a display screen is located includes consecutive N sub-periods, and a magnification of the amplification circuit in the N sub-periods is inversely proportional to a magnitude of the noise signal in the N sub-periods, N>1.