Capacitance Detection Circuit With Frequency-Based Interference Suppression
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Solution Overview
Problem
Existing capacitance detection technologies face challenges in sensitivity and accuracy due to low-frequency interference signals, which affect the accurate determination of user interactions in electronic devices.
Innovation Solution
A capacitance detection circuit comprising a drive module, conversion module, and control module, where the conversion module includes a suppression module that filters out interference signals with frequencies below or above a certain threshold, enhancing the sensitivity and accuracy of capacitance detection by generating an output voltage while suppressing unwanted signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If capacitance detection is performed without frequency filtering, then the detection coverage includes all frequency ranges, but low-frequency interference signals reduce the sensitivity and accuracy of capacitance detection
Solution Approach 1:
The patent applies frequency filtering by changing the frequency parameter of the detection signal. The suppression module filters out interference signals with frequencies lower than a first frequency or higher than a second frequency, thereby eliminating low-frequency interference while preserving the useful capacitance detection signal band.
Solution Approach 2:
The patent introduces a suppression module as an intermediary component between the conversion module and processing module. This module acts as a mediator that selectively removes harmful frequency components from the signal while allowing the useful capacitance detection signals to pass through to the processing stage.
2Measurement precision
If a suppression module is added to filter interference signals, then the sensitivity and accuracy of capacitance detection improve, but the device complexity increases
Solution Approach 1:
The suppression module is designed with multi-functionality, serving both to filter low-frequency interference signals and to maintain the useful capacitance detection signal band. By integrating frequency filtering capabilities into a single module within the existing circuit architecture, the patent achieves interference suppression without proportionally increasing overall device complexity.
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 interference signals, thereby improving the sensitivity and accuracy of capacitance detection, allowing for more precise user interaction monitoring in electronic devices.
Implementation Method 1
the control module is configured to control the first suppression module to suppress an interference signal with a frequency that is less than a first frequency or greater than a second frequency when the conversion module generates the output voltage
Data Source
AI summary
A capacitance detection circuit, a detection chip, and an electronic device are provided. The circuit includes: a first drive module, a conversion module, a processing module, and a control module. The first drive module is configured to charge a first capacitor to be detected. The conversion module is configured to perform charge conversion processing on the first capacitor to be detected to generate an output voltage. The control module is configured to control a first suppression module of the conversion module to suppress an interference signal with a frequency less than a first frequency or greater than a second frequency when the conversion module generates the output voltage, and the second frequency is greater than the first frequency. The processing module is configured to determine a capacitance change before and after the first capacitor to be detected is affected by an applied electric field based on the output voltage.