Capacitance Detection Circuit with Bidirectional Cancellation
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Solution Overview
Problem
Existing capacitance detection technologies face challenges in achieving high sensitivity and accuracy, especially when the initial capacitance is large and the variable quantity is small, leading to difficulties in detecting changes in capacitance effectively.
Innovation Solution
A detection circuit comprising a driving circuit, a cancelling circuit, and a switching circuit that periodically charges and cancels the initial capacitance of a detection capacitor through bidirectional charge transfer, converting the capacitive signal into a voltage signal for improved sensitivity and accuracy, and further incorporating a filter, ADC, and DSP for noise suppression and signal processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional capacitance detection is used with large initial capacitance, then the detection system can operate with simple circuitry, but the detection sensitivity becomes insufficient and small capacitance changes cannot be detected
Solution Approach 1:
The patent extracts and removes the initial capacitance component from the detection capacitor through bidirectional charge transfer. The cancelling circuit separates the initial capacitance (which causes low sensitivity) from the variable capacitance signal, allowing only the small changes to be detected with high sensitivity.
Solution Approach 2:
The patent introduces a cancelling circuit as an intermediary component between the detection capacitor and the signal processing stage. This intermediary circuit performs bidirectional charge transfer to eliminate the initial capacitance while preserving the variable signal, enabling high-sensitivity detection without directly modifying the detection capacitor itself.
2Measurement precision
If the detection sensitivity is increased to detect small capacitance changes, then detection accuracy improves, but noise and interference become more significant and affect detection reliability
Solution Approach 1:
The patent converts the harmful effect of initial capacitance (which masks small signals) into a beneficial cancellation process. By using bidirectional charge transfer, the initial capacitance is systematically eliminated, and the same mechanism enhances the detection of small variable signals while suppressing noise and interference.
Solution Approach 2:
The patent employs periodic bidirectional charge transfer operations to systematically cancel the initial capacitance. The periodic nature of this cancellation process, synchronized with the detection cycles, allows for consistent noise suppression and reliable detection of variable capacitance signals throughout operation.
3Measurement precision
If bidirectional charge transfer is used to cancel initial capacitance, then detection sensitivity and accuracy improve, but the device complexity increases due to additional circuit components
Solution Approach 1:
The patent merges the initial capacitance cancellation function with the variable signal detection function into a single integrated bidirectional charge transfer process. By combining these functions, the patent eliminates the need for separate cancellation and detection circuits, reducing overall device complexity while maintaining high detection sensitivity and accuracy.
Solution Approach 2:
The patent designs the cancelling circuit to perform multiple functions: it cancels the initial capacitance, preserves the variable capacitance signal, and provides noise suppression. This multi-functional approach eliminates the need for separate dedicated circuits for each function, thereby improving detection performance without proportionally increasing 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 enhances capacitance detection sensitivity, accuracy, and dynamic range, effectively suppressing noise and interference, and improving the Signal-to-Noise Ratio, thereby enabling precise capacitance detection in various applications.
Implementation Method 1
a corresponding signal to be detected can be detected by detecting a change in a detection capacitor
Data Source
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AI summary
The present application provides a detection circuit and an electronic device. The detection circuit includes a driving circuit, a cancelling circuit, and a switching circuit. Each driving module of the driving circuit is coupled to a capacitor to be detected for charging it; each cancelling module of the cancelling circuit is coupled to the capacitor to be detected to perform capacitance cancellation through two directions; each cancelling module of the switching circuit is coupled to the switching module to perform conversion of a capacitive signal and then output. The present application can improve a detection accuracy of the capacitor.