Capacitive Signal Detection Circuit for Parasitic Capacitance Immunity
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Solution Overview
Problem
Conventional signal detection circuits face challenges in miniaturization and detection accuracy due to the need for high withstand voltage elements and the influence of parasitic capacitance when detecting signals from switching elements, especially in high voltage applications.
Innovation Solution
A signal detection circuit that compares the detection target signal with a reference signal, using capacitors to input both signals equally, thereby reducing the impact of parasitic capacitance and allowing for integration of components, improving detection accuracy while maintaining a compact circuit size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional signal detection circuits use high withstand voltage elements to detect signals from switching elements in high voltage applications, then detection reliability is improved, but circuit size increases and miniaturization becomes difficult
Solution Approach 1:
The patent introduces a capacitor as an intermediary component between the high voltage switching element and the detection circuit. The capacitor couples the detection target signal from the switching element to the detection circuit, allowing the use of low withstand voltage elements in the detection circuit while maintaining reliable detection in high voltage applications. This mediator enables signal transmission without requiring the detection components to directly withstand high voltages.
Solution Approach 2:
The patent creates a replicated version of the signal through capacitive coupling, where the detection target signal is copied and transmitted to the detection circuit via the capacitor. This allows the detection circuit to work with low voltage copies of the original high voltage signal, enabling miniaturization with low withstand voltage elements while maintaining detection reliability.
2Measurement precision
If conventional signal detection circuits directly connect detection elements to switching element terminals, then detection accuracy is improved, but parasitic capacitance adversely affects detection results
Solution Approach 1:
The capacitor serves as a mediator that blocks the direct path for parasitic capacitance effects while transmitting the detection target signal. By coupling the signal through the capacitor rather than direct connection, the detection circuit is isolated from adverse parasitic capacitance effects that would otherwise degrade detection accuracy.
3Device complexity
If conventional circuits use direct connection for signal detection, then device complexity is reduced, but detection accuracy deteriorates due to parasitic capacitance
Solution Approach 1:
The capacitor is a simple component that acts as an effective intermediary, adding minimal complexity to the circuit while significantly improving detection accuracy by eliminating parasitic capacitance effects. The solution maintains simplicity with just one additional component rather than complex shielding or compensation circuits.
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 proposed solution enhances detection accuracy and prevents an increase in circuit size by equally affecting both signals with parasitic capacitance, enabling the use of low withstand voltage elements and optimizing signal detection in high voltage applications.
Implementation Method 1
the influence of parasitic capacitance when detecting signals from switching elements
Data Source
AI summary
A signal detection circuit detects, as a detection target signal, a signal of a main terminal of a switching element by comparing the detection target signal with a reference signal. The signal detection circuit includes: a signal generation unit generating the reference signal; a first capacitor having a first terminal connected with the main terminal of the switching element; a second capacitor having a first terminal connected with an output terminal of the signal generation unit; and a detection circuit receiving, as input signals, a signal output from a second terminal of the first capacitor and a signal output from a second terminal of the second capacitor, and the detection circuit detecting the detection target signal based on the input signals.