Conduction Noise Filtering Circuit with Common Mode Detection
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Solution Overview
Problem
Existing conduction noise filtering circuits do not adequately inhibit conduction noise on power lines and fail to effectively attenuate common mode noise, which can lead to electromagnetic interference affecting electronic devices.
Innovation Solution
A conduction noise filtering circuit comprising a first coil part, a second coil part, a detector, and a capacitor, where the detector magnetically couples with the coils to detect common mode noise and an amplifier supplies offset power to the capacitor to offset the noise, thereby reducing common mode noise through a connection terminal shared by both coil parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing conduction noise filtering circuits are used, then the device structure is simple, but the inhibition performance of conduction noise is insufficient
Solution Approach 1:
The filtering circuit is divided into multiple functional modules: a first coil part connected to the power line, a second coil part connected to the output terminal, a detector for detecting common mode noise, and a capacitor for supplying offset power. This segmentation allows each module to perform its specific function efficiently, improving overall noise inhibition performance while maintaining reasonable circuit complexity
Solution Approach 2:
The detector acts as an intermediary element that detects common mode noise on the power line and converts it into a signal that can be processed by the capacitor. The capacitor then supplies offset power based on the detected noise signal, effectively counteracting the common mode noise. This intermediary mechanism enables precise noise cancellation without requiring complex circuit structures
2Reliability
If existing noise filtering circuits are used, then the circuit design is simple, but the feedback control for attenuating noise is insufficient
Solution Approach 1:
The detector continuously monitors common mode noise on the power line and provides real-time feedback information. The capacitor receives this feedback signal and dynamically adjusts the offset power supply to counteract the detected noise. This feedback mechanism ensures that the filtering circuit adapts to varying noise conditions, significantly improving noise attenuation performance
Solution Approach 2:
The capacitor supplies offset power in advance based on the detected common mode noise signal, preventing the noise from affecting the output terminal. By taking preliminary action to counteract the noise before it propagates further, the circuit achieves effective noise attenuation without requiring complex post-processing mechanisms
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 inhibits conduction noise, enhancing detection and tracking performance while maintaining a compact design, as evidenced by the circuit diagrams and graphs illustrating reduced noise terminal voltage within allowable limits.
Implementation Method 1
a detector configured to detect common mode noise flowing on at least one selected from the first coil part and the second coil part
Implementation Method 2
a capacitor configured to supply offset power offsetting the detected common mode noise to a connection terminal to which the first coil part and the second coil part are connected in common
Data Source
AI summary
A conduction noise filtering circuit configured to inhibit conduction noise is provided. The conduction noise filtering circuit includes a first coil part configured to be supplied with alternating current (AC) power, a second coil part configured to be connected to the first coil part in series, a detector configured to detect common mode noise from at least one selected from the first coil part and the second coil part, and a capacitor configured to supply a current offsetting common mode noise between power lines connecting the first coil part and the second coil part in series.