Common mode filter and signal transmission circuit
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Solution Overview
Problem
Traditional common-mode noise suppression methods cause signal discontinuity and lack flexibility in frequency adjustment, making it difficult to correct frequency offsets caused by parasitic effects, and are costly.
Innovation Solution
A common mode filter and signal transmission circuit comprising a substrate, conductive layers, conductive lines, and passive components, which allow for filtering common-mode signals and adjusting the frequency band, presenting high impedance at specific resonance frequencies to suppress noise, while maintaining differential signal transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If traditional common mode filter components are used, then common-mode noise suppression is achieved, but signal discontinuity occurs and frequency adjustment flexibility is lost
Solution Approach 1:
The patent implements a dynamically adjustable common mode filter where the cutoff frequency can be changed by switching between different capacitor values (C1, C2, C3, C4) connected through switch elements. This allows the filter to adapt to different frequency requirements while maintaining continuous signal transmission, resolving the contradiction between noise suppression and frequency adjustment flexibility.
Solution Approach 2:
The filter circuit is designed to perform multiple functions: it can suppress common-mode noise across different frequency ranges by adjusting the capacitor configuration, and it maintains signal continuity unlike traditional filters. The universal design allows a single circuit to handle various frequency requirements without requiring multiple separate filter components.
2Object-affected harmful factors
If traditional common mode filter components are used, then common-mode noise suppression is achieved, but frequency offset correction becomes difficult and additional costs increase
Solution Approach 1:
The patent incorporates a feedback mechanism where the filter's performance can be monitored and adjusted. By using switchable capacitor configurations, the system can detect frequency offsets caused by parasitic effects and correct them by switching to appropriate capacitor values, making frequency offset correction easy and cost-effective.
Solution Approach 2:
The filter allows easy correction of frequency offsets by changing the electrical parameters (capacitor values) of the circuit. Different capacitor combinations (C1, C2, C3, C4) provide different cutoff frequencies, enabling straightforward adjustment to compensate for parasitic effects without requiring complex calibration procedures or additional expensive components.
3Speed
If clock frequency is increased to achieve transmission requirements, then transmission speed improves, but high-frequency noise interference increases
Solution Approach 1:
The patent employs a dynamic filter configuration that can adjust its cutoff frequency to match the operating clock frequency. As the clock frequency increases to improve transmission speed, the filter can be reconfigured (by switching capacitors) to maintain effective noise suppression at the new higher frequency, thus allowing speed improvement without proportionally increasing noise interference.
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 circuit effectively filters out common-mode noise, adjusts frequency bands, and reduces charge accumulation and resonance, enhancing signal-to-noise ratio and transmission efficiency.
Implementation Method 1
The common mode filter and the signal transmission circuit of the present disclosure may filter out the common-mode signal transmitted in the differential-signal lines and can adjust the frequency band of filtering through passive components, so that high impedance may be presented over the common-mode signal at a specific resonance frequency
Data Source
AI summary
A common mode filter comprises a substrate, a first conductive layer, a ground layer, two conductive lines and two passive components. The substrate has a first surface, a second surface and a plurality of through holes, wherein the plurality of through holes respectively pass through the first surface and the second surface. The first conductive layer is disposed on the first surface of the substrate. The ground layer is disposed on the first surface of the substrate and spaced from the first conductive layer. The two conductive lines are disposed on the second surface of the substrate, wherein one end of each of the two conductive lines is electrically connected to the first conductive layer through one of the plurality of through holes. The two passive components are electrically connected to the ground layer and the first conductive layer.