Noise Filter Ground Pattern Segmentation for AC Power Supply
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Solution Overview
Problem
Existing power supply apparatuses using commercial AC power suffer from incomplete noise suppression due to common impedance between Y capacitors connected to a common ground, leading to increased terminal noise.
Innovation Solution
The power supply apparatus includes separate first and second capacitors connected to the live and neutral sides of the AC line, respectively, with distinct ground patterns on the substrate that are electrically isolated from each other, preventing common impedance and allowing full noise suppression efficacy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If Y capacitors are connected to a common ground terminal through common impedance on the substrate, then the device complexity is reduced, but the noise suppression effect deteriorates due to ground potential changes
Solution Approach 1:
The patent divides the common ground connection into separate ground patterns for each Y capacitor. Instead of connecting both Y capacitors to a single common ground terminal through shared impedance, each capacitor has its own dedicated ground pattern that connects to the frame ground independently, eliminating the common impedance path that causes noise coupling.
Solution Approach 2:
The patent introduces the frame ground as an intermediary structure that receives connections from multiple separate ground patterns. The frame ground acts as a low-impedance intermediary that consolidates the separate ground connections without creating harmful common impedance between the Y capacitors, thereby maintaining noise suppression effectiveness.
2Object-affected harmful factors
If separate ground patterns are used for each capacitor to prevent common impedance, then the noise suppression effect is improved, but the device complexity increases
Solution Approach 1:
The patent merges multiple separate ground patterns at the frame ground level. While the ground patterns are separated on the substrate to avoid common impedance, they are combined at the frame ground which provides a low-impedance common reference. This merging at the appropriate level achieves noise suppression without excessive complexity.
Solution Approach 2:
The patent transitions the ground connection from a two-dimensional substrate plane to a three-dimensional structure by using the frame ground as a vertical intermediary. The separate ground patterns on the substrate connect to different points on the frame ground structure, eliminating common impedance in the planar dimension while maintaining a unified ground reference through the vertical dimension.
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
This configuration effectively bypasses noise to the frame ground and the AC power supply's ground, preventing ground potential changes and ensuring complete noise suppression by the capacitors.
Implementation Method 1
a first capacitor including at least one capacitor, one end of the first capacitor being connected to a live side of an AC line of an AC voltage supplied from an AC power supply; a second capacitor including at least one capacitor, one end of the second capacitor being connected to a neutral side of the AC line
Data Source
AI summary
The noise filter includes a first capacitor that is mounted on a substrate, and includes one end connected to a live side of an AC line of an AC voltage supplied from an AC power supply, a second capacitor including one end connected to a neutral side of the AC line, a first ground pattern to which another end of the first capacitor is connected, and a second ground pattern to which another end of the second capacitor is connected. The first ground pattern and the second ground pattern are not connected electrically on the substrate.