Electromagnetic Interference Filter for Power Supply Size Reduction
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Solution Overview
Problem
Conventional power supplies with electromagnetic interference filters, particularly those using donut-shaped cores, increase device size and manufacturing costs due to the need for separate choke coils and manual production, and cause noise in display devices due to magnetic flux interference.
Innovation Solution
A power supply with an electromagnetic interference filter featuring electromagnetically coupled cores and tube-shaped bobbins with winding regions, utilizing leakage inductance to remove differential mode interference without separate choke coils, and automatic production methods to reduce costs and size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If separate choke coils are used to remove differential mode electromagnetic interference, then electromagnetic interference removal effectiveness is improved, but device volume increases
Solution Approach 1:
The patent combines the functions of common mode interference removal and differential mode interference removal into a single integrated electromagnetic interference filter. The filter simultaneously removes both common mode electromagnetic interference through its core structure and differential mode electromagnetic interference through leakage inductance, eliminating the need for separate choke coils and reducing overall device volume.
Solution Approach 2:
The electromagnetic interference filter is designed to perform multiple functions: it removes common mode electromagnetic interference, removes differential mode electromagnetic interference through leakage inductance, and integrates both functions in a single device. This multi-functional design eliminates the need for separate components and reduces the overall volume of the power supply.
2Object-affected harmful factors
If donut-shaped cores with two coils wound in opposite directions are used, then common mode electromagnetic interference is removed, but manufacturing complexity increases and production rate decreases
Solution Approach 1:
The patent divides the electromagnetic interference filter into separate functional modules: a first filter for removing common mode electromagnetic interference and a second filter for removing differential mode electromagnetic interference. This segmentation allows each module to be designed and manufactured independently, simplifying the overall manufacturing process and enabling automated production while maintaining effective common mode interference removal.
3Volume of moving object
If electromagnetic interference filter is disposed adjacently to the back cover, then space is saved, but magnetic flux interference causes noise
Solution Approach 1:
The patent extracts the differential mode interference removal function from a separate component and implements it within the electromagnetic interference filter itself through leakage inductance. This integration allows the filter to handle both common mode and differential mode interference in a single unit, enabling compact placement near the back cover without causing noise issues, as the leakage inductance effectively suppresses differential mode interference that would otherwise cause noise.
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 reduces the size and manufacturing costs of power supplies, minimizes noise interference with display devices, and enhances production efficiency by integrating common and differential mode interference removal within a single core structure, allowing for thinner, more marketable electronic equipment.
Implementation Method 1
first and second coils respectively wound around the first and second bobbins to remove common mode electromagnetic interference included in power transmitted from a power line
Implementation Method 2
the electromagnetic interference filter removing differential mode electromagnetic interference due to leakage inductance formed due to the leakage of magnetic flux flowing through the cores
Data Source
AI summary
The power supply includes: an electromagnetic interference filter including a first filter which has a pair of electromagnetically coupled cores having at least two leg parts, first and second bobbins each having a tube-shaped body part having a penetration hole into which each of the leg parts is inserted and having a winding region defined as the circumference of the outer peripheral surface of the body part, and first and second coils respectively wound around the first and second bobbins to remove common mode electromagnetic interference included in power transmitted from a power line, the electromagnetic interference filter removing differential mode electromagnetic interference due to leakage inductance formed due to the leakage of magnetic flux flowing through the cores; a power factor corrector correcting a power factor of the power where the electromagnetic interference is removed; and a power converter switching the power-factor-corrected power into a driving power having a predetermined voltage level.