Switching Power Supply Shield Layout for Lead Wire Noise Suppression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional switching power supply devices experience noise voltage generation due to leakage magnetic flux in long lead wires of components, which affects external loads and control circuits, especially when using capacitors with leads.
Innovation Solution
A switching power supply device equipped with an electromagnetic shield member having an annular-shaped conductor frame with a penetration region, positioned to allow leakage magnetic flux to pass through, inducing a canceling magnetic field via eddy currents, thereby suppressing magnetic flux density and noise voltage in lead wires.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the lead wire length is increased to prevent component contact, then the component body is protected from contact with circuit components below, but the noise voltage generated by leakage magnetic flux increases
Solution Approach 1:
An electromagnetic shield member is introduced as an intermediary between the leakage magnetic flux and the lead wires. The shield member includes a shield portion positioned to intercept the leakage magnetic flux before it reaches the lead wires, thereby preventing the harmful electromagnetic induction while allowing the lead wires to maintain their necessary length for component support.
2Object-affected harmful factors
If conventional shielding structures are used, then noise voltage suppression is improved, but the shielding effect on long lead wires is insufficient
Solution Approach 1:
The shield member is designed with a localized shield portion that is specifically positioned to intercept leakage magnetic flux in the critical area where lead wires are most susceptible to electromagnetic induction. This targeted approach provides effective noise suppression exactly where needed, rather than using comprehensive shielding that would be excessive for long lead wires.
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 electromagnetic shield effectively reduces noise voltage in lead wires by generating a magnetic field that cancels leakage magnetic flux, improving noise suppression efficiency.
Implementation Method 1
the leakage magnetic flux acts on the shield portion, a magnetic field in a direction in which the leakage magnetic flux is canceled is generated by a current flowing in a circumferential direction of the frame body
Implementation Method 2
a magnetic field in a direction in which the leakage magnetic flux is canceled is generated by a current flowing in a circumferential direction of the frame body
Data Source
AI summary
A switching power supply device in which lead wires of a capacitor element have tip portions connected to a printed wiring board, and a space between lead wires serves as a magnetic flux passage space for a leakage magnetic flux emitted from a power conversion circuit. An electromagnetic shield member is provided with a shield portion having a metal frame body and a penetration region inside the frame body. The leakage magnetic flux acts on the shield portion, and a current flows in the circumferential direction of the frame body, thereby generating a magnetic field in a direction of canceling the leakage magnetic flux, and suppressing a magnetic flux density of the leakage magnetic flux passing through the magnetic flux passage space.