Heat Sink Connection Layout for Switching Power Supply Noise Reduction
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Solution Overview
Problem
Switching power supplies emit high-frequency noise into the air and transfer noise to circuit grounds, causing interference and emission via AC lines, which existing methods fail to adequately address.
Innovation Solution
Incorporating a noise absorption component, such as an inductor, between the heat sink and a low-impedance pattern in the printed substrate to attenuate high-frequency noise, reducing emissions and transfers to the primary-side circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a heat dissipation device is used to discharge heat from the semiconductor element, then heat dissipation is improved, but high-frequency noise is generated and emitted into the air and transferred to the circuit ground
Solution Approach 1:
An inductor is introduced as an intermediary component between the heat sink and the printed substrate. This inductor acts as a mediator that allows thermal conduction while blocking high-frequency noise transmission. The inductor's impedance to high-frequency signals prevents noise from reaching the circuit ground, while its thermal properties enable heat dissipation from the semiconductor element.
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
Significantly reduces high-frequency noise emissions from the heat sink and minimizes noise transfer to the primary-side circuit, improving electromagnetic compatibility and reducing interference.
Implementation Method 1
an inductor that is connected between the connection portion of the heat sink and a part of the pattern, and absorbs electrical noise induced to the heat sink
Implementation Method 2
a heat sink that includes a connection portion and dissipates heat generated in the semiconductor element
Data Source
AI summary
A switching power supply apparatus includes a printed substrate, a transformer, a primary-side circuit, a secondary-side circuit, and some components. A semiconductor element is mounted on the printed substrate. A heat sink includes a connection portion and dissipates heat generated in the semiconductor element. The connection portion is connected to the printed substrate by soldering. A conductive pattern is formed on the printed substrate. An inductor is connected between the connection portion of the heat sink and a part of the pattern, and absorbs electrical noise induced to the heat sink.