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How to fix power supply EMC issues

This video “Simple Trick to Improve EMC – Easy Filter Design for Power Supply” hosted by Robert Feranec and Thomas Eichstetter, explains the concept of electromagnetic compatibility (EMC) issues in power supplies and demonstrates practical methods for designing an effective filter to reduce noise and interference. The presenters, Robert and Thomas, discuss the setup of a power supply, measure the noise sources, and identify the critical components causing issues such as high-frequency current changes leading to differential and common-mode noise. Using practical examples and real-time measurements with tools like spectrum analyzers and network analyzers, they emphasize the importance of understanding circuit behavior, such as resonance frequencies and parasitic effects, to design optimized filters. By introducing a simple LC filter and applying a unique logarithmic “RF Wallpaper” tool, they show how to calculate, simulate, and implement filters effectively.

The video also highlights key tips for diagnosing EMC problems and emphasizes the importance of distinguishing between differential and common-mode noise to select appropriate filtering components. For differential noise, an inductor and capacitor can be used to create a voltage divider for attenuation. The presenters demonstrate how to measure and analyze component impedance and resonance, ensuring the selected filter operates effectively within the problem frequency range. The video concludes with practical measurements before and after filter implementation, showcasing a significant reduction in noise and compliance with EMC standards. The presenters also encourage viewers to explore additional learning resources and offer a teaser for future videos focusing on advanced topics like common-mode noise filtering.