High efficiency is the hallmark of modern DC/DC converters—but it comes at a price: electromagnetic interference. In industrial systems powered by a 24 V DC bus, non-isolated converters like Würth Elektronik’s MagI³C power modules are essential for supplying various subsystems. Yet, their switching behavior introduces EMI that can compromise system reliability and regulatory compliance.
This appnote dives into the heart of EMI filter design, starting with the physics of conducted and radiated emissions, and the distinction between differential and common mode noise. It explores how parasitic effects in passive components influence filter performance and how to counteract them with smart design choices.
Using real-world measurements and validated filter topologies, the document walks through the design of LC filters that achieve up to 60 dB attenuation. With the help of Würth Elektronik’s REDEXPERT tool, developers can simulate impedance behavior and optimize component selection.
The result is a robust filter concept that ensures compliance with IEC 55032 standards - and at the same time increases the performance of the overall system.
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Download: ANS018
