EMI, SI, and PI- Overcoming Common Challenges in the Design of Power Electronics
Laird
This white paper from Laird addresses the key challenges facing modern power electronics design — specifically EMI suppression, signal integrity (SI), and power integrity (PI). As industries like automotive, green energy, and telecom demand higher power densities in increasingly compact form factors, traditional noise reduction techniques using basic inductor coils and filtering are often insufficient. Designers face trade-offs between achieving low noise, managing thermal performance, and maintaining small product profiles. The paper highlights how common-mode noise produces radiated EMI that is significantly more intense than differential-mode noise, requiring dedicated suppression strategies. Modern power systems have evolved to use more complex switching topologies, higher operating frequencies, and advanced semiconductor platforms like GaN and GaN-SiC, but these advances can compound existing EMI challenges. High power designs also introduce thermal management concerns, as heat accumulation and flux saturation in ferrite cores can lead to nonlinear behavior and reduced component lifetimes. To address these interrelated challenges, the paper recommends a comprehensive, multi-component approach using high-inductance ferrite solutions — including cable cores, high-mu ferrite beads, inductor and balun cores, and power ferrite chokes — deployed across different stages of a design. When ferrites alone are insufficient, additional shielding and thermal materials can be applied at the board and enclosure level to ensure compliance with FCC and CISPR conducted EMI limits.