Practical EMI considerations for low-power AC/DC supplies

Learn how to find and fix several EMI issues commonly found in isolated low-power AC/DC supplies.

Electromagnetic interference (EMI) is an essential part of every power-supply design, but too often gets relegated to the end of the design flow, at which point its resolution can be time-consuming, costly and inefficient. This seven-part video series will help dispel fears about EMI, and show how to find and fix the issues.

Most EMI issues are caused by component parasitics that are not even represented in design schematics, such as transformer input/output capacitance, stray capacitance and inductances on the board assembly. EMI filter components have a parasitic capacitance and inductance that limit their useful frequency range, and can even make EMI worse.

To highlight the debugging techniques, this series of videos shows practical examples throughout, using a high-density 65-W USB power delivery active clamp flyback adapter. These examples will illustrate how a few basic changes result in an almost 50 dB improvement at the fundamental switching frequency without a major sacrifice in efficiency, size or cost.

Why should I take this training?

  • These techniques can be immediately applied to customers’ existing projects
  • Testing and mitigation techniques are presented which are not well known in industry
  • Topic begins with basic EMI concepts which will be useful to new engineers
  • Nearly every product requires EMI compliance

What will I learn?

  • Introduction to EMI testing and what causes EMI
  • Differential-mode vs common-mode EMI
  • EMI mitigation tips and tricks
  • Troubleshooting & debug of a real example

Additional information

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