Summary 

Every power inductor and power transformer should be properly characterized in terms of its impedance for a full range of frequencies up to at least 10 MHz for typical switching frequencies. This is a tremendous help in resolving problems with your switching waveforms, EMI, snubber design, and magnetics performance. It is also invaluable in showing problems with manufacturing errors and poor workmanship.

Whether you are designing or using magnetics at 1 W or 1 MW, the importance of making these measurements cannot be overstated. Do not overlook or skip this crucial part of your design and manufacturing process. It will always save you time and money during your product development.

References

Additional Reading

  • AP300 Frequency Response Analyzer Manual, www.apinstruments.com.
  • “Measuring Frequency Response”, Ray Ridley, www.switchingpowermagazine.com/downloads/Measuring%20Frequency%20Response.pdf.
  • “Core Loss Modeling and Measurement”, Chris Oliver, Micrometals,  www.switchingpowermagazine.com/downloads/New%20Core%20Loss%20model.pdf
  • “Modeling Ferrite Core Losses”, Ray Ridley, www.switchingpowermagazine.com/downloads/7%20Modeling%20Ferrite%20Core%20Losses.pdf
  • “Proximity Loss in Magnetics Windings”, Ray Ridley, www.switchingpowermagazine.com/downloads/13%20Proximity%20Loss.pdf