Better Core Geometry Is Why Planar Magnetics Win

Focus:

Sometimes it is said that planar magnetics perform better than wound magnetics. What does it mean "to perform better"? Essentially, it is to have lower losses at the same volume, core material, operating power and frequency. The losses in transformers are defined by the value of the magnetizing current. Therefore, to understand how transformer geometry influences losses, we must determine how the core geometry affects the magnetizing current. As the analysis in this article shows, a lower core height leads to lower losses. For inductors, it will be shown that the flatter core allows for storing more energy at the same current.

What you’ll learn:

• How to understand why planar transformers are more efficient
• How to understand why the lower profile core leads to lower losses in planar transformers
• How to understand why the lower profile core leads to greater energy storage in inductors

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Author & Publication:

Gregory Mirsky, Design Engineer, Deer Park, Ill., How2Power Today, Aug 15 2025

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