Magnetics and Power Supplies – There’s a Lot of Questions to Address

VP Applications Engineering - North America Excelsys Technologies Ltd. Kevin Parmenter & PSD Contributor


Magnetics and Power Supplies

One of the key design issues of power supplies are the magnetics used in them.  The magnetics are core to the safety – compliance, efficiency, thermal performance, de-rating, size and weight – and are therefore linked to the overall viability of the power supply product.

It is my privilege to chair a rap session on this topic at APEC this year, on Tuesday March 6, 2018 at 5 PM at the Convention Center.  A panel of technical experts will debate the question, “which makes the most difference in power supply design – magnetics or semiconductor devices?” and take questions from the audience.

As the components industry becomes more commoditized, who is investing R&D dollars in magnetics and/or silicon semiconductors? In many circles, the magnetics are thought of as “how much am I willing to pay for your compressed dirt and sand?” That, of course, is the wrong way to think of it.  Other questions the industry is facing are along the lines of:

  • Who’s waiting for whom?
  • Are the wide band gap device makers waiting for the magnetics companies to create new materials or have they been ready all along? 
  • Are new materials needed for the cores?

Wire is not advancing very much, and design decisions such as whether to use Litz or flat wire and insulated foil have been around for a while.  Not much has changed in insulating materials when it comes to tape, varnish and such. That begs more questions: Where are the breakthroughs; where are they needed; and who is willing to invest in them?  

Magnetics and semiconductor companies and enterprises in the pharmaceutical industry have a similar problem. Large investments in R&D are needed, however margins are tight and once prototype parts are proven in a design, the production buyers send RFQs to everyone who ever made a magnetic device or component. More often than not, the company that invested sees their time and money go to waste when the production buy goes to a no-name company in a far-off land that simply copies the component design and construction, with absolutely zero investment in innovation. However, it’s also true that a power converter can only be as good as the sum of its parts.

Packaging is becoming more of an issue and differentiator. We may see more combined co-packaging of semiconductors and magnetics going forward.  There are many unanswered questions as to what makes the most difference between semiconductors, magnetics and/or packaging combinations.  Who will be the investors in the components and products needed and commit the time and technology, intellectual property to advance power conversion technologies forward in the future ? The answer may depend on which industry has the most influence. Is it high-voltage, lower voltage, higher current, off-line low power, off- line high power, DC-DC , VRM supplies, or inverter designs?  Its certainly not the same for each and every power converter design and topology.

As you can tell, there’s much to debate. To get involved, come to the RAP session at APEC 2018 I look forward to the discussion!