New Topologies Placing Increased Importance on Magnetics

Kevin Parmenter, Director, Applications Engineering, Taiwan Semiconductor, NA



You can now buy commercial power converters using wide bandgap semiconductors, specifically gallium nitride devices, as the basis of their design off the shelf. Although WBG-based designs are not 10 times smaller, 99.99% efficient or switch at five MHz all at once, as marketers predicted when they were first launched, applications using both GaN and Silicon Carbide (SiC) devices do lead to better performance. We always wanted power conversion designs to use 650-volt-or-greater -- rather than 450-volt – parts for 400-volt applications, and the extra margin these devices offer improves reliability.

Of course, power conversion and magnetics are linked. Another unintended benefit of using GaN parts is that it forces engineers to create better PCB and magnetics designs. The resulting power supplies have higher power density, are more compact and the magnetics have changed to accommodate the WBG devices. These power converters are becoming mainstream. (I confirmed their availability from stock at Digikey and Mouser, which is what every engineer does. We check to see if the products are in stock = “real.” If not, we forget about them.)

In commercial designs, digital control is often being used as the best way to make WBG devices work. Since WBG parts run at higher voltages, I am seeing power electronics engineers taking advantage of the higher voltages in their designs – especially for motor drives, electric vehicle power trains and charging, grid-tied systems, LED lighting (277-480 V+ AC mains) and more.  In all these applications, the associated parts around the WBG devices also need to be higher voltage. Think discrete devices, capacitors, power rectifiers to small-signal transistors, and so on. In many applications 1 KV is not enough, so 2-3 KV parts are needed on the primary side.  The 1N4007 is not enough anymore!   

For all these reasons, the magnetics and power conversion markets are growing. The overall commercial power supply market is expected to grow from USD 28.00 billion in 2020 to USD 34.92 billion by 2023, at a CAGR of 6.7%.  And the global magnetics market is expected to grow from USD 10.76 billion in 2019 at a compound annual growth rate (CAGR) of 5.9%.

For the power supply market, the make vs. buy scale is ever moving towards “buy,” or it seems.  The power converters on the market now exceed all known regulatory and compliance requirements for safety 62368-60601, EN61000-X-X, UL508A, etc. +, as well as for global EMC - FCC class B, EN55022-B plus others and all materials compliance requirements. The power density and dollars (or euros, etc.) per watt are astounding and warranties are going from five years to seven and even 10 years. This also extends to LED lighting since these applications are just power supplies with a different load. 

On recent projects I have been involved in, I simply chose an off-the-shelf supply because it offered better value, was less time to market and came without regulatory headaches; in other words, everything was done for me at a price I cannot touchby doing it myself. It is truly exceptional to see the performance and value of the components, and even complete power converters, that you can get for the money spent.