A New Design Paradigm for GaN Based LLC Converter

in today's power electronics products, quality and reliability are given. Great emphases are placed on efficiency, power density and cost. With recent advances made in gallium nitride power devices (GaNs), it is expected that GaNs will make significant impacts to all three areas mentioned above. Thanks to the significantly reduced output capacitance of GaN devices, it enables GaN to operate at a switching frequency more than ten times higher than its silicon counterparts. To illustrate the impact of GaN on efficiency, density and even design practices, three decades of development of LLC resonant converter for computer server are highlighted. By virtue of higher switching frequency beyond 1MHz, the bulky magnetic components for LLC converters are replaced with distributed magnetics and then integrated in a form of matrix transformer with simple PCB winding. The new generation of DC/DC converters are characterized with an order of magnitude higher power density, and with higher efficiency and additionally with dramatic reduction of labor contents in the manufacturing process. Even though this paper only demonstrated the impact of GaN for computer server application, similar can be said for wide range of application for for IT, communication equipment, consumer electronics, lightings and other electronics equipment.