T03.9 - ISOP LLC Converter with Integrated Magnetics for Server Power Supplies

In recent years, Artificial Intelligence (AI) has been increasing its demand for power to such an extent that it is driving major architectural changes in the server racks. One of these changes proposes replacing the 54V distribution with a higher voltage bus (800 VDC or ±400 VDC) within the load rack, presenting new challenges and opportunities for innovation in the power supplies used. This paper presents a technique to increase the power density of fixed ratio, input-series output-parallel (ISOP) converters by integrating the transformer of two LLC converters into a single magnetic core of nearly the same size. The technique is suitable for ISOP converters with more than 2 modules. An improved version of a previous design [1] is presented using this technique to nearly double power density while offering similar electrical performance.