8 48V-CENTRIC POWER MODULES www.vicorpower.com Issue 1 2025 Power Electronics Europe www.power-mag.com The Case for 48V Centric Power Modules Has Never Been Stronger Advancing semiconductor technology and global competitive forces have resulted in a stunning increase in the power density of numerous equipment types in the industrial, automotive, aerospace and high-performance computing markets over the last ten years. The vast energy required to power generative AI computing data centers is at the forefront of this megatrend. If power systems engineers do not consider new approaches to address these exponential increases, power supplies will become an ever-greater contributor to increased system size (specifically volume), weight and cost. Furthermore, all other things being equal, the rise in equipment power demands will see an equivalent rise in thermal management requirements, contributing to the expansion of power system form factors and recurring costs. Clearly, new approaches (including architectures, topologies and packaging methods) and innovative solutions are urgently needed. 48V-centric power modules with high conversion efficiency and power density have arrived to meet these intertwined and complex challenges. Evolution from 12V to 48V Power Delivery Networks The transition across numerous markets from 12V toward 48V power delivery networks (PDN’s) is accelerating. For example, the first 48V PDN electric vehicles are on the road today with many in development, and 48V distribution within data center racks among Hyperscalers is now commonplace. Power system design engineers should weigh the relative merits of 48V PDNs as a logical starting point for the power delivery architecture of their electrical power subsystem. The transition to 48V-centric power distribution is not without challenges. The 12V centric power component ecosystem offers maturity and know-how accumulated over about 75 years. There is a multiplicity of 12V optimized power component and power supply options available on the market, and power system designers are typically comfortable with this technology in all its facets. By comparison, the 48V-centric power components and subsystems are less established, with wide 48V adoption in data center server racks first appearing in 2021. Power system engineers are less familiar with power components and subsystems needed to support a 48V-centric PDN design, and have relatively less development experience with 48V distribution hub architectures. However, by sourcing 48V DC-DC converter power modules, with integrated magnetics can eliminate areas of technical and commercial risk and uncertainty, as the module manufacturer assumes all design, sourcing, testing, quality and reliability responsibilities, shielding the end system designer from this ecosystem immaturity (Figure 1). Additionally, many existing 12V subsystem loads are fully cost-optimized and are not financially or functionally sensible to replace in the short to medium term, so bridging between a 48V and 12V centric PDN can achieve the optimal system design. Importantly, both 12V and 48V are considered SELV (Safety Extra Low Voltage) levels, so moving to 48V power distribution hubs does not compromise human safety. Types of 48V-Centric Power Modules There are many types of power modules that offer a full DC-DC converter function, with high power density and some that incorporate integrated magnetics. High voltage (up to 920VDC) BCM’s (fixed-ratio DC-DC bus converter modules), are typically galvanically isolated (4,242V is typical and a conversion ratio of K = 1/8 yields 50VOUT from 400VIN for example and a K = 1/16 yields 50VOUT from 800VIN). NBM’s (low-voltage non-isolated fixedratio bus converters) are also available (K = 1/4 yields 12V from 48VIN) and enable the bridging function between the 48V and 12V centric PDN’s. Regulated DC-DC converters are also available. A good example of a regulated fixed-ratio converter is the DCM3735, a 2kW, 160A, 48V to 12V converter (Figure 2). Power system engineers can take advantage of these power modules by utilizing higher system bus distribution voltages requiring lower current to deliver Figure 1: The 12V ecosystem is well established and in many cases is fully cost-optimized. So bridging between a 48V and 12V-centric power delivery network using DC-DC converter modules is the optimal solution to ease the path to 48V power designs. By Maury Wood, VP Strategic Marketing & BU Operations, Vicor
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