A novel topology to achieve 4:1 voltage step down, aimed at 48 V to 12 V conversion in data center applications, is presented. The so-called dc-transformer topologies have become a very active area of research to improve the overall efficiency of data centers in response to a shift from a 12 Vdc bus architecture to a 48 Vdc bus architecture. In particular, switched-capacitor topologies have been investigated due to their high power density, efficiency, and low reliance on magnetics. However, switched-capacitor topologies have challenges associated with the hard-charging of capacitors and are often forced to make design compromises that reduce their overall performance. The proposed topology maintains many of the advantages of a switched capacitor topology, such as reduced component stresses, and very low reliance on magnetics, while also inherently avoiding any hard-charging of the flying capacitors. This allows the converter to operate at a very low frequency, such as 60 kHz, with a small inductor, such as 100 nH, and use low voltage stress devices to achieve a peak efficiency of more than 99% for 48 V to 12 V conversion and a power density of 800 W/in ³ .

中文翻译：

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零电感电压多电平总线转换器

提出了一种实现 4:1 降压的新型拓扑，旨在将数据中心应用中的 48 V 转换为 12 V。为了响应从 12 Vdc 总线架构向 48 Vdc 总线架构的转变，所谓的直流变压器拓扑已成为一个非常活跃的研究领域，以提高数据中心的整体效率。特别是，开关电容器拓扑由于其高功率密度、效率和对磁性的低依赖而受到研究。然而，开关电容器拓扑面临与电容器硬充电相关的挑战，并且经常被迫做出降低其整体性能的设计妥协。所提出的拓扑保留了开关电容器拓扑的许多优点，例如降低了组件应力，以及对磁性的依赖非常低，同时还本质上避免了快速电容器的任何硬充电。这允许转换器在非常低的频率（例如 60 kHz）下运行，并使用小电感器（例如 100 nH），并使用低压应力器件实现 48 V 至 12 V 转换的 99% 以上的峰值效率功率密度为 800 W/in ³ .