Data center power demands are growing fast. To address this situation, next-generation data centers are moving to 48 V bus architectures to reduce distribution loss on the bus bar of server racks.
One important research topic regarding this architecture is stepping down from 48 V to the point-of-load voltage, which is usually implemented by an intermediate bus converter followed by a voltage regulator, with the benefits of high efficiency and reutilization of 12 V legacy systems.
Many topologies have been explored for the 48-to-12 V intermediate bus applications, such as inductor-based converters. However, since capacitors have higher energy densities compared with inductors, switched-capacitor based converters have the potential to achieve higher power density and have gained increasing attention in performance-driven applications. Integrating resonant conductors into cascaded switch-capacitor converters further improves performance.
To address this potential, researchers at UC Berkeley developed a novel resonant switched-capacitor based converter. The Berkeley converter uses a simple structure and operation principle, and has the potential to achieve dramatic efficiency and power density improvement over existing leading alternatives.
In addition to data center applications, the invented converter can also be expanded for higher conversion ratio, or operated in the reverse direction for voltage step-up.
Other possible applications that can potentially benefit from this invention include portable electronics, electric vehicles and solar photovoltaics.
A prototype of a 48-to-12 V bus converter based on the Berkeley design achieved 99.0% peak efficiency, 98.0% full-load efficiency, and 4068 W/in3 power density, all of which are the highest in existing reported works.