New-Tech Europe Magazine | July 2016 | Digital edition

Figure 1. Connected devices are expected to produce 500 zettabytes of data annually by 2020.

is a growing difference between the server’s minimum power at light load and its power at full-load. Fortunately power distribution architectures are becoming more flexible, with real-time adaptive capabilities that maintain optimal efficiency under all operating conditions. Adapting the Power Architecture A distributed power architecture typically comprises an Intermediate Bus Converter (IBC) that operates from a 48Vdc input supplied by a front-end AC/DC converter, as shown in figure 1. The IBC provides a 12V intermediate bus that supplies low- voltage DC-DC point-of-load (POL) converters positioned close to major power-consuming components on the board, such as processors, System on Chips or FPGAs. Multiple POLs may be used to supply core, I/O and any other voltage rails. The IBC’s

48Vdc input and 12V output voltages were historically chosen to minimize down-conversion losses and losses proportional to current and distance when supplying typical server boards. However, given the changes in core voltage, current draw, maximum power and the difference between full- load and no-load power, these fixed voltages are less suited to maintaining optimal efficiency in modern systems. The ability to set different voltages, and change these dynamically in real- time, is needed to allow a system to adapt continuously for best efficiency. Adaptive Control Requires a Common Protocol PMBus is an industry-standard protocol for communicating with digitally controllable power supplies from the front-end, through the advanced bus and to the point-of-load converters (figure 2). By monitoring the status of

Alleviating the Energy Consumption Concern While looking at potentially establishing higher maximum equipment operating temperatures to save on cooling costs, operators also recognize the importance of improving the overall energy efficiency of data center equipment; to reduce the direct energy consumed but also the heat generated and hence the cost of cooling. Maximizing efficiency at every point is vital, throughout the servers, their power supplies and through the system-management software. Despite this, peak power consumption continues to increase to meet the demands for increased computing capability and the consumption of a typical server board has increased from a few hundred watts to 2kW or 3kW today, and could reach 5kW or more in the future. As a result, there

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