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    Chipmakers warming up to 48V datacenter movement

    By Majeed Ahmad | January 19, 2017

    The single-stage conversion from 48V voltage bus to the point-of-load (PoL) in cloud server racks offers significant reductions in distribution and conversion power losses. (Image source: Maxim Integrated)

    With the emergence of 48V datacenter architecture on the server rails, is there a greener cloud on the horizon in 2017? A lot depends on the availability of chips that can efficiently facilitate the 48V single conversion to the point-of-load (PoL) while providing the projected 16x reduction in distribution loss and 30 percent lower conversion loss.

    The efficiency of two-stage power conversion in today’s 12V datacenters is already peaking at 90 percent. So Google proposed a new 48V server and distribution infrastructure at the Open Compute Project (OCP) Summit held in March 2016. Three chipmakers coincided their product and technology announcements with Google’s green cloud initiative.

    Vicor introduced a factorized power architecture in which two components deliver 48V to the CPU. A pre-regulator module (PRM) takes input from 48V distribution bus and delivers a controlled input to the voltage transformation modules (VTMs), which generate a voltage that is 1/24th of the input.

    Next, ST unveiled a power controller that implements direct digital power conversion and thus eliminates intermediate conversion stages to minimize losses during the power distribution. It can manage up to six converters while implementing power efficiency features such as current sharing, proportional energy control, and adaptive interleaving.

    Then, there is Maxim Integrated with its DC/DC voltage regulators, claiming to facilitate single-stage conversion from 48V to PoL. However, it’s a little less than a year since Google came up with the idea of a 48V rack standard, and we haven’t heard much from chip vendors since then.

    Apparently, the 12V rails are well entrenched, so the shift toward 48V distribution bus is most likely going to be gradual. Meanwhile, chipmakers need to figure out key design issues, for instance, how close can voltage regulates be placed to CPUs.

    Moreover, how can semiconductor firms integrate more functions near the points of the power load. The chip announcements during 2017 will determine the amount of traction 48V cloud servers are going to get while they coexist with the 12V multi-phase designs.