Dynamic bus voltage adjusts power to load requirements
An energy saving potential could control power at an appropriate level to suit board requirements. This dynamic bus voltage technology is said to result in a significant cutback in both energy consumption and power dissipation.
It's clear that our world is becoming increasingly dependent upon information and communications technology with demand growing for more online services, faster networking, and increased data processing and data storage capabilities. And there is still considerable room for expansion in businesses, national government and local authorities, and society in general, even in the largest developed economies. Fast growth in Internet services and cloud computing is driving the expansion and building of new computing-intensive environments, such as huge datacentres, across the world.
Certainly an argument can be made in terms of the overall energy usage for all this increasingly ubiquitous networked processing capability—it enables remote working and reduces the need for commuting or even traveling considerably longer distances, as just one example among many. But there are still concerns over the direct environmental impact of the fast growing, data-processing facilities and infrastructure that drives the cloud.
A key challenge for datacentre operators is the minimisation of energy expenditure at the board level, so we should therefore take a moment to look at the typical power system used today and ask if it can deliver greater efficiency.
The architecture increasingly being used by power system designers is the Intermediate Bus Architecture (IBA), which uses intermediate bus converters (IBCs) to convert the traditional 48VDC distribution-level power line used in telecoms or datacoms down to a static 12VDC, typically. This 12V first "down-conversion" level feeds a number of DC/DC point-of-load (POL) regulators, which supply the final load voltages at a chip's logic supply levels of 3V or below.
The choice of 12VDC has been made to ensure a high enough voltage to deliver all the power required by the board, or load, in times of high data traffic. However, this approach becomes highly inefficient when the traffic demand is low. So what would be highly useful in this instance is a way to vary the fixed 12VDC to a more appropriate level to suit network demand. All of which brings us to the Dynamic Bus Voltage architecture, or DBV.
The DBV architecture is an evolution of the Intermediate Bus Architecture and provides the possibility to dynamically adjust the power envelope to meet load conditions. It achieves this by adjusting the intermediate bus voltage—previously the 12-VDC fixed bus voltage—via the use of advanced digital power control and optimised hardware combined with an energy-optimiser series of algorithms. This can lead to reductions in both energy consumption and power dissipation, which in turn contributes to a reduction in the amount of cooling required.
Ericsson data says that DBV technology makes it possible to reduce board power consumption by somewhere between 3 per cent and 10 per cent, depending on the board application. This potential for energy saving is a substantial one, especially when taking into account that 1W saved at the board level can result in a 3W saving at the power grid level. This is a significant saving that we cannot afford to ignore.
- Patrick Le Fèvre
EE Times/Marketing and Communication Director
Ericsson Power Modules
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