EETimes India - September 16-30, 2008 - (Page 6) News Innovations clean up design from start to finish By Patrick Le Fevre Marketing Director Ericsson Power Modules Design for Environment (DfE) is not a concept—it is a philosophy. We believe in long-term engagement to preserve nature and the environment. During the late seventies, when Ericsson considered the next generation of mobile networks’ equipment, the optimisation of power efficiency was already its priority. DfE is often associated with products, though it is important to remember that behind products there is a human element. Prior to any DfE initiative, there is a need to build a common understanding of what it means, and to educate people regarding the complete chain from individual behaviour such as conserving electricity and recycling paper. Figure 1: Efficiency timeline. Power module level In 1983, the time when most of the power supplies were linear, Ericsson launched a switching DC/DC converter (PKA) that raised the power efficiency available from conventional products having 63 per cent to 80 per cent. Ericsson’s DC /DC power module using Schottky diodes, power MOSFET and a switching frequency of 300KHz improved power efficiency from 63 per cent to almost 80 per cent. In the late nineties, the introduction of syn- chronous rectification and lower loss topologies made 90 per cent efficiency possible. However, despite permanent improvements, the conventional approach using analogue control reached the limits of what was possible for such technology. By mid-2000, Ericsson began research into new technologies such as digital power control and digital power management. The latest result of this research is onboard DC/DC converter BMR453, which besides having the possibility for systems’ managers to control the module through a PMBus, has a flat 96 per cent effi- ciency from low-load to high-load conditions. Ericsson has developed a DC/ DC converter that will contribute to the significant reduction of CO2 released by systems such as radio base stations, routers, to a certain extent data-centres, and other information communication technology equipment during their operation. Way of working The PKA—a DC/DC converter designed and manufactured 20 years ago—introduced a number of innovations: a new building practice based on a ceramic substrate, a light design with no flying components, no unnecessary chemicals and compounds used in manufacturing, and its shipping packaging based on folded cardboard. Behind those innovations, there were a number of environmental concerns and education paths regarding how to harmonise products with the environment. The removal of moulding compound not only reduced moisture penetration—which was a serious cause of failure in those days—but the avoidance of such chemical substances limited continued on page Figure 2: Life cycle assessment of Ericsson radio base stations. 6 EE Times-India | September 16-30, 2008 | www.eetindia.com http://www.eetindia.co.in/SEARCH/SUMMARY/industry-news/design for environment.HTM?ClickFromNewsletter_080916 http://www.eetindia.co.in/SEARCH/SUMMARY/technical-articles/radio base station.HTM?ClickFromNewsletter_080916 http://www.eetindia.co.in/SEARCH/SUMMARY/technical-articles/MOSFET.HTM?ClickFromNewsletter_080916 http://www.eetindia.com
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