Ericsson's 1/8 Brick Converter Offers High Performance And Cost Efficiency

With the increase in demand for high-speed communications and broadband everywhere, systems architects are facing an increase in demand for remotely located low and medium power systems requiring an average of 100W of power. Because these systems are deployed in high-volumes, they have to be cost effective without compromising quality and reliability, and that is what Power Modules has achieved with PKB-A, said Patrick Le Fèvre Marketing and Communication Director at Ericsson Power Modules.



Combining low power consumption, high efficiency, and cost effectiveness while guaranteeing high quality and reliability level are often perceived as a complex equation. That is the challenge that Ericsson designers had to address, and the PKB-A is the result of best practice deployed across various disciplines at Power Modules. In this respect, combining electrical and mechanical design, layout optimization and an easy-to-manufacture methodology are all part of Ericsson Power Modules' DfM (Design for Manufacturing) concept. Excellent thermal design makes it possible to utilize full power so that the 100W ceiling is easily passed with a cost efficient product.



Currently, the PKB-A series comprises two models within the PKB 4000A 48V input (38V to 72V) platform. These are the PKB 4111A (5V/25A) and the PKB 4910A (3.3V/30A). Both products are available for surface mount use as SI versions, and through-hole assembly use as PI versions. At its nominal voltage (48V) at 50% load, PKB 4111A (5V) has a typical efficiency of 93.1% and 92.3% at full load, whilst the PKB 4910A (3.3V) offers 92.7% at 50% load and 91.0% at full load.



To address the needs of ICT applications requiring higher functional isolation, the PKB-A is designed to sustain 2250Vdc input to output isolation. Its low profile of 8.5mm (0.335) allows designers to layout in a chassis using a narrow board-pitch below the traditional 0.8 inch, and thanks to low building practices, significantly improve airflow across the board.



Primarily designed to power 100W boards in 48V Information and Communication Technology applications, as a result of its optimized cost structure and efficiency, PKB-A is an ideal board-mounted power module to power micro-cells repeaters, local transmitters also many other on-board power applications such as servers, routers and wide range of systems where cost reduction is the aim. Specific examples include 100W boards powering systems such as 5V intermediate bus architecture, memories, DSP, FPGA, ASIC and other integrated circuits requiring 5V and/or 3.3V.



The PKB-A is pinout compatible with quarter-brick units making it simple to replace older, low efficient 100W quarter-bricks when upgrading boards. It is compliant with the RoHS directive 2002/95/EC.



Comprehensive protections embrace output over-voltage and short-circuit protection, input under-voltage protection, and over-temperature protection. Other features include monotonic startup, remote sense and control, and a choice of remote control logic - negative or positive.



In technology terms, the PKB-A is based on the deployment of a board-integrated transformer, and its layout has been optimized to minimize hot spots and to reduce layer-to-layer power losses. On the top side, the layout and positioning of components have been optimized to simplify cooling when converters are mounted onto a cold-wall via a thermal pad.