DC/DC modules for low voltage applications. The new generation of board mounted modules in thick-copper multi-layer technology

On-board modules have decisively changed the face of distributed power supply. Even for extremely cost sensitive components of switching systems such as line cards, board mounted modules offer ever more attractive solutions. The Siemens high-tech power hybrids presented at Intelec 94 achieved full acceptance within EWSD for the first time. On the other hand, the ongoing reduction of operating voltage for high-speed processing requires a new, future-oriented approach to power supply, especially with respect to the unsatisfactory efficiency of Schottky rectified modules. This paper presents the new module family created to satisfy the existing and future requirements for board mounted power supply for telecom. The 1.8 V and 3.3 V modules have been realized on the basis of self-controlled synchronous rectification in a novel cascaded buck and push-pull converter. The technological highlights such as: thick-copper multi-layer technique; fully integrated magnetics; COB (chip-on-board) power semiconductors; open board design with DIL SMD pins are discussed, as well as the practical results of the realized modules. Finally an outlook into a future characterized by profound and rapid change is given.