AN702

www.DataSheet4U.com AN702 Vishay Siliconix Efficient ISDN Power Converters Using the Si9100 INTRODUCTION One of the latest technology revolutions, an integrated worldwide telecommunications network, will be accompanied by another advance in power conversion technology. The integrated services digital network (ISDN) will allow different forms of information (voice, computer data, video, facsimile, etc.) to be transmitted over the telephone network. The International Consultative Committee for Telephone and Telegraph (CCITT) has proposed standards for the interfaces required to implement ISDN. Although the standards have yet to be formally adopted, telecommunications companies are moving ahead with pilot test programs, and semiconductor makers are developing chip sets to build ISDN hardware. Every network terminator (NT), signal regenerator (RG), and terminal equipment (TE) unit used for the implementation of ISDN will require a power converter.[1] operation, as well as during equipment connections and disconnections. The Si9100 power IC facilitates compliance with these design requirements with a minimum number of external parts. To illustrate this capability, a discontinuous conduction mode (DCM) flyback converter was built and tested. Measured efficiency was greater than 80% for a wide range of loads, and 60% efficiency was achieved with only a 15-mW load. Before describing the circuit concepts in detail, it is instructive to note the main features of the ISDN power-feedin...