Design of power distribution to preserve and optimize specified performance

With the rapid expansion of services and network convergence, a significant part of the modern wireless and wireline networks are powered by low power (up to 500 W) or medium (15 to 250 A output current) power systems as defined by Telcordia (former Bellcore) in TR-TSY-967 and GR-947-CORE respectively. There are several parameters such as dynamic response, static regulation, ripple voltage, and noise characteristics normally defined to specify performance of these products. However, the actual system configuration or the power distribution to the powered equipment, including the input of the equipment, is rarely considered when specifying and reviewing the above characteristics. In this paper the impact of a system's configuration on it's performance as indicated by those parameters is analyzed. The potential impact of the power system's parameters on the overall system operation is included. The analysis is based on measurements taken for several configurations and typical 48 V power systems and includes the test setup. Influence of system configuration, including connection point and size of the backup batteries, length and routing of power wiring, value of filter capacitors installed at the backplane of the equipment powered and the distribution circuitry are analyzed. The impact of the power distribution configuration on EMI performance is discussed as well. Some recommendations about the optimization of system configuration and layout are proposed in order to preserve specified performance. Design practices gathered from discussions with a number of users are included.