D2 Channel Bank: Power Conversion
01 October 1972
The D2 Channel Bank depends on a variety of power supply voltages for its operation. The Power Systems Converter Circuit (PSCC), driven by the minus-48-volt central office battery source provides the seven regulated dc voltages required by the D2 Channel Bank. By using a high-powered switching-type regulator for primary regulation followed by a dc-to-dc converter for voltage transformation, high efficiency and compactness arc achieved. Series-type regulators with high-gain feedback circuits are used to stabilize the voltages for three of the outputs where very stringent voltage requirements exist. Overvoltage turn down, interlocking of critical voltages, voltage tracking and overcurrent protection are also provided. The switching regulator and dc-to-dc converter are designed to operate at commutating frequencies above 20 kHz to eliminate acoustical noise. The power supply is packaged to facilitate manufacturing, testing, and maintenance. The unit is arranged to be mounted in the same type rack as the rest of the D2 Channel Bank. 1.1 Requirements The power supply requirements are shown in Table I. It is seen that 1713