Feeding Circuit With Reduced Power Consumption
Original Publication Date: 1983-Sep-01
Included in the Prior Art Database: 2005-Feb-07
A resistive feeder for extension circuits in a line switching system is most suitable. However, its power consumption must be kept at a minimum. Indeed, as the busy/idle status ratio of the extension circuit is typically in the .1 to .2 range, power consumption during idle status is 5 to 10 times greater than busy status consumption. Known is a feeder schematically represented in Fig. 1. A DC voltage Vo is provided through a switch Ts and a f filter to point A, powering the DC/DC converter and the subscriber telephone line. Comparator C1 receives a voltage V1 from a line circuit and a sawtooth wave signal Vs. Comparator C1 controls the operation of transistor switch Ts by controlling its base current by means of current sink S1. The typical value of current from sink S1 is 10 mA during both busy and idle status.