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Feeding Circuit With Reduced Power Consumption

IP.com Disclosure Number: IPCOM000047072D
Original Publication Date: 1983-Sep-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 2 page(s) / 67K

Publishing Venue

IBM

Related People

Bonnet, Y: AUTHOR [+2]

Abstract

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.

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Feeding Circuit With Reduced Power Consumption

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. Two implementations are contemplated: a circuit providing a linear current adaptation versus line current, and a circuit providing two-step busy/idle current values. Linear adaptivity : For reducing power consumption, current sink S2 and resistor Rs have been added in comparator C1, and connected as indicated in Fig. 1. These connections permit one to take advantage of loop status information which is rendered available in comparator C1 by means of resistor Rs. The new circuitry thus obtained now sets the output current of C1 within two limits, i.e., 1.7 mA through sink S1 during the idle status up to 10 mA d...