METHOD AND MEANS FOR POWERING SPAN LINES

摘要

An essentially non-dissipative, strap-free, continuously adjustable power unit inherently impervious to shorts and open circuits for powering repeaters in a Tl or similar telephone span line is disclosed. The unit uses a pulse-width modulated inverter in the converter input circuit to produce a variable-voltage D.C. output to the span line. The pulse width or duty cycle of the inverter is controlled by a control logic which senses the span line current and maintains it at a selectable predetermined level without any appreciable power dissipation.