Power feed system for telephone and/or information technology terminals

Claim 2

A power feed system for a terminal which is at least partly fed by a telephone transmission and power supply link, said system comprising: a power converter type switch mode power supply unit connected to said link; a regulator connected to an input of said power supply unit and including a current limiter through which said terminal is at least partly fed by said link; means for progressively starting up said power supply unit when said terminal is powered up via said link, by temporarily delaying the supply of power to the terminal by the switch mode power supply unit.

Claim 3

Power feed system according to claim 1, characterized in that the temporary delaying of the supply of power is provided by a means for temporarily delaying the supply of power comprising said current limiter and a time-delay circuit comprising a capacitor and a resistor in series between the grid and the source of said MOS transistor, and a second capacitor connected between the source of the MOS transistor and a ground wire via a further transistor, said time-delay circuit turning off a switch mode transistor of the switch mode power supply unit during charging of the second capacitor when the terminal is powered up via the link.

Claim 4

A power feed system for a terminal which is at least partly fed by a telephone transmission and power supply link, said system comprising: a power converter type switch mode power supply unit connected to said link; a regulator connected to an input of said power supply unit, said regulator comprising an MOS transistor having a grid and having a source connected to a positive power feed wire of the terminal, said MOS transistor monitoring the continuity of said positive power feed wire according to the signal applied to its grid, a resistor divider bridge for biasing said grid of said MOS transistor, said bridge comprising plural resistors connected between the positive power feed wire and a ground wire and having an intermediate point to which said grid is connected, and a current limiter through which said terminal is at least partly fed by said link, said current limiter comprising a PNP transistor having a base, a collector connected to said grid, and an emitter connected via a low-value resistor to said base and to said source of said MOS transistor; and means for progressively starting up said power supply unit when said terminal is powered up via said link.

Claim 5

A power feed system for a terminal which is at least partly fed by a telephone transmission and power supply link, said system comprising: a power converter type switch mode power supply unit connected to said link; a regulator connected to an input of said power supply unit, said regulator comprising an MOS transistor having a grid and having a source connected to a positive power feed wire of the terminal, said MOS transistor monitoring the continuity of said positive power feed wire according to the signal applied to its grid, a resistor divider bridge for biasing said grid of said MOS transistor, said bridge comprising plural resistors connected between the positive power feed wire and a ground wire and having an intermediate point to which said grid is connected, and a current limiter through which said terminal is at least partly fed by said link, said current limiter comprising a PNP transistor having a base, a collector connected to said grid, and an emitter connected via a low-value resistor to said base and to said source of said MOS transistor; and means for progressively starting up said power supply unit when said terminal is powered up via said link.

Claim 6

A power feed system according to claim 3, wherein said base of said PNP transistor is connected to said positive power feed wire upstream of said MOS transistor.