Device for limiting the working voltage mechanical switches in telephony
AssigneeSGS-Thomson Microelectronics S.A.
InventorsAntonio Andreini, Pietro Consiglio, Pietro Erratico, Enrico M. A. Ravanelli
Life of this patent
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Abstract
Device for limiting the working voltage for mechanical switches in telephony includes terminals for connection to a telephone line, a connection and power supply branch for a control circuit extending from a first terminal, the branch having a first switch, the cathode terminal of a first Zener diode and the source terminal of a first MOSFET transistor being connected to the output terminal of the first switch, the gate terminal of the first MOSFET transistor being connected, through the anode terminal of the Zener diode, to the first terminal. The current absorbed by the device may be adjusted.
Claims25
A device for limiting a working voltage for mechanical switches in telephony, comprising:
- terminals for connection to a telephone line;
- a connection and power supply branch for a control circuit coupled to a first terminal and having a first switch including an output terminal, a first zener diode having a first cathode terminal coupled to the output terminal, a first MOSFET transistor having a source terminal coupled to the output terminal, a gate terminal coupled to an anode terminal of the first zener diode and the first terminal;
- and
- means for adjusting a current absorbed by the device.
A device for limiting a working voltage for mechanical switches in telephony, comprising:
- terminals for connection to a telephone line;
- a connection and power supply branch circuit coupled to a first terminal and having a first switch including an output terminal, a first zener diode having a first cathode terminal coupled to the output terminal, a first MOSFET transistor having a source terminal coupled to the output terminal, a gate terminal coupled to an anode terminal of the first zener diode and the first terminal;
- and
- a control circuit, coupled to the connection and power supply branch circuit, for controlling a current consumed by the device.
A device for limiting a working voltage for a mechanical telephone switchhook, the device comprising:
- first and second terminals for connection to a telephone line;
- a connection and power supply branch circuit coupled to the first terminal and including:
- a mechanical switch having an output terminal,
- a first zener diode having a first cathode terminal coupled to the output terminal,
- a first MOSFET transistor having a source terminal coupled to the output terminal, and a gate terminal coupled to an anode terminal of the first zener diode and to the first terminal;
- switching means for connecting the telephone line to a talk circuit;
- and
- a control circuit, coupled to the connection and power supply branch, for controlling the switching means.
Dependencies are inferred from the claim text.