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    TELEPHONE SUBSCIBER CIRCUIT AND TELEPHONE COUPLING CIRCUIT
    1.
    发明专利
    TELEPHONE SUBSCIBER CIRCUIT AND TELEPHONE COUPLING CIRCUIT 失效

    公开(公告)号：JPH07184237A

    公开(公告)日：1995-07-21

    申请号：JP26730394

    申请日：1994-10-31

    Applicant: ST MICROELECTRONICS SRL

    Inventor： TORAZZINA ALDO

    IPC: H04M1/00 ,  H04M1/654 ,  H04M1/738 ,  H04Q3/42

    Abstract: PURPOSE: To reduce the cost of a device and the area required for integration of a circuit and to improve the reliability of the device by reducing the number of parts. CONSTITUTION: A single photo coupler 3 is provided which has an input terminal connected to a terminal of a telephone line and is connected to a transmission circuit for call signal transmission connected between two terminals of the telephone line and is connected to the output terminal of a speech circuit 20 connected to a line terminal through a (diode) bridge circuit 2 and a switch 1. This photo coupler 3 has an output terminal for connection to a subscriber device to which power is not supplied from the telephone line. This subscriber circuit realizes coupling between the telephone line and the subscriber device while keeping galvanic isolation.

    TELEPHONE SUBSCRIBER CIRCUIT
    2.
    发明专利
    TELEPHONE SUBSCRIBER CIRCUIT 失效

    公开(公告)号：JPH07312629A

    公开(公告)日：1995-11-28

    申请号：JP26521094

    申请日：1994-10-28

    Applicant: ST MICROELECTRONICS SRL

    Inventor： TORAZZINA ALDO

    IPC: H04M1/00 ,  H04M1/654 ,  H04M1/738 ,  H04M11/00

    Abstract: PURPOSE: To provide a telephone subscriber circuit in which the hook-on/off of a subscriber's line is driven by using a single DC insulating element FD, and a signal is transferred from a subscriber's station equipment to which power is not supplied through the subscriber's line on the subscriber's line. CONSTITUTION: A telephone subscriber's circuit is provided with a speech circuit linked through a diode bridge circuit D with a subscriber's line. The input terminal of the speech circuit and electronic switches Q1 and Q2 connected between the speech circuit and the diode bridge circuit D are connected through voltage generating circuit means Q5 and R4 and level converting circuit means Q4 and R5 with the output terminal of a photocoupler being a DC insulating element.

    INTEGRATED CIRCUIT, INTERFACE CIRCUIT, WATT LOSS PROCESSING CIRCUIT AND WATT LOSS RESTRICTION METHOD
    3.
    发明专利
    INTEGRATED CIRCUIT, INTERFACE CIRCUIT, WATT LOSS PROCESSING CIRCUIT AND WATT LOSS RESTRICTION METHOD 失效

    公开(公告)号：JPH07135672A

    公开(公告)日：1995-05-23

    申请号：JP9351294

    申请日：1994-05-02

    Applicant: ST MICROELECTRONICS SRL

    Inventor： PASETTI MAURO ,  SAVIOTTI VANNI ,  TORAZZINA ALDO

    IPC: H04Q3/42 ,  H04M3/18 ,  H04M19/00

    Abstract: PURPOSE: To protect related external components by detecting and comparing a longitudinal current/lateral current so as to control an output current of a final amplifier stage thereby keeping a supply current of a telephone subscriber line to be a threshold level or over at all times. CONSTITUTION: A comparator circuit means 6 connects final amplifier stages 4, 5 to a reference circuit means 11 when a mean value of a common mode current is smaller than a prescribed threshold level via a connection changeover means 10, and connects the final amplifier stages 4, 5 to reference circuit means 12, 13 when the mean value of the common mode current is larger than the prescribed threshold level depending on the detection of a longitudinal current. Thus, the upstream current outputted from the amplifier stages 4, 5 is decreased. Moreover, when a lateral current of a prescribed threshold level is produced, the comparator circuit means 6 deenergizes an external watt loss component 3 via a control circuit means T. The reference circuit means 12, 13 specify maximum output currents that differ from each other by a value higher than the threshold level and come from the amplifier stages 4, 5. Thus, the longitudinal current higher than a prescribed threshold level is maintained at all times on a telephone subscriber line 2.

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