Telephonic communications – Subscriber line or transmission line interface – Network interface device
Patent
1992-12-16
1994-08-09
Dwyer, James L.
Telephonic communications
Subscriber line or transmission line interface
Network interface device
379324, 379399, 379387, H04M 1900, H04M 100
Patent
active
053373553
ABSTRACT:
A circuit is described which comprises an operational amplifier, two resistors connected between the telephone line and the inputs of the amplifier, a capacitor which is charged via a first bipolar transistor controlled by the amplifier via a first FET transistor, a second bipolar transistor in parallel to the connection of the first transistor and the capacitor, a second FET transistor, identical to the first and having its source and gate terminals connected to the corresponding terminals of the first, and two current generators connected to the drain terminals respectively of the first and the second FET transistor and to the bases, respectively, of the first and second bipolar transistor. The currents of the two generators and the other parameters of the circuit are such as to hold the first and second bipolar transistors in a conductive and a switched off state respectively, except when the line voltage fails below a minimum predetermined value; in which case the first and second transistors commute to the switched off and conductive states respectively. The circuit has a lower "voltage loss" than known circuits.
REFERENCES:
patent: 4628249 (1986-12-01), Ikefuji et al.
patent: 4639551 (1987-01-01), Kaire
patent: 4811391 (1989-03-01), Van Dongen et al.
Castello Rinaldo
Tomasini Luciano
Dwyer James L.
Fournier Paul A.
SGS--Thomson Microelectronics S.r.l.
LandOfFree
Supply circuit device for a user's telephone circuit, having a l does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Supply circuit device for a user's telephone circuit, having a l, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Supply circuit device for a user's telephone circuit, having a l will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-222188