Loop current monitor circuitry and method for a communication system
First Claim
1. A communication system, comprising:
- phone line side circuitry capable of being coupled to phone lines through an isolation barrier;
a DC holding circuit within said phone line side circuitry; and
monitor circuitry having as an output a loop current monitor signal that is indicative of a DC loop current passing through said DC holding circuit, the phone line side circuitry configured to transmit information to the isolation barrier that is indicative of said DC loop current.
1 Assignment
0 Petitions
Accused Products
Abstract
Monitor circuitry is disclosed that produces a loop current monitor signal indicative of the DC loop current passing through DC holding circuitry, which may be part of phone line side circuitry that may be connected to phone lines. This loop current monitor signal may be digitized and then communicated across an isolation barrier to powered side circuitry as digital information representative of the DC loop current levels in the phone lines. Example embodiments for the monitor circuitry are also disclosed, such as a MOS transistor, for which the monitor signal is the drain current of the MOS transistor, and an external resistor, for which the monitor signal is a voltage associated with the external resistor.
-
Citations
33 Claims
-
1. A communication system, comprising:
-
phone line side circuitry capable of being coupled to phone lines through an isolation barrier;
a DC holding circuit within said phone line side circuitry; and
monitor circuitry having as an output a loop current monitor signal that is indicative of a DC loop current passing through said DC holding circuit, the phone line side circuitry configured to transmit information to the isolation barrier that is indicative of said DC loop current. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
-
-
12. A method for monitoring DC loop current in a communication system capable of being connected to phone lines, comprising:
-
coupling an isolation barrier between powered side circuitry and phone line side circuitry that may be connected to phone lines;
providing a DC holding circuit within said phone line side circuitry that may be connected to receive current from said phone lines; and
monitoring a DC loop current within said DC holding circuit to produce a loop current monitor signal indicative of said DC loop current, the phone line side circuitry configured to transmit information to the isolation barrier that is indicative of said DC loop current. - View Dependent Claims (13, 14, 15, 16)
-
- 17. A loop current monitor circuit for DC holding circuitry within a communication system capable of being connected to phone lines comprising monitor circuitry connected to said DC holding circuit to provide a loop current monitor signal indicative of a DC loop current passing through said DC holding circuit, the communication system configured to transmit information to an isolation barrier that is indicative of the DC loop current.
-
23. A method for monitoring DC loop current within DC holding circuit of a communication system capable of being connected to phone lines, comprising:
-
monitoring a DC loop current with a DC holding circuit; and
generating a loop current monitor signal indicative of said DC loop current, the communication system configured to transmit information to an isolation barrier that is indicative of the DC loop current. - View Dependent Claims (24, 25, 26)
-
-
27. A communication system, comprising:
-
phone line side circuitry capable of being coupled to phone lines;
a DC holding circuit within said phone line side circuitry; and
monitor circuitry having as an output a loop current monitor signal that is indicative of a DC loop current passing through said DC holding circuit, wherein said monitor circuitry comprises a MOS transistor and a drain current of said MOS transistor is said loop current monitor signal, wherein said DC holding circuit comprises a first MOS transistor connected such that a DC loop current passes through said first MOS transistor, wherein said monitor circuitry comprises a second MOS transistor having its gate coupled to a gate of said first MOS transistor and having its source coupled to a source of said first MOS transistor. - View Dependent Claims (28)
-
-
29. A method for monitoring DC loop current in a communication system capable of being connected to phone lines, comprising:
-
coupling an isolation barrier between powered side circuitry and phone line side circuitry that may be connected to phone lines;
providing a DC holding circuit within said phone line side circuitry that may be connected to receive current from said phone lines; and
monitoring a DC loop current within said DC holding circuit to produce a loop current monitor signal indicative of said DC loop current, wherein said providing step includes positioning a first MOS transistor within said DC holding circuit, wherein said monitoring step circuit includes coupling a second MOS transistor in parallel with said first MOS transistor, and wherein a drain of said second MOS transistor provides said loop current monitor signal.
-
- 30. A loop current monitor circuit for DC holding circuitry within a communication system capable of being connected to phone lines comprising monitor circuitry connected to said DC holding circuit to provide a loop current monitor signal indicative of a DC loop current passing through said DC holding circuit, wherein said DC holding circuit comprises a first MOS transistor, wherein said monitor circuitry comprises a second MOS transistor coupled in parallel with said first MOS transistor, and wherein a drain of said second MOS transistor provides a current signal that is said loop current monitor signal.
-
32. A method for monitoring DC loop current within DC holding circuit of a communication system capable of being connected to phone lines, comprising:
-
monitoring a DC loop current with a DC holding circuit; and
generating a loop current monitor signal indicative of said DC loop current, wherein said DC holding circuit comprises a first MOS transistor, wherein said monitoring step comprises positioning a second MOS transistor in parallel with said first MOS transistor, and wherein said generating step comprises utilizing a drain current of said second MOS transistor as said loop current monitor signal. - View Dependent Claims (33)
-
Specification