Loop current monitor circuitry and method for a communication system

• US 6,959,083 B2
• Filed: 06/30/2003
• Issued: 10/25/2005
• Est. Priority Date: 04/22/1997
• Status: Expired due to Fees

• Current Assignee: Silicon Laboratories Incorporated
• Original Assignee: Silicon Laboratories Incorporated
• Inventors: Scott, Jeffrey W., Krone, Andrew W., Welland, David R., Sooch, Navdeep S.
• Primary Examiner(s): Tran, Sinh
• Assistant Examiner(s): Swerdlow, Daniel
• Application Number:
  US10/610,136
• Publication Number:
  US 20040091100A1
• Time in Patent Office: 848 Days
• Field of Search: 379/412, 379/93.05, 379/393, 379/413
• US Class Current: 379/412
• CPC Class Codes: H04L 25/0266 Arrangements for providing Galvanic isolation, e.g. by means of magnetic or capacitive coupling
• CPC Class Codes: H04L 25/06 Dc level restoring means; Bias distortion correction ; Decision circuits providing symbol by symbol detection
• CPC Class Codes: H04L 7/033 using the transitions of the received signal to control the phase of the synchronising-signal-generating means, e.g. using a phase-locked loop
• CPC Class Codes: H04M 1/573 Line monitoring circuits for detecting caller identification
• CPC Class Codes: H04M 11/06 Simultaneous speech and data transmission, e.g. telegraphic transmission over the same conductors
• CPC Class Codes: H04M 19/001 Current supply source at the exchanger providing current to substations
• CPC Class Codes: H04M 19/02 providing ringing current or supervisory tones, e.g. dialling tone or busy tone
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

An audio signal processor which modifies audio signal components outside the conventional audio frequency band. The processor includes a Delta Sigma Modulator (DSM) that receives a non-interpolated digital audio signal sampled at a frequency of at least 198 kHz.

Claims

1. A communication system, comprising:

phone line side circuitry capable of being coupled to phone lines and 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 digital information to the isolation barrier that is indicative of said DC loop current, the digital information including multi-bit information providing more than two values of the DC loop current.

2. The communication system of claim 1, further comprising powered side circuitry capable of being coupled to said phone line side circuitry through the isolation barrier.

3. The communication system of claim 2, further comprising said isolation barrier coupled between said phone line side circuitry and said powered side circuitry.

4. The communication system of claim 3, wherein said isolation barrier comprises one or more capacitors.

5. The communication system of claim 4, wherein digital information is communicated across said isolation barrier.

6. The communication system of claim 1, wherein the loop current monitor signal is a voltage signal, the system further comprising an analog-to-digital converter coupled to receive the voltage signal and to produce a digitized value indicative of a DC loop current through said DC holding circuit that may be communicated across said isolation barrier.

7. A communication system, comprising:

phone line side circuitry capable of being coupled to phone lines and an isolation barrier that comprises a plurality of isolation elements, the phone line side circuitry being configured to provide an output signal for sending data to the phone lines;

powered side circuitry for coupling to the phone line side circuitry through said isolation barrier, the powered side circuitry being configured to be isolated from the phone lines in order to satisfy phone line isolation regulatory standards;

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;

wherein the powered side circuitry is configured to communicate a first digital differential signal to at least two of the isolation barrier elements, the at least two isolation barrier elements comprising at least a first isolation capacitor and a second isolation capacitor and wherein the phone line side circuitry is configured to interpret the first digital differential signal digitally;

wherein the phone line side circuitry is configured to communicate a second digital differential signal to the first isolation capacitor and the second isolation capacitor, wherein the first and second digital differential signals are communicated across the same first and second isolation capacitors so that the first and second isolation capacitors bidirectionally transfer the first and second digital differential signals and wherein the powered side circuitry is configured to interpret the second digital differential signal digitally;

wherein the powered side circuitry is further configured to provide a clock signal to the phone line side circuitry through at least one of the plurality of isolation elements; and

wherein the powered side circuitry and the phone line side circuitry are further configured so that at least one power supply is generated within the phone line side circuitry from power provided from the powered side circuitry while still maintaining the isolation required by the phone line isolation regulatory standards.

8. The communication system of claim 7, further comprising said isolation barrier coupled between said phone line side circuitry and said powered side circuitry.

9. The communication system of claim 7, wherein each of said plurality of isolation elements of said isolation barrier comprises a capacitor.

10. The communication system of claim 7, wherein a portion of said plurality of isolation elements of said isolation barrier each comprises a capacitor.

11. The communication system of claim 7, wherein digital information is communicated across said isolation barrier.

12. The communication system of claim 7, wherein the loop current monitor signal is a voltage signal, the system further comprising an analog-to-digital converter coupled to receive the voltage signal and to produce a digitized value indicative of a DC loop current through said DC holding circuit that may be communicated across said isolation barrier.

13. The communication system of claim 7, wherein the information that is transmitted to the isolation barrier that is indicative of the DC loop current is digital information.

14. The communication system of claim 7, wherein said powered side circuitry is further configured to provide a clock signal to the phone line side circuitry through an isolation element that is separate from the first isolation capacitor and the second isolation capacitor.

15. The communication system of claim 7, wherein the first digital differential signal includes both data information and control information.

16. A communication system, comprising:

phone line side circuitry capable of being coupled to phone lines and an isolation barrier that comprises a plurality of isolation elements, the phone line side circuitry being configured to provide an output signal for sending data to the phone lines;

powered side circuitry for coupling to the phone line side circuitry through said isolation barrier, the powered side circuitry being configured to be isolated from the phone lines in order to satisfy phone line isolation regulatory standards;

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;

wherein the powered side circuitry is configured to communicate a first digital differential signal to at least two of the isolation barrier elements, the at least two isolation barrier elements comprising at least a first isolation capacitor and a second isolation capacitor and wherein the phone line side circuitry is configured to interpret the first digital differential signal digitally;

wherein the phone line side circuitry is configured to communicate a second digital differential signal to the first isolation capacitor and the second isolation capacitor, wherein the first and second digital differential signals are communicated across the same first and second isolation capacitors so that the first and second isolation capacitors bidirectionally transfer the first and second digital differential signals and wherein the powered side circuitry is configured to interpret the second digital differential signal digitally;

wherein the powered side circuitry is further configured to provide a clock signal to the phone line side circuitry through at least one of the plurality of isolation elements, the clock signal being provided from the powered side circuitry to the phone line side circuitry through an isolation element that is separate from the first isolation capacitor and the second isolation capacitor;

wherein the powered side circuitry and the phone line side circuitry are further configured so that at least one power supply is generated within the phone line side circuitry from power provided from the powered side circuitry, while still maintaining the isolation required by the phone line isolation regulatory standards; and

wherein at least one of the first digital differential signal and the second digital differential signal includes both data and control information.

17. The communication system of claim 16, further comprising said isolation barrier coupled between said phone line side circuitry and said powered side circuitry.

18. The communication system of claim 16, wherein each of said plurality of isolation elements of said isolation barrier comprises a capacitor.

19. The communication system of claim 16, wherein a portion of said plurality of isolation elements of said isolation barrier each comprises a capacitor.

20. The communication system of claim 16, wherein digital information is communicated across said isolation barrier.

21. The communication system of claim 16, wherein the loop current monitor signal is a voltage signal, the system further comprising an analog-to-digital converter coupled to receive the voltage signal and to produce a digitized value indicative of a DC loop current through said DC holding circuit that may be communicated across said isolation barrier.

22. 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, the isolation barrier comprising a plurality of isolation elements;

configuring the powered side circuitry to communicate a first digital differential signal to at least two of the isolation barrier elements, the at least two isolation barrier elements comprising at least a first isolation capacitor and a second isolation capacitor, wherein the powered side circuitry is configured to be isolated from the phone line in order to satisfy phone line isolation regulatory standards and wherein the phone line side circuitry is configured to interpret the first digital differential signal digitally;

configuring the phone line side circuitry to communicate a second digital differential signal to the first isolation capacitor and the second isolation capacitor, wherein the first and second digital differential signals are communicated across the same first and second isolation capacitors so that the first and second isolation capacitors bidirectionally transfer the first and second digital differential signals, the phone line side circuitry further configured to provide an output signal for sending data to the phone line and wherein the powered side circuitry is configured to interpret the second digital differential signal digitally;

configuring the powered side circuitry to provide a clock signal to the phone line side circuitry through at least one of the plurality of isolation elements;

configuring the powered side circuitry and the phone line side circuitry so that at least one power supply is generated within the phone line side circuitry from power provided from the powered side circuitry while still maintaining the isolation required by the phone line isolation regulatory standards;

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.

23. The method of claim 22, wherein the clock signal is provided from the powered side circuitry to the phone line side circuitry through an isolation element that is separate from the first isolation capacitor and the second isolation capacitor.

24. The method of claim 22, wherein the first digital differential signal includes both data information and control information.

25. The method of claim 22, wherein each of said plurality of isolation elements of said isolation barrier comprises a capacitor.

26. The method of claim 22, wherein a portion of said plurality of isolation elements of said isolation barrier each comprises a capacitor.

27. The method of claim 22, further comprising converting said loop current monitor signal into digital information an transmitting said digital information across said isolation barrier.

28. The method of claim 22, 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.

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, the isolation barrier comprising a plurality of isolation elements;

configuring the powered side circuitry to communicate a first digital differential signal to at least two of the isolation barrier elements, the at least two isolation barrier elements comprising at least a first isolation capacitor and a second isolation capacitor, wherein the powered side circuitry is configured to be isolated from the phone lines in order to satisfy phone line isolation regulatory standards and wherein the phone line side circuitry is configured to interpret the first digital differential signal digitally;

configuring the phone line side circuitry to communicate a second digital differential signal to the first isolation capacitor and the second isolation capacitor, wherein at least one of the first digital differential signal and the second digital differential signal includes both data and control information and wherein the first and second digital differential signals are communicated across the same first and second isolation capacitors so that the first and second isolation capacitors bidirectionally transfer the first and second digital differential signals, the phone line side circuitry further configured to provide an output signal for sending data to a phone line and wherein the powered side circuitry is configured to interpret the second digital differential signal digitally;

configuring the powered side circuitry to provide a clock signal to the phone line side circuitry through at least one of the plurality of isolation elements, wherein the clock signal is provided from the powered side circuitry to the phone line side circuitry through an isolation element that is separate from the first isolation capacitor and the second isolation capacitor; and

configuring the powered side circuitry and the phone line side circuitry so that at least one power supply is generated within the phone line side circuitry from power provided from the powered side circuitry, while still maintaining the isolation required by the phone line isolation regulatory standards;

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.

30. The method of claim 29, wherein each of said plurality of isolation elements of said isolation barrier comprises a capacitor.

31. The method of claim 29, wherein a portion of said plurality of isolation elements of said isolation barrier each comprises a capacitor.

32. The method of claim 29, further comprising converting said loop current monitor signal into digital information and transmitting said digital information across said isolation barrier.