Method and system for isolated current and voltage monitoring

• US 7,432,720 B1
• Filed: 08/04/2006
• Issued: 10/07/2008
• Est. Priority Date: 08/04/2006
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Quaife, Philip Richard
• Primary Examiner(s): Nguyen; Vincent Q.
• Assistant Examiner(s): ZHU, JOHN X
• Application Number:
  US11/499,010
• Time in Patent Office: 795 Days
• Field of Search: 324/522, 324/537, 340/652
• US Class Current: 324/522
• CPC Class Codes: G01R 15/22 using light-emitting devices, e.g. LED, optocouplers G01R31/31901 takes precedence
• CPC Class Codes: G01R 22/10 using digital techniques

Abstract

An embodiment of the invention provides a method for monitoring electrical characteristic on an electronic circuit board. This electrical characteristic can be voltage or current. The electrical characteristic is measured at a first location. The first location is at a high voltage called primary potential. The electrical characteristic is converted to a proportional frequency. The frequency is sent through an isolation circuit to a second location for monitoring. The second location is at a low voltage called secondary potential. The frequency is provided as input to an environment monitoring circuit at the second location.

Claims

1. A method for monitoring an electrical characteristic on an electronic circuit board, the method comprising:

receiving the electrical characteristic to be monitored, wherein the electrical characteristic is measured at a power input section operating at a first electrical potential, the power input section transferring a signal associated with the electrical characteristic through a the first DC path to a digital circuit section operating at a second electrical potential in a second location;

converting the electrical characteristic to a frequency, wherein the frequency indicates a magnitude of the electrical characteristic; and

sending the frequency via an optocoupler through a second path for monitoring at the second location by an environment-monitoring circuit section, wherein the second location is at a different electrical potential than the power input section, the environmental-monitoring circuit section using the frequency to monitor the electrical characteristic with regard to a function of the digital circuit section operating using the signal received through the first DC path.

2. The method of claim 1, wherein the electrical characteristic includes voltage.

3. The method of claim 1, wherein the electrical characteristic includes current.

4. The method of claim 1, wherein a potential at the first location ranges from 60 to 100 volts.

5. The method of claim 1, wherein a potential at the second location ranges from 0 to 12 volts.

6. The method of claim 1, wherein the electrical characteristic at the second location is in digital form.

7. The method of claim 1, wherein the electrical characteristic at the second location is in analog form.

8. The method of claim 1, further comprising:

converting the frequency to the electrical characteristic at the second location for monitoring the electrical characteristic.

9. The method of claim 1, wherein the electrical characteristic is monitored in real time.

10. The method of claim 1, wherein sending the frequency via the optocoupler comprises using an optical transmission path to transfer the frequency to the second location while keeping the first location and the second location electrically isolated.

11. The method of claim 1, wherein the optocoupler comprises a light emitting diode or light sensor.

12. A system for monitoring an electrical characteristic on an electronic circuit board, the system comprising:

an active fuse logic on the electronic circuit board, the active fuse logic providing the electrical characteristic at a first location operating at a first electrical potential, the active fuse logic configured to transfer a signal associated with the electrical characteristic through a first DC path to a digital circuit section operating at a second electrical potential in a second location;

an electrical characteristic-to-frequency converter, the electrical characteristic-to-frequency converter converting the electrical characteristic to a frequency, wherein the frequency is indicative of a magnitude of the electrical characteristic;

an optocoupler, the optocoupler sending the frequency through a second path from the first location to a second location for monitoring; and

an environment-monitoring circuit, the environment-monitoring circuit section monitoring the frequency at the second location, the environmental-monitoring circuit section using the frequency to monitor the electrical characteristic with regard to a function of the digital circuit section operating using the signal received through the first DC path.

13. The system of claim 12, wherein the first location and the second location are on a single integrated circuit.

14. The system of claim 12, wherein the optocoupler is configured to use an optical transmission path to transfer the frequency to the second location while keeping the first location and the second location electrically isolated.

15. The system of claim 12, wherein the environmental-monitoring circuit is configured to convert the frequency to the electrical characteristic at the second location for monitoring the electrical characteristic.

16. The system of claim 12, wherein the optocoupler comprises a light emitting diode or light sensor.

17. An apparatus for monitoring an electrical characteristic on an electronic circuit board, the apparatus comprising:

means for receiving the electrical characteristic to be monitored, wherein the electrical characteristic is received at a power input section of the electronic circuit board, wherein the power input section is at a first potential, the power input section transferring a signal associated with the electrical characteristic through a first DC path to a digital circuit section operating at a second electrical potential in a second location;

means for converting the electrical characteristic to a frequency, wherein the frequency indicates a magnitude of the electrical characteristic at the power input section of the electronic circuit board;

means for sending the frequency to a second location through a second path for monitoring, wherein the frequency is transferred through an optocoupler, wherein the second location is at a second potential, wherein the second potential is an operation potential of digital circuitry that is substantially different from the first potential; and

means for monitoring the frequency at the second location to monitor the electrical characteristic with regard to a function of the digital circuit section operating using the signal received through the first DC path.

18. The apparatus of claim 17, wherein the means for sending the frequency via the optocoupler comprises means for using an optical transmission path to transfer the frequency to the second location while keeping the first location and the second location electrically isolated.

19. The apparatus of claim 17, further comprising means for converting the frequency to the electrical characteristic at the second location for monitoring the electrical characteristic.

20. The apparatus of claim 17, wherein the optocoupler comprises a light emitting diode or light sensor.