Method and apparatus for control and fault detection of an electric load circuit

• US 20040004483A1
• Filed: 07/02/2002
• Published: 01/08/2004
• Est. Priority Date: 07/02/2002
• Status: Active Grant

• Current Assignee: Delphi Technologies, Inc. (BorgWarner Incorporated)
• Original Assignee: Delphi Technologies, Inc. (BorgWarner Incorporated)
• Inventors: Hazelton, Lawrence Dean
• Granted Patent: US 6,759,851 B2
• Time in Patent Office: Days
• US Class Current: 324/522
• CPC Class Codes: G01R 19/16528 using digital techniques or performing arithmetic operations using digital techniques to measure a voltage or a current, see G01R19/25
• CPC Class Codes: G01R 31/50 Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections testing of sparking plugs H01T13/58

Abstract

The present invention provides an improvement over conventional electric circuit monitoring devices in that it provides a device and method to passively monitor the performance of an electrical circuit to a load device, including faults that occur intermittently. The invention is capable of identifying the location and type of malfunction in the event of a fault.

Claims

1. A circuit to control and monitor an electric load having a first and a second end, comprising:

a first switch electrically coupled between a first electric potential and said first end of the electric load;

a second switch electrically coupled between said second end of the electric load and a second electric potential;

a load drive controller operable to control each of said switches; and

a comparison circuit for detecting a fault condition in said circuit by comparing an electric potential at said first end of the electric load with a first known potential and by comparing an electric potential at said second end of the electric load with a second known potential.

2. The circuit of claim 1, wherein the comparison circuit comprises a plurality of comparators such that a first input to each of said comparators is in electrical contact with said electric load, and a second input to each of said comparators comprises the first or the second known potential.

3. The circuit of claim 2, wherein said each switch and the first and second known potentials are appropriately biased with an effective amount of electric potential to enable detection of a type and location of a fault condition.

4. The circuit of claim 3, wherein the load drive controller is operably coupled to an external controller to receive a control signal and to send a fault detection result.

5. The circuit of claim 4, wherein the load drive controller is operable to control each of said switches in a manner such that a first output from the comparison circuit indicates a fault condition.

6. The circuit of claim 4, wherein the load drive controller is operable to control each of said switches in a manner such that a second output from the comparison circuit indicates the type and location of a fault condition.

7. The circuit of claim 2, wherein the output from each said comparator is either a logic high or logic low.

8. The circuit of claim 1, wherein the electric load comprises an inductive device.

9. The circuit of claim 1, wherein the electric load comprises a resistive device.

10. The circuit of claim 1, wherein each said switch comprises a field effect transistor.

11. The circuit of claim 1, wherein each said switch comprises a bipolar transistor.

12. The circuit of claim 1, wherein each said switch comprises an electromagnetic relay.

13. The circuit of claim 1, wherein the first electric potential is battery voltage in a vehicle electrical system.

14. The circuit of claim 1, wherein the second electric potential is ground in a vehicle electrical system.

15. The circuit of claim 1, wherein the first electric potential is a preset voltage.

16. The circuit of claim 1, wherein the second electric potential is a neutral voltage.

17. The circuit of claim 4, wherein the comparator circuit is internal to said external controller.

18. A circuit for control and diagnosis of an electric load having a first and a second end, comprising:

a first switch electrically coupled between a first electric potential and said first end of the electric load;

a second switch electrically coupled between said second end of the electric load and a second electric potential;

a load drive controller operable to control each of said switches; and

a plurality of comparators, wherein a first input to each of said comparators is in electrical contact with said electric load with an appropriate bias potential, and a second input to each of said comparators comprises a first or a second known potential; and

an output from each said comparator.

19. The circuit of claim 18, wherein the load drive controller is operable to control each said switch in a manner such that the output from each said comparator indicates a fault condition in said circuit.

20. The circuit in claim 19, wherein the load drive controller is operably coupled to an external controller, such that the load drive controller responsive to an input from said external controller, and is capable of communicating a first result indicating said fault condition to said external controller.

21. The circuit in claim 18, wherein detection of a fault condition in said circuit occurs during operation of said load.

22. The circuit of claim 18, wherein the load drive controller is operable to control each said switch in a manner such the output from each said comparator indicates a type and location of said fault condition.

23. The circuit in claim 22, wherein the load drive controller is operably coupled to an external controller, such that the load drive controller is responsive to an input from said external controller, and is able to communicate a second result indicating said type and location of said fault condition to said external controller.

24. A method for controlling and monitoring an electric load, comprising:

providing a circuit comprising an electric load with a first and a second end, a first switch electrically coupled between a first electric potential and said first end of the electric load, a second switch electrically coupled between said second end of the electric load and a second electric potential, a load drive controller operable to control each of said switches;

activating said first and second switches;

comparing an electric potential at said first end of the electric load with a first known potential and comparing an electric potential at said second end of the electric load with a second known potential; and

obtaining an output from each said comparison.

25. The method in claim 24, further comprising communicating the output from each said comparison to an external controller.

26. The method of claim 24, further comprising detecting a fault condition in said circuit from the output from each said comparison.

27. The method of claim 24, wherein the step of activating said first and second switches comprises closing the first and second switches.

28. The method of claim 24, wherein the step of activating said first and second switches comprises opening the first and second switches.

29. The method in claim 26, further comprising communicating the fault condition as a first result to an external controller.

30. The method of claim 24, wherein the step of activating said first and second switches comprises controlling each of said switches in a manner that will identify a type and location of a fault condition.

31. The method of claim 30, further comprising detecting a type and location of a fault condition in said circuit from the output from each said comparison.

32. The method of claim 31, further comprising communicating the type and location of a fault condition as a second result to an external controller.

33. The method in claim 24, wherein the load drive controller is operably coupled to an external controller, such that the load drive controller is responsive to an input from an external controller and is able to communicate a second result indicating a type and location of said fault condition to said external controller.