System and method for monitoring operation of switch elements

• US 8,766,490 B2
• Filed: 03/25/2011
• Issued: 07/01/2014
• Est. Priority Date: 03/25/2011
• Status: Expired due to Fees

• Current Assignee: EnerDel, Inc. (Ener1, Inc.)
• Original Assignee: EnerDel, Inc. (Ener1, Inc.)
• Inventors: Capps, Charles
• Primary Examiner(s): Amrany, Adi
• Application Number:
  US13/072,101
• Publication Number:
  US 20120242171A1
• Time in Patent Office: 1,194 Days
• Field of Search: 307/134, 307/9.1, 307/109
• US Class Current: 307/134
• CPC Class Codes: B60R 16/03 for supply of electrical power to vehicle subsystems or for circuit arrangements for charging batteries H02J7/00
• CPC Class Codes: G06F 13/40 Bus structure for computer networks G06F15/163; for optical bus networks H04B10/25

Abstract

Systems and methods are provided for monitoring operation of a circuit having a DC power supply, a load, and a switch element connecting the DC power supply to the load. The system includes a capacitive element coupling a first input node of a sensor element to a first interconnection node of the circuit between a first voltage supply terminal of the DC power supply and the load. The system also includes a grounding structure coupling a second input node of the sensor element to a ground plane isolated from the DC power supply. In the system, the grounding structure is positioned with respect to a second interconnection node of the circuit, between a second voltage supply terminal of the DC power supply and the load, so as to define a stray capacitance for carrying a transient signal resulting from the opening or closing of the switch element, which can be detected through the sensor element for monitoring the current switch state of the switch element.

Claims

1. A system for monitoring operation of a circuit having a DC power supply, a load, and a switch element connecting the DC power supply to the load, the system comprising:

a sensor element having a first input node, a second input node, and an output node;

a capacitive element coupling the first input node of the sensor element to a first interconnection node of the circuit between a first voltage supply terminal of the DC power supply and the load; and

a grounding structure coupling the second input node of the sensor element to a ground plane that is galvanically isolated from the DC power supply, wherein the grounding structure is positioned with respect to a second interconnection node of the circuit between a second voltage supply terminal of the DC power supply and the load so as to define a stray capacitance for carrying a transient signal resulting from an opening or closing of the switch element.

2. The system of claim 1, further comprising:

a receive circuit coupled to the output node of the sensor element and configured for processing an output signal at the output node.

3. The system of claim 2, wherein the receive circuit is configured for generating a fault signal in response to failing to detect from the sensor element an intended opening or closing of the switch element.

4. The system of claim 3, wherein the receive circuit further comprises a gated latch circuit for maintaining the fault signal until a power supply for the receive circuit is disconnected.

5. The system of claim 3, wherein the receive circuit further comprises a gated latch circuit for maintaining the fault signal until a reset signal is received.

6. The system of claim 1, wherein a distance between the grounding structure and the second interconnection node is between about 0.5 inches and about 5 inches.

7. The system of claim 1, wherein the transient signal is generated by a response of a parasitic inductance of the circuit to the at least one of the opening of the switch element and closing of the switch element.

8. A battery operated system, comprising:

a battery module;

a load circuit;

a switch element for coupling the battery module to the load circuit;

a controller element for operating the switch element and having a grounding structure coupled to a ground plane that is galvanically isolated from the battery module; and

a path coupling a first interconnection node between a first supply terminal of the battery module and the load circuit to a second interconnection node between a second supply terminal of the battery module and the load circuit, the path including a capacitive element coupling the controller element to the first interconnection node and a stray capacitance coupling the controller element to the second interconnection node, wherein the grounding structure is positioned with respect to the second interconnection node so as to define the stray capacitance, and wherein the stray capacitance is configured for carrying a transient signal resulting from an opening or closing of the switch element.

9. The system of claim 8, wherein a distance between the grounding structure and the second interconnection node is between about 0.5 inches and about 5 inches.

10. The system of claim 8, wherein the transient signal is generated by a response of a parasitic inductance of the system to the opening or closing of the switch element.

11. The system of claim 8, wherein the controller element includes a sensor element having a first input node coupled to the capacitive element, a second input node coupled to the grounding structure, and an output node.

12. The system of claim 11, wherein the controller further comprises a receive circuit coupled to the output node of the sensor element and configured for processing an output signal at the output node.

13. The system of claim 12, wherein the receive circuit is configured for generating a fault signal in response to failing to detect from the sensor element an intended opening or closing of the switch element.

14. The system of claim 13, wherein the receive circuit further comprises a gated latch circuit for maintaining the fault signal until the occurrence of a reset event.

15. The system of claim 13, wherein the controller is configured for disconnecting the battery module from the load circuit in response to the fault signal.

16. A method for monitoring operation of a circuit having a DC power supply, a load, and a switch element connecting the DC power supply to the load, the method comprising:

capacitively coupling a first input node of a sensor element to a first interconnection node of the circuit between a first supply terminal of the DC power supply and the load;

coupling a second input node of the sensor element to a grounding structure coupled to a ground plane galvanically isolated from the DC power supply, the grounding structure being positioned with respect to a second interconnection node of the circuit between voltage second supply terminal of the DC power supply to define a stray capacitance for carrying a transient signal resulting from an opening or closing of the switch element; and

processing an output signal at an output node of the sensor element.

17. The method of claim 16, wherein the step of processing further comprises generating a fault signal in response to failing to detect from the sensor element an intended opening or closing of the switch element.

18. The method of claim 17, wherein the step of processing further comprises maintaining the fault signal until the occurrence of a reset event.

19. The method of claim 17, wherein the step of processing further comprises disabling the system in response to the fault signal.