Integrated circuit and method for classification of electrical devices and short circuit protection

• US 7,904,260 B2
• Filed: 02/28/2008
• Issued: 03/08/2011
• Est. Priority Date: 02/28/2007
• Status: Active Grant

• Current Assignee: STMicroelectronics Incorporated (STMicroelectronics NV)
• Original Assignee: STMicroelectronics Incorporated (STMicroelectronics NV)
• Inventors: Mirowski, Marian, Burlak, Gary Joseph
• Primary Examiner(s): Charioui; Mohamed
• Assistant Examiner(s): Ngon; Ricky
• Application Number:
  US12/039,065
• Publication Number:
  US 20080208491A1
• Time in Patent Office: 1,104 Days
• Field of Search: 702 57- 65, 702124-126, 702/183, 702/185, 702/189, 702/193, 702/198, 320/106, 324/426, 324/433, 307 1- 87, 307112-157
• US Class Current: 702/57
• CPC Class Codes: H02H 3/12 responsive to underload or no-load for motors H02H7/0827

Abstract

An integrated circuit device and method for classifying electrical devices is disclosed. A reference current response of a plurality of electrical devices is determined and stored in a memory. Real-time current response of a specific electrical device is measured and stored in the memory. A processor compared the measured real-time current response of the specific electrical device to the reference current responses of the plurality of electrical devices. A classification of the electrical device is then made based on the comparison.

Claims

1. A method for classifying as to type electrical devices adapted to receive power from an output port of a respective power control circuit coupled to a battery, comprising:

storing reference current responses of different types of electrical devices in a memory, wherein the reference current responses include reference in-rush currents as a function of time;

calculating a first steady state current from the reference current responses;

calculating a second steady state current from a measured real-time current response of a specific electrical device, wherein the measured real-time current response includes a real-time in-rush current;

comparing, by a processor, the measured real-time current response of the specific electrical device to the reference current responses;

classifying the specific electrical device as having a first classification type based on the current response comparison;

comparing the first steady state current to the second steady state current of the specific electrical device; and

classifying the specific electrical device as having a second classification type based on the steady state current comparison.

2. The method according to claim 1, further comprising:

comparing the first classification type to the second classification type;

if the first and second classification types are the same, assigning a valid classification type to the specific electrical device, the valid classification type identifying the specific electrical device-type; and

reporting the valid classification type.

3. The method according to claim 2, further comprising reporting an invalid classification type if the first and second classification types are different.

4. The method according to claim 3, wherein the classification types of the electrical devices are reported via a vehicle communication network.

5. The method according to claim 1, wherein the electrical devices relate to trailers towed by a vehicle, the method further comprising:

classifying types of the plurality of electrical devices adapted to receive power from the battery; and

identifying a trailer-type based on the classification types of the plurality of electrical devices.

6. The method according to claim 1, wherein the classification type identifies the electrical devices as an incandescent bulb, a gas discharge bulb, an LED, or a battery.

7. The method according to claim 1, further comprising:

determining a maximum threshold current for the output port to which the electrical device is connected, the maximum threshold current being a short circuit current limit at the output port and being based on the characteristic of the output port;

measuring a third steady state current flowing in the electrical device for pre-selected times;

calculating, by the processor, a learned short circuit threshold current value from the third steady state current values, the learned short circuit current value being less than the maximum threshold current value;

comparing the second steady state current to the maximum threshold current and to the learned short circuit current;

if the second steady state current is greater than the maximum threshold current, reporting a hard short circuit condition at the output port; and

if the second steady state current is more than the learned short circuit current but less than the maximum threshold current, reporting a soft short circuit condition at the output port.

8. The method according to claim 7, wherein the calculation of the learned short circuit current value comprises:

calculating, by the processor, an average steady state current value; and

determining the learned short circuit current value by multiplying the average steady state current value with a pre-selected fractional number.

9. The method according to claim 7, further comprising:

repeating measurement of the second steady state current flowing in the electrical device; and

comparing the second steady state current to the maximum threshold current and to the learned short circuit current.

10. The method according to claim 9, further comprising:

incrementing a first counter if the second steady state current is greater than the maximum threshold current; and

reporting a valid hard short circuit condition if the count value of the first counter exceeds a first count.

11. The method according to claim 10, further comprising removing power from the output port by reducing duty cycle of the power control circuit responsive to the valid hard short circuit condition.

12. The method according to claim 9, further comprising:

incrementing a second counter if the second steady state current is more than the learned short circuit current but less than the maximum threshold current; and

reporting a valid soft short circuit condition if the count value of the second counter exceeds a second count.

13. An integrated circuit device for classifying as to type electrical devices adapted to receive power from an output port of a respective power control circuit coupled to a battery, comprising:

a memory adapted to store a reference current response of different types of electrical devices, wherein the reference current response includes a reference in-rush current as a function of time;

a processor electrically coupled to the memory, the processor adapted to calculate a first steady state current from the reference current response;

a power control circuit adapted to be electrically coupled to an electrical device, the power control circuit adapted to control the power delivered to the electrical device responsive to a power control signal from the processor;

a current sense circuit adapted to be electrically coupled to the electrical device, the current sense circuit adapted to measure the current flowing in the electrical device and provide a current sense signal representative of the measured real-time current response to the processor; and

the processor further adapted to calculate a second steady state current from the measured real-time current response, classify the electrical device as to a first classification type by comparing the stored reference current response to the measured real-time current response, and classify the electrical device as to a second classification type by comparing the first steady state current to the second steady state current.

14. The integrated circuit device of claim 13, wherein the power control signal is a pulse width modulated signal adapted to control a duty cycle of the power control circuit.

15. The integrated circuit device of claim 13, wherein the processor is further adapted to decrease a duty cycle of the power control circuit responsive to the current sense signal indicating a short circuit condition at the output port.

16. The integrated circuit device of claim 13, wherein the power control circuit, the processor and the memory are implemented in a trailer tow connector adapted to regulate power in one or more types of electrical devices adapted to be installed in a trailer attached to a vehicle.

17. The integrated circuit device of claim 13, wherein the battery is adapted to be installed in a vehicle adapted to tow a trailer and wherein the power control circuit, the processor and the memory are adapted to be implemented in a trailer tow connector.

18. A method for identifying a short circuit state at an output port of a trailer tow connector having a plurality of output ports each configured to provide power to an electrical device installed in a trailer attached to a vehicle, the trailer tow connector having a processing circuit coupled to a memory, the method comprising:

determining, by the processing circuit, a learned short circuit current value of the output port, the learned short circuit current value being based on a fractional value multiplied by the average of a plurality of measured steady state learn-phase load currents at the output port, the learn-phase load currents being continually determined while a load is connected;

storing the learned short circuit current value in the memory;

measuring the load current at the output port with a measurement circuit;

comparing, by the processing circuit, the load current value to the learned short circuit current value; and

identifying the short circuit condition based on the comparison.

19. The method according to claim 18, wherein the load current is the steady state current.

20. The method according to claim 18, wherein the load current is the average value of a plurality of sampled current values.

21. The method according to claim 18, wherein the determination of the learned short circuit current further comprises:

measuring a plurality of the steady state learn-phase load current at the output port for a selected number of times at selected time intervals;

storing the plurality of measured steady state learn-phase load current values in the memory;

selecting, by the processor, a subset of the steady state learn-phase load current values;

generating the learned short circuit current by multiplying an average of the subset of the steady state learn-phase current values with the fractional value.

22. A method for classifying as to type electrical devices adapted to receive power from an output port of a respective power control circuit coupled to a battery, comprising:

storing reference current responses of different types of electrical devices in a memory, wherein the reference current responses include reference in-rush currents as a function of time;

calculating, by a processor, a steady state current from a measured real-time current response of a specific electrical device, wherein the measured real-time current response includes a real-time in-rush current;

determining if the measured in-rush current is substantially equal to the reference in-rush current;

assigning a potential first classification type to the specific electrical device if the measured in-rush current is substantially equal to the reference in-rush current, the assigned potential first classification type indicating that the specific electrical device may potentially be a first type of electrical device subject to validation;

determining if the steady state current is substantially equal to the reference steady state current;

assigning a potential second classification type to the specific electrical device if the steady state current is substantially equal to the reference steady state current, the assigned potential second classification type indicating that the specific electrical device may potentially be a second type of electrical device subject to validation;

comparing the potential first classification type to the potential second classification type;

assigning a valid classification type to the specific electrical device if the potential first and second classification types are the same, the valid classification type identifying the specific electrical device-type; and

reporting the valid classification type.

23. The method according to claim 22, further comprising reporting an invalid classification type if the potential first and second classification types are different.

24. The method according to claim 23, wherein the classification types of the electrical devices are reported via a vehicle communication network.

25. A method for classifying as to type electrical devices adapted to receive power from an output port of a respective power control circuit coupled to a battery, comprising:

determining a maximum threshold current for the output port to which the electrical device is connected, the maximum threshold current being a short circuit current limit at the output port and being based on the characteristic of the output port;

measuring a steady state current flowing in the electrical device for pre-selected times;

calculating, by a processor, a learned short circuit threshold current value from the steady state current values, the learned short circuit current value being less than the maximum threshold current value;

measuring a real-time steady state current flowing in the electrical device;

comparing the measured real-time steady state current to the maximum threshold current and to the learned short circuit current;

reporting a hard short circuit condition at the output port if the measured real-time steady state current is greater than the maximum threshold current; and

reporting a soft short circuit condition at the output port if the measured real-time steady state current is more than the learned short circuit current but less than the maximum threshold current.

26. The method according to claim 25, wherein the calculation of the learned short circuit current value comprises:

calculating, by the processor, an average steady state current value; and

determining the learned short circuit current value by multiplying the average steady state current value with a pre-selected fractional number.

27. The method according to claim 25, further comprising:

repeating measurement of the real-time steady state current flowing in the electrical device; and

comparing the measured real-time steady state current to the maximum threshold current and to the learned short circuit current.

28. The method according to claim 27, further comprising:

incrementing a first counter if the measured real-time steady state current is greater than the maximum threshold current; and

reporting a valid hard short circuit condition if the count value of the first counter exceeds a first count.

29. The method according to claim 28, further comprising removing power from the output port by reducing duty cycle of the power control circuit responsive to the valid hard short condition.

30. The method according to claim 27, further comprising:

incrementing a second counter if the measured real-time steady state current is more than the learned short circuit current but less than the maximum threshold current; and

reporting a valid soft short circuit condition if the count value of the second counter exceeds a second count.

31. A method for classifying as to type electrical devices adapted to receive power from an output port of a respective power control circuit coupled to a battery, comprising:

storing reference current responses of different types of electrical devices in a memory;

measuring a real-time current response of a specific electrical device;

comparing, by a processor, the measured real-time current response of the specific electrical device to the reference current responses of the plurality of electrical devices;

classifying the specific electrical device as to type based on the current response comparison;

determining a high threshold current for the output port to which the electrical device is connected, the high threshold current being a short circuit current limit at the output port and being based on the characteristic of the output port;

measuring a steady state current flowing in the electrical device for pre-selected times; and

calculating a learned short circuit current value from the steady state current values, the learned short circuit current value being less than the high threshold current value.

32. The method as set forth in claim 31, further comprising:

measuring a real-time steady state current flowing in the electrical device;

comparing the measured real-time steady state current to the high threshold current and to the learned short circuit current;

reporting a hard short circuit condition at the output port if the measured real-time steady state current is greater than the high threshold current; and

reporting a soft short circuit condition at the output port if the measured real-time steady state current is more than the learned short circuit current but less than the high threshold current.

33. The method as set forth in claim 32, wherein the calculation of the learned short circuit current value comprises:

calculating, by the processor, an average steady state current value; and

determining the learned short circuit current value by multiplying the average steady state current value with a pre-selected fractional number.

34. The method as set forth in claim 32, further comprising:

repeating measurement of the real-time steady state current flowing in the electrical device; and

comparing the measured real-time steady state current to the high threshold current and to the learned short circuit current.

35. The method as set forth in claim 34, further comprising:

incrementing a first counter if the measured real-time steady state current is greater than the high threshold current; and

reporting a valid hard short circuit condition if the count value of the first counter exceeds a first count.

36. The method as set forth in claim 35, further comprising removing power from the output port by reducing duty cycle of the power control circuit responsive to the valid hard short circuit condition.

37. The method as set forth in claim 34, further comprising:

incrementing a second counter if the measured real-time steady state current is more than the learned short circuit current but less than the high threshold current; and

reporting a valid soft short circuit condition if the count value of the second counter exceeds a second count.