CALIBRATION OF A LOAD CONTROL DEVICE FOR A LIGHT-EMITTING DIODE LIGHT SOURCE

• US 20160181911A1
• Filed: 12/18/2015
• Published: 06/23/2016
• Est. Priority Date: 12/19/2014
• Status: Active Grant

• Current Assignee: Lutron Technology Company LLC
• Original Assignee: Lutron Electronics Company Incorporated (Lutron Electronics)
• Inventors: Knauss, Matthew, Nuhfer, Matthew W., Udall, Christopher G.
• Granted Patent: US 9,954,435 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01R 19/16538 in AC or DC supplies G01R19/16519 and G01R19/16528 take precedence
• CPC Class Codes: H02M 1/0009 Devices or circuits for detecting current in a converter
• CPC Class Codes: H02M 3/04 by static converters
• CPC Class Codes: H05B 45/12 using optical feedback
• CPC Class Codes: H05B 45/14 using electrical feedback from LEDs or from LED modules
• CPC Class Codes: H05B 45/3725 Switched mode power supply [SMPS]
• CPC Class Codes: H05B 47/19 via wireless transmission

Abstract

A load regulation device for controlling the amount of power delivered to an electrical load may be able to calibrate the magnitude of an output voltage of the load regulation device in order to control the magnitude of a load voltage across the electrical load to a predetermined level. The load regulation device may receive the feedback from a calibration device adapted to be coupled to load wiring near the electrical load. The feedback may indicate when the magnitude of the load voltage across the electrical load has reached a predetermined level. The load regulation device may gradually adjust the magnitude of the output voltage, receive the feedback from the calibration device, and then use the feedback to determine the magnitude of the output voltage corresponding to when the magnitude of the load voltage across the electrical load has reached the predetermined level.

Claims

1. A load regulation device for controlling the amount of power delivered to an electrical load, the load regulation device comprising:

a load regulation circuit configured to generate an output voltage for producing a load voltage across the electrical load; and

a control circuit configured to adjust the magnitude of the output voltage of the load regulation circuit based on external feedback indicating whether the magnitude of the load voltage across the electrical load has reached a predetermined level.

2. The load regulation device of claim 1, wherein the external feedback indicates whether the magnitude of the load voltage has exceeded the predetermined level.

3. The load regulation device of claim 2, wherein the control circuit is configured to gradually increase the magnitude of the output voltage until the external feedback indicates that the magnitude of the load voltage across the electrical load has reached or exceeded the predetermined level.

4. The load regulation device of claim 3, wherein the control circuit is configured to gradually increase the magnitude of the output voltage through a plurality of periodic steps.

5. The load regulation device of claim 3, wherein the control circuit is configured to decrease the magnitude of the output voltage to a final magnitude after receiving the external feedback that the magnitude of the load voltage across the electrical load has exceeded the predetermined level.

6. The load regulation device of claim 5, wherein the load regulation device further comprises a memory and wherein the control circuit is configured to store the final magnitude of the output voltage in the memory for use during normal operation of the load regulation device.

7. The load regulation device of claim 1, wherein the load regulation device is coupled to the electrical load via load wiring, the load wiring characterized by an impedance that causes the magnitude of the load voltage across the electrical load to be different than the magnitude of the output voltage generated by the load regulation circuit.

8. The load regulation device of claim 7, wherein the control circuit is configured to receive the external feedback via the load wiring.

9. The load regulation device of claim 8, wherein the external feedback comprises a current spike and the load regulation device is configured to gradually increase the magnitude of the output voltage until sensing the current spike.

10. The load regulation device of claim 9, wherein the load regulation device is configured to gradually increase the magnitude of the output voltage through a plurality of periodic steps.

11. The load regulation device of claim 8, wherein the external feedback comprises regular-interval current spikes and the load regulation device is configured to gradually increase the magnitude of the output voltage until no current spike is sensed for a period longer than the regular interval.

12. The load regulation device of claim 11, wherein the load regulation device is configured to gradually increase the magnitude of the output voltage through a plurality of periodic steps.

13. The load regulation device of claim 8, wherein the external feedback comprises a digital message.

14. The load regulation device of claim 7, wherein the control circuit is configured to receive the external feedback from an external calibration device coupled to the load wiring near the electrical load.

15. The load regulation device of claim 7, further comprising:

a communication circuit configured to receive a digital message from an external calibration device coupled to the load wiring near the electrical load, wherein the digital message indicates whether the magnitude of the load voltage across the electrical load has reached the predetermined level.

16. The load regulation device of claim 1, further comprising:

a communication circuit configured to receive a digital message indicating whether the magnitude of the load voltage across the electrical load has reached the predetermined level.

17. The load regulation device of claim 16, wherein the communication circuit comprises a wireless communication circuit.

18. The load regulation device of claim 16, wherein the communication circuit is configured to wirelessly receive the digital message from an input device.

19. The load regulation device of claim 18 wherein the input device comprises a light sensor.

20. The load regulation device of claim 18, wherein the input device comprises a mobile communication device.

21. The load regulation device of claim 17, wherein the communication circuit is configured to wirelessly receive the digital message from an external calibration device coupled to load wiring near the electrical load.

22. The load regulation device of claim 16, wherein the control circuit is configured to start gradually adjusting the magnitude of the output voltage in response to receiving the digital message via the communication circuit in order to determine the magnitude of the output voltage at which the magnitude of the load voltage across the electrical load has reached the predetermined level.

23. The load regulation device of claim 1, wherein the control circuit is configured to automatically determine the magnitude of the output voltage at which the magnitude of the load voltage across the electrical load has reached the predetermined level.

24. The load regulation device of claim 23, wherein the automatic determination occurs when the load regulation device is powered up.

25. The load regulation device of claim 24, wherein the automatic determination occurs when the load regulation device is first powered up.

26. The load regulation device of claim 24, wherein the automatic determination occurs each time that the load regulation device is powered up.

27. The load regulation device of claim 1, wherein the electrical load comprises an LED light source, and the load regulation circuit comprises an LED driver for controlling the magnitude of the output voltage to adjust the intensity of the LED light source.

28. The load regulation device of claim 27, wherein the predetermined level is a rated voltage of the LED light source.

29. The load regulation device of claim 27, further comprising a circuit for controlling the light intensity of the LED light source via pulse width modulation (PWM) or pulse frequency modulation (PFM).

30. The load regulation device of claim 1, wherein the control circuit is configured to start gradually adjusting the magnitude of the output voltage in response to an actuation of a button on the load regulation device in order to determine the magnitude of the output voltage at which the magnitude of the load voltage across the electrical load has reached the predetermined level.

31. A load regulation device for controlling the amount of power delivered to at least first and second electrical loads, the load regulation device comprising:

a first load regulation circuit configured to generate a first output voltage for producing a first load voltage across the first electrical load;

a second load regulation circuit configured to generate a second output voltage for producing a second load voltage across the second electrical load; and

a control circuit configured to adjust the magnitude of the first and second output voltages of the respective load regulation circuits, the control circuit configured to gradually adjust the magnitude of the first output voltage and to receive external feedback indicating whether the magnitude of the first load voltage across the first electrical load has reached a first predetermined level, the control circuit further configured to gradually adjust the magnitude of the second output voltage and to receive external feedback indicating whether the magnitude of the second load voltage across the second electrical load has reached a second predetermined level.

32. A load control system for controlling the amount of power delivered from a power source to an electrical load, the load control system comprising:

a load regulation device configured to be coupled to the electrical load via load wiring and to generate an output voltage for producing a load voltage across the electrical load; and

a calibration device configured to be coupled to the load wiring near the electrical load and to provide feedback to the load regulation device indicating whether the magnitude of the load voltage across the electrical load has reached a predetermined level,

wherein the load regulation device is configured to adjust the magnitude of the output voltage based on the feedback from the calibration device indicating whether the magnitude of the load voltage across the electrical load has reached the predetermined level.

33. The system of claim 32, wherein the calibration device is configured to provide the feedback indicating whether the magnitude of the load voltage across the electrical load has exceeded the predetermined level.

34. The system of claim 32, wherein the load regulation device is configured to gradually increase the magnitude of the output voltage until receiving the feedback indicating that the magnitude of the load voltage across the electrical load has reached or exceeded the predetermined level.

35. The system of claim 34, wherein the load regulation device is configured to gradually increase the magnitude of the output voltage through a plurality of periodic steps.

36. The system of claim 32, wherein the load regulation device is configured to decrease the magnitude of the output voltage after receiving the feedback indicating that the magnitude of the load voltage across the electrical load has exceeded the predetermined level.

37. The system of claim 32, wherein the calibration device is configured to provide the feedback by transmitting a digital message to the load regulation device.

38. The system of claim 37, wherein the calibration device is configured to transmit the digital message via the load wiring.

39. The system of claim 37, wherein the calibration device is configured to wirelessly transmit the digital message.

40. The system of claim 32, wherein the calibration device is configured to provide the feedback via the load wiring.

41. The system of claim 40, wherein the calibration device is configured to provide the feedback by conducting a current pulse through the load wiring and wherein the load regulation device is configured to gradually increase the magnitude of the output voltage until sensing a current spike.

42. The system of claim 41, wherein the load regulation device is configured to gradually increase the magnitude of the output voltage through a plurality of periodic steps.

43. The system of claim 40, wherein the calibration device is configured to provide the feedback by conducting regular-interval current pulses through the load wiring and wherein the load regulation device is configured to gradually increase the magnitude of the output voltage until no current spike is sensed for a period longer than the regular interval.

44. The system of claim 43, wherein the load regulation device is configured to gradually increase the magnitude of the output voltage through a plurality of periodic steps.

45. The system of claim 32, wherein the calibration device is configured to measure the magnitude of the load voltage prior to providing the feedback.

46. A calibration circuit for calibrating an output voltage of a load regulation device for an electrical load, the load regulation device coupled to the electrical load via load wiring, the calibration circuit comprising:

a voltage sense circuit configured to sense a magnitude of a load voltage developed across the electrical load; and

a communication circuit configured to provide feedback via the load wiring when the voltage sense circuit indicates that the magnitude of the load voltage has reached or exceeded a predetermined level.

47. The calibration circuit of claim 46, further comprising:

electrical terminals adapted to be coupled to the load wiring adjacent to the electrical load.

48. The calibration circuit of claim 46, wherein the communication circuit is configured to provide the feedback via one or more current spikes conducted through the load wiring.

49. The calibration circuit of claim 48, wherein the communication circuit comprises a current sink circuit configured to conduct a pulse of current through the load wiring when the magnitude of the load voltage has reached or exceeded the predetermined level.

50. The calibration circuit of claim 49, wherein the voltage sense circuit comprises a shunt regulator for indicating to the communication circuit when the magnitude of the load voltage has reached or exceeded the predetermined level.

51. The calibration circuit of claim 48, wherein the communication circuit comprises a current sink circuit configured to conduct one or more pulses of current through the load wiring when the magnitude of the load voltage has not reached or exceeded the predetermined level.

52. The calibration circuit of claim 46, wherein the communication circuit is configured to provide the feedback by transmitting a digital message via the load wiring.

53. The calibration circuit of claim 52, wherein the voltage sense circuit comprises a digital controller responsive to a scaled voltage that is proportional to the magnitude of the load voltage, the digital controller configured to cause the communication circuit to transmit the digital message when the magnitude of the load voltage has reached or exceeded the predetermined level.

54. A load regulation device for controlling the amount of power delivered to an electrical load, the load regulation device comprising:

a load regulation circuit configured to generate an output voltage for producing a load voltage across the electrical load; and

a control circuit configured to gradually adjust the magnitude of the output voltage of the load regulation circuit and to receive external feedback indicating whether the magnitude of the load voltage across the electrical load has reached a predetermined level.

55. The load regulation device of claim 54, wherein the control circuit is configured to receive the external feedback from an external calibration device coupled to load wiring near the electrical load.