ELECTRONIC CONTROL TO REGULATE POWER FOR SOLID-STATE LIGHTING AND METHODS THEREOF

• US 20100123403A1
• Filed: 11/16/2009
• Published: 05/20/2010
• Est. Priority Date: 11/17/2008
• Status: Active Application

• Current Assignee: Express Imaging Systems, LLC
• Original Assignee: Express Imaging Systems, LLC
• Inventors: Reed, William G.
• Granted Patent: US 9,125,261 B2
• Time in Patent Office: Days
• US Class Current: 315/193
• CPC Class Codes: H05B 45/3725 Switched mode power supply [SMPS]
• CPC Class Codes: H05B 45/46 having LEDs disposed in parallel lines
• CPC Class Codes: H05B 45/48 having LEDs organised in strings and incorporating parallel shunting devices
• CPC Class Codes: Y02B 20/30 Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]

Abstract

Apparatus and methods to regulate an input power applied to a plurality of light emitters are provided. A regulator device includes a plurality of switches and a control circuit that controls the plurality of switches. The plurality of switches selectively couple respective strings of the light emitters in series to the input power to emit light when deactivated. The control circuit may deactivate a number of the switches to couple the respective light emitters to the input power in response to a sensed operational parameter of the input power. The control circuit may adjust the number of the switches deactivated in response to a change in the sensed operational parameter of the input power. A number of the light emitters may be coupled to the input power regardless of the sensed operational parameter of the input power.

Claims

1. A regulator device to regulate an input power applied to a plurality of light emitters, comprising:

a plurality of switches each of which selectively electrically couples a respective number of the light emitters to receive the input power when the switch is deactivated; and

a control circuit coupled to receive the input power and controllingly coupled to the plurality of switches, the control circuit configured to sense an operational parameter of the input power, the control circuit to deactivate a number of the switches to electrically couple the respective light emitters to the input power and a first number of the light emitters responsive to the sensed operational parameter of the input power, and to adjust the number of the switches deactivated responsive to a change in the sensed operational parameter of the input power, where the first number of the light emitters are coupled to the input power regardless of the sensed operational parameter of the input power.

2. The regulator device of claim 1 wherein the control circuit deactivates a number of the switches to electrically couple the respective light emitters in series to the input power to emit light responsive to the sensed operational parameter of the input power, and wherein the control circuit adjusts the number of the switches deactivated to adjust the number of light emitters electrically coupled in series to the input power responsive to a change in the sensed operational parameter of the input power.

3. The regulator device of claim 2 wherein the control circuit senses at least one of a current value and a voltage value of the input power applied to the number of light emitters electrically coupled in series to the input power.

4. The regulator device of claim 1 wherein each of the plurality of switches is electrically coupled to a respective one of the light emitters.

5. The regulator device of claim 1 wherein a first switch of the plurality of switches is selectively operable to electrically short a first number of the light emitters, wherein a second switch of the plurality of switches is selectively operable to electrically short a second number of the light emitters, the second number being twice the first number.

6. The regulator device of claim 1 wherein the control circuit adjusts the number of switches deactivated to adjust the number of the respective light emitters electrically coupled in series to the input power to achieve a target voltage drop across the total number of light emitters electrically coupled in series to the input power responsive to a change in the sensed operational parameter of the input power.

7. The regulator device of claim 1 wherein the control circuit adjusts the number of switches deactivated to adjust the number of the respective light emitters electrically coupled in series to the input power to achieve a target current value of a current flowing through the total number of light emitters electrically coupled in series to the input power responsive to a change in the sensed operational parameter of the input power.

8. The regulator device of claim 1 wherein the control circuit includes a microcontroller, the microcontroller activates and deactivates a number of the switches to adjust a total number of the plurality of light emitters electrically coupled in series to the input power responsive to the sensed operational parameter of the input power.

9. The regulator device of claim 1 wherein the control circuit includes an analog-to-digital converter (ADC) to activate and deactivate a number of the switches to adjust a total number of the plurality of light emitters electrically coupled in series to the input power responsive to the sensed operational parameter of the input power.

10. The regulator device of claim 1 wherein the control circuit includes a plurality of comparators each of which is electrically coupled to a respective number of the switches to activate and deactivate the respective number of the switches to adjust a total number of the plurality of light emitters electrically coupled in series to the input power responsive to the sensed operational parameter of the input power.

11. The regulator device of claim 1 wherein the control circuit includes a current sensor to sense a current value of the input power, and wherein the current sensor comprises one of a resistive sensor, a Hall-effect sensor, and a sense-coil type sensor.

12. The regulator device of claim 1 wherein the control circuit includes a plurality of pulse width modulation (PWM) modules each of which electrically coupled to drive a respective one of the plurality of switches.

13. The regulator device of claim 12 wherein at least one of the PWM modules drives the respective switch with a pulse stream of increasing duty cycle to activate the respective switch.

14. The regulator device of claim 12 wherein at least one of the PWM modules drives the respective switch with a pulse stream of decreasing duty cycle to deactivate the respective switch.

15. The regulator device of claim 12 wherein the control circuit further includes a triangle wave generator to provide a triangular-wave signal to the PWM modules.

16. The regulator device of claim 1, further comprising:

a voltage regulator to provide a regulated input power to power the control circuit, the voltage regulator electrically coupled to receive power from a base string of light emitters of the plurality of light emitters that is coupled to receive the input power.

17. The regulator device of claim 1 wherein the control circuit and the switches are parts of a processor.

18. An illumination device, comprising:

a first plurality of light emitters coupled to an input power;

a second plurality of light emitters; and

a control system electrically coupled to the second plurality of light emitters and the input power, the control system to sense an operational parameter of the input power, the control system configured to electrically couple a number of the second plurality of light emitters in series to the input power and with the first plurality of light emitters responsive to the sensed operational parameter of the input power exceeding a first threshold value.

19. The illumination device of claim 18, further comprising:

a rectifier circuit coupled to receive an alternating current (AC) power and the control system to rectify the AC power to provide the input power in direct current (DC) form to the control system, wherein the control system is configured to measure a waveform of the AC power.

20. The illumination device of claim 18, further comprising:

a rectifier circuit coupled to receive an alternating current (AC) power and the control system to rectify the AC power to provide the input power in direct current (DC) form to the control system, the rectifier circuit including a bridge rectifier having at least one light-emitting diode (LED).

21. The illumination device of claim 18 wherein the control system senses at least one of a current value and a voltage value of the input power and electrically couples a number of the second plurality of light emitters in series to the input power and with the first plurality of the light emitters responsive to the sensed at least one of the current value and the voltage value of the input power exceeding the respective threshold current value or threshold voltage value.

22. The illumination device of claim 18 wherein the control system electrically couples all of the second plurality of light emitters in series to the input power and with the first plurality of light emitters responsive to the sensed operational parameter of the input power exceeding a second threshold value that is greater than the first threshold value.

23. The illumination device of claim 18 wherein the control system includes a microcontroller and a plurality of transistors each of which is electrically coupled to the microcontroller to be controlled thereby, wherein the microcontroller deactivates at least one of the transistors to electrically couple a number of the second plurality of light emitters in series to the input power and with the first number of the light emitters responsive to the sensed operational parameter of the input power being between the first threshold value and a second threshold value.

24. The illumination device of claim 18 wherein the control system includes an analog-to-digital converter (ADC) and a plurality of transistors each of which is electrically coupled to the ADC to be controlled thereby, wherein the ADC deactivates at least one of the transistors to electrically couple the a number of the second plurality of light emitters in series to the input power and with the first plurality of light emitters responsive to the sensed operational parameter of the input power being between the first threshold value and a second threshold value.

25. The illumination device of claim 18 wherein the control system includes a plurality of comparators and a plurality of transistors, each of the comparators controllingly coupled to a respective number of the transistors, each of the transistors electrically coupled to a respective number of the second plurality of light emitters, wherein each of the comparators compares the sensed operational parameter of the input power to a respective threshold value and deactivates the respective transistors to electrically couple the respective number of the second plurality of light emitters in series to the input power and with the first plurality of light emitters responsive to the sensed operational parameter of the input power being between the respective threshold value and a second threshold value.

26. The illumination device of claim 19 wherein the control system includes a current sensor to sense a current value of the input power, and wherein the current sensor comprises one of a resistive sensor, a Hall-effect sensor, and a sense-coil type sensor.

27. The illumination device of claim 18 wherein the light emitters comprise solid-state light emitters.

28. The illumination device of claim 18 wherein the light emitters comprise LEDs.

29. The illumination device of claim 19, further comprising:

an energy storage element coupled to an output of the rectifier circuit to provide a substantially constant DC voltage for the light emitters.

30. The illumination device of claim 18, further comprising:

a voltage regulator to provide a regulated input power to power the control system, the voltage regulator electrically coupled to receive power from the first plurality of light emitters.

31. The illumination device of claim 30 wherein the voltage regulator is coupled to a first node in a base string of light emitters formed by the first plurality of light emitters, at least one of the light emitters in the base string being between the first node and an electrical ground to provide a DC voltage to the voltage regulator.

32. The illumination device of claim 30, further comprising:

a rectifier electrically coupled between the voltage regulator and the first plurality of light emitters to rectify the power received by the voltage regulator from the first plurality of light emitters; and

an energy storage element electrically coupled between the rectifier and the voltage regulator.

33. The illumination device of claim 18 wherein the control system and at least one of the light emitters are parts of an LED-array light source.

34. The illumination device of claim 18 wherein the control system and at least one of the light emitters are parts of a monolithic LED light source.

35. An illumination device, comprising:

a plurality of light emitters, a first number of light emitters of the plurality of light emitters being electrically coupled in series to an input power;

a plurality of switches which when deactivated electrically couple a respective number of the light emitters to the input power in addition to the first number of the light emitters; and

a control circuit controllingly coupled to the plurality of switches to activate and deactivate the switches in response to a sensed operational parameter of the input power being greater than a first threshold value.

36. The illumination device of claim 35, further comprising:

a rectifier circuit coupled to an alternating current (AC) power to rectify the AC power and coupled to provide the input power in direct current (DC) form to the control circuit and the first number of the light emitters, wherein the control circuit is configured to measure a waveform of the AC power.

37. The illumination device of claim 35, further comprising:

a rectifier circuit coupled to an alternating current (AC) power to rectify the AC power and coupled to provide the input power in direct current (DC) form to the control circuit and the first number of the light emitters, the rectifier circuit including a bridge rectifier having at least one light-emitting diode (LED).

38. The illumination device of claim 35 wherein a first switch of the plurality of switches is electrically coupled to short a second number of the light emitters, wherein a second switch of the plurality of switches is electrically coupled to short a third number of the light emitters, the third number being twice the second number.

39. The illumination device of claim 35 wherein each of the plurality of switches is electrically coupled to short a respective one of the light emitters when activated.

40. The illumination device of claim 35 wherein the control circuit activates all of the switches responsive to the sensed operational parameter of the input power being below the first threshold value.

41. The illumination device of claim 35 wherein the control circuit deactivates a first number of the switches responsive to the sensed operational parameter of the input power being at a first value above the first threshold value.

42. The illumination device of claim 41 wherein the control circuit deactivates a first number plus a second number of the switches responsive to the sensed operational parameter of the input power being at a second value above the first threshold value, the second value being greater than the first value.

43. The illumination device of claim 41 wherein the control circuit deactivates all of the switches responsive to the sensed operational parameter of the input power being above a second threshold value, the second threshold value being greater than the first threshold value.

44. The illumination device of claim 35 wherein the plurality of light emitters comprises a plurality of solid-state light emitters.

45. The illumination device of claim 35 wherein the plurality of light emitters comprises a plurality of LEDs.

46. The illumination device of claim 36, further comprising:

an energy storage element coupled to an output of the rectifier circuit to provide a substantially constant DC voltage for the light emitters.

47. The illumination device of claim 35 wherein the control circuit includes a current sensor to sense a current value of the input power, and wherein the current sensor comprises one of a resistive sensor, a Hall-effect sensor, and a sense-coil type sensor.

48. The illumination device of claim 35 wherein the control circuit includes a plurality of pulse width modulation (PWM) modules each of which electrically coupled to drive a respective one of the plurality of switches.

49. The illumination device of claim 48 wherein at least one of the PWM modules drives the respective switch with a pulse stream of increasing duty cycle to activate the respective switch.

50. The illumination device of claim 48 wherein at least one of the PWM modules drives the respective switch with a pulse stream of decreasing duty cycle to deactivate the respective switch.

51. The illumination device of claim 48 wherein the control circuit further includes a triangle wave generator to provide a triangular-wave signal to the PWM modules.

52. The illumination device of claim 35, further comprising:

a voltage regulator to provide a regulated input power to power the control circuit, the voltage regulator electrically coupled to receive power from the first number of light emitters.

53. The illumination device of claim 52 wherein the voltage regulator is coupled to a first node in a base string of light emitters formed by the first number of light emitters, at least one of the light emitters in the base string being between the first node and an electrical ground to provide a DC voltage to the voltage regulator.

54. The illumination device of claim 52, further comprising:

a rectifier electrically coupled between the voltage regulator and the first number of light emitters to rectify the power received by the voltage regulator from the first number of light emitters; and

an energy storage element electrically coupled between the rectifier and the voltage regulator.

55. The regulator device of claim 35 wherein the control circuit and the switches are parts of a processor.

56. The regulator device of claim 35 wherein the control circuit and at least one of the light emitters are parts of an LED-array light source.

57. The regulator device of claim 35 wherein the control circuit and at least one of the light emitters are parts of a monolithic LED light source.

58. A method to regulate an input power, comprising:

determining a number of light emitters of a plurality of light emitters to be electrically coupled the input power based on an operational parameter of the input power; and

electrically coupling the number of light emitters of the plurality of light emitters to the input power based on the operational parameter of the input power, the number of the light emitters coupled to the input power being between a value M and a value N where the value N is equal to a total quantity of light emitters in the plurality of light emitters, the value M being a positive number greater than zero but less than the value N.

59. The method of claim 58, further comprising:

sensing the operational parameter of the input power.

60. The method of claim 58 wherein electrically coupling a number of light emitters of the plurality of light emitters to the input power based on the operational parameter of the input power comprises electrically coupling a number M of the light emitters in series to the input power in response to the operational parameter of the input power being equal to or less than a threshold value.

61. The method of claim 58 wherein electrically coupling a number of light emitters of the plurality of light emitters to the input power based on the operational parameter of the input power comprises electrically coupling a number R of the light emitters in series to the input power responsive to the sensed operational parameter of the input power being equal to or greater than a threshold value, where the number R is a positive number between M and N.

62. The method of claim 58 wherein electrically coupling a number of light emitters of the plurality of light emitters to the input power based on the operational parameter of the input power comprises varying the number of the light emitters electrically coupled in series to the input power to be between the value M and the value N by a variable increment responsive to the sensed operational parameter of the input power, the variable increment ranging between 1 and a value equal to N−

M.

63. The method of claim 62 wherein varying the number of the light emitters electrically coupled in series to the input power to be between the value M and the value N by a variable increment comprises varying the number of the light emitters electrically coupled in series to the input power to be between the value M and the value N by a number of 2 to the P^th power, where P is a positive integer greater than or equal to zero.

64. The method of claim 58 wherein electrically coupling a number of light emitters of the plurality of light emitters to the input power based on the operational parameter of the input power comprises varying the number of the light emitters electrically coupled in series to the input power to be between the value M and the value N by an increment or decrement equal to 1 responsive to the sensed operational parameter of the input power being greater than a threshold value.

65. The method of claim 58 wherein electrically coupling a number of light emitters of the plurality of light emitters to the input power based on the operational parameter of the input power comprises deactivating a number of a plurality of switches to electrically couple a respective number of the light emitters to the input power in response to the operational parameter of the input power being greater than a threshold value, the respective number of the emitters coupled to the input power being between the value M and the value N.

66. The method of claim 59 wherein sensing the operational parameter of an input power comprises sensing at least one of a current value and a voltage value of the input power.

67. The method of claim 58 wherein electrically coupling a number of light emitters of a plurality of light emitters to the input power comprises electrically coupling a number of solid-state light emitters of a plurality of solid-state light emitters to the input power.

68. The method of claim 58 wherein electrically coupling a number of light emitters of a plurality light emitters to the input power comprises electrically coupling a number of light-emitting diodes (LEDs) of a plurality of LEDs to the input power.

69. A method to regulate an input power, comprising:

electrically coupling a number of light emitters of a plurality of light emitters to the input power; and

maintaining a first operational parameter of the input power proximate to a target value by adjusting a total number of light emitters of the plurality of light emitters electrically coupled to the input power responsive to a variation in a second operational parameter of the input power.

70. The method of claim 69 wherein electrically coupling a number of light emitters of a plurality of light emitters to an input power comprises electrically coupling a number of solid-state light emitters of a plurality of solid-state light emitters to the input power.

71. The method of claim 69 wherein electrically coupling a number of light emitters of a plurality of light emitters to the input power comprises electrically coupling a number of light-emitting diodes (LEDs) of a plurality of LEDs to the input power.

72. The method of claim 69 wherein maintaining a first operational parameter of the input power proximate to a target value comprises maintaining a current value of the input power proximate to a target current value.

73. The method of claim 69 wherein adjusting a total number of light emitters of the plurality of light emitters electrically coupled to the input power responsive to a variation in a second operational parameter of the input power comprises electrically coupling a first number of light emitters of the plurality of light emitters in series to the input power responsive to the second operational parameter of the input power being equal to or less than a first threshold value.

74. The method of claim 73, further comprising:

electrically coupling a variable number of light emitters of the plurality of light emitters in series to the input power responsive to the second operational parameter of the input power being between the first threshold value and a second threshold value that is greater than the first threshold value, where the variable number is greater than the first number.

75. The method of claim 74, further comprising:

electrically coupling all of the light emitters of the plurality of light emitters in series to the input power responsive to the second operational parameter of the input power exceeding the second threshold value.

76. The method of claim 69 wherein adjusting a total number of light emitters of the plurality of light emitters electrically coupled to the input power responsive to a variation in a second operational parameter of the input power comprises adjusting the number of light emitters of the plurality of light emitters electrically coupled in series to the input power proportionally to the variation in the second operational parameter of the input power.

77. The method of claim 69 wherein adjusting a total number of light emitters of the plurality of light emitters electrically coupled to the input power responsive to a variation in a second operational parameter of the input power comprises electrically coupling substrings of light emitters of the plurality of light emitters in series to the input power responsive to a variation in the second operational parameter of the input power.

78. The method of claim 69 wherein maintaining a first operational parameter of the input power proximate to a target value by adjusting a total number of light emitters of the plurality of light emitters electrically coupled to the input power responsive to a variation in a second operational parameter of the input power comprises maintaining the first operational parameter of the input power proximate to the target value by adjusting a total number of light emitters of the plurality of light emitters electrically coupled in series to the input power to achieve a voltage drop across the number of light emitters electrically coupled in series to the input power responsive to a variation in the second operational parameter of the input power.

79. The method of claim 69 wherein the first and the second operational parameters of the input power are the same as one another.

80. The method of claim 69 wherein the first and the second operational parameters of the input power are different from one another.

81. An illumination device, comprising:

a light emitting diode-based rectifier that includes a plurality of diodes arranged as a bridge circuit, at least one of the plurality of diodes being a light emitting diode, the bridge circuit coupleable to an alternating current (AC) power and operable to rectify the AC power and provide a direct current (DC) power output.

82. The illumination device of claim 81 wherein the bridge circuit includes four legs, each of the legs including at least one light emitting diode.