Power control methods and apparatus

• US 20050213352A1
• Filed: 03/14/2005
• Published: 09/29/2005
• Est. Priority Date: 03/15/2004
• Status: Active Grant

• Current Assignee: Signify North America Corporation (Signify N.V.)
• Original Assignee: Color Kinetics Incorporated (Signify N.V.)
• Inventors: Lys, Ihor A.
• Granted Patent: US 7,459,864 B2
• Time in Patent Office: Days
• US Class Current: 363/17
• CPC Class Codes: H02M 1/0012 Control circuits using digital or numerical techniques in DC/DC converters H02M3/157, H02M3/33515; in DC-AC converters H02M7/53873
• CPC Class Codes: H02M 1/0019 the disturbance parameters being load current fluctuations
• CPC Class Codes: H02M 1/008 Plural converter units for generating at two or more independent and non-parallel outputs, e.g. systems with plural point of load switching regulators
• CPC Class Codes: H02M 1/4225 using a non-isolated boost converter
• CPC Class Codes: H02M 1/425 using a single converter stage both for correction of AC input power factor and generation of a high frequency AC output voltage
• CPC Class Codes: H02M 1/4291 by using a Buck converter to switch the input current
• CPC Class Codes: H02M 3/155 using semiconductor devices only
• CPC Class Codes: H02M 3/156 with automatic control of output voltage or current, e.g. switching regulators
• CPC Class Codes: H02M 3/157 with digital control
• CPC Class Codes: H02M 3/33561 having more than one ouput with independent control
• CPC Class Codes: H05B 45/10 Controlling the intensity of the light
• CPC Class Codes: H05B 45/14 using electrical feedback from LEDs or from LED modules
• CPC Class Codes: H05B 45/24 using electrical feedback from LEDs or from LED modules
• CPC Class Codes: H05B 45/305 Frequency-control circuits
• CPC Class Codes: H05B 45/355 Power factor correction [PFC]; Reactive power compensation
• CPC Class Codes: H05B 45/3725 Switched mode power supply [SMPS]
• CPC Class Codes: H05B 45/375 using buck topology
• CPC Class Codes: H05B 45/38 using boost topology
• CPC Class Codes: H05B 45/385 using flyback topology
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

Methods and apparatus for providing and controlling power to at least some types of loads. In one example, a controlled predetermined power is provided to a load without requiring any feedback information from the load (i.e., without monitoring a load voltage and/or load current). In another example, a “feed-forward” power driver for an LED-based light source combines the functionality of a DC-DC converter and a light source controller, and is configured to control the intensity of light generated by the light source based on modulating the average power delivered to the light source in a given time period, without monitoring and/or regulating the voltage or current provided to the light source. In various examples, significantly streamlined circuits having fewer components, higher overall power efficiencies, and smaller space requirements are realized. Based on various power driver configurations, lighting apparatus incorporating one or more power drivers for one or more LED-based loads may be implemented, and multiple such lighting apparatus may be coupled together to form a lighting network in which operating power is efficiently provided throughout the network.

Claims

1. An apparatus, comprising:

at least one energy transfer element to store input energy derived from a power source and to provide output energy to a load;

at least one switch coupled to the at least one energy transfer element to control at least the input energy stored to the at least one energy transfer element; and

at least one switch controller configured to receive at least one control signal representing a desired load power and control the at least one switch in response to the at least one control signal, wherein the at least one switch controller does not receive any feedback information relating to the load to control the at least one switch.

2. The apparatus of claim 1, wherein the apparatus is configured such that neither a load voltage nor a load current is monitored or regulated.

3. The apparatus of claim 2, wherein the at least one switch controller is configured to control at least one of a frequency and a duty cycle of multiple switching operations of the at least one switch so as to provide a controllably variable power to the load.

4. The apparatus of claim 1, wherein:

the at least one switch includes only one single switch;

a DC supply voltage provides the power source;

the apparatus is configured to apply a first converted DC voltage across the load; and

the at least one switch controller is further configured to control the one single switch to facilitate a first conversion of the DC supply voltage to the first converted DC voltage and concurrently provide a controllably variable power to the load.

5. The apparatus of claim 1, wherein the at least one switch controller is further configured to control at least one power factor correction apparatus based at least in part on the at least one control signal representing the desired load power.

6. The apparatus of claim 1, wherein the at least one switch controller is configured to control the at least one switch based on at least one of a voltage output by the power source and a current drawn from the power source, and the at least one control signal representing a desired load power.

7. The apparatus of claim 6, wherein the at least one switch controller is configured as an addressable device so as to facilitate control of the apparatus via a network.

8. The apparatus of claim 7, wherein the at least one control signal representing the desired power to the load is formatted using a DMX protocol.

9. The apparatus of claim 6, further comprising an energy transfer arrangement that includes the at least one energy transfer element, the at least one switch, and at least one diode, wherein the energy transfer arrangement is configured as one of a buck converter, a boost converter, a buck-boost converter, a CUK converter, a flyback converter and a forward converter.

10. The apparatus of claim 9, wherein the at least one switch controller is configured to control the at least one switch to perform multiple switching operations in at least one time period, each switching operation transferring a predetermined quantum of the input energy to the at least one energy transfer element.

11. The apparatus of claim 10, wherein the at least one switch controller is configured to control the multiple switching operations so as to vary at least one of:

the predetermined quantum of the input energy for at least two switching operations; and

a number of the multiple switching operations in the at least one time period, so as to provide a controllably variable power to the load.

12. The apparatus of claim 9, wherein the at least one switch controller is configured to control the at least one switch using a discontinuous mode switching technique.

13. The apparatus of claim 12, wherein the at least one switch controller is configured to control at least one of a frequency and a duty cycle of multiple switching operations of the at least one switch, based on the at least one control signal representing the desired load power.

14. The apparatus of claim 13, wherein the at least one switch controller is configured to controllably vary the duty cycle of the multiple switching operations, based on the at least one control signal representing the desired load power, while holding substantially constant the frequency of the multiple switching operations.

15. The apparatus of claim 13, wherein the at least one switch controller is configured to controllably vary the duty cycle of the multiple switching operations, based on the at least one control signal representing the desired load power.

16. The apparatus of claim 15, wherein the at least one switch controller is configured to controllably vary the duty cycle of the multiple switching operations based at least on the current drawn from the power source.

17. The apparatus of claim 16, further comprising at least one current sensing device, coupled to the at least one switch, to generate a value representing the current drawn from the power source, wherein the at least one switch controller is configured to controllably vary the duty cycle of the multiple switching operations based on a comparison of the value representing the current drawn from the power source and the at least one control signal representing the desired power to the load.

18. The apparatus of claim 17, wherein the at least one switch controller comprises:

a comparator to make the comparison of the value representing the current drawn from the power source and the at least one control signal representing the desired power to the load;

an oscillator to generate a pulse stream having the frequency of the multiple switching operations; and

a pulse width modulator, coupled to the comparator, the oscillator, and the at least one switch, and configured to generate a pulse width modulated signal, based on the comparison and the pulse stream, to control the at least one switch.

19. The apparatus of claim 15, wherein the at least one switch controller is configured to controllably vary the duty cycle of the multiple switching operations based at least on the voltage output from the power source.

20. The apparatus of claim 19, wherein the at least one switch controller is configured to controllably vary the duty cycle of the multiple switching operations based on a comparison of a value representing the voltage output by the power source and the at least one control signal representing the desired power to the load.

21. The apparatus of claim 20, wherein the at least one switch controller comprises:

an analog to digital converter, coupled to the voltage output by the power source, to generate the value representing the voltage output by the power source;

an oscillator to generate a pulse stream having the frequency of the multiple switching operations; and

a processor to make the comparison of the value representing the voltage output by the power source and the at least one control signal representing the desired power to the load, the processor further configured to generate a pulse width modulated signal, based on the comparison and the pulse stream, to control the at least one switch.

22. The apparatus of claim 13, wherein the at least one switch controller is configured to controllably vary the frequency of the multiple switching operations, based on the at least one control signal representing the desired load power, while holding substantially constant the duty cycle of the multiple switching operations.

23. The apparatus of claim 13, wherein the at least one switch controller is configured to controllably vary the frequency of the multiple switching operations, based on the at least one control signal representing the desired load power.

24. The apparatus of claim 23, wherein the at least one switch controller is configured to controllably vary the frequency by controllably varying an effective frequency of the multiple switching operations using a pulse number modulation technique.

25. The apparatus of claim 24, wherein the at least one switch controller comprises a pulse generation controller, the pulse generation controller comprising:

an oscillator to generate a pulse stream having a reference frequency; and

at least one component configured to receive the pulse stream having the reference frequency and output a modified pulse stream having the effective frequency of the multiple switching operations, wherein the effective frequency may be controllably varied based on the at least one control signal representing the desired load power.

26. The apparatus of claim 25, wherein the at least one component comprises:

an N-bit register to store a digital value representing the effective frequency, based on the at least one control signal representing the desired load power;

an N-bit accumulator, coupled to the oscillator, to receive the pulse stream as a clock signal having the reference frequency; and

an adder, coupled to the N-bit register and the N-bit accumulator, to add the digital value stored in the N-bit register and an accumulator value stored in the N-bit accumulator to provide a summed value,

wherein the summed value is provided as an input to the N-bit accumulator, and the modified pulse stream having the effective frequency is provided as a carry signal output by the N-bit accumulator.

27. The apparatus of claim 26, wherein the number N is selected such that a minimum-to-maximum frequency ratio for the effective frequency, defined by the quantity (1:

2^N), is less than a predetermined required minimum ratio, so as to enhance a power resolution capability of the pulse generation controller.

28. The apparatus of claim 27, wherein the predetermined required minimum ratio is approximately 1:

1000, and wherein the number N is greater than 10.

29. The apparatus of claim 27, wherein the digital value representing the effective frequency includes an offset related to a difference between the minimum-to-maximum frequency ratio and the predetermined required minimum ratio.

30. The apparatus of claim 29, wherein the at least one component further comprises a shift register, coupled to the N-bit register, to receive the at least one control signal representing the desired load power and provide the offset to the digital value.

31. The apparatus of claim 25, wherein the at least one switch controller is configured to determine the duty cycle of the multiple switching operations based at least on a comparison of a value representing the current drawn from the power source and a set point value representing a desired duty cycle.

32. The apparatus of claim 25, wherein the at least one switch controller is configured to determine the duty cycle of the multiple switching operations based at least on a comparison of a value representing the voltage output from the power source and a set point value representing a desired duty cycle.

33. The apparatus of claim 13, wherein the at least one switch controller is configured to control both of the frequency and the duty cycle of the multiple switching operations of the at least one switch, based on the at least one control signal representing the desired power to the load.

34. The apparatus of claim 33, wherein the at least one switch controller is configured to control the frequency by controllably varying an effective frequency of the multiple switching operations using a pulse number modulation technique.

35. The apparatus of claim 34, wherein the at least one switch controller is configured to controllably vary the duty cycle of the multiple switching operations based at least on the current drawn from the power source.

36. The apparatus of claim 34, wherein the at least one switch controller is configured to controllably vary the duty cycle of the multiple switching operations based at least on the voltage output from the power source.

37. The apparatus of claim 13, wherein the at least one switch controller comprises a processor to receive the at least one control signal representing the desired power to the load, the processor being configured to control at least one of the frequency and the duty cycle of the multiple switching operations based on a relative range of the desired power to the load.

38. The apparatus of claim 37, wherein the desired power to the load includes at least a first range and a second range, wherein the processor is configured to control only one of the frequency and the duty cycle of the multiple switching operations in the first range, and wherein the processor is configured to control both of the frequency and the duty cycle of the multiple switching operations in the second range.

39. The apparatus of claim 37, wherein the desired power to the load includes at least a first range, a second range, and a third range, and wherein the processor is configured to control only the frequency of the multiple switching operations in the first range, only the duty cycle of the multiple switching operations in the second range, and both of the frequency and the duty cycle of the multiple switching operations in the third range.

40. The apparatus of claim 37, wherein the processor is an addressable device so as to facilitate control of the apparatus via a network.

41. The apparatus of claim 40, wherein the at least one control signal representing the desired power to the load is formatted using a DMX protocol.

42. The apparatus of claim 37, wherein the at least one switch controller is configured to determine the duty cycle of the multiple switching operations based at least on the current drawn from the power source.

43. The apparatus of claim 37, wherein the at least one switch controller is configured to determine the duty cycle of the multiple switching operations based at least on the voltage output from the power source.

44. The apparatus of claim 13, wherein the at least one energy transfer element includes at least one of a tapped inductor and a transformer with a non-unity turns ratio.

45. The apparatus of claim 44, wherein the energy transfer arrangement is configured as a buck converter.

46. The apparatus of claim 45, further comprising the load, wherein the load includes at least one LED.

47. A method, comprising acts of:

A) storing input energy derived from a power source to at least one energy transfer element;

B) providing output energy from the at least one energy transfer element to a load;

C) controlling at least the input energy stored to the at least one energy transfer element via at least one switch coupled to the at least one energy transfer element;

D) receiving at least one control signal representing a desired load power; and

E) controlling the at least one switch in response to the at least one control signal without receiving any feedback information relating to the load.

48. The method of claim 47, wherein the act B) comprises an act of:

providing the output energy without regulating either a load voltage or a load current.

49. The method of claim 47, wherein the act E) comprises an act of:

controlling the at least one switch without monitoring either a load voltage or a load current.

50. The method of claim 49, wherein the act B) comprises an act of:

providing the output energy without regulating either a load voltage or a load current.

51. The method of claim 50, wherein the act E) comprises an act of:

controlling at least one of a frequency and a duty cycle of multiple switching operations of the at least one switch so as to provide a controllably variable power to the load.

52. The method of claim 47, wherein the at least one switch includes only one single switch, wherein a DC supply voltage provides the power source, wherein a first converted DC voltage is applied across the load, and wherein the act E) comprises an act of:

controlling the one single switch to facilitate a first conversion of the DC supply voltage to the first converted DC voltage and concurrently provide a controllably variable power to the load.

53. The method of claim 47, further comprising an act of:

controlling at least one power factor correction apparatus based at least in part on the at least one control signal representing the desired load power.

54. The method of claim 47, wherein the act E) comprises an act of:

E1) controlling the at least one switch based on at least one of a voltage output by the power source and a current drawn from the power source, and the at least one control signal representing a desired load power.

55. The method of claim 54, further comprising an act of transmitting the at least one control signal representing the desired power to the load as at least one addressed control signal.

56. The method of claim 55, further comprising an act of formatting the at least one control signal representing the desired power to the load using a DMX protocol.

57. The method of claim 54, further comprising an energy transfer arrangement that includes the at least one energy transfer element, the at least one switch, and at least one diode, wherein the energy transfer arrangement is configured as one of a buck converter, a boost converter, a buck-boost converter, a CUK converter, a flyback converter and a forward converter.

58. The method of claim 57, wherein the act E1) comprises an act of:

E2) controlling the at least one switch to perform multiple switching operations in at least one time period, each switching operation transferring a predetermined quantum of the input energy to the at least one energy transfer element.

59. The method of claim 58, wherein the act E2) comprises an act of:

controlling the multiple switching operations so as to vary at least one of;

the predetermined quantum of the input energy for at least two switching operations; and

a number of the multiple switching operations in the at least one time period, so as to provide a controllably variable power to the load.

60. The method of claim 57, wherein the act E1) comprises an act of:

E2) controlling the at least one switch using a discontinuous mode switching technique.

61. The method of claim 60, wherein the act E2) comprises an act of:

E3) controlling at least one of a frequency and a duty cycle of multiple switching operations of the at least one switch, based on the at least one control signal representing the desired load power.

62. The method of claim 61, wherein the act E3) comprises an act of:

controllably varying the duty cycle of the multiple switching operations, based on the at least one control signal representing the desired load power, while holding substantially constant the frequency of the multiple switching operations.

63. The method of claim 61, wherein the act E3) comprises an act of:

E4) controllably varying the duty cycle of the multiple switching operations, based on the at least one control signal representing the desired load power.

64. The method of claim 63, wherein the act E4) comprises an act of:

E5) controllably varying the duty cycle of the multiple switching operations based at least on the current drawn from the power source.

65. The method of claim 64, further comprising at least one current sensing device, coupled to the at least one switch, to generate a value representing the current drawn from the power source, wherein the act E5) comprises an act of:

E6) controllably varying the duty cycle of the multiple switching operations based on a comparison of the value representing the current drawn from the power source and the at least one control signal representing the desired power to the load.

66. The method of claim 65, wherein the act E6) further comprises acts of:

making a comparison of the value representing the current drawn from the power source and the at least one control signal representing the desired power to the load;

generating a pulse stream having the frequency of the multiple switching operations; and

generating a pulse width modulated signal, based on the comparison and the pulse stream, to control the at least one switch.

67. The method of claim 63, wherein the act E4) comprises an act of:

E5) controllably varying the duty cycle of the multiple switching operations based at least on the voltage output from the power source.

68. The method of claim 67, wherein the act E5) comprises an act of:

E6) controllably varying the duty cycle of the multiple switching operations based on a comparison of a value representing the voltage output by the power source and the at least one control signal representing the desired power to the load.

69. The method of claim 68, wherein the act E6) comprises acts of:

generating a pulse stream having the frequency of the multiple switching operations;

making the comparison of the value representing the voltage output by the power source and the at least one control signal representing the desired power to the load; and

generating a pulse width modulated signal, based on the comparison and the pulse stream, to control the at least one switch.

70. The method of claim 61, wherein the act E3) comprises an act of:

controllably varying the frequency of the multiple switching operations, based on the at least one control signal representing the desired load power, while holding substantially constant the duty cycle of the multiple switching operations.

71. The method of claim 61, wherein the act E3) comprises an act of:

E4) controllably varying the frequency of the multiple switching operations, based on the at least one control signal representing the desired load power.

72. The method of claim 71, wherein the act E4) comprises an act of:

E5) controllably varying the frequency by controllably varying an effective frequency of the multiple switching operations using a pulse number modulation technique.

73. The method of claim 72, wherein the act E5) comprises acts of:

E6) generating a pulse stream having a reference frequency; and

E7) generating a modified pulse stream based on the pulse stream having the reference frequency, the modified pulse stream having the effective frequency of the multiple switching operations.

74. The method of claim 73, wherein the act E7) comprises acts of:

storing an N-bit digital value representing the effective frequency, based on the at least one control signal representing the desired load power;

inputting the pulse stream as a clock signal having the reference frequency to an N-bit accumulator; and

adding the N-bit digital value to an accumulator value stored in the N-bit accumulator to provide a summed value,

inputting the summed value to the N-bit accumulator; and

providing the modified pulse stream having the effective frequency as a carry signal output by the N-bit accumulator.

75. The method of claim 74, further comprising an act of:

selecting the number N such that a minimum-to-maximum frequency ratio for the effective frequency, defined by the quantity (1;

2^N), is less than a predetermined required minimum ratio, so as to enhance a power resolution capability of the pulse generation controller.

76. The method of claim 75, wherein the predetermined required minimum ratio is approximately 1:

1000, and wherein the number N is greater than 10.

77. The method of claim 75, further comprising an act of:

including an offset to the N-bit digital value representing the effective frequency, wherein the offset relates to a difference between the minimum-to-maximum frequency ratio and the predetermined required minimum ratio.

78. The method of claim 73, further comprising an act of:

determining the duty cycle of the multiple switching operations based at least on a comparison of a value representing the current drawn from the power source and a set point value representing a desired duty cycle.

79. The method of claim 73, further comprising an act of:

determining the duty cycle of the multiple switching operations based at least on a comparison of a value representing the voltage output from the power source and a set point value representing a desired duty cycle.

80. The method of claim 61, wherein the act E3) comprises an act of:

E4) controlling both of the frequency and the duty cycle of the multiple switching operations of the at least one switch, based on the at least one control signal representing the desired power to the load.

81. The method of claim 80, wherein the act E4) comprises an act of:

controlling the frequency by controllably varying an effective frequency of the multiple switching operations using a pulse number modulation technique.

82. The method of claim 81, wherein the act E4) comprises an act of:

controlling the duty cycle of the multiple switching operations based at least on the current drawn from the power source.

83. The method of claim 81, wherein the act E4) comprises an act of:

controlling the duty cycle of the multiple switching operations based at least on the voltage output by the power source.

84. The method of claim 61, wherein the act E3) comprises an act of:

E4) controlling at least one of the frequency and the duty cycle of the multiple switching operations based on a relative range of the desired power to the load.

85. The method of claim 84, wherein the desired power to the load includes at least a first range and a second range, and wherein the act E4) comprises acts of:

controlling only one of the frequency and the duty cycle of the multiple switching operations in the first range; and

controlling both of the frequency and the duty cycle of the multiple switching operations in the second range.

86. The method of claim 84, wherein the desired power to the load includes at least a first range, a second range, and a third range, and wherein the act E4) comprises acts of:

controlling only the frequency of the multiple switching operations in the first range;

controlling only the duty cycle of the multiple switching operations in the second range; and

controlling both of the frequency and the duty cycle of the multiple switching operations in the third range.

87. The method of claim 84, further comprising an act of transmitting the at least one control signal representing the desired power to the load as at least one addressed control signal.

88. The method of claim 87, further comprising an act of formatting the at least one control signal representing the desired power to the load using a DMX protocol.

89. The method of claim 84, wherein the act E4) comprises an act of:

determining the duty cycle of the multiple switching operations based at least on the current drawn from the power source.

90. The method of claim 84, wherein the act E4) comprises an act of:

determining the duty cycle of the multiple switching operations based at least on the voltage output by the power source.

91. The method of claim 61, wherein the at least one energy transfer element includes at least one of a tapped inductor and a transformer with a non-unity turns ratio.

92. The method of claim 91, wherein the energy transfer arrangement is configured as a buck converter.

93. The method of claim 92, further comprising the load, wherein the load includes at least one LED.