Methods and apparatus for high power factor controlled power delivery using a single switching stage per load

• US 7,511,437 B2
• Filed: 05/08/2006
• Issued: 03/31/2009
• Est. Priority Date: 02/10/2006
• Status: Active Grant

• Current Assignee: Signify North America Corporation (Signify N.V.)
• Original Assignee: Philips Solid-State Lighting Solutions (Koninklijke Philips N.V.)
• Inventors: Rabiner, Mark David, Lys, Ihor A., Shikh, Igor
• Primary Examiner(s): Vu; David Hung
• Assistant Examiner(s): Le; Tung X
• Application Number:
  US11/429,715
• Publication Number:
  US 20070188114A1
• Time in Patent Office: 1,058 Days
• Field of Search: 315149-152, 315224-225, 315/247, 315/291, 315/307, 315/362
• US Class Current: 315/307
• CPC Class Codes: H02M 1/4225 using a non-isolated boost converter
• CPC Class Codes: H05B 45/14 using electrical feedback from LEDs or from LED modules
• CPC Class Codes: H05B 45/305 Frequency-control circuits
• CPC Class Codes: H05B 45/325 Pulse-width modulation [PWM]
• 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 45/385 using flyback topology
• CPC Class Codes: H05B 45/39 Circuits containing inverter bridges
• CPC Class Codes: H05B 45/50 responsive to malfunctions or undesirable behaviour of LEDs; responsive to LED life; Protective circuits
• CPC Class Codes: H05B 45/59 for reducing or suppressing flicker or glow effects
• CPC Class Codes: H05B 47/18 via data-bus transmission
• CPC Class Codes: Y02B 20/30 Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]
• 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 high power factor power transfer to a load using a single switching stage. In exemplary implementations, a controllable variable power may be delivered to a load using a single switching stage while maintaining high power factor, in some cases without requiring any feedback information relating to the load conditions (i.e., without monitoring load voltage and/or current) to control normal switching operations in the single switching stage, and without requiring regulation of load voltage and/or load current. In one example, a single stage high power factor driver is used to control power delivery to an LED-based light source.

Claims

1. A lighting apparatus, comprising:

at least a first load that includes at least one first LED-based light source; and

a switching power supply including a first single switching stage for the first load, the switching power supply configured to provide power factor correction and a first load power to the first load via control of the first single switching stage,

wherein the switching power supply further is configured to control the first single switching stage to provide the first load power without monitoring or regulating a first load current or a first load voltage associated with the first load, the switching power supply further comprising a rectifier configured to be coupled to an A.C. voltage source and provide as an output a rectified voltage waveform; and

at least one controller configured to control first switching operations of the first single switching stage,

wherein the first single switching stage comprises at least a first energy transfer arrangement configured to provide the first load power to the first load based on a periodic coupling of the rectified voltage waveform to the first energy transfer arrangement, and

wherein the at least one controller is configured to control first switching operations of the first single switching stage to implement the periodic coupling of the rectified voltage waveform to the first energy transfer arrangement and the provision of the first load power to the first load.

2. The apparatus of claim 1, wherein the at least one first LED-based light source is configured to generate essentially white light.

3. The apparatus of claim 2, wherein the at least one first LED-based light source includes at least one white LED.

4. The apparatus of claim 1, wherein the switching power supply further is configured to control the first single switching stage such that a power factor associated with the apparatus is approximately or equal to unity.

5. The apparatus of claim 1, wherein the first energy transfer arrangement includes a plurality of components arranged in a flyback converter configuration.

6. The apparatus of claim 1, wherein the at least one controller is configured to control the first switching operations such that the first single switching stage operates in a discontinuous mode.

7. The apparatus of claim 1, wherein the at least one controller is configured to control the first switching operations based at least in part on at least one of the rectified voltage waveform and a current drawn from the rectifier.

8. The apparatus of claim 7, wherein the at least one controller further is configured to control the first switching operations based at least in part on first information representing a first desired load power for the first load.

9. The apparatus of claim 8, wherein:

the first information includes a first lighting command representing a first value for the first desired load power during a first time period and a second lighting command representing a second value for the first desired load power during a second time period immediately following the first time period, wherein the second value is greater than the first value; and

the at least one controller is configured to control the first switching operations so as to gradually increase the first load power from the first value to the second value via at least one intervening value between the first value and the second value.

10. The apparatus of claim 9, wherein the at least one controller is configured to process the first and second lighting commands so as to generate at least one additional lighting command representing the at least one intervening value.

11. The apparatus of claim 8, wherein the at least one controller is configured to control at least one of a duty cycle and a frequency of the first switching operations.

12. The apparatus of claim 11, wherein:

the at least one controller is configured to control the duty cycle and the frequency of the first switching operations; and

the at least one controller is further configured to apportion respective weights associated with the duty cycle and the frequency of the first switching operations based at least in part on the first information representing the first desired load power.

13. The apparatus of claim 12, wherein the at least one controller is configured to equally apportion the weights associated with the duty cycle and the frequency of the first switching operations.

14. The apparatus of claim 12, wherein a first parameter t_gain represents the duty cycle as a percentage of a maximum duty cycle, wherein a second parameter t_gain represents the frequency as a percentage of a maximum frequency, and wherein the at least one controller is configured to apportion the weights associated with the duty cycle and the frequency such that a product given by (t_gain)² multiplied by f_gain is less than or equal to one.

15. The apparatus of claim 12, wherein a first parameter t_gain represents the duty cycle as a percentage of a maximum duty cycle, wherein a second parameter f_gain represents the frequency as a percentage of a maximum frequency, and wherein the at least one controller is configured to apportion the weights associated with the duty cycle and the frequency such that (t_gain)²=f_gain.

16. The apparatus of claim 1, further comprising:

a second load that includes at least one second LED-based light source,

wherein the switching power supply includes a second single switching stage for the second load, the switching power supply configured to provide the power factor correction, the first load power, and a second load power to the second load via control of the second single switching stage, and

wherein the at least one controller is configured to control the second single switching stage to provide the second load power without monitoring or regulating a second load current or a second load voltage associated with the second load.

17. The apparatus of claim 16, wherein the second single switching stage comprises:

a second energy transfer arrangement configured to provide the second load power to the second load based on a second periodic coupling of the rectified voltage waveform to the second energy transfer arrangement,

wherein the at least one controller is configured to control second switching operations of the second single switching stage to implement the second periodic coupling of the rectified voltage waveform to the second energy transfer arrangement and the provision of the second load power to the second load.

18. The apparatus of claim 17, wherein the at least one controller is configured to independently control the first switching operations and the second switching operations based at least in part on first information representing a first desired load power and second information representing a second desired load power.

19. The apparatus of claim 18, wherein:

the at least one first LED-based light source includes at least one first LED configured to generate first radiation having a first spectrum; and

the at least one second LED-based light source includes at least one second LED configured to generate second radiation having a second spectrum different from the first spectrum.

20. The apparatus of claim 19, wherein the at least one controller is configured as an addressable device so as to facilitate control of the apparatus via a network.

21. The apparatus of claim 19, wherein the at least one first LED includes at least one first white LED.

22. The apparatus of claim 21, wherein the at least one second LED includes at least one second white LED.

23. The apparatus of claim 22, wherein the at least one controller is configured as an addressable device so as to facilitate control of the apparatus via a network.

24. The apparatus of claim 1, wherein the switching power supply further comprises:

open circuit protection circuitry configured to detect an open circuit condition representing an absence or a failure of at least the first load, wherein the switching power supply further is configured to interrupt operation of at least the first single switching stage upon detection of the open circuit condition.

25. A lighting method, comprising acts of:

A) generating first light from a first load including at least one first LED-based light source; and

B) providing power factor correction and a first load power to the first load via control of a first single switching stage without monitoring or regulating a first load current or a first load voltage associated with the first load,

wherein the first single switching stage includes a first energy transfer arrangement, and wherein the act B) further comprises an act of;

B1) controlling first switching operations of the first switching stage so as to periodically couple a rectified voltage waveform to the first energy transfer arrangement.

26. The method of claim 25, wherein the act A) comprises an act of:

generating essentially white light from the at least one first LED-based light source.

27. The method of claim 25, wherein the act B) comprises an act of:

controlling the first single switching stage such that a power factor associated with the first single switching stage is approximately or equal to unity.

28. The method of claim 25, wherein the first energy transfer arrangement includes a plurality of components arranged in a flyback converter configuration.

29. The method of claim 25, wherein the act B1) comprises an act of:

controlling the first switching operations such that the first single switching stage operates in a discontinuous mode.

30. The method of claim 25, wherein the act B1) comprises an act of:

B2) controlling the first switching operations based at least in part on at least one of the rectified voltage waveform and a current associated with the rectified voltage waveform.

31. The method of claim 25, wherein the act B1) comprises an act of:

B3) controlling the first switching operations based at least in part on first information representing a first desired load power for the first load.

32. The method of claim 31, wherein:

the first information includes a first lighting command representing a first value for the first desired load power during a first time period and a second lighting command representing a second value for the first desired load power during a second time period immediately following the first time period, wherein the second value is greater than the first value; and

the act B3) comprises an act of;

B4) controlling the first switching operations so as to gradually increase the first load power from the first value to the second value via at least one intervening value between the first value and the second value.

33. The method of claim 32, wherein the act B4) comprises an act of:

processing the first and second lighting commands so as to generate at least one additional lighting command representing the at least one intervening value.

34. The method of claim 31, wherein the act B3) comprises an act of:

B5) controlling at least one of a duty cycle and a frequency of the first switching operations.

35. The method of claim 34, wherein the act B5) comprises acts of:

B6) controlling the duty cycle and the frequency of the first switching operations; and

B7) apportioning respective weights associated with the duty cycle and the frequency of the first switching operations based at least in part on the first information representing the first desired load power.

36. The method of claim 35, wherein the act B7) comprises an act of:

equally apportioning the weights associated with the duty cycle and the frequency of the first switching operations.

37. The method of claim 35, wherein a first parameter t_gain represents the duty cycle as a percentage of a maximum duty cycle, wherein a second parameter f_gain represents the frequency as a percentage of a maximum frequency, and wherein the act B7) comprises an act of:

apportioning the weights associated with the duty cycle and the frequency such that a product given by (t_gain)² multiplied by f_gain is less than or equal to one.

38. The method of claim 35, wherein a first parameter t_gain represents the duty cycle as a percentage of a maximum duty cycle, wherein a second parameter f_gain represents the frequency as a percentage of a maximum frequency, and wherein the act B7) comprises an act of:

apportioning the weights associated with the duty cycle and the frequency such that (t_gain)²=f_gain.

39. The method of claim 25, further comprising acts of:

C) generating second light from a second load including at least one second LED-based light source; and

D) providing a second load power to the second load via control of a second single switching stage without monitoring or regulating a second load current or a second load voltage associated with the second load.

40. The method of claim 39, wherein the second single switching stage includes a second energy transfer arrangement, and wherein the act D) further comprises an act of:

D1) controlling second switching operations of the second switching stage so as to periodically couple the rectified voltage waveform to the second energy transfer arrangement.

41. The method of claim 40, wherein the act D1) comprises an act of:

independently controlling the first switching operations and the second switching operations based at least in part on first information representing a first desired load power and second information representing a second desired load power.

42. The method of claim 41, wherein:

the at least one first LED-based light source includes at least one first LED configured to generate first radiation having a first spectrum; and

the at least one second LED-based light source includes at least one second LED configured to generate second radiation having a second spectrum different from the first spectrum.

43. The method of claim 42, wherein the at least one first LED includes at least one first white LED.

44. The method of claim 43, wherein the at least one second LED includes at least one second white LED.

45. The method of claim 25, further comprising acts of:

detecting an open circuit condition representing an absence or a failure of at least the first load; and

interrupting operation of at least the first single switching stage upon detection of the open circuit condition.