HYBRID LIGHT SOURCE

• US 20100066260A1
• Filed: 09/03/2009
• Published: 03/18/2010
• Est. Priority Date: 09/05/2008
• Status: Active Grant

• Current Assignee: Lutron Technology Company LLC
• Original Assignee: Lutron Electronics Company Incorporated (Lutron Electronics)
• Inventors: Newman, Robert C. JR., Spira, Joel S., Taipale, Mark S., Ozbek, Mehmet, Corrigan, Keith Joseph, Dobbins, Aaron
• Granted Patent: US 8,228,002 B2
• Time in Patent Office: Days
• US Class Current: 315/246
• CPC Class Codes: H05B 35/00 Electric light sources using a combination of different types of light generation
• CPC Class Codes: H05B 39/045 with high-frequency bridge converters H05B39/048 takes precedence
• CPC Class Codes: H05B 39/08 by shifting phase of trigger voltage applied to gas-filled controlling tubes also in controlled semiconductor devices in converters H02M5/00; with regulation G05F1/44
• CPC Class Codes: H05B 41/392 using semiconductor devices, e.g. thyristor
• CPC Class Codes: H05B 41/3921 with possibility of light intensity variations
• CPC Class Codes: H05B 45/10 Controlling the intensity of the light
• CPC Class Codes: H05B 45/39 Circuits containing inverter bridges

Abstract

A hybrid light source comprises a discrete-spectrum lamp (for example, a fluorescent lamp) and a continuous-spectrum lamp (for example, a halogen lamp). A control circuit individually controls the amount of power delivered to the discrete-spectrum lamp and the continuous-spectrum lamp in response to a phase-controlled voltage generated by a connected dimmer switch, such that a total light output of the hybrid light source ranges throughout a dimming range. The discrete-spectrum lamp is turned off and the continuous-spectrum lamp produces all of the total light intensity of the hybrid light source when the total light intensity is below a transition intensity. The continuous-spectrum lamp is driven by a continuous-spectrum lamp drive circuit, which is operable to conduct a charging current of a power supply of the dimmer switch and to provide a path for enough current to flow through the hybrid light source, such that the magnitude of the current exceeds rated latching and holding currents of a thyristor of the dimmer.

Claims

1. A hybrid light source adapted to receive power from an AC power source and to produce a total light intensity, the total light intensity controlled throughout a dimming range from a low-end intensity and high-end intensity, the hybrid light source comprising:

a continuous-spectrum light source circuit having a continuous-spectrum lamp for producing a percentage of the total light intensity;

a discrete-spectrum light source circuit having a discrete-spectrum lamp for producing a percentage of the total light intensity; and

a control circuit coupled to both the continuous-spectrum light source circuit and the discrete-spectrum light source circuit for individually controlling the amount of power delivered to each of the continuous-spectrum lamp and the discrete-spectrum lamp, such that the total light intensity of the hybrid light source ranges throughout the dimming range, the percentage of the total light intensity produced by the discrete-spectrum lamp being greater than the percentage of the total light intensity produced by the continuous-spectrum lamp when the total light intensity is near the high-end intensity;

wherein the percentage of the total light intensity produced by the discrete-spectrum lamp decreases and the percentage of the total light intensity produced by the continuous-spectrum lamp increases as the total light intensity is decreased below the high-end intensity, the control circuit operable to control the discrete-spectrum lamp when the total light intensity is below a transition intensity, such that the percentage of the total light intensity produced by the continuous-spectrum lamp is greater than the percentage of the total light intensity produced by the discrete-spectrum lamp when the total light intensity is below the transition intensity.

2. The hybrid light source of claim 1, wherein the control circuit is operable to turn off the discrete-spectrum lamp when the total light intensity is below a transition intensity, such that the continuous-spectrum lamp produces all of the total light intensity of the hybrid light source and the hybrid light source generates a continuous spectrum of light when the total light intensity is below the transition intensity.

3. The hybrid light source of claim 2, wherein the discrete-spectrum lamp comprises a gas discharge lamp.

4. The hybrid light source of claim 3, wherein the discrete-spectrum light source drive circuit comprises a ballast circuit for driving the gas discharge lamp.

5. The hybrid light source of claim 4, further comprising:

two input terminals adapted to be operatively coupled to the AC power source; and

a rectifier circuit coupled between the input terminals and generating a rectified voltage at an output.

6. The hybrid light source of claim 5, wherein the ballast circuit comprises a bus capacitor coupled across the output of the rectifier circuit for producing a bus voltage.

7. The hybrid light source of claim 6, wherein the ballast circuit comprises an inverter circuit for converting the bus voltage to a high-frequency AC voltage, and a resonant tank circuit for coupling the high-frequency AC voltage to the gas discharge lamp, the control circuit coupled to the inverter circuit for controlling the magnitude of a lamp current conducted through the gas discharge lamp.

8. The hybrid light source of claim 5, wherein the continuous-spectrum light source circuit comprises a semiconductor switch coupled in series electrical connection with the continuous-spectrum lamp, the control circuit coupled to the semiconductor switch for controlling the amount of power delivered to the continuous-spectrum lamp.

9. The hybrid light source of claim 8, wherein the continuous-spectrum lamp comprises a halogen lamp.

10. The hybrid light source of claim 8, wherein the series combination of the semiconductor switch and the continuous-spectrum lamp is coupled across the output of the rectifier circuit for receiving the rectified voltage.

11. The hybrid light source of claim 8, further comprising:

a second rectifier circuit coupled between the input terminals and generating a second rectified voltage at an output, the series combination of the semiconductor switch and the continuous-spectrum lamp coupled across the output of the second rectifier circuit for receiving the second rectified voltage.

12. The hybrid light source of claim 3, further comprising:

two input terminals adapted to be operatively coupled to the AC power source;

a first rectifier circuit coupled between the input terminals and generating a first rectified voltage at an output;

a bus capacitor coupled across the output of the rectifier circuit for producing a bus voltage;

an inverter circuit for converting the bus voltage to a high-frequency AC voltage;

a resonant tank circuit for coupling the high-frequency AC voltage to the gas discharge lamp, the control circuit coupled to the inverter circuit for controlling the magnitude of a lamp current conducted through the gas discharge lamp;

a second rectifier circuit coupled between the input terminals and generating a second rectified voltage at an output; and

a semiconductor switch coupled in series electrical connection with the continuous-spectrum lamp, the series combination of the semiconductor switch and the continuous-spectrum lamp coupled across the output of the second rectifier circuit for receiving the second rectified voltage, the control circuit coupled to the semiconductor switch for controlling the amount of power delivered to the continuous-spectrum lamp.

13. The hybrid light source of claim 2, wherein the control circuit turns the discrete-spectrum lamp on and off around the transition intensity with some hysteresis.

14. The hybrid light source of claim 1, wherein the continuous-spectrum light source circuit is controlled such that a correlated color temperature of the hybrid light source decreases as the total light intensity is decreased.

15. The hybrid light source of claim 14, wherein the continuous-spectrum light source circuit is controlled such that the correlated color temperature of the hybrid light source decreases as the total light intensity is decreased below the transition intensity.

16. The hybrid light source of claim 1, further comprising:

a housing, the discrete-spectrum lamp and continuous-spectrum lamp located within the housing.

17. The hybrid light source of claim 16, wherein the housing is at least partially translucent.

18. The hybrid light source of claim 1, wherein the continuous-spectrum lamp comprises a low-voltage lamp and the low-efficiency light source drive circuit comprises a low-voltage drive circuit and a low-voltage transformer.

19. The hybrid light source of claim 18, wherein the continuous-spectrum lamp comprises a low-voltage halogen lamp and the continuous-spectrum light source drive circuit comprises a low-voltage halogen drive circuit and a low-voltage transformer.

20. The hybrid light source of claim 1, wherein the discrete-spectrum lamp comprises a solid-state light source and the discrete-spectrum light source drive circuit comprises a solid-state light source drive circuit.

21. The hybrid light source of claim 1, wherein the solid-state light source comprises an LED light source and the solid-state light source drive circuit comprises an LED drive circuit.

24. The method of claim 17, further comprising the step of:

enclosing the discrete-spectrum lamp and the continuous-spectrum lamp together in a housing.

22. A method of illuminating a light source to produce a total light intensity throughout a dimming range from a low-end intensity to a high-end intensity, the method comprising the steps of:

illuminating a discrete-spectrum lamp to produce a percentage of the total light intensity;

illuminating a continuous-spectrum lamp to produce a percentage of the total light intensity;

mounting the discrete-spectrum lamp and the continuous-spectrum lamp to a common support;

individually controlling the amount of power delivered to each of the discrete-spectrum lamp and the continuous-spectrum lamp, such that the total light intensity of the hybrid light source ranges throughout the dimming range;

controlling the high-efficiency lamp and the continuous-spectrum lamp near the high-end intensity, such that the percentage of the total light intensity produced by the discrete-spectrum lamp is greater than the percentage of the total light intensity produced by the continuous-spectrum lamp when the total light intensity is near the high-end intensity;

decreasing the percentage of the total light intensity produced by the discrete-spectrum lamp as the total light intensity decreases;

increasing the percentage of the total light intensity produced by the continuous-spectrum lamp as the total light intensity decreases;

turning off the discrete-spectrum lamp when the total light intensity is below a transition intensity; and

controlling the continuous-spectrum lamp such that the continuous-spectrum lamp produces all of the total light intensity of the hybrid light source and the hybrid light source generates a continuous spectrum of light when the total light intensity is below the transition intensity.

23. The method of claim 22, wherein the color temperature of the hybrid light source decreases as the total light intensity is decreased below the transition intensity.

25. A hybrid light source adapted to receive power from an AC power source and to produce a total luminous flux, the total luminous flux controlled throughout a dimming range from a minimum luminous flux and a maximum luminous flux, the hybrid light source comprising:

a continuous-spectrum light source circuit having a continuous-spectrum lamp for producing a percentage of the total luminous flux;

a discrete-spectrum light source circuit having a discrete-spectrum lamp for producing a percentage of the total luminous flux; and

a control circuit coupled to both the continuous-spectrum light source circuit and the discrete-spectrum light source circuit for individually controlling the amount of power delivered to each of the continuous-spectrum lamp and the discrete-spectrum lamp, such that the total luminous flux of the hybrid light source ranges throughout the dimming range from the minimum luminous flux to the maximum luminous flux, the percentage of the total luminous flux produced by the discrete-spectrum lamp being greater than the percentage of the total luminous flux produced by the continuous-spectrum lamp when the total luminous flux is near the maximum luminous flux;

wherein the percentage of the total luminous flux produced by the discrete-spectrum lamp decreases and the percentage of the total luminous flux produced by the continuous-spectrum lamp increases as the total luminous flux is decreased below the maximum luminous flux, such that the total luminous flux generated by the hybrid light source has a continuous spectrum for at least a portion of the dimming range.

26. The hybrid light source of claim 25, wherein the control circuit turns off the discrete-spectrum lamp when the total luminous flux is below a transition intensity, such that the continuous-spectrum lamp produces all of the total luminous flux of the hybrid light source and the hybrid light source generates a continuous spectrum of light when the total luminous flux is below the transition intensity.

27. The hybrid light source of claim 26, wherein the total luminous flux generated by the hybrid light source has a discrete spectrum when the total luminous flux is above the transition intensity.

28. A dimmable hybrid light source adapted to receive a phase-controlled voltage, the hybrid light source comprising:

a discrete-spectrum light source circuit comprising a discrete-spectrum lamp;

a continuous-spectrum light source circuit comprising a continuous-spectrum lamp operable to conduct a continuous-spectrum lamp current;

a zero-crossing detect circuit for detecting when the magnitude of the phase-controlled voltage becomes greater than a predetermined zero-crossing threshold voltage each half-cycle of the phase-controlled voltage; and

a control circuit coupled to both the discrete-spectrum light source circuit and the continuous-spectrum light source circuit for individually controlling the amount of power delivered to each of the discrete-spectrum lamp and the continuous-spectrum lamp in response to the zero-crossing detect circuit, such that a total light output of the hybrid light source ranges from a minimum total intensity to a maximum total intensity, the control circuit operable to control the discrete-spectrum lamp when the total light intensity is below a transition intensity, such that the percentage of the total light intensity produced by the continuous-spectrum lamp is greater than the percentage of the total light intensity produced by the discrete-spectrum lamp when the total light intensity is below the transition intensity;

wherein the control circuit controls the amount of power delivered to the continuous-spectrum lamp to be greater than or equal to a minimum power level after the magnitude of the phase-controlled voltage becomes greater than the predetermined zero-crossing threshold voltage each half-cycle of the phase-controlled voltage when the total light intensity is above the transition intensity.

29. The hybrid light source of claim 28, wherein the continuous-spectrum light source circuit comprises at least one semiconductor switch coupled so as to control the flow of the continuous-spectrum lamp current through the continuous-spectrum lamp.

30. The hybrid light source of claim 29, wherein the control circuit controls the continuous-spectrum light source circuit to drive the semiconductor switch to be conductive and non-conductive with a duty cycle, the control circuit adjusting the duty cycle of the continuous-spectrum light source circuit to a minimum duty cycle such that the continuous-spectrum lamp conducts the continuous-spectrum lamp current after the magnitude of the phase-controlled voltage becomes greater than the predetermined zero-crossing threshold voltage each half-cycle of the phase-controlled voltage.

31. The hybrid light source of claim 30, wherein the control circuit adjusts the duty cycle of the continuous-spectrum light source circuit to a second duty cycle greater than the minimum duty cycle such that the continuous-spectrum lamp conducts the continuous-spectrum lamp current before the magnitude of the phase-controlled voltage becomes greater than the predetermined zero-crossing threshold voltage each half-cycle of the phase-controlled voltage.

32. The hybrid light source of claim 31, wherein the control circuit adjusts the duty cycle of the continuous-spectrum light source circuit to from the second duty cycle to the minimum duty cycle across a period of time when the zero-crossing detect circuit detects that the magnitude of the phase-controlled voltage has become greater than the predetermined zero-crossing threshold voltage.

33. The hybrid light source of claim 30, wherein the continuous-spectrum lamp comprises a low-voltage halogen lamp and the continuous-spectrum light source drive circuit comprises a low-voltage halogen drive circuit and a low-voltage transformer.

34. The hybrid light source of claim 29, further comprising:

two input terminals adapted to receive the phase-controlled voltage;

a voltage doubler circuit coupled between the input terminals and generating a bus voltage at an output, the discrete-spectrum light source circuit coupled to the output of the voltage doubler circuit for receiving the bus voltage.

35. The hybrid light source of claim 34, wherein the discrete-spectrum lamp comprises a fluorescent lamp and the discrete-spectrum light source drive circuit comprises a ballast circuit for driving the fluorescent lamp, the ballast circuit comprising an inverter circuit for converting the bus voltage to a high-frequency AC voltage, and a resonant tank circuit for coupling the high-frequency AC voltage to the fluorescent lamp, the control circuit coupled to the inverter circuit for controlling the magnitude of a lamp current conducted through the fluorescent lamp.

36. The hybrid light source of claim 34, further comprising:

a rectifier circuit coupled between the input terminals and generating a rectified voltage at an output, the series combination of the semiconductor switch and the continuous-spectrum lamp of the continuous-spectrum light source circuit coupled across the output of the rectifier circuit for receiving the second rectified voltage.

37. The hybrid light source of claim 28, wherein the continuous-spectrum light source circuit comprises a semiconductor switch coupled in series electrical connection with the continuous-spectrum lamp for controlling the amount of power delivered to the continuous-spectrum lamp.

38. The hybrid light source of claim 37, further comprising:

two input terminals adapted to receive the phase-controlled voltage;

a first rectifier circuit coupled between the input terminals and generating a first rectified voltage at an output, the discrete-spectrum light source circuit coupled to the output of the first rectifier circuit for receiving the first rectified voltage.

39. The hybrid light source of claim 38, wherein the ballast circuit comprises a bus capacitor coupled across the output of the first rectifier circuit for producing a bus voltage, an inverter circuit for converting the bus voltage to a high-frequency AC voltage, and a resonant tank circuit for coupling the high-frequency AC voltage to the fluorescent lamp, the control circuit coupled to the inverter circuit for controlling the magnitude of a lamp current conducted through the fluorescent lamp.

40. The hybrid light source of claim 38, wherein the series combination of the semiconductor switch and the continuous-spectrum lamp of the continuous-spectrum light source circuit is coupled across the output of the first rectifier circuit for receiving the first rectified voltage.

41. The hybrid light source of claim 38, further comprising:

a second rectifier circuit coupled between the input terminals and generating a second rectified voltage at an output, the series combination of the semiconductor switch and the continuous-spectrum lamp of the continuous-spectrum light source circuit coupled across the output of the second rectifier circuit for receiving the second rectified voltage.

42. The hybrid light source of claim 37, wherein the control circuit is operable to control the semiconductor switch of the continuous-spectrum light source circuit to pulse-width modulate the voltage provided across the continuous-spectrum lamp to control the amount of power delivered to the continuous-spectrum lamp when the magnitude of the phase-controlled voltage is above the predetermined zero-crossing threshold voltage.

43. The hybrid light source of claim 28, wherein the continuous-spectrum lamp comprises a halogen lamp and the continuous-spectrum light source drive circuit comprises a halogen drive circuit.

44. The hybrid light source of claim 28, wherein the zero-crossing threshold voltage of the zero-crossing detect circuit has a first magnitude when the phase-controlled voltage is less than the zero-crossing threshold voltage, and a second magnitude when the phase-controlled voltage is greater than the zero-crossing threshold voltage, the first magnitude greater than the second magnitude.

45. The hybrid light source of claim 28, wherein the control circuit turns off the discrete-spectrum lamp when the total light intensity is below the transition intensity, such that the continuous-spectrum lamp produces all of the total light intensity of the hybrid light source when the total light intensity is below the transition intensity

46. A dimmable hybrid light source adapted to receive a phase-controlled voltage, the hybrid light source comprising:

a discrete-spectrum light source circuit comprising a discrete-spectrum lamp;

a continuous-spectrum light source circuit comprising a continuous-spectrum lamp operable to conduct a continuous-spectrum lamp current;

a zero-crossing detect circuit for detecting when the magnitude of the phase-controlled voltage is approximately zero volts; and

a control circuit coupled to both the discrete-spectrum light source circuit and the continuous-spectrum light source circuit for individually controlling the amount of power delivered to each of the discrete-spectrum lamp and the continuous-spectrum lamp in response to the zero-crossing detect circuit;

wherein the control circuit controls the continuous-spectrum light source circuit such that the continuous-spectrum lamp is operable to conduct the continuous-spectrum lamp current when the phase-controlled voltage across the hybrid light source is approximately zero volts.

47. The hybrid light source of claim 46, wherein the continuous-spectrum light source circuit comprises at least one semiconductor switch coupled so as to control the flow of the continuous-spectrum lamp current through the continuous-spectrum lamp.

48. The hybrid light source of claim 47, further comprising:

two input terminals adapted to receive the phase-controlled voltage;

a voltage doubler circuit coupled between the input terminals and generating a bus voltage at an output, the discrete-spectrum light source circuit coupled to the output of the voltage doubler circuit for receiving the bus voltage.

49. The hybrid light source of claim 48, wherein the discrete-spectrum lamp comprises a fluorescent lamp and the discrete-spectrum light source drive circuit comprises a ballast circuit for driving the fluorescent lamp, the ballast circuit comprising an inverter circuit for converting the bus voltage to a high-frequency AC voltage, and a resonant tank circuit for coupling the high-frequency AC voltage to the fluorescent lamp, the control circuit coupled to the inverter circuit for controlling the magnitude of a lamp current conducted through the fluorescent lamp.

50. The hybrid light source of claim 48, further comprising:

a rectifier circuit coupled between the input terminals and generating a rectified voltage at an output, the series combination of the semiconductor switch and the continuous-spectrum lamp of the continuous-spectrum light source circuit coupled across the output of the rectifier circuit for receiving the second rectified voltage.

51. The hybrid light source of claim 47, wherein the control circuit controls the continuous-spectrum light source circuit to drive the semiconductor switch to be conductive and non-conductive with a duty cycle, the control circuit adjusting the duty cycle of the continuous-spectrum light source circuit to a maximum duty cycle such that the continuous-spectrum lamp conducts the continuous-spectrum lamp current when the magnitude of the phase-controlled voltage across the hybrid light source is approximately zero volts.

52. The hybrid light source of claim 51, wherein the continuous-spectrum lamp comprises a low-voltage halogen lamp and the continuous-spectrum light source drive circuit comprises a low-voltage halogen drive circuit and a low-voltage transformer.

53. The hybrid light source of claim 46, wherein the continuous-spectrum light source circuit comprises a semiconductor switch coupled in series electrical connection with the continuous-spectrum lamp for controlling the amount of power delivered to the continuous-spectrum lamp.

54. The hybrid light source of claim 53, further comprising:

two input terminals adapted to receive the phase-controlled voltage;

a first rectifier circuit coupled between the input terminals and generating a first rectified voltage at an output, the discrete-spectrum light source circuit coupled to the output of the first rectifier circuit for receiving the first rectified voltage.

55. The hybrid light source of claim 54, wherein the discrete-spectrum lamp comprises a fluorescent lamp and the discrete-spectrum light source drive circuit comprises a ballast circuit for driving the fluorescent lamp, the ballast circuit comprising a bus capacitor coupled across the output of the first rectifier circuit for producing a bus voltage, and an inverter circuit for converting the bus voltage to a high-frequency AC voltage, and a resonant tank circuit for coupling the high-frequency AC voltage to the fluorescent lamp, the control circuit coupled to the inverter circuit for controlling the magnitude of a lamp current conducted through the fluorescent lamp.

56. The hybrid light source of claim 54, wherein the series combination of the semiconductor switch and the continuous-spectrum lamp of the continuous-spectrum light source circuit is coupled across the output of the first rectifier circuit for receiving the first rectified voltage.

57. The hybrid light source of claim 54, further comprising:

a second rectifier circuit coupled between the input terminals and generating a second rectified voltage at an output, the series combination of the semiconductor switch and the continuous-spectrum lamp of the continuous-spectrum light source circuit coupled across the output of the second rectifier circuit for receiving the second rectified voltage.

58. The hybrid light source of claim 46, wherein the continuous-spectrum lamp comprises a halogen lamp and the continuous-spectrum light source drive circuit comprises a halogen drive circuit.

59. The hybrid light source of claim 46, wherein the zero-crossing threshold voltage of the zero-crossing detect circuit has a first magnitude when the phase-controlled voltage is less than the zero-crossing threshold voltage, and a second magnitude when the phase-controlled voltage is greater than the zero-crossing threshold voltage, the first magnitude greater than the second magnitude.

60. A lighting control system receiving power from an AC power source, the lighting control system comprising:

a hybrid light source comprising a discrete-spectrum light source circuit having a discrete-spectrum lamp and a continuous-spectrum light source circuit having a continuous-spectrum lamp, the hybrid light source adapted to be coupled to the AC power source and to individually control the amount of power delivered to each of the discrete-spectrum lamp and the continuous-spectrum lamp; and

a dimmer switch comprising a thyristor adapted to be coupled in series electrical connection between the AC power source and the hybrid light source, the thyristor operable to be rendered conductive for a conduction period each half-cycle of the AC power source, such that the hybrid light source is operable to control the amount of power delivered to each of the discrete-spectrum lamp and the continuous-spectrum lamp in response to the conduction period of the thyristor, the thyristor characterized by a rated latching current;

wherein the continuous-spectrum light source circuit of the hybrid light source provides a path for enough current to flow from the AC power source through the hybrid light source, such that the magnitude of the current exceeds a rated latching current of the thyristor of the dimmer switch when the thyristor is rendered conductive.

61. The lighting control system of claim 60, wherein the hybrid light source further comprises a control circuit coupled to the discrete-spectrum light source circuit and the continuous-spectrum light source circuit for individually controlling the amount of power delivered to each of the discrete-spectrum lamp and the continuous-spectrum lamp.

62. The lighting control system of claim 61, wherein the continuous-spectrum light source circuit comprises at least one semiconductor switch coupled so as to control the flow of a continuous-spectrum lamp current through the continuous-spectrum lamp.

63. The lighting control system of claim 62, wherein the dimmer switch further comprises a power supply coupled in parallel electrical connection with the thyristor and operable to conduct a charging current through the hybrid light source when the thyristor is non-conductive, the control circuit operable to control the continuous-spectrum light source circuit to drive the semiconductor switch to be conductive and non-conductive with a duty cycle, the control circuit adjusting the duty cycle of the continuous-spectrum light source circuit to a first duty cycle when the thyristor of the dimmer switch is non-conductive, such that the continuous-spectrum light source circuit conducts the charging current.

64. The lighting control system of claim 63, wherein the thyristor of the dimmer switch is further characterized by a rated holding current, the control circuit of the hybrid light source further operable to adjust the duty cycle of the continuous-spectrum light source circuit to a second duty cycle after the thyristor is rendered conductive, such that the continuous-spectrum light source circuit provides the path for enough current to flow from the AC power source through the hybrid light source, such that the magnitude of the current exceeds the rated holding current of the thyristor of the dimmer.

65. The lighting control system of claim 64, wherein the control circuit adjusts the duty cycle of the continuous-spectrum light source circuit to from the first duty cycle to the second duty cycle across a period of time when the thyristor of the dimmer switch is rendered conductive, such that the continuous-spectrum light source circuit provides the path for enough current to flow from the AC power source through the hybrid light source, such that the magnitude of the current exceeds the rated latching current of the thyristor of the dimmer.

66. The lighting control system of claim 62, wherein the continuous-spectrum lamp comprises a low-voltage halogen lamp, and the continuous-spectrum light source circuit comprises a low-voltage halogen drive circuit and a low-voltage transformer coupled between the low-voltage halogen lamp and the low-voltage halogen drive circuit.

67. The lighting control system of claim 62, wherein the hybrid light source comprises a rectifier circuit adapted to be coupled in series between the dimmer switch and the AC power source and to generate a rectified voltage at output terminals, the continuous-spectrum light source circuit coupled to the output terminals of the rectifier circuit for receiving the rectified voltage.

68. The lighting control system of claim 60, wherein the continuous-spectrum light source circuit comprises a semiconductor switch coupled in series electrical connection with the continuous-spectrum lamp for controlling the amount of power delivered to the continuous-spectrum lamp.

69. The lighting control system of claim 68, wherein the continuous-spectrum light source circuit is operable to pulse-width modulate the voltage provided across the continuous-spectrum lamp when the thyristor of the dimmer switch is rendered conductive to provide the path for enough current to flow from the AC power source through the hybrid light source, such that the magnitude of the current exceeds the rated latching current of the thyristor of the dimmer switch.

70. The lighting control system of claim 69, wherein the continuous-spectrum light source circuit is operable to adjust a duty cycle of the voltage provided across the continuous-spectrum lamp from a maximum duty cycle to a minimum duty cycle when the thyristor of the dimmer switch is rendered conductive to provide the path for enough current to flow from the AC power source through the hybrid light source, such that the magnitude of the current exceeds the rated latching current of the thyristor of the dimmer switch.

71. The lighting control system of claim 70, wherein the continuous-spectrum lamp comprises a line-voltage halogen lamp, and the continuous-spectrum light source circuit comprises a halogen drive circuit for driving the halogen lamp.

72. A lighting control system receiving power from an AC power source, the lighting control system comprising:

a hybrid light source comprising a discrete-spectrum light source circuit having a discrete-spectrum lamp and a continuous-spectrum light source circuit having a continuous-spectrum lamp, the hybrid light source adapted to be coupled to the AC power source and to individually control the amount of power delivered to each of the discrete-spectrum lamp and the continuous-spectrum lamp; and

a dimmer switch comprising a thyristor adapted to be coupled in series electrical connection between the AC power source and the hybrid light source, the thyristor operable to be rendered conductive for a conduction period each half-cycle of the AC power source, such that the hybrid light source is operable to control the amount of power delivered to each of the discrete-spectrum lamp and the continuous-spectrum lamp in response to the conduction period of the thyristor, the thyristor characterized by a rated latching current and a rated holding current, the dimmer switch further comprising a power supply coupled in parallel electrical connection with the thyristor and operable to conduct a charging current through the hybrid light source when the thyristor is non-conductive;

wherein the continuous-spectrum light source circuit of the hybrid light source is operable to conduct the charging current when the thyristor is non-conductive, the continuous-spectrum light source circuit further operable, after the thyristor is rendered conductive, to provide a path for enough current to flow from the AC power source through the hybrid light source, such that the magnitude of the current exceeds the rated latching current and the rated holding current of the thyristor of the dimmer.

73. The lighting control system of claim 72, wherein the hybrid light source further comprises a control circuit coupled to the discrete-spectrum light source circuit and the continuous-spectrum light source circuit for individually controlling the amount of power delivered to each of the discrete-spectrum lamp and the continuous-spectrum lamp.

74. The lighting control system of claim 73, wherein the continuous-spectrum light source circuit comprises at least one semiconductor switch coupled so as to control the flow of a continuous-spectrum lamp current through the continuous-spectrum lamp.

75. The lighting control system of claim 74, wherein the control circuit controls the continuous-spectrum light source circuit to drive the semiconductor switch to be conductive and non-conductive with a duty cycle, the control circuit adjusting the duty cycle of the continuous-spectrum light source circuit to a first duty cycle when the thyristor of the dimmer switch is non-conductive, such that the continuous-spectrum light source circuit conducts the charging current, the control circuit further adjusting the duty cycle of the continuous-spectrum light source circuit to a second duty cycle after the thyristor is rendered conductive, such that the continuous-spectrum light source circuit provides the path for enough current to flow from the AC power source through the hybrid light source, such that the magnitude of the current exceeds the rated holding current of the thyristor of the dimmer.

76. The lighting control system of claim 75, wherein the control circuit adjusts the duty cycle of the continuous-spectrum light source circuit to from the first duty cycle to the second duty cycle across a period of time when the thyristor of the dimmer switch is rendered conductive, such that the continuous-spectrum light source circuit provides the path for enough current to flow from the AC power source through the hybrid light source, such that the magnitude of the current exceeds the rated latching current of the thyristor of the dimmer.

77. The lighting control system of claim 76, wherein the continuous-spectrum lamp comprises a low-voltage halogen lamp, and the continuous-spectrum light source circuit comprises a low-voltage halogen drive circuit and a low-voltage transformer coupled between the low-voltage halogen lamp and the low-voltage halogen drive circuit.

78. The lighting control system of claim 73, wherein the continuous-spectrum light source circuit comprises a semiconductor switch coupled in series electrical connection with the continuous-spectrum lamp for controlling the amount of power delivered to the continuous-spectrum lamp.

79. The lighting control system of claim 78, wherein the continuous-spectrum light source circuit is operable to pulse-width modulate the voltage provided across the continuous-spectrum lamp to control the amount of power delivered to the continuous-spectrum lamp.

80. The lighting control system of claim 79, wherein the control circuit pulse-width modulates the voltage provided across the continuous-spectrum lamp after the thyristor of the dimmer switch is rendered conductive to provide the path through the continuous-spectrum lamp for enough current to flow from the AC power source through the hybrid light source, such that the magnitude of the current exceeds the rated holding current of the thyristor of the dimmer switch after the thyristor is rendered conductive.

81. The lighting control system of claim 80, wherein the control circuit pulse-width modulates the voltage provided across the continuous-spectrum lamp when the thyristor of the dimmer switch is rendered conductive to provide the path for enough current to flow from the AC power source through the hybrid light source, such that the magnitude of the current exceeds the rated latching current of the thyristor of the dimmer switch.

82. The lighting control system of claim 78, wherein the semiconductor switch is rendered conductive when the thyristor of the dimmer switch is non-conductive, such that the continuous-spectrum lamp is operable to conduct the charging current of the power supply.

83. The lighting control system of claim 78, wherein the continuous-spectrum lamp comprises a line-voltage halogen lamp, and the continuous-spectrum light source circuit comprises a halogen drive circuit for driving the halogen lamp.

84. The lighting control system of claim 73, wherein the control circuit controls the continuous-spectrum light source circuit such that the continuous-spectrum light source circuit conducts charging current of the power supply of the dimmer switch when the thyristor is non-conductive each half-cycle of the AC power source.

85. The lighting control system of claim 84, wherein the control circuit controls the continuous-spectrum light source circuit when the thyristor of the dimmer switch is rendered conductive to provide the path for enough current to flow from the AC power source through the hybrid light source, such that the magnitude of the current exceeds the rated latching current of the thyristor of the dimmer switch.

86. The lighting control system of claim 85, wherein the control circuit controls the continuous-spectrum light source circuit after the thyristor of the dimmer switch is rendered conductive to provide the path for enough current to flow from the AC power source through the hybrid light source, such that the magnitude of the current exceeds the rated holding current of the thyristor of the dimmer switch after the thyristor is rendered conductive.

87. A method of illuminating a light source in response to a phase-controlled voltage from a dimmer switch, the dimmer switch coupled in series electrical connection with between an AC power source and the light source, the dimmer switch comprising a thyristor for generating the phase-controlled voltage, the thyristor characterized by a rated latching current, the method comprising the steps of:

enclosing the discrete-spectrum lamp and the continuous-spectrum lamp together in a translucent housing;

individually controlling the amount of power delivered to each of the discrete-spectrum lamp and the continuous-spectrum lamp in response to the phase-controlled voltage; and

conducting enough current from the AC power source and through bidirectional semiconductor switch of the dimmer and the continuous-spectrum lamp to exceed the rated latching current of the thyristor of the dimmer switch.

88. The method of claim 87, further comprising the steps of:

controlling the flow of a continuous-spectrum lamp current through the continuous-spectrum lamp using at least one semiconductor switch; and

driving the semiconductor switch to be conductive and non-conductive with a duty cycle.

89. The method of claim 88, wherein the dimmer switch further comprises a power supply coupled in parallel electrical connection with the thyristor and operable to conduct a charging current through the hybrid light source when the thyristor is non-conductive, the method further comprising the step of:

adjusting the duty cycle of the duty cycle of the continuous-spectrum light source circuit to a first duty cycle when the thyristor of the dimmer switch is non-conductive, such that the continuous-spectrum light source circuit conducts the charging current.

90. The method of claim 89, wherein the thyristor of the dimmer switch is further characterized by a rated holding current, the method further comprising the step of:

adjusting the duty cycle of the continuous-spectrum light source circuit to a second duty cycle after the thyristor is rendered conductive, such that the continuous-spectrum light source circuit provides the path for enough current to flow from the AC power source through the hybrid light source, such that the magnitude of the current exceeds the rated holding current of the thyristor of the dimmer.

91. The method of claim 90, further comprising the step of:

adjusting the duty cycle of the continuous-spectrum light source circuit to from the first duty cycle to the second duty cycle across a period of time when the thyristor of the dimmer switch is rendered conductive, such that the continuous-spectrum light source circuit provides the path for enough current to flow from the AC power source through the hybrid light source, such that the magnitude of the current exceeds the rated latching current of the thyristor of the dimmer.