HYBRID GAS DISCHARGE LAMP-LED LIGHTING SYSTEM

• US 20080315791A1
• Filed: 06/24/2007
• Published: 12/25/2008
• Est. Priority Date: 06/24/2007
• Status: Active Grant

• Current Assignee: Philips Lighting Holding BV (Signify N.V.)
• Original Assignee: Cirrus Logic Incorporated
• Inventors: Melanson, John L.
• Granted Patent: US 8,102,127 B2
• Time in Patent Office: Days
• US Class Current: 315/297
• CPC Class Codes: F21Y 2113/00 Combination of light sources
• CPC Class Codes: F21Y 2113/20 of different form
• CPC Class Codes: H05B 35/00 Electric light sources using a combination of different types of light generation

Abstract

A lighting system and method combine at least one LED and at least one gas discharge lamp within a common housing. The lighting system includes a control system to dependently operate each LED and each gas discharge lamp during overlapping, non-identical periods of time. In at least one embodiment, the control system can provide light output by activating LEDs during gas discharge preheating operations and thus extend the useful life of each gas discharge lamp. When dimming the lighting system, the control system can reduce current to the gas discharge lamps and one or more gas discharge lamps can be phased out as dimming levels decrease. As dimming levels decrease, one or more of the LEDs can be activated or groups of LEDs can be phased in to replace the light output of the dimmed gas discharge lamps. Thus, the lighting system can reduce power consumption at low dimming levels.

Claims

1. A hybrid gas discharge lamp-light emitting diode (LED) lighting system comprising:

a housing;

an LED retained by the housing;

a gas discharge lamp retained by the housing; and

a control system coupled to the LED and the gas discharge lamp to dependently operate the LED and gas discharge lamp during overlapping, non-identical periods of time.

2. The lighting system of claim 1 wherein the control system is further configured to (i) preheat filaments of the gas discharge lamp for a first period of time prior to causing an arc within the gas discharge lamp, (ii) activate the LED during the first period of time, and (iii) cause an arc within the gas discharge lamp during a second period of time.

3. The lighting system of claim 2 wherein the control system is further configured to deactivate the LED during at least a portion of the second period of time.

4. The lighting system of claim 1 wherein the control system is further configured to coordinate current level adjustment to the LED and the gas discharge lamp to dim the lighting system.

5. The lighting system of claim 4 further comprising:

multiple LEDs retained by the housing; and

multiple gas discharge lamps retained by the housing; and

wherein the control system is further configured to (i) dim each LED and each gas discharge lamp to a first light output level and (ii) further dim only a subset of the gas discharge lamps to a second light output level, wherein the first light output level is greater than the second light output level.

6. The lighting system of claim 5 wherein the second light output level is zero.

7. The lighting system of claim 5 wherein the subset is a proper subset.

8. The lighting system of claim 4 further comprising:

multiple LEDs retained by the housing; and

multiple gas discharge lamps retained by the housing; and

the control system is further configured to decrease current to each gas discharge lamp and increase current to each LED.

10. The lighting system of claim 1 wherein the gas discharge lamp includes a gas chamber to contain a gas and the LED is contained within the gas chamber.

11. The lighting system of claim 1 wherein the gas discharge lamp and the LED are coupled separately to the housing.

12. The lighting system of claim 1 wherein the gas discharge lamp is a fluorescent lamp.

13. The lighting system of claim 1 further comprising:

a power factor correction circuit; and

a light source driver coupled to the LED, the gas discharge lamp, the power factor correction circuit, and the control system.

9. The lighting system of clam 8 wherein the control system is further configured to decrease current to each gas discharge lamp and, with no more than an insubstantial delay, increase current to each LED and the insubstantial delay is no more than 3 seconds.

14. A lighting system control system to control a hybrid gas discharge lamp-light emitting diode (LED) lighting system, the control system comprising:

a first output to provide an LED control signal;

a second output to provide a gas discharge lamp control signal; and

circuitry to dependently operate at least one LED and at least one gas discharge lamp during overlapping, non-identical periods of time.

15. The control system of claim 14 wherein the control system is further configured to (i) warm filaments of the gas discharge lamp for a first period of time prior to causing an arc within the gas discharge lamp, (ii) activate the LED during the first period of time, and (iii) cause an arc within the gas discharge lamp during a second period of time.

16. The control system of claim 15 wherein the control system is further configured to deactivate the LED during at least a portion of the second period of time.

17. The control system of claim 14 further comprising:

an input to receive a dimming signal, wherein the control system is further configured to coordinate current level adjustment to the LED and the gas discharge lamp to dim the lighting system in accordance with the dimming signal.

18. The control system of claim 14 further comprising:

an input to receive a dimming signal, wherein the control system is further configured to respond to the dimming signal and (i) dim each LED and each gas discharge lamp to a first light output level and (ii) further dim only a subset of the gas discharge lamps to a second light output level, wherein the first light output level is greater than the second light output level.

19. A method of controlling a hybrid gas discharge lamp-light emitting diode (LED), the method comprising:

supplying a control signal to a control system configured to control operation of an LED and a gas discharge lamp retained by a housing; and

operating the LED and gas discharge lamp dependently during overlapping, non-identical periods of time.

20. The method of claim 19 further comprising:

preheating filaments of the gas discharge lamp for a first period of time prior to causing an arc within the gas discharge lamp;

activating the LED during the first period of time; and

causing an arc within the gas discharge lamp during a second period of time.

21. The method of claim 20 further comprising:

deactivating the LED during at least a portion of the second period of time.

22. The method of claim 19 further comprising:

coordinating current level adjustment to the LED and the gas discharge lamp to dim the lighting system.

23. The method of claim 22 wherein the housing further retains multiple LEDs and multiple gas discharge lamps, the method further comprising:

dimming each LED and each gas discharge lamp to a first light output level; and

further dimming only a subset of the gas discharge lamps to a second light output level, wherein the first light output level is greater than the second light output level.

24. The method of claim 22 wherein the housing further retains multiple LEDs and multiple gas discharge lamps, the method further comprising:

decreasing current to each gas discharge lamp and increase current to each LED.

25. The method of claim 24 further comprising:

decreasing current to each gas discharge lamp and, with no more than an insubstantial delay, increase current to each LED wherein the insubstantial delay is no more than 3 seconds.