Constant Lumen Output Control System

• US 20090206775A1
• Filed: 10/17/2005
• Published: 08/20/2009
• Est. Priority Date: 10/17/2005
• Status: Active Grant

• Current Assignee: ABL IP Holding LLC (Acuity Brands, Inc.)
• Original Assignee: ABL IP Holding LLC (Acuity Brands, Inc.)
• Inventors: Green, John D., Ries, Jack L.
• Granted Patent: US 8,390,211 B2
• Time in Patent Office: Days
• US Class Current: 315/307
• CPC Class Codes: H05B 41/392 using semiconductor devices, e.g. thyristor

Abstract

A constant lumen output control system for providing a constant lumen output throughout the life of a lamp at the mean or preset lumen level. The lumen con system (315) coupled to a lamp driver (310) initially reduces the power to the lamp (330) to prevent the lamp from being operated at power levels that result excess mean or preset lumen levels. With increased lamp usage, the lumen control system gradually increases power to the lamp to compensate for lamp lumen depreciation due to light-reducing mechanisms. By compensating for lamp lumen depreciation the lamp is operated at a constant mean or preset lumen output throughout the life of the lamp.

Claims

1. A method of providing constant lumen output control to a lumen output device, comprising

determining a number of operating hours for a lamp,

determining a number of lamp starts for the lamp,

creating a degradation value by combining the number of operating hours and the number of lamp starts,

forming an output ratio for outputting power to the lamp using the degradation value and a target lamp output, and

setting a reduced power level for the lamp using the output ratio

2. The method of claim 1, wherein the target lamp output is specific to the particular type of lamp.

3. The method of claim 1, wherein the reduced power level is adjusted throughout the life of the lamp to maintain a constant lumen output

4. The method of claim 3, wherein the adjustment compensates for lamp degradation within the lamp

5. The method of claim 1, further comprising resetting the number of operating hours and the number of lamp starts when the lamp is replaced

6. The method of claim 5, wherein a lamp voltage comparison is used to determine when the lamp has been replaced

7. The method of claim 1, wherein the step of determining the number of operating hours, the step of determining the number of lamp starts, the step of creating a degradation value, the step of forming an output ratio and the step of setting a reduced power level are performed by a processor

8. A method of providing constant lumen output control to a lumen output device, comprising

determining a stabilized lamp operating voltage for a lamp,

determining a number of lamp starts for the lamp,

creating a degradation value by combining the stabilized lamp operating voltage and the number of lamp starts,

forming an output ratio for outputting power to the lamp using the degradation value and a target lamp output, and

setting a reduced power level for the lamp using the output ratio

9. The method of claim 8, wherein the target lamp output is specific to the particular type of lamp

10. The method of claim 8, wherein the reduced power level is adjusted throughout the life of the lamp to maintain a constant lumen output

11. The method of claim 10, wherein the adjustment compensates for lamp degradation within the lamp

12. The method of claim 8, further comprising resetting the number of lamp starts when the lamp is replaced

13. The method of claim 12, wherein a lamp voltage comparison is used to determine when the lamp has been replaced

14. The method of claim 8, wherein the step of determining the stabilized lamp operating voltage for a lamp, the step of determining the number of lamp starts, the step of creating a degradation value, the step of forming an output ratio and the step of setting a reduced power level are performed by a processor

15. A lumen output control circuit, comprising

a timer for measuring a number of operating hours for a lamp,

a counter for measuring a number of lamp starts for the lamp,

a processor for processing a plurality of light degradation equations and output ratios based on the number of operating hours and the number of lamp starts, and a non-volatile storage device for storing lamp information and lamp constants

16. The circuit of claim 15, wherein the processor sets a reduced power level for the lamp

17. The circuit of claim 15, wherein the non-volatile storage device stores the number of operating hours for the lamp

18. The circuit of claim 15, wherein the non-volatile storage device stores the number of lamp starts for the lamp

19. The circuit of claim 15, wherein the non-volatile storage device stores a lamp voltage for each lamp start for the lamp

20. A lumen output control circuit, comprising

means for determining a stabilized lamp operating voltage for a lamp,

a counter for measuring a number of lamp starts for the lamp,

a processor for processing a plurality of light degradation equations and

output ratios based on the stabilized lamp operating voltage for the lamp and the number of lamp starts for the lamp, and

a non-volatile storage device for storing lamp diagnostic information and lamp constants

21. The circuit of claim 20 wherein the processor sets a reduced power level for the lamp

22. The circuit of claim 20, wherein the non-volatile storage device stores the stabilized lamp operating voltage for the lamp

23. The circuit of claim 20, wherein the non-volatile storage device stores the number of lamp starts for the lamp

24. A ballast, comprising

a power supply for providing power to a lamp,

a ballast control circuit connected to the power supply for controlling ballast operations,

a sensing circuit for providing lamp feedback information to the ballast, and

a lumen output control circuit connected to the power supply, the ballast control circuit, the lamp driver and the sensing circuit configured to adjust power input to the lamp from the ballast

25. The ballast of claim 24, further comprising a lamp driver connected to the ballast control circuit for providing an on/off mechanism for the ballast

26. The ballast of claim 24, wherein the lumen output control circuit comprises

a timer for measuring a number of operating hours for a lamp,

a counter for measuring a number of lamp starts for the lamp,

a processor for processing a plurality of light degradation equations and output ratios based on the number of operating hours and the number of lamp starts, and

a non-volatile storage device for storing lamp information and lamp constants

27. The ballast of claim 24, wherein the processor sets a reduced power level for the lamp

28. The ballast of claim 24, wherein the lumen output control circuit comprises

means for determining a stabilized lamp operating voltage for a lamp,

a counter for measuring a number of lamp starts for the lamp,

a processor for processing a plurality of light degradation equations and output ratios based on the stabilized lamp operating voltage and the number of lamp starts, and

a non-volatile storage device for storing lamp diagnostic information and lamp constants

29. The ballast of claim 28, wherein the processor sets a reduced power level for the lamp

30. An illumination system, comprising

a plurality of ballasts, each ballast having a lumen output control circuit for adjusting power input to a lamp from the ballast thereby creating a constant lumen output from the lamp, and

a plurality of lamps connected to the plurality of ballasts for providing illumination

31. The system of claim 30, wherein the lumen output control circuit comprises

a timer for measuring a number of operating hours for a lamp,

a counter for measuring a number of lamp starts for the lamp,

a processor for processing a plurality of light degradation equations and output ratios based on the number of operating hours and the number of lamp starts, and

a non-volatile storage device for storing lamp information and lamp constants

32. The system of claim 31, wherein the processor sets a reduced power level for the lamp

33. The system of claim 30, wherein the lumen output control circuit comprises

means for determining a stabilized lamp operating voltage for a lamp,

a counter for measuring a number of lamp starts for the lamp,

a processor for processing a plurality of light degradation equations and output ratios based on the stabilized lamp operating voltage and the number of lamp starts, and

a non-volatile storage device for storing lamp diagnostic information and lamp constants

34. The system of claim 33, wherein the processor sets a reduced power level for the lamp

35. A method of providing constant lumen output control to a lumen output device, comprising

determining a peak re-ignition voltage for a lamp,

calculating a root mean square of a lamp operating voltage,

creating a degradation value by forming a ratio of the peak re-ignition voltage and the root mean square of the lamp operating voltage,

forming an output ratio for outputting power to the lamp using the degradation value and a target lamp output, and

setting a reduced power level for the lamp using the output ratio