MX2008005114A - Constant lumen output control system - Google Patents

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 contr 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.

Description

LUMEN CONSTANT OUTPUT CONTROL SYSTEM FIELD OF THE INVENTION The present invention relates to a lumen output control of a light source. More particularly, the invention provides a method and system for increasing and decreasing a ballast output energy, which is connected to a light source, to provide a constant light output during the life of the light source.

BACKGROUND OF THE INVENTION Over time, the lumen output of a lamp decreases steadily. The lumen output can be defined as a unit of luminous flux equal to the light emitted at a solid unit angle by a uniform point source of the intensity of a candle. In terms of energy, a lumen is 1/683 watts of radiant energy at a frequency of 540 x 1012 Hz. Degradation of the lumen output in the lamp can occur for a variety of reasons, for example, lumen wear of the lamp, the interaction of the lamp with a ballast, the voltage variations supplied, dirt or dust in the lamp and the ambient temperature in an accessory. Figure 1 illustrates a lumen degradation curve for a typical quartz metal halide high intensity discharge (HID) lamp using a conventional ballast. Figure 1 is a graph 100 illustrating two curves in relation to an X axis 102 (hours of lamp operation) and a Y axis 104 (lumens per watt of the lamp). Curve 106 illustrates the degradation curve for a constant wattage self-transformer magnetic lamp (CWA) and curve 108 illustrates a degradation curve for a Prismatron ™ lamp. As the hours of operation of the lamp for the lamp increase, the lumen output of the lamp decreases.

The decrease in lumen output occurs due to a variety of processes that occur within the lamp. A factor that contributes to this decrease is the loss of chemicals that contributes to the light output. These chemicals can be lost through portions of the lamp structure, for example, an arch container. Another factor that contributes to the degradation of light is the metal that is deposited on the wall of the tube of the lamp arch. A HID lamp is started by applying a very high voltage through an arc tube to decompose high pressure gases inside the lamp in a driving state. After this decomposition, the high current normally flows through the relatively low voltage arc which heats the electrodes, which subsequently enter into thermionic emission. This tends to expel molecules from the metal electrode material that eventually condense in the wall of the arc tube, causing a "darkening" and lowering the light transmission of the arc tube.

Due to such degradation in the lumen output, many lighting applications are designed using an average light level. This average light level, or lamp lumen, is defined when an HID lamp is forty percent of its rated life. Typically, to achieve a minimum light level emission, a lighting system designer will design a lighting system at the average light level. Once the lamp is at a point beyond the average light level, it is usually necessary to replace the lamp to maintain a desired light output level.

In HID applications, a ballast is used to control the operating energy delivered to a lamp. Figure 2 is a block diagram 200 illustrating a typical ballast 202. Ballast 202 regulates the energy of lamp 204 which is received as an input voltage from a power source (not shown). The ballast 202 also provides appropriate start conditions for the lamp 204 at startup.

Some ballast designs use magnetic transformers. As a result, the output level of a lamp can not be varied and is limited to a full power output or some fixed output level less than full power. Other ballast designs, such as electronic ballasts, provide a continuous variation of the lamp voltage between full power and a predetermined lower limit.

However, a problem with conventional ballast systems, which use an average light level to establish a desired lamp output, is that the ballast initially consumes additional energy during the period of time prior to achieving the average light level. Feeding the lamp to the full output prior to achieving the average light level causes an output higher than necessary, which consumes more energy than necessary to provide the desired light output.

Therefore, there is a need and desire for a ballast that has an energy regulation technique to output the energy to the lamp, which will create a constant lumen output of the lamp, thus decreasing the power consumption of the lamp system .

SUMMARY OF THE INVENTION The present invention provides a constant output lumen control system having the ability to provide a constant lumen output of a lamp over the life of the lamp. The lighting system initially reduces the energy of the lamp and subsequently varies the energy delivered to the lamp to compensate for the light reduction mechanisms that will eventually affect the lumen output of the lamp. By properly adjusting the energy delivered to the lamp, the lighting system provides a constant light output from the lamp.

BRIEF DESCRIPTION OF THE DRAWINGS The above advantages and other features of the invention will be more apparent from the detailed description of the exemplary embodiments of the invention provided below with reference to the accompanying drawings.

Figure 1 is a graph illustrating a lumen degradation curve for a typical standard metal halide HID lamp; where a) Prismatron of holophane vs. magnetic ballasts, MH standard LPW lamp during life (400 MH), b) Prismatron LPW lamp, c) magnetic CWA lamp LPW, 104) lumens per watt of lamp and 102) hours of operation of lamp.

Figure 2 is a block diagram illustrating a typical ballast design; where a) input voltage, 202) HID ballast and 204) HID lamp.

Figure 3 is a block diagram illustrating a ballast design that includes a lumen control circuit in accordance with an embodiment of the invention; where a) input power, b) lamp feedback, c) lamp power setting, d) lamp operating control, e) lamp on / off control, f) lamp current feedback, g) feedback of lamp voltage, h) non-volatile storage, i) total lamp hours, j) cumulative starts, k) historical lamp voltage, I) lamp life constants, 304) power factor correction, 306) supply power, 308) basic ballast control circuit, 310) lamp controller, 312) sensory circuits, 330) lamp, 314) computer control, 318) ballast operating software, 317) timers, 319) counters and 302) ballast .

Figure 4 is a graph illustrating a degradation of lamp output as a function of the number of starts of the lamp; where a) lamp output wear due to excessive number of starts, 404) percentage of lamp output and 402) number of starts.

Figure 5 is a graph illustrating a re-lighting cycle for an HID lamp for detecting lamp replacement; where a) lamp voltage vs time, b) lamp replaced, 504) lamp voltage and 502 percent re-lighting cycle.

Figure 6 is a flow chart illustrating the steps of the process of one embodiment of the control circuit of the invention; where a) no, b) yes, 602) power on, 604) full energy to the lamp, 606) read variable CLO, 608) start heating timer of 20 minutes, 610) start accumulated lamp timer, 612) increase number of starts, 614) have the 20 minutes of warm-up elapsed ?, 616) new lamp ?, 618) reset hours to 10, starts at 1, 620) write hours, starts, lamp voltage, 622) lumen output hourly lamp, 624) correct number of starts, 626) goal ratio to current lumens, 628) power establishment of lumen / energy curve and 630) set internal attenuation level.

Figure 7 is a block diagram of a lighting system for implementing a first exemplary embodiment of the present invention; where a) input power, 702) power supply, 302) ballast and 330) lamp.

Figure 8 is a graph illustrating the energy consumption of a conventional ballast and a ballast in accordance with an embodiment of the invention; where a) energy saving of constant light output vs constant energy, b) constant light, c) constant energy, 804) percentage of lamp energy and 802) time (hours).

Figure 9A is a graph illustrating a peak re-ignition voltage as the voltage of the lamp varies with time; where a) lamp voltage and b) time.

Figure 9B is a graph illustrating the relationship between a voltage crest factor and the life of the lamp; where a) VCF and b) lamp life.

DETAILED DESCRIPTION OF THE INVENTION In the following detailed description, reference will be made to the accompanying drawings, which are part of it, and which are shown by way of illustration of specific embodiments in which the invention can be practiced. These modalities are described in sufficient detail to enable those skilled in the art to practice the invention, and it must be understood that other modalities may be used, and that structural, logical and programming changes may be made without departing from the scope of the invention. present invention.

Figure 3 is an exemplary lighting control system 300 employed in a ballast 302. The ballast 302 includes a power factor correction circuit 304, a power supply 306, a ballast control circuit 308, a lamp controller 310, sensory circuits 312 and a lighting control system 315. The lighting control system 315 includes a computer control circuit 314 and a non-volatile storage device 316. The non-volatile storage device 316 can use any format of comparable non-volatile memory, for example, dynamic random access memory (DRAM), flash memory, magnetosistant random access memory (MRAM), etc. The computer control circuit 314 may utilize a microprocessor or other comparable processing device to conduct mathematical processing to adjust the power supplied to the lamp 330 to achieve a constant lumen output of the lamp 330. The non-volatile storage device 316 provides storage for various computational equations, mathematical constants, ballast operating software 318, timers 317, meters 319 and information regarding various types of lamps and their specific operating requirements, which are used by the computer control circuit 314 during processing. The lamp 330 can be any type of high intensity discharge lamp (HID), such as HID lamps that use high pressure mercury, high pressure sodium or any other suitable gas.

The ballast control circuit 308 adjusts the energy received from the power supply 306 to be used by the lamp 330. The ballast control circuit 308 receives a power-up signal from the lamp and an operational control signal from the lamp of the computer control circuit 314. The ballast control circuit 308 also receives a lamp feedback signal from the sensory circuits 312 and provides operating power to the lamp controller 310. The lamp controller 310 turns on the lamp 330, receives operating energy of the ballast control circuit 308 and provides operating power to the sensory circuits 312. The lamp controller 310 receives an on / off control signal from the computer control circuit lamp 314 for use in discontinued power that is supplied to the lamp 330. The sensory circuits 312 monitor the power input supplied to the lamp 330 and provide feedback about the operation of the lamp 330 to the computer control circuit 314 and the ballast control circuit 308. The sensory circuits 312 send a lamp current feedback signal and a lamp voltage feedback signal to the computer control circuit 314. The sensing circuits 312 also send a lamp feedback signal to the ballast control circuit 308 to monitor other important operating parameters of the lamp. the lamp.

The lighting control system 315 uses various factors and parameters to determine the rate of degradation for a particular type of lamp 330. The parameters and factors are used to control the output of the lamp 330 during its life cycle. For example, the lighting control system 315 can use hours of operation (total hours the lamp has been operating) and lamp starts (total number of start sequences for the lamp) to determine a rate of degradation of the output of the lamp. lumen of the lamp 330. Other parameters can be considered to determine the degradation rate. For example, a stabilized lamp operating voltage, lamp re-ignition voltage, current peak factors or a combination thereof can be used. Based on the degradation rate of the lamp 330, the lighting control system 315 adjusts the power supplied to the lamp 330 to provide a constant lumen output of the lamp 330.

The ballast operating software 318 resides in the non-volatile storage 316 and provides a variety of timers 317. For example, the timers 317 include an accumulated lamp timer to measure the number of hours of operation for the lamp 330 and a timer of lamp heating to determine when the lamp 330 has achieved a steady state after being started to be used by the computer control circuit 314. The ballast operation software 318 also provides meters 319 to measure the number of lamp starts for the lamp 330 The ballast operating software 318 also controls the operation of the ballast 302 and the energy output by the ballast 302.

Figure 4 illustrates a diagram 400, which compares the number of starts of the lamp with a percentage of the lamp output energy for the lamp 330. The X-axis 402 represents a number of lamp starts for the lamp 330 and Y axis 404 represents a percentage of lamp output 330. The output of lamp 330, which is illustrated using a curve 406, degrades due to lamp lumen wear as the number of starts of the lamp 330 increases.

In calculating the degradation due to the number of hours the lamp 330 is in operation, the computer control circuit 314 uses what is known as a heat loss equation to determine the degradation of the lamp due to the hours of operation to use when calculating the setting of the attenuation level for lamp 330. The second-order polynomial equation determines the value for heat loss.

Heat Loss = A x Hours2 + B x Hours + C Eq. 1 The heat loss equation is stored in the non-volatile storage device 316 together with the constants A, B and C, which are associated with the type particular of lamp 330 which is being powered by ballast 302. The constants A, B & C are derived from at least one squared curve fitting using experimental data, based on the loss of light due to the number of hours in operation of the lamp 330. The process of deriving the constants A, B and C can also be done using a search table that relates the variables, but such an approach would require additional storage space in the non-volatile storage device 316.

In calculating the degradation due to the number of lamp starts, the computational control circuit 314 uses what is known as an initial loss equation to determine the lamp degradation due to the number of lamp starts to be used in calculating the setting the attenuation level for the particular type of lamp 330. The following second order polynomial equation determines the value for the start loss.

Loss of Start = D x Hours2 + E x Hours2 + F Eq. 2 The start loss equation is stored in the non-volatile storage device 316 together with the constants D, E and F, which are associated with a particular type of lamp 330 that is being powered by the ballast 302. The constants D , E and F are derived and stored in the non-volatile storage device 316 in a manner similar to constants A, B and C.

The values of heat loss and start loss for the lamp 330 are combined to calculate an expected general level of light loss at a given point in the life cycle of the lamp 330. A ratio is then calculated using the expected level of loss of light at a given point in the life cycle of the lamp 330 and a predetermined lumen output target is stored in the non-volatile storage 316. For example, an expected lamp output for a given point (200 hours) it can be 95% of the initial lamp output, while the predetermined lumen output target is 85%. Thus, the output wattage of the lamp 330 is decreased by an appropriate amount to reduce the light output of the lamp 330 to a predetermined lumen output target. Although the target lumen output of the lamp 330 may be set at any reasonable lumen output, two important output establishments that may be used are an end-of-life lumen output and an average lumen output. The average lumen output is typically the average light output after 40% of the expected life of the 330 lamp has passed and is usually set by the lamp manufacturer 330.

By using the expected lumen output to current lumen output ratio, the energy supplied to the lamp 330 can be adjusted by the lighting control system 315 to establish an appropriate source wattage for the lamp 330. For example, if the lamp 330 is a HID quartz metal halide lamp, a lumen output for the lighting control system 315 could vary 18 times a change in wattage due to the ratio between the wattage of the lamp and the light output delivered for the particular type of lamp 330. Therefore, the wattage of the ballast 302 for the lamp 330 is changed in a ratio of 1/18 to obtain the desired constant lumen output.

Thus, as the number of hours in operation and the beginnings of the lamp accumulate, the lighting control system 315 continuously evaluates the degradation of the lamp 330 to compensate for the degradation of the lumen of the lamp by increasing the wattage output. supplied from the ballast 302 to the lamp 330. When the lamp 330 is degraded to a point at which the lamp 330 requires more energy than its maximum energy rating (100%) to maintain the desired lumen output level, the Lighting control 315 will limit the output of energy by the ballast 302 to the maximum energy rating of the lamp 330. By limiting the lamp 330 to its maximum energy rating, safety is improved since the lamp 330 is not overloaded, which could damage the circuit inside the ballast 302 and the lamp 330. Once the life cycle of the lamp 330 is completed, the lamp 330 is subsequently replaced.

After the lamp 330 is replaced, values such as the number of hours of operation and the number of lamp starts stored in the non-volatile storage device 316 are reset. Although it is possible to reset the non-volatile storage device 316 manually, a re-establishment means can be employed using a form of lamp replacement detection. The lamp replacement detection technique can be employed using software included in the ballast operating software 318, which is stored in the non-volatile storage device 316 to be used by the computer control circuit 314. When comparing the voltage of lamp measured from the lamp 330 with the lamp voltage stored in the memory, the computer control circuit 314 determines whether a change in the lamp voltage has occurred, which would indicate that the lamp 330 has been replaced.

Thus, a lamp replacement detection technique can use the fact that as a lamp ages, many electrical variables associated with the lamp change. For example, an averaged root-to-square (RMS) voltage through the lamp 330 and a re-ignition voltage for the lamp 330 change over time. The lamp replacement detection technique uses the software included in the ballast operation software 318 to store these voltages and other variables in the non-volatile storage device 316. Each time the lamp 330 is started, a stabilized lamp voltage it is compared to a stored stabilized lamp voltage setting. If a step in the voltage is greater than a predetermined limit level stored in the non-volatile storage device 316, then it is determined that the lamp 330 has been replaced. For example, if a decrease of 5 volts in the lamp voltage is determined by a computer control circuit 314 after the lamp voltage has stabilized, it is determined that lamp 330 has been replaced. After said determination, the number of hours of operation and the number of starts of the lamp are reset in the non-volatile storage device 316.

Figure 5 illustrates the replacement technique described above using the comparison of lamp start voltages. The graph 500 graphs a percentage of the lighting cycle 502 against a lamp start voltage 504 using the curve 506. During each start, the voltage of the lamp 330 is obtained and compared to a lamp voltage stored in the storage device not -Vatile 316 of the previous lamp start. If the lamp voltage stage between starts is greater than the predetermined limit, for example, a stage of 160 volts 508 to 100 volts 510, the lighting control system 315 determines that the lamp 330 has been replaced since the stabilized lamp voltage was reduced by 60 volts from a previous lamp operation. Subsequently, the number of hours of operation and the number of lamp starts stored in the non-volatile storage device 316 are re-established. Those skilled in the art will recognize that there are many other comparable means to perform the lamp replacement detection described above.

Figure 6 is a flow chart 600 of process steps implemented by the lighting control system 315. The blocks in the flow chart 600 may perform in the order shown, outside the order shown or they may be performed in parallel. In step 602, the energy is applied to the ballast 302 by lighting the lamp 330.

Then, in step 604, lamp 330 is set to full power. In step 606, the ballast 302 obtains a variety of constant lumen output control (CLO) values, for example, total lamp starts, historical lamp voltage and lamp life constants based on the particular type of used lamp 330 of the non-volatile storage device 316. In step 608, the ballast 302 initiates a lamp heating timer having a predetermined heating time setting, for example, 20 minutes. In step 610, the accumulated lamp timer is started. The lamp heating timer and the accumulated lamp timer are created using the timers 317, which are stored in the non-volatile storage device 316 for use by the computer control circuit 314. Then, in step 612, the ballast 302 increments the counter 319 (FIG. 3) by measuring the number of lamp starts and stores the new lamp start value in the non-volatile storage device 316. In step 614, the ballast 302 determines whether the time period The default heating has elapsed to ensure that the wattage of the lamp and the voltage have stabilized. If the heating time period has not elapsed, the process returns to step 614. In step 616, if the heating time period has elapsed, the ballast 302 determines whether the lamp 330 has been replaced using the technique described in FIG. Figure 5 If the lamp 330 has been replaced, then, in step 618, the ballast 302 restores the number of hours of operation and the number of starts of the lamp to their predetermined reset values. For example, the hours of operation are assigned a value of 10 and the number of starts is assigned a value of 1. If the lamp 330 has not been replaced, the process proceeds to step 620 where the ballast 302 writes the current value for the number of hours of operation, the number of lamp starts, and a lamp start voltage that is being used by the lamp 330 in the non-volatile storage device 316.

In step 622, the ballast 302 determines the output of lamp lumen projected for the lamp 330 based on the degradation curve stored in the non-volatile storage device 316 for the particular lamp type. Subsequently, in step 624, the degradation of the lamp due to the number of starts is derived from the stored compensation curve for the particular type of lamp 330 that is being used. In step 626, the target output lumens of the lamp 330 are provided in accordance with the current lumens calculated to adjust the energy supplied to the lamp 330 to maintain a constant lumen output of the lamp 330. In step 628, the ballast 302 determines the actual power setting, in watts, at which the lamp 330 should be adjusted to provide the target lumens by converting the output lumens to watts. The conversion is calculated from a light output against the energy curve for the type of lamp 330 that is being used. In step 630, the ballast 302 adjusts the output wattage of the lamp 330 by establishing an internal reduced energy level setting.

Thus, by using the ballast 302 which can adjust the power input to the lamp 330, a lighting system can be implemented which is efficient and effective according to the cost.

As mentioned above, the ballast 302 can also use the stabilized lamp operating voltage to maintain a constant lumen output for the lamp 330. Instead of combining the results of the heat loss equations and start loss, the circuit Computational Control 314 calculates a value for what is known as Slov, and combines the Slov and the start loss equations to maintain a constant lumen output for the lamp 330. The Slov represents the stabilized lamp operating voltage and can be determined by using the following second-degree polynomial equation.

Slov = G x Hours2 + H x Hours + I The value for the Slov is stored in the non-volatile storage device 316 together with the constants G, H and I, which are associated with a particular type of lamp 330 that is being powered by the ballast 302. The constants G, H and I are derived and stored in a non-volatile storage device 316 in a manner similar to constants A, B and C.

Figure 7 illustrates a lighting system 700 using multiple ballasts 302. The lighting system 700 includes multiple ballasts 302, each connected to a power supply 702 to control the lumen output of a lamp 330 connected to each ballast 302.

Thus, the lighting system 700 utilizes multiple ballasts 302 and lamps 330 to illuminate larger areas which could be used in a variety of lighting applications.

Figure 8 is a diagram 800 illustrating the energy consumption of a lamp 330 using a conventional ballast and ballast 302. In Figure 8, a time component (X axis 802) and a lamp energy percentage component. (Y axis 804) are used to compare a constant light output 806 produced by the lamp 330 using ballast supply energy 302 against the light output 808 of the lamp 330 using conventional ballast supply power. Since a conventional ballast can not adjust the power input to the lamp 330, the conventional ballast provides full power to the lamp 330 when full power is not needed. The area indicated at 810 between the curves 806 and 808 illustrates the wasted energy when a lamp 330 is conventionally controlled. Thus, the energy consumed by a lamp 330 which is controlled by a conventional ballast exceeds the energy consumed by a lamp 330 which is controlled by the ballast 302. By adjusting the power output of the ballast 302, the lamp 330 is provided with only the enough energy to maintain an established lumen output level. Thus, the energy costs are reduced since the ballast 302 does not overload the lamp 330 by supplying more energy than required.

As mentioned with reference to Figure 3, another alternative for the heating hours and the lamp starts uses re-ignition voltage, or more specifically the voltage peak factor (VCF). The re-ignition of the lamp discharge occurs each time the lamp current changes polarity. As a result, the arc and the electron flow must be reestablished, which takes a finite amount of time. This time creates a resultant arc impedance change, which results in an instantaneous increase in the lamp voltage that is limited by the instantaneous open circuit voltage of the ballast. The time and voltage needed to re-establish the arc are dependent on the ability of the electrode to supply electrons and continue the recombination process. As the HID 330 lamp ages, the ability of the electrode and fill gas to provide and transport electrons decreases. The resulting magnitude of the voltage peak, measured at the current zero crossing, it is called the re-ignition voltage, which increases subsequently. Referring now to Figure 9A, the peak re-ignition voltage for a new HID lamp is shown in reference numeral 910. After some time, the peak re-ignition voltage for this old HID lamp is shown in FIG. reference number 920. Therefore the peak re-ignition voltage is a factor that varies with the age of the lamp.

The VCF is defined using the peak re-ignition and the RMS lamp operating voltage that can be used to monitor lamp life. More specifically, the VCF is the ratio of the peak re-ignition voltage to the RMS voltage of the operating voltage of the lamp. Since the VCF changes as the peak re-ignition voltage changes with the age of the lamp, the VCF varies with the age of the lamp. The graph 930 in Figure 9B illustrates the variation of the VCF with the life of the lamp. Thus, monitoring the VCF can be used as a parameter to estimate the heating hours of the lamp 330 and provide data to the computational control 314 to adjust the energy of the lamp 330 to maintain a constant lumen output.

Although the invention has been described in detail in connection with an exemplary embodiment, it should be understood that the invention is not limited to the previously disclosed embodiment. Rather, the invention may be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not described herein, but which are commensurate with the spirit and scope of the invention. In particular, the specific modalities of the constant lumen output control system described should be taken as exemplary and not limiting. For example, the ballast 302 can also determine the lumen degradation of the lamp 330 by measuring the change in the RMS voltage, voltage and current peak factors, re-ignition voltage or combination of these lamp parameters 330 or by monitoring the lumens emanating from the lamp 330, by lumens received in a task that is being illuminated by the lamp 330. Accordingly, the invention is not limited by the foregoing description or drawings, but is limited only by the scope of the attached claims.

Claims (35)

1. CLAIMS 1. A method for providing constant lumen output control to a lumen output device, comprising: determining a number of hours of operation for a lamp, determining a number of lamp starts for the lamp, creating a value of degradation by combining the number of hours of operation and the number of lamp starts, forming an output ratio to draw energy from the lamp using the degradation value and a target lamp output and establishing a reduced energy level for the lamp using the output ratio.
2. 2. The method according to claim 1, wherein the objective lamp output is specific to the particular type of lamp.
3. 3. The method according to claim 1, wherein the reduced energy level is adjusted throughout the life of the lamp to maintain a constant lumen output.
4. 4. The method according to claim 3, wherein the adjustment compensates for the degradation of the lamp within the lamp.
5. 5. The method according to claim 1, further comprising resetting the number of hours of operation and the number of starts of the lamp when the lamp is replaced.
6. 6. The method according to claim 5, wherein the lamp voltage comparison is used to determine when the lamp has been replaced.
7. 7. The method according to claim 1, wherein the step of determining the number of hours of operation, 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 stage of establishing a reduced energy level are performed by a processor.
8. 8. A method for 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 when combining the lamp operation voltage stabilized and the number of lamp starts, form an output ratio to draw energy from the lamp using the degradation value and a target lamp output and establish a reduced energy level for the lamp using the ratio of exit.
9. 9. The method according to claim 8, wherein the objective lamp output is specific to the particular type of lamp.
10. 10. The method according to claim 8, wherein the reduced energy level is adjusted throughout the life of the lamp to maintain a constant lumen output.
11. 11. The method according to claim 10, wherein the adjustment compensates for the degradation of the lamp within the lamp.
12. 12. The method according to claim 8, further comprising resetting the number of lamp starts when the lamp is replaced.
13. 13. The method according to claim 12, wherein a lamp voltage comparison is used to determine when the lamp has been replaced.
14. 14. The method according to claim 8, wherein the step of determining the lamp operating voltage stabilized 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 stage of establishing a reduced energy level are played by a processor.
15. 15. A lumen output control circuit comprising: a timer for measuring the number of hours of operation for a lamp, a counter for measuring a number of lamp starts for the lamp, a processor for processing a plurality of energy degradation equations, light and output proportions based on the number of hours of operation and the number of lamp starts and a non-volatile storage device for storing lamp information and lamp constants.
16. 16. The circuit according to claim 15, wherein the processor establishes a reduced energy level for the lamp.
17. 17. The circuit according to claim 15, wherein the non-volatile storage device stores the number of hours of operation for the lamp.
18. 18. The circuit according to claim 15, wherein the non-volatile storage device stores the number of lamp starts for the lamp.
19. 19. The circuit according to claim 15, wherein the non-volatile storage device stores a lamp voltage for each lamp start for the lamp.
20. 20. A lumen output control circuit comprising: means for determining a stabilized lamp operating voltage for a lamp, a meter for measuring a number of lamp starts for the lamp, a processor for processing a plurality of efficiency degradation equations, light and output proportions 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 diagnostic information of the lamp and lamp constants.
21. 21. The circuit according to claim 20, wherein the processor establishes a reduced energy level for the lamp.
22. 22. The circuit according to claim 20, wherein the non-volatile storage device stores the stabilized lamp operating voltage for the lamp.
23. 23. The circuit according to claim 20, wherein the non-volatile storage device stores the number of lamp starts for the lamp.
24. 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 sensory circuit for providing feedback information of the ballast lamp and a circuit of lumen output control connected to the power supply, the ballast control circuit, the lamp controller and the sensory circuit configured to adjust the power input for the ballast lamp.
25. 25. The ballast according to claim 24, further comprising a lamp driver connected to the ballast control circuit to provide an on / off mechanism for the ballast.
26. 26. The ballast according to claim 24, wherein the lumen output control circuit comprises: a timer for measuring a number of hours of operation for a lamp, a counter for measuring a number of lamp starts for the lamp, a processor for processing a plurality of light-degrading equations and output proportions based on the number of hours of operation and the number of lamp starts and a non-volatile storage device for storing lamp information and lamp constants .
27. 27. The ballast according to claim 24, wherein the processor establishes a reduced energy level for the lamp.
28. 28. The ballast according to 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-degrading equations and output proportions based on the stabilized lamp operating voltage for the lamp and the number of lamp starts and a non-volatile storage device for storing diagnostic information of the lamp. lamp and lamp constants.
29. 29. The ballast according to claim 28, wherein the processor establishes a reduced energy level for the lamp.
30. 30. A lighting system comprising: a plurality of ballasts, each ballast having a lumen output control circuit for adjusting the power input to a lamp of each ballast, thereby creating a constant lumen output of the lamp and a plurality of lamps connected to the plurality of ballasts to provide illumination.
31. 31. The system according to claim 30, wherein the lumen output control circuit comprises: a timer for measuring a number of hours of operation for a lamp, a counter for measuring a number of lamp starts for the lamp, a processor for processing a plurality of light-degrading equations and output proportions based on the number of hours of operation and the number of lamp starts and a non-volatile storage device for storing lamp information and lamp constants .
32. 32. The system according to claim 31, wherein the processor establishes a reduced energy level for the lamp.
33. 33. The system according to 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-degrading equations and output proportions based on the stabilized lamp operating voltage and the number of lamp starts and a non-volatile storage device for storing diagnostic information of the lamp and constants of the lamp.
34. 34. The system according to claim 33, wherein the processor establishes a reduced energy level for the lamp.
35. 35. A method for providing constant lumen output control to a lumen output device, comprising: determining a peak re-ignition voltage for the lamp, calculating a root-to-square average of a lamp operating voltage, creating a degradation value by forming a ratio of the peak re-ignition voltage and the root mean to the square of the operating voltage of the lamp, forming an output ratio to draw energy from the lamp using the degradation value and a lumen output target and set a reduced energy level for the lamp using the output ratio.