WO2012109758A1

WO2012109758A1 - Device and method for operating an illumination device

Info

Publication number: WO2012109758A1
Application number: PCT/CA2012/050095
Authority: WO
Inventors: Gregory Bernard Sheehan; Thomas George Foxall; Tom William Thornton; Milen Moussakov
Original assignee: Light-Based Technologies Incorporated
Priority date: 2011-02-18
Filing date: 2012-02-17
Publication date: 2012-08-23

Abstract

The present technology provides a device and a corresponding method for controlling dimming of an illumination device. The device comprises an input module (512) configured to receive a dimming signal (511); an output module (516) configured to provide a drive signal to the illumination device; and a control module (514) operatively coupled to the input module (512) and the output module (516) and configured to determine at least one signal characteristic of the dimming signal, the control module (514) configured to modify a stored dimming range when the at least one signal characteristic is outside the stored dimming range and the control module (514) further configured to generate the drive signal at least in part based on the received dimming signal (511) and the stored dimming range; wherein said control module (514) is operative to modify the stored dimming range during active dimming control of the illumination device. In addition, the control module (514) is configured to determine the validity of the stored dimming range.

Description

DEVICE AND METHOD FOR OPERATING AN

ILLUMINATION DEVICE

TECHNICAL FIELD

[0001] The present technology pertains in general to operation of illumination devices, specifically to dimming of illumination devices.

BACKGROUND

[0002] Many dimmers including electronic and combinations of a dimmer with a transformer used in or considered for installation in typical residential uses are typically limited for use with incandescent illumination devices including standard line voltage and low- voltage halogen lamps. While dimming of illumination devices such as fluorescent tubes and/or compact fluorescent lamps (CFLs), for example, is possible, such illumination devices cannot be dimmed with residential dimmers typically used in today's homes. In addition, the advance of solid-state lighting (SSL) has increased acceptance of SSL illumination devices beyond commercial applications. While light- emitting diodes (LEDs) in SSL illumination devices can be dimmed and controlled in many ways, existing SSL illumination devices are largely incompatible for use with typical residential dimmers.

[0003] Typical residential dimmers including phase-cut dimmers are directly or, if the illumination device requires a low operating voltage, indirectly, via a transformer, provided to the illumination device. Figure 1 illustrates an example setup. As such, the waveform of the dimming signal provided by the dimmer and/or transformer can differ significantly from standard line voltage and vary depending on, for example, the type of dimmer, the transformer, the dimmer manufacturer, or from dimmer to dimmer. In addition, the waveform is often complex and distorted, and can be difficult to relate to a specific type of dimmer and the like. Figure 2A and Figure 2B illustrate example voltage waveforms of voltage output signals of a typical electronic low voltage dimmer- transformer combination, where the transformer is in a switched mode power supply. Figures 2A and 2B clearly illustrate envelopes but do not resolve high frequency variations of the corresponding waveforms of the output signals. Figure 2A illustrates about three periods of a waveform for low output power and Figure 2B one period of a waveform for high output power. The examples shown in Figures 2A and 2B are for dimming power levels of 5% and 100% respectively. Figures 3 A to 3C illustrate example voltage waveforms of output signals associated with a typical low-voltage dimmer-transformer combination, where the transformer is a magnetic transformer such as for example a transformer with a steel core configured to step down a 120 VAC (50Hz or 60Hz) line voltage to low voltage e.g. 12V AC or 24VAC. Figure 3A to 3B, each illustrate about three periods of output signals. Figure 3 A illustrates a waveform for low output power, Figure 3B for medium output power, and Figure 3C for high output power. The examples shown in Figures 3A to 3C are for dimming power levels of 5%, 50% and 100% respectively. Other dimmers may produce output signals similar to pulse width or pulse code modulated waveforms (not illustrated), for example.

[0004] As dimming of an incandescent illumination device requires control of the heat of its filament, many residential dimmers typically only control how much power is provided to a connected illumination device. As such, residential dimmers do not further control the waveform of the dimming signal. Various types of illumination devices including fluorescent or LED-based light sources, however, require certain control over the waveform beyond that provided by a dimmer for incandescent illumination devices. Corresponding illumination devices typically require precise DC current control, PWM, PCM or other pulse control of the dimming signal. Some dimming systems including residential dimmers may further be subject to power factor and/or electrical interference control.

[0005] Renesas Electronics announced an apparatus that can dim SSL illumination devices based on the dimming signals provided by certain residential dimmers including electronic and phase-cut dimmers, for example, which provides a learning mode in which the device learns the minimum and maximum voltages defining the full dimming range. This apparatus, however, requires calibration to work with a particular dimmer- transformer combination and as such only operates reliably in the calibrated configuration. The apparatus is not resilient against changes of the dimmer-transformer combination or to variations in the characteristics of dimmers of the same type, make or model without recalibration. Lack of calibration can cause what is commonly referred to as "dead travel" wherein certain changes to the dimmer setting may not cause any effect or do not cause the desired effect on the light level provided by the illumination device. Manual activation and control of the required calibration makes the use of such devices tedious and cumbersome.

[0006] Therefore there is a need for a solution that overcomes at least one of the deficiencies in the art.

[0007] This background information is provided to reveal information believed by the applicant to be of possible relevance to the present technology. No admission is necessarily intended, nor should be construed, that any of the preceding information constitutes prior art against the present technology. SUMMARY

[0008] An object of the present technology is to provide a device and method for operating an illumination device. In accordance with an aspect of the present technology, there is provided a device for controlling dimming of an illumination device, the device comprising: an input module configured to receive a dimming signal; and a control module operatively coupled to the input module and configured to determine an instant dimmer signature at least in part based upon the dimming signal and compare the instant dimmer signature with a stored dimmer signature, thereby determining if dimming information associated with the stored dimmer signature is acceptable for generation of a drive signal, the control module further configured to generate a drive signal at least in part based on the received dimming signal when the comparison of the instant dimmer signature and the stored dimmer signature meets a predetermined threshold.

[0009] In accordance with another aspect of the present technology, there is provided a method for controlling dimming of an illumination device, the method comprising: receiving a dimming signal; determining an instant dimmer signature at least in part based upon the dimming signal; comparing the instant dimmer signature with a stored dimmer signature associated with the stored dimming range thereby determining if dimming information associated with the stored dimmer signature is acceptable for generation of a drive signal; generating a drive signal at least in part based on the received dimming signal when the comparison of the instant dimmer signature and the stored dimmer signature meets a predetermined threshold.

[0010] In accordance with another aspect of the present technology, there is provided a computer program product comprising a memory having stored thereon code for controlling dimming of an illumination device, the code when executed by a processor causing the processor to perform the steps of: receiving a dimming signal; determining an instant dimmer signature at least in part based upon the dimming signal; comparing the instant dimmer signature with a stored dimmer signature associated with the stored dimming range thereby determining if dimming information associated with the stored dimmer signature is acceptable for generation of a drive signal; generating a drive signal at least in part based on the received dimming signal when the comparison of the instant dimmer signature and the stored dimmer signature meets a predetermined threshold.

[0011] In accordance with an aspect of the present technology, there is provided a device for controlling dimming of an illumination device, the device comprising: an input module configured to receive a dimming signal; and a control module operatively coupled to the input module and configured to determine at least one signal characteristic of the dimming signal, the control module configured to modify a stored dimming range when the at least one signal characteristic meets a predetermined criterion and generate a drive signal at least in part based on the received dimming signal, the control module further configured to provide said drive signal to the illumination device; wherein said control module is operative to modify the stored dimming range during active dimming control of the illumination device, said control module further configured to receive and evaluate an identifier, said identifier at least in part indicative of validity of the stored dimming range and upon determination of invalidity of the stored dimming range the control module is configured to re-initialize the stored dimming range.

[0012] In accordance with another aspect of the present technology, there is provided a method for controlling dimming of an illumination device, the method comprising: receiving a dimming signal and an identifier; determining validity of a stored dimming range based at least in part on the identifier and re-initializing the stored dimming range when the stored dimming range is invalid; determining at least one signal characteristic of the dimming signal; modifying the stored dimming range when the at least one signal characteristic meets a predetermined criterion; and generating a drive signal at least in part based on the received dimming signal and the stored dimming range.

[0013] In accordance with another aspect of the present technology, there is provided a computer program product comprising a memory having stored thereon code for controlling dimming of an illumination device, the code when executed by a processor causing the processor to perform the steps of: receiving a dimming signal and an identifier; determining validity of a stored dimming range based at least in part on the identifier and re-initializing the stored dimming range when the stored dimming range is invalid; determining at least one signal characteristic of the dimming signal; modifying a stored dimming range when the at least one signal characteristic meets a predetermined criterion; and generating a drive signal at least in part based on the received dimming signal and the stored dimming range.

BRIEF DESCRIPTION OF THE FIGURES

[0014] Figure 1 illustrates a block diagram of an example setup of a dimmer, optional transformer and lamp according to the prior art.

[0015] Figure 2A and 2B illustrate example voltage waveforms of voltage output signals of a typical electronic low voltage dimmer-transformer combination at different power levels, where the transformer is in a switched mode power supply.

[0016] Figure 3A to 3C illustrates example voltage waveforms of output signals associated with a typical low-voltage dimmer-transformer combination at different power levels, where the transformer is a magnetic transformer.

[0017] Figure 4 illustrates a block diagram of an example setup of a dimmer, optional transformer and illumination device according to embodiments of the present technology. [0018] Figure 5 illustrates a block diagram of an embodiment of a dimming signal converter such as shown in Figure 4 according to embodiments of the present technology. [0019] Figure 6 illustrates a schematic of a RC filter circuit suitable for determining a root mean square of the voltage of a dimming signal for use in a dimming signal converter according to some embodiments of the present technology.

[0020] Figure 7 illustrates a flow diagram of a method for determining a dimming range according to some embodiments of the present technology.

[0021] Figure 8A illustrates a schematic of a circuit for determining a signature signal for determining a signature according to embodiments of the present technology.

[0022] Figure 8B illustrates an example waveform for a dimmer signal provided by a low- voltage dimmer and transformer combination. [0023] Figure 8C shows the waveform of Figure 8B after it has been rectified (indicated by the solid line) and the signal averaged (indicated by the dashed line) according to embodiments of the present technology.

[0024] Figure 8D illustrates an example signature signal for a typical dimmer signal similar to that provided by a low-voltage dimmer and transformer combination as illustrated in Figure 8B.

[0025] Figure 9 illustrates a flow diagram of a method for reinitiating a dimming range according to embodiments of the present technology.

[0026] Figure 10 illustrates a flow diagram of a method for powering up the device according to embodiments of the present technology. [0027] Figure 11 illustrates a flow diagram of a method for updating the stored values of the dimming signal, dimming range and dimmer signature according to embodiments of the present technology.

DETAILED DESCRIPTION OF THE TECHNOLOGY

Definitions [0028] As used herein the term illumination device is used to describe a device that emits radiation in a region or combination of regions of the electromagnetic spectrum, for example the visible region, infrared and/or ultraviolet region. An illumination device can have monochromatic, quasi-monochromatic, polychromatic or broadband spectral emission characteristics. An illumination device can include one or more light sources such as semiconductor, organic, polymer or polymeric light-emitting diodes, blue or UV pumped phosphor coated light-emitting diodes, optically pumped nanocrystal light- emitting diodes (LEDs), high-intensity discharge (HID), fluorescent tube, compact fluorescent lamp, gas discharge, incandescent, electric arc, plasma, electroluminescent, radioluminscent, or other illumination devices. Furthermore, the term illumination device can refer to an electric lamp, bulb, fixture, or luminaire.

[0029] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this technology belongs.

[0030] The present technology can be employed to operate an illumination device in combination with different dimmers without requiring manual calibration by a user of a particular dimmer before or during dimming of the illumination device with the particular dimmer. According to embodiments, the present technology can be employed to determine a drive signal for dimming illumination devices wherein the drive signal is based on a dimming signal which can be provided by different dimmers and used to operate the illumination device during operation.

[0031] The present technology can be employed to dynamically adjust/extract the dimmer setting as indicated by a signal characteristic of a dimmer signal that is provided by a corresponding dimmer or dimmer/transformer combination - also further referred to herein as a "dimmer", that can effectively be dimmed irrespective of certain variations in dimming signals of different dimmers. The present technology can provide dimming over a full dimming range by adaptive learning of signal characteristics of corresponding dimming signals within the range of dimmer settings during operation of the illumination device.

[0032] According to embodiments, the present technology can be employed in a dimming signal converter that can be used in combination with different dimmers of different type, kind, make, model and/or sample independent of the manufacturer of the dimmer. The dimming signal converter does not require a separate learning or calibration mode. The dimming signal converter associates at least a dimming range and a dimmer signature with a particular dimmer, and can detect changes in the dimmer and dynamically reconfigure the system by reinitiating an adaptive learning process during operation, for example in response to reconnection with a different dimmer.

[0033] According to embodiments, a dimmer signature comprises one or more instant dimmer signatures. An instant dimmer signature is determined by the dimming signal converter based upon one or more properties of a dimming signal. According to embodiments, a dimmer signature comprises one instant dimmer signature associated with a dimming signal provided at a particular dimmer setting. According to some embodiments, a dimmer signature comprises two or more instant dimmer signatures associated with respective two or more dimming signals provided at a respective number of dimmer settings.

[0034] According to some embodiments, a dimmer signature is used by the dimming signal converter to determine whether a certain dimming range can be further used by the dimming signal converter to adequately map the dimming signal into a drive signal for proper dimming of the illumination device or if the dimming range needs to be reinitialized. For this purpose the dimming signal converter verifies one or more instant dimming signatures against a stored dimmer signature. If the verification fails, the dimming signal converter re-initializes the dimming range.

[0035] According to embodiments, a dimming signal converter is configured to receive and evaluate one or more identifiers, wherein this evaluation provides a means for the determination of the validity of a previously stored range of dimmer settings. For example, upon the confirmation of the validity of a previously stored range of dimmer settings, the process of adaptive learning of signal characteristics representative of dimmer settings is not required, thereby mitigating the repetition of this process. However, should a signal characteristic be reflective of a new maximum or new minimum dimming range value, the modification of the appropriate portion of the stored range of dimming settings would be modified accordingly. According to embodiments an identifier can be representative of one or any combination of: the last used dimming setting, a loss of power, a change in load provided by the illumination device, deactivation of the supply of power, a signature representative of the dimmer or dimmer/transformer combination, or the like. [0036] According to some embodiments, the dimming signal converter can be configured to determine drive signals that can vary within a predetermined voltage and/or current range irrespective of the range of variation of the voltage and/or current provided by the dimming signal. As such the dimming signal converter may be configured to be used in combination with dimming signals that can vary across one or more large, small or other predetermined voltage and/or current ranges of dimming signals. The range of variation of the drive signal provided by a dimming signal converter may be configured to accommodate driving of one or more types of illumination devices and/or light sources. [0037] Figure 4 illustrates a block diagram 400 of an example setup of a dimmer 410, optional transformer 415 and illumination device 420 according to embodiments of the present technology. Some embodiments of the apparatus shown in block diagram 400 may comprise a dimmer 410 and illumination device 420, without an associated transformer 415. The dimmer 410 receives an input voltage 411, for example a 110V/60Hz or 220V/50Hz line voltage, and generates and output signal 412. The optional transformer 415 converts the output signal 412 into output signal 413. Example output signals for a switched mode power supply transformer are shown in Figures 2A to 2B. Example output signals for a magnetic transformer are shown in Figures 3 A to 3C. Depending on the setup the output signal 412 or 413 is referred to as the dimming signal that is provided to the dimming signal converter 430. The dimming signal converter 430 converts the dimming signal into a drive signal 431. While the dimming signal converter is coupled with the illumination device 420, it does not need to be directly coupled to it. As such, and depending on the embodiment, the dimming signal converter 430 may be coupled with, coupled to, form part of or an integral part of a driving device (not illustrated) for driving the illumination device. It is noted that, depending on the embodiment, the dimming signal converter may be operatively disposed external of the illumination device between the dimmer and the illumination device. According to an embodiment, the dimming signal converter may be included (not illustrated) in the illumination device, for example operatively coupled or integrated with a controller of the illumination device.

[0038] Having further regard to Figure 4, the output signal presented to the dimming signal converter can be representative of a signal generated by a dimming device alone. In embodiments of this configuration, the dimmer is substantially directly connected to the dimming signal converter. According to embodiments, a signature evaluated from the output signal can be reflective of the dimmer's characteristics.

[0039] In some embodiments, the output signal presented to the dimming signal converter can be representative of a signal generated by a dimming device and subsequently modified by a transformer. In these embodiments, a signature evaluated from the output signal can be reflective of the dimmer's characteristics as well as the transformer's characteristics. A signature of a dimmer/transformer combination is likely to be more complex than a signature associated with a dimmer alone. [0040] Figure 5 illustrates a block diagram of an embodiment of a dimming signal converter 510 (such as shown in Figure 4 as dimming signal converter 430), according to embodiments of the present technology. The dimming signal converter comprises an input module 512 for receiving a dimming signal 511, an optional output module 516 for providing a drive signal 513, and a control module 514 for processing the dimming signal or another signal based thereon provided by the input module 512 into the drive signal 513 or another signal configured for receipt by the output module 516 for generation of the drive signal 513. The dimming signal converter 510 and/or the control module 514 is/are configured as follows and as further described herein.

Dimming Range [0041] According to some embodiments, the dimming signal converter is configured to determine a dimming range from dimming signals while being able to concurrently operate an operatively connected illumination device. As such, a corresponding dimming signal converter does not require interruption of normal operation of an operatively connected illumination device in order to determine a dimming range and to perform adequate dimming. According to some embodiments, a corresponding dimming signal converter can determine a certain signal characteristic indicative of the dimming indicated by dimming signals and determine the dimming range based upon the signal characteristics of a series of dimming signals. Such a dimming signal converter is configured to determine the lower and upper limit of the dimming range based upon respective lowest and highest signal characteristics as described in more detail below. [0042] According to some embodiments, the dimming signal converter is configured to determine a dimming range by modifying a stored dimming range when at least one signal characteristic meets one or more predetermined criteria. A predetermined criterion can be indicative that the at least one signal characteristic is inside or outside of a stored dimming range, or that the signal characteristic provides a certain confidence, signal-to-noise ratio or that the signal characteristic has a certain other nature. The modification of the stored dimming range can include resetting the dimming range to a predetermined dimming range, increasing or decreasing a minimum or maximum of the stored dimming range or both minimum and maximum of the stored dimming range, or otherwise adjust the stored dimming range, for example.

[0043] According to embodiments, the dimming signal converter is configured to convert dimming signals into drive signals so that a predetermined characteristic of the drive signals varies within a certain drive signal range and is adequate for indicating an amount of light that is to be generated and/or emitted by the light sources of the illumination device and/or the illumination device. Depending on the embodiment, the dimming signal converter may be configured to employ the dimming signal as a source of power for operating the illumination device or at least as a control signal for determining dimming of light sources that are supplied with power otherwise. Depending on the embodiment, if the dimming signal provides only a control signal for dimming but no power for driving the light sources, power may be provided to the dimming signal converter or another component of the illumination device via an operative connection to a source of power, for example a line/mains or transformed voltage directly and/or via a transformer or the like.

[0044] Depending on the embodiment, the signal characteristic may be associated with a root mean square, instant or time-averaged product or other function of the voltage and/or the electric current provided by the dimming signal. As such, the signal characteristic may be indicative or correspond with an instant or time averaged power provided by the dimming signal. Depending on the embodiment, the signal characteristic may vary based on the load attached to the output of the dimming signal converter, including the illumination device and/or light sources included therein that are connected to the dimming signal converter and/or a driver device for driving the light sources and/or illumination device, for example. Depending on the embodiment, the dimming signal converter may be configured to adjust a dimming range and/or a dimmer signature in response to load-induced variations of the dimming signal, for example. This may be useful, for example, when the dimming signal converter is separate from the illumination device and the illumination device, for example, a bulb or other light source thereof is replaced with one of another type or one having a different power requirement. This may be useful in various embodiments of a dimming signal converter, including those in which the dimming signal also provides power for activating the illumination device.

[0045] Figure 6 illustrates a schematic of an example RC filter circuit 600 suitable for determining an average value of the dimming signal which may be used to approximate a root mean square (RMS) value of the voltage of the dimming signal that is provided at input terminal 601. This RC filter circuit can be used in a dimming signal converter according to an embodiment of the present technology. The RC filter circuit includes an output terminal 609, resistors 610, 620 and 630, and capacitors 640 and 650, each of them may be characterized by its own respective nominal resistance or capacitance. Resistors 610 and 620 act as a voltage divider for the dimming signal that is provided at input terminal 601. The dimming signal 601 may for example be the output signal from a dimmer/transformer combination. Resistor 630 and capacitors 640 and 650 in circuit 600 can act as a CRC filter. The RC filter circuit 600 is interconnected as illustrated and can provide a direct current (DC) voltage at output terminal 609 that is indicative of the amount of dimming indicated by a dimming signal provided by electronic dimmer and/or dimmer-transformer combinations when the dimming signal is provided at input terminal 601. Depending on the embodiment, other circuits for determining an average value, RMS or other signal characteristic may be employed. Drive Signal

[0046] According to embodiments, the drive signal provided by a dimming signal converter is based on the dimming signal and the dimming range as further explained herein. For this purpose, and depending on the embodiment, the dimming signal converter may map the dimming signal into the drive signal based on the upper and lower limit of the dimming range and a predetermined mapping function. Depending on the embodiment, a drive signal may be determined independent of a mapping function, upon initial energization of the dimming signal converter. Depending on the embodiment, the mapping function may comprise one or more look-up and/or interpolation steps. Depending on the embodiment, the mapping function may be configured to provide a predetermined feedback to a user operating a dimmer by correlating the light output of the illumination device with the dimmer setting in a certain manner. For example, the dimming signal converter may be configured to allow calibrating luminance variation or other characteristics of the light output of the illumination device with respect to the dimmer settings. It is noted that such a feedback may be subject to further processing of the drive signal by certain components and/or the response of the light source(s) to its input signal included in the illumination device. [0047] Depending on the embodiment, the mapping function may be linear, polynomial, logarithmic, exponential, S-curve, a combination thereof or otherwise characterized, or an inverse of same. According to an embodiment, the mapping function comprises a square law mapping/dimming of the dimming signal into the drive signal. Square law mapping/dimming may be employed to imitate a luminance variation or other characteristic property of incandescent light sources with LED-based illumination devices. Depending on the embodiment, the mapping function may be programmable, for example, by a manufacturer, installer, maintenance staff, user of the dimming signal converter or illumination device, and/or other person, for example. Accordingly, a dimming signal converter may be preconfigured with a plurality of mapping functions and provide selection therefrom for use by the dimming signal converter during operation, for example.

[0048] According to an embodiment, the dimming signal converter is configured to account for dead travel of the dimmer setting proximate the minimum and/or maximum of the dimming range. For example the mapping function may be configured to associate all signal characteristics that are proximate the minimum or maximum dimming range within a defined distance, with respective minimum or maximum drive signals. Depending on the embodiment, proximity associated with the minimum dimming range may have a defined distance different from the distance associated with the maximum dimming range. The defined distance may be predetermined, determined based upon one or more statistical analyses of fluctuations or other aspects of one or more dimming signals, or otherwise determined, for example. As such, the dimming signal converter may be configured to restrict a dimming range during determination of same based on variations in signal characteristics, by keeping the stored dimming range narrower than the range of variations of the signal characteristics of the dimming signals associated with a particular dimmer. Accordingly, the minimum and/or maximum of the dimming range may saturate independent of the respective lowest or highest signal characteristics as determined by the dimming signal converter at the time. Depending on the embodiment, the dimming signal converter may vary drive signals across a limited or full range irrespective.

Method for Determining a Dimming Range

[0049] According to some embodiments, a method for determining a dimming range may be employed in a dimming signal converter and implemented in hardware, software and/or firmware, and may be performed in an analog, a digital or a mixed analog-digital fashion. Depending on the embodiment, details of such a method and/or its invocation may be subject to occurrence of predetermined events. For example, a corresponding method may be invoked, maintained, suspended, interrupted or cancelled in correlation with certain events. According to an embodiment, a method for determining a dimming range may be controlled digitally but invoked by analog circuitry that can detect changes to a certain signal characteristic associated with the dimming signal. Such a method may furthermore be invoked on an interrupt basis and performed by adequate components included in the control module of the dimming signal converter. According to some embodiments, the method can be invoked at a predetermined interval, period or frequency, for example.

[0050] Figure 7 illustrates a flow diagram of an example method 700 for determining a dimming range according to some embodiments of the present technology. The method 700 starts at step 710 with determining an initial dimming range to be used initially when the dimming signal converter determines certain changes to and/or of the dimmer, or upon first energization, for example. The initial dimming range is stored in a store in or operatively associated with the dimming signal converter. The initial dimming range may be preset and can be defined by a predetermined width and center and/or a lower and upper limit, for example. Depending on the embodiment, the width can be substantially zero or non-zero. Depending on the embodiment, an initial dimming range may not be or not be fully employed for an initial determination of a drive signal upon initial energization of the dimming signal converter. In such a case, an initial drive signal may be determined irrespective of the initial dimming range. Depending on the embodiment, the initial drive signal may be determined based only on the power provided by the dimming signal, or based only on parts of the initial dimming range, for example. [0051] According to an embodiment, if, for example upon initial energization, a difference between the signal characteristic of the dimming signal and a substantial zero-width dimming range cannot be determined, a predetermined substantial zero width and as such the corresponding center may be left as they are (not illustrated). According to an embodiment, the initial dimming range can be defined using a center disposed at a level associated with half the light output of the illumination device, for example. According to some embodiments, the dimming signal converter utilizes a previously stored dimming range for as long as it does not determine certain changes to and/or of the dimmer. As such, provision of a drive signal by the dimming signal converter upon a subsequent turn on may be first subject to verification of an instant dimmer signature determined based upon an instant dimming signal against the stored dimmer signature.

[0052] The method 700 further comprises steps 720, 730, 740, 750 and 760 through which it may loop as illustrated subject to occurrence of certain events as further described herein or in another adequate sequence, depending on the embodiment. Furthermore and as illustrated in Figure 7, steps 720, 730, 740, 750 and 760 of the example method 700 involve determination of the RMS of the voltage of the dimming signal as an example signature characteristic of the dimming signal. As described herein, other signature characteristics may be employed depending on the embodiment. As illustrated and according to some embodiments, in step 720, the RMS of the dimming signal is determined and then compared with a stored minimum RMS in step 730. If the current RMS is smaller than the stored minimum RMS, the method proceeds to step 750 and expands the dimming range by setting the stored minimum RMS to the current minimum RMS, if not, the method proceeds to step 740. In step 740, the RMS of the dimming signal is compared with a stored maximum RMS. If the current RMS is larger than the stored maximum RMS, the method proceeds to step 760 and expands the dimming range by setting the stored maximum RMS to the current maximum RMS, if not, the method proceeds/loops back to step 720. Likewise, step 750 and step 760 proceed to step 720 upon completion. Dimmer Signature

[0053] According to embodiments, a dimmer signature comprises one or more instant dimmer signatures. An instant dimmer signature is determined by the dimming signal converter based upon one or more properties of a dimming signal. According to an embodiment, a dimmer signature comprises one instant dimmer signature associated with a dimming signal provided at a particular dimmer setting. According to some embodiments, a dimmer signature comprises two or more instant dimmer signatures associated with respective two or more dimming signals provided at a respective number of dimmer settings. [0054] According to some embodiments, a dimmer signature is used by the dimming signal converter to determine whether a certain dimming range can be further used by the dimming signal converter to adequately map the dimming signal into a drive signal for proper dimming of the illumination device or if the dimming range needs to be reinitiated. For this purpose the dimming signal converter verifies instant dimming signatures against the stored dimmer signature. If the verification fails, the dimming signal converter reinitiates the dimming range. In order to perform such verification, a stored dimming signature is required.

[0055] According to embodiments, the dimming signal converter can differentiate between dimmers that exhibit certain differences in dimming signals that otherwise indicate nominally equal dimming. Accordingly, the dimming signal converter is configured to determine a dimmer signature based on an analysis of the waveforms of one or more dimming signals provided by a particular dimmer. For this purpose and according to some embodiments, the dimming signal converter determines one or more properties associated with dimming signals that are characterized by different signal characteristics.

[0056] According to some embodiments, the dimming signal converter first generates instant dimmer signatures for storage in the stored dimmer signature. Depending on the embodiment, this may occur before the dimming signal converter begins verification of instant dimmer signatures and/or last until occurrence of one or more predetermined events. For example, the dimming signal converter may generate instant dimming signatures solely for storage in the stored dimmer signature for a predetermined amount of time, until the dimming range has been sampled in a predetermined manner, or other event. Depending on the embodiment, the dimming signal converter may use some instant dimmer signatures and add them to a stored dimmer signature after it has started verification of dimming signals, for example when an instant dimmer signatures is associated with a signal characteristic outside of the stored dimming range.

[0057] Depending on the embodiment, stored dimmer signatures may be generated as described or pre-provided and/or expanded by the dimming signal converter. For this purpose, the dimming signal converter can generate a dimmer signature and/or expand an already stored dimmer signature irrespective of whether one or more of its elements were pre-provided by adding additional instant dimmer signatures to the stored dimmer signature as it processes new dimming signals that have not been previously supplied to the dimming signal converter. Depending on the embodiment, the dimming signal converter may limit the number of instant dimmer signatures in a stored dimmer signature in a number of ways, for example, per dimmer (if so configured), by the amount of memory available for saving the dimmer signature or other measures. Depending on the embodiment, the dimmer signal converter may be pre-provided with information including one or more dimmer signatures during manufacture, installation or at other times.

[0058] According to some embodiments, the dimming signal converter determines one or more properties of the dimming signal and a corresponding signal characteristic that indicates the dimming of the illumination device. According to some embodiments, the correlation between the signal characteristic and the one or more properties form a part of the dimmer signature. According to some embodiments, the dimming signal converter may add the correlation as an element to the dimmer signature. Depending on the embodiment, the dimming signal converter may perform such a step provided the correlation differs from other elements already included in the dimmer signature in a predetermined manner. During verification of the dimming signal against a stored dimmer signature, a corresponding difference may be determined based on differences between the signal characteristic and/or properties of the correlation and the signal characteristics and/or properties of the proximate elements of the dimmer signature.

[0059] Depending on the embodiment, properties of the dimming signal may relate to the waveform of the dimming signal, the impedance of the wiring and/or the dimmer that are attached to the input module of the dimming signal converter (collectively referred to as input of the dimming signal converter), a measure associated with the dynamic range of a dimming signal, a measure associated with the degree of symmetry between half-waves of a dimming signal or other aspects associated with the dimming signal. For example, properties of the dimming signal used for determination of an instant dimmer signature can relate to the voltage, the electric current, and/or a combination thereof as provided by the dimming signal and/or time or frequency components thereof. Such properties may include one or more discrete samples of the dimming signal taken at corresponding times, an indication of a noise signal embedded in the dimming signal such as a signal to noise (S/N) ratio and/or noise floor, first or higher order derivatives and/or frequency components of the dimming signal, inductance of the input of the dimming signal converter and/or other aspects. Depending on the embodiment, such properties may be digitized and/or stored in a digital form, for example in a memory/store as described herein. Depending on the embodiment, such properties may be acquired through the use of one or more of analog, digital or mixed analog-digital filters, for example, high-, low-, band-, bandpass-, comb-, or other filters, for example. In another example embodiment, the properties may be acquired through the use of a circuit designed to characterize the slopes of the rectified signal. This approach would for example produce a digital signature in which the pulse on/off time, duration or duty cycle(s) were a function of the slope and height of the rectified signal, or other suitable unique characteristics of the rectified signal. Depending on the embodiment, the signature characteristic may vary with the dimmer setting, and the signature is stored together with a measurable quantity indicative of the dimmer setting such as for example the average or RMS power of the signal. [0060] Figure 8A illustrates a schematic of an example circuit 800 for determining a signature signal according to an embodiment of the present technology. The circuit 800 has an input terminal 801 for receiving a dimming signal and an output terminal 809 for providing a signature signal and includes resistors 810, 820 and 830, capacitors 840 and 850, and operational amplifier (OpAmp) 860. The circuit 800 is interconnected as illustrated and can provide a signature signal at output terminal 809 for use in determination of an instant dimmer signature. Circuit 800 may act as a high-pass or band-pass filter and comparator to transform the rectified signal into a signature that can be coded in terms of its parameters such as for example the pulse on/off times, duration or duty cycle(s). In some embodiments, a comparator (not shown) may be connected to the output 809 to square-up the output signal from OpAmp 860. Depending on the embodiment, a resistor (not shown) may be added between a threshold or reference voltage and the inverting input of the OpAmp 860 to control the threshold at which the pulsed outputs are high. Depending on the embodiment, the OpAmp 860 may have a high gain to act as a comparator. Depending on the embodiment, the OpAmp 860 may be chosen such that the circuit 800 produces a dimming signature with a preferred limiting voltage and pulse shape. In some embodiments, the OpAmp 860 may be chosen to be a single polarity 0V to 5V-supplied OpAmp able to produce a 5V square wave dimming signature, for example.

[0061] Figure 8B illustrates an example waveform for a typical dimmer signal similar to that provided by a low-voltage dimmer and transformer combination as illustrated in Figure 3B. Figure 8B shows three full cycles of the periodic signal. The example waveform shown in Figure 8B is an example of an input signal to the signature circuit illustrated in Figure 8 A. Figure 8B illustrates the example waveform before rectification. Figure 8C shows the waveform of Figure 8B after it has been rectified 83 (indicated by the solid line) and the average signal 84 (indicated by the dashed line). The average signal may be derived through the use of a low-pass filter such as for example the circuit illustrated in Figure 6. Figure 8D illustrates an example signature signal including pulses 81 and 82 for a typical dimmer signal similar to that provided by a low-voltage dimmer and transformer combination as illustrated in Figure 8B, for example. Depending on the embodiment, the voltage of the signature signal may be limited such as for example in Figure 8D where the signal is limited to 5V. The example circuit may produce similar signature signals from dimming signals of other types of dimmers. The width and spacing of pulses 81 and 82 may be considered in the determination of the dimmer signature. Depending on the embodiment, the dimmer signature may be input to a controller (not shown in Figure 8A) such as for example a computer or microcontroller.

[0062] Depending on the embodiment, the dimming signal converter may discretely sample the signature signal and store a digitized representation of the sampled signature signal, extract the width of the widest pulse and store a digitized version thereof and/or perform other forms of analog/digital conversion in order to determine the contribution of the signature signal to the dimmer signature store the corresponding information. As such, circuit 800 may be used during generation of a dimmer signature and/or verification of dimmer signals with a dimmer signature. It is noted, that the width(s) of the pulses 81 can be indicative of the amount of dimming indicated by a dimmer signal. As such circuit 800 may be used similar to the RC filter circuit 600 illustrated in Figure 6 for determining a signal characteristic. According to an embodiment, example circuit 800 may be employed in a dimming signal converter as described for determining a signature signal, and further for determining a signal characteristic, for example an RMS associated with the dimming signal. A corresponding dimming signal converter may not require a separate circuit for determining a signal characteristic.

Verification of Dimmer Signature

[0063] According to some embodiments, the dimming signal converter is configured to determine a deviation of an instant dimmer signature from a stored dimmer signature. For this purpose, and depending on the embodiment, the dimming signal converter may determine a deviation in a number of ways. According to some embodiments, upon determination of the instant dimmer signature, the dimming signal converter can determine corresponding portions, further referred to as a proximate or an interpolated element, of the stored dimmer signature by proximity, interpolation and/or in another manner. Depending on the embodiment, proximity may be determined based on a predetermined way of measuring distance and/or by linear or other polynomial interpolation as further explained herein.

[0064] According to some embodiments, the dimming signal converter determines a proximate or interpolated element of the stored dimmer signature that fits the instant dimmer signature in a predetermined manner. Depending on the embodiment a proximate and/or interpolated element may be determined based upon proximity and/or interpolation of respective signal characteristics and then subsequently based upon proximity and/or interpolation of the respective properties of the stored dimmer signature. Then the dimming signal converter determines the difference between the proximate/interpolated element and the instant dimmer signature. For this purpose the element and the instant dimmer signature may be regarded as scalars or vectors of real or complex numbers, for example. Depending on the embodiment, the dimming signal converter may determine a deviation of the instant dimmer signature from the stored dimmer signature by determining the difference vector between the proximate/interpolated element of the stored dimmer signature and the instant dimmer signature and then determine the length of the difference vector. Depending on the embodiment, the deviation may be determined by taking the square root of the sum of squares of the components of the difference vector, or the sum of the absolute difference of such components, by determining a weighted or a non- weighted sum of the elements of the difference vector, by determining a cross-correlation between the instant dimmer signature and one or more elements of the stored dimmer signature, or in another manner. [0065] According to embodiments of the present technology, the dimming signal converter stores information about an initial dimming range, a stored dimmer signature, and or a nominal dimming range for at least one dimmer. Depending on the embodiment, the dimming signal converter may be configured to retain stored dimming ranges and stored dimmer signatures for more than one dimmer. For such purposes, and depending on the embodiment, the dimming signal converter may store corresponding information in a memory device which may be part of or external to the dimming signal converter. According to some embodiments, the dimmer signal converter reinitiates a dimming range when an instant dimmer signature deviates from a stored dimmer signature by more than a certain threshold. Depending on the embodiment, the threshold can be predetermined or dynamically determined based on analysis of one or more previously determined thresholds, one or more other measurements considered for the determination of a threshold, or other information. Depending on the embodiment, different thresholds may be used for different signal characteristics.

Method for Determining Re-initializing of a Dimming Range [0066] According to some embodiments, a method for determining whether a dimming range needs to be re-initialized may be employed in a dimming signal converter and implemented in hardware, software and/or firmware, and may be performed in an analog, a digital or a mixed analog-digital fashion. Depending on the embodiment, details of such a method may be subject to occurrence of predetermined events. For example, corresponding methods may be invoked, maintained, suspended, interrupted or cancelled in correlation with certain events. According to an embodiment, such a method may be invoked on an interrupt basis and performed by suitable components included in the control module of the dimming signal converter. A method for determining reinitiating of a dimming range may be performed independently or in correlation with a method for determining a dimming range.

[0067] According to embodiments, a dimming signal converter is configured to receive and evaluate one or more identifiers, wherein this evaluation provides a means for the determination of the validity of a previously stored range of dimmer settings. For example, upon the confirmation of the validity of a previously stored range of dimmer settings, the process of adaptive learning of signal characteristics representative of dimmer settings is not required, thereby mitigating the repetition of this process. However, if the previously stored range of dimmer settings is determined to be invalid, the dimming signal converter is configured to re-initialize the dimmer settings and commence with the adaptive learning process of the signal characteristics. According to embodiments an identifier can be representative of one or any combination of: the last used dimming setting, a loss of power, a change in load provided by the illumination device, deactivation of the supply of power, a signature representative of the dimmer or dimmer/transformer combination, or the like.

[0068] However and according to some embodiments, should a signal characteristic be reflective of a new maximum or new minimum dimming range value, the modification of the appropriate portion of the stored range of dimming settings would be modified accordingly.

[0069] It will be appreciated that other suitable mechanisms may be employed to cause the dimming range to be re-initialized when desired, wherein one or more of these suitable mechanisms may be associated with a representative identifier. For example, in some embodiments the dimming range may be re-initialized when the dimming signal converter detects an open load such as may occur when an LED in an illumination device is disconnected while the illumination device is being powered.

[0070] According to some embodiments, if the signal characteristic of an instant dimming signal does not match close enough with corresponding information based on a stored dimmer signature, the dimming signal converter may perform one or more actions including reinitiating the dimming range, updating of the dimmer signature, erasing and/or regeneration of a new and/or additional dimmer signature, for example. This applies specifically to dimming signals with signal characteristics that are within a stored dimming range unless the dimming signal converter is configured to adequately infer such information by extrapolation.

[0071] Figure 9 illustrates a flow diagram of an example method 900 for determining if a stored dimming range of a dimming signal converter needs to be reinitiated. The method 900 includes steps for generating and storing a dimmer signature and for comparing information extracted from an instant dimmer signal with a stored dimmer signature.

[0072] The method 900 employs an RMS of the voltage of the dimming signal as an example signal characteristic of the dimming signal. As described herein, other signature characteristics may be employed depending on the embodiment. The method 900 comprises step 910 in which a dimmer signature is determined by generation and/or selection, depending on the embodiment. The generation of the dimmer signature can be performed by cumulative addition of instant dimmer signatures that then become elements of a corresponding stored dimmer signature.

[0073] According to some embodiments, a dimming signal converter is configured to select one stored dimmer signature from a plurality of previously stored dimmer signatures. The selection comprises assessment of differences of the previously stored dimming signals with a plurality of instant dimmer signatures and choosing (selecting) the one stored dimmer signature from the plurality that provides a predetermined best fit. Depending on the embodiment, a corresponding dimming signal converter may modify the selected stored dimmer signature by replacing, adding and/or deleting elements thereof based on instant dimmer signatures, for example. As such the selection can be performed in combination with generation of a dimmer signature. According to an embodiment, a correspondingly configured dimming signal converter may employ a combination of selection and generation of dimmer signatures at and/or during predetermined times of operation. For example, a selection of dimmer signatures may be employed until sufficient samples of instant dimming signatures have been acquired.

[0074] The example method 900 includes step 920 in which a signature signal and RMS of an instant dimming signal are determined. The signature signal can be adequately converted as described herein to enable comparison with the dimmer signature. The actual comparison occurs in step 930 and is described in detail herein. If the comparison yields that the instant dimming signal differs by more than a predetermined threshold from corresponding information determined based upon the dimmer signature as described herein, the method 900 proceeds to reinitialize the dimming range in step 940 with further proceeds back to step 910. If the comparison yields that the instant dimming signal is within the predetermined threshold, the method 900 loops back to step 920.

[0075] Figure 10 illustrates a flow diagram of an example method 1000 for powering up the device. The method 1000 determines if the dimming signal and dimmer signature have changed. If either or both dimming signal and dimmer signature have changed, then the device re-initializes the stored dimming range of a dimming signal converter. The method 1000 includes steps for reading the instant dimming signal and instant dimmer signature, and for comparing them with stored values.

[0076] The power-up sequence 1000 commences at step 1010. The method reads the instant dimming signal and the stored value of the dimming signal at steps 1020 and 1025 respectively. The instant dimming signal is compared to the stored value at step 1030. If the instant dimming signal is not substantially the same as the stored value i.e. it differs by more than a predetermined amount then the stored dimming range is reinitialized at step 1040 and the power-up sequence completes at step 1050. If the instant dimming signal is substantially the same as the stored value i.e. it differs by less than a predetermined amount then the method proceeds to step 1060.

[0077] The method 1000 reads the instant dimmer signature and the stored dimmer signature at steps 1060 and 1065 respectively. The instant dimmer signature is compared to the stored value at step 1070. If the instant dimmer signature is not substantially the same as the stored signature i.e. it differs by more than a predetermined degree of fit then the stored dimming range is re-initialized at step 1040 and the power-up sequence completes at step 1050. If the instant dimmer signature is substantially the same as the stored signature i.e. it differs by less than a predetermined amount then the method proceeds to step 1080.

[0078] At step 1080 the method 1000 reads the stored dimming range and the power- up sequence completes at step 1050. [0079] Figure 11 illustrates a flow diagram of an example method 1100 for updating the stored values of the dimming signal, dimming range and dimmer signature when one or more of these values change during operation of the device. The method 1100 includes steps for detecting changes and storing the new values. [0080] The method 1100 commences at step 1110. At step 1110 a timer is set to a suitable value. One embodiment sets the timer to a value of 20s. The value may be chosen to allow the device to establish a steady state after changes have been made to the dimming signal, dimming range or dimmer signature. The instant dimming signal is compared with the stored dimming signal at step 1120. If the instant dimming signal is not substantially the same as the stored value i.e. it differs by more than a predetermined amount then the method 1100 returns to step 1110 and the timer is re-set. If the instant dimming signal is substantially the same as the stored value i.e. it differs by less than a predetermined amount then the method 1100 proceeds to step 1130. The instant dimming range is compared with the stored dimming range at step 1130. If the instant dimming range is not substantially the same as the stored value i.e. it differs by more than a predetermined amount then the method 1100 returns to step 1110 and the timer is re-set. If the instant dimming range is substantially the same as the stored value i.e. it differs by less than a predetermined amount then the method 1100 proceeds to step 1140.The instant dimmer signature is compared with the stored dimmer signature at step 1140. If the instant dimmer signature is not substantially the same as the stored value i.e. it differs by more than a predetermined degree of fit then the method 1100 returns to step 1110 and the timer is re-set. If the instant dimming signature is substantially the same as the stored value i.e. it differs by less than a predetermined degree of fit then the method 1100 proceeds to step 1150. [0081] In other example methods, the order of steps 1120, 1130 and 1140 may be varied i.e. the method can check the dimmer signal, dimming range and dimmer signature in any order.

[0082] The timer is checked at step 1150 to see whether it has expired. If the timer has not expired, the method 1100 returns to step 1120. If the timer has expired, the method 1100 proceeds to step 1160. At step 1160, the instant values of dimmer signal, dimming range and dimmer signature are stored, and the method 1100 returns to step 1110. [0083] According to some embodiments, the present technology provides a device for controlling dimming of an illumination device which includes an input module configured to receive a dimming signal and a control module operatively coupled to the input module and configured to determine at least one signal characteristic of the dimming signal. The control module is configured to modify a stored dimming range when the at least one signal characteristic meets a predetermined criterion and also generate a drive signal at least in part based on the received dimming signal. Furthermore, the control module is configured to provide the drive signal to the illumination device for operation thereof. In addition, the control module is operative to modify the stored dimming range during active dimming control of the illumination device.

[0084] According to some embodiments, the above noted predetermined criterion is indicative that the at least one signal characteristic is outside the stored dimming range.

[0085] According to some embodiments, the control module is configured to determine a dimmer signature at least in part based upon the dimming signal and to compare the dimmer signature with a stored dimmer signature associated with the stored dimming range. The control module is further configured to reset the stored dimming range to a predetermined dimming range when the dimmer signature and the stored dimmer signature differ by more than a predetermined threshold. [0086] According to some embodiments, the present technology provides a method for controlling dimming of an illumination device, and comprises the steps of receiving a dimming signal; determining at least one signal characteristic of the dimming signal; modifying a stored dimming range when the at least one signal characteristic meets a predetermined criterion; and generating a drive signal at least in part based on the received dimming signal and the stored dimming range; wherein said determining and modifying are performed during active dimming control of the illumination device. According to some embodiments, the present technology provides a computer program product comprising a memory having stored thereon code for controlling dimming of an illumination device, the code when executed by a processor causing the processor to perform the above noted method. [0087] According to some embodiments, the predetermined criterion identified in the method above is indicative that the at least one signal characteristic is outside the stored dimming range

[0088] According to some embodiments, the method further comprises determining a dimmer signature at least in part based upon the dimming signal; comparing the dimmer signature with a stored dimmer signature associated with the stored dimming range and resetting the stored dimming range to a predetermined dimming range when the dimmer signature and the stored dimmer signature differ by more than a predetermined threshold. [0089] It will be appreciated that, although specific embodiments have been described herein for purposes of illustration, various modifications may be made without departing from the spirit and scope of the invention. In particular, it is within the scope of the invention to provide a computer program product or program element, or a program storage or memory device such as a transmission medium, magnetic or optical wire, tape or disc, or the like, for storing signals readable by a machine, for controlling the operation of a computer according to the method of the invention and/or to structure its components in accordance with the system of the invention.

[0090] Further, each step of the methods may be executed on a general computer, such as a personal computer, server or the like and pursuant to one or more, or a part of one or more, program elements, modules or objects generated from any programming language, such as C, C++, Java, Perl, PL/1, or the like. In addition, each step, or a file or object or the like implementing each said step, may be executed by special purpose hardware or a circuit module designed for that purpose.

[0091] It is obvious that the foregoing embodiments of the technology are examples and can be varied in many ways. Such present or future variations are not to be regarded as a departure from the spirit and scope of the technology, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.

Claims

A device for controlling dimming of an illumination device, the device comprising:

a. an input module (512) configured to receive a dimming signal (511); and b. a control module (514) operatively coupled to the input module (512) and configured to determine an instant dimmer signature at least in part based upon the dimming signal (511) and compare the instant dimmer signature with a stored dimmer signature, thereby determining if dimming information associated with the stored dimmer signature is acceptable for generation of a drive signal, the control module (514) further configured to generate a drive signal (513) at least in part based on the received dimming signal (511) when the comparison of the instant dimmer signature and the stored dimmer signature meets a predetermined threshold.

The device of claim 1, wherein the control module (514) is configured to reset the stored dimming information to a predetermined dimming range when the instant dimmer signature and the stored dimmer signature differ by more than the predetermined threshold.

The device of claim 1, wherein the dimming signal (511) is provided by a dimmer or a dimmer / transformer combination.

The device of claim 1, wherein the control module (514) is configured to determine at least one signal characteristic of the dimming signal (511) and further configured to modify the stored dimming information when the at least one signal characteristic meets a predetermined criterion.

The device of claim 4, wherein the control module (514) is operative to modify the stored dimming information during active dimming control of the illumination device.

A method for controlling dimming of an illumination device, the method comprising:

a. receiving a dimming signal (1020); b. determining an instant dimmer signature (1060) at least in part based upon the dimming signal;

c. comparing the instant dimmer signature with a stored dimmer signature (1070) associated with the stored dimming range thereby determining if dimming information associated with the stored dimmer signature is acceptable for generation of a drive signal;

d. generating a drive signal at least in part based on the received dimming signal when the comparison of the instant dimmer signature and the stored dimmer signature meets a predetermined threshold. 7. The method of claim 6, further including resetting the stored dimming

information to a predetermined dimming range when the instant dimmer signature and the stored dimmer signature differ by more than the predetermined threshold.

8. The method of claim 6, wherein further comprising determining at least one signal characteristic of the dimming signal and modifying the stored dimming information when the at least one signal characteristic meets a predetermined criterion.

9. The method of claim 8, wherein determining and modifying during active dimming control of the illumination device. 10. The method of claim 6, wherein step b) comprises determining a phase angle of the dimming signal, and step c) comprises identifying one or more elements of the stored dimmer signature for comparison with the instant dimmer signature based upon a root mean square (RMS) of the dimming signal.

11. A computer program product comprising a memory having stored thereon code for controlling dimming of an illumination device, the code when executed by a processor causing the processor to perform the steps of:

a. receiving a dimming signal (1020);

b. determining an instant dimmer signature (1060) at least in part based upon the dimming signal;

c. comparing the instant dimmer signature with a stored dimmer signature

(1070) associated with the stored dimming range thereby determining if dimming information associated with the stored dimmer signature is acceptable for generation of a drive signal;

d. generating a drive signal at least in part based on the received dimming signal when the comparison of the instant dimmer signature and the stored dimmer signature meets a predetermined threshold.

12. The computer program product of claim 11, further including resetting the stored dimming information to a predetermined dimming range when the instant dimmer signature and the stored dimmer signature differ by more than the predetermined threshold. 13. The computer program product of claim 11, wherein further comprising determining at least one signal characteristic of the dimming signal and modifying the stored dimming information when the at least one signal characteristic meets a predetermined criterion.

14. The computer program product of claim 13, wherein determining and modifying during active dimming control of the illumination device.

15. The computer program product of claim 11, wherein step b) comprises determining a phase angle of the dimming signal, and step c) comprises identifying one or more elements of the stored dimmer signature for comparison with the instant dimmer signature based upon a root mean square (RMS) of the dimming signal.

16. A device for controlling dimming of an illumination device, the device comprising:

a. an input module (512) configured to receive a dimming signal; and b. a control module (514) operatively coupled to the input module (512) and configured to determine at least one signal characteristic of the dimming signal (511), the control module (514) configured to modify a stored dimming range when the at least one signal characteristic meets a predetermined criterion and generate a drive signal at least in part based on the received dimming signal, the control module (514) further configured to provide said drive signal to the illumination device, said control module (514) further configured to receive and evaluate an identifier, said identifier at least in part indicative of validity of the stored dimming range and upon determination of invalidity of the stored dimming range the control module (514) is configured to re-initialize the stored dimming range. 17. The device of claim 16, wherein the identifier is representative of one or more of a last used dimming setting, a loss of power, a change in load provided by the illumination device, deactivation of a supply of power and a signature representative of a device providing the dimming signal.

18. The device according to claim 17, wherein the device providing the dimming signal is a dimmer or a dimmer/transformer combination.

19. A method for controlling dimming of an illumination device, the method comprising:

a. receiving a dimming signal (1020) and an identifier (1025, 1060);

b. determining validity of a stored dimming range based at least in part on the identifier and re-initializing (1040) the stored dimming range when the stored dimming range is invalid;

c. determining at least one signal characteristic (720) of the dimming signal;

d. modifying the stored dimming range (750, 760) when the at least one signal characteristic meets a predetermined criterion; and

e. generating a drive signal at least in part based on the received dimming signal and the stored dimming range.

20. The method of claim 19, wherein the identifier is representative of one or more of a last used dimming setting, a loss of power, a change in load provided by the illumination device, deactivation of a supply of power and a signature representative of a device providing the dimming signal.

21. The method according to claim 20, wherein the device providing the dimming signal is a dimmer or a dimmer/transformer combination. A computer program product comprising a memory having stored thereon code for controlling dimming of an illumination device, the code when executed by a processor causing the processor to perform the steps of:

a. receiving a dimming signal (1020) and an identifier (1025, 1060);

c. determining at least one signal characteristic (720) of the dimming signal;

d. modifying a stored dimming range (750, 760) when the at least one signal characteristic meets a predetermined criterion; and

The computer program product of claim 22, wherein the identifier is representative of one or more of a last used dimming setting, a loss of power, a change in load provided by the illumination device, deactivation of a supply of power and a signature representative of a device providing the dimming signal.

The computer program product according to claim 23, wherein the device providing the dimming signal is a dimmer or a dimmer/transformer combination.