Patent Application
20170164440
The disclosed embodiments relate generally to methods and systems for dimming solid-state lighting devices, such as light emitting diodes (LEDs), and more particularly to a method and system for dimming LEDs using a single dimmable driver that can accept multiple types of dimmers.
LEDs have the potential to revolutionize the efficiency, appearance, and quality of lighting. See http://www.energystar.gov/index.cfm?c=lighting.pr_what_are. The United States Department of Energy estimates that rapid adoption of LED lighting in the U.S. could provide savings of roughly $265 billion, avoid 40 new power plants, and reduce lighting electricity demand by 33% by 2027. Thus, the market for LED lighting is expected to grow significantly in the coming years compared to traditional, non-LED based lighting.
As the adoption of LED technology has evolved, lighting controls have become an integral part of the lighting selection process for energy savings and visual comfort. With this increased reliance on controls have come new challenges for lighting designers, specifiers, contractors, and distributors. Consider, for example, a typical lighting fixture that includes a lamp (LEDs) driven by a driver (AC-to-DC converter). The driver is usually configured to operate either with wall switches that provide a step dimming function, a 0-10 V dimmer that provides a more smooth dimming function, or the ubiquitous phase-cut dimmer commonly used with conventional incandescent lights. Existing step dimming drivers, however, are not compatible (i.e., do not operate properly) with 0-10 V dimmers or phase-cut dimmers. Nor are existing 0-10 V dimming drivers compatible with wall switches or phase-cut dimmers, or existing phase-cut dimming drivers with wall switches and 0-10 V dimmers.
The above incompatibility among the different types of dimmable drivers forces lighting specifiers to make sure that the fixtures they select for aesthetics and performance purposes are also compatible with the dimming controls they plan to use in a given room or space. Lighting contractors must also make sure they order and receive fixtures that are compatible with the dimming controls being used for a given project. But as the dimming control systems are not always specified beforehand by the lighting specifiers, or because the specifications sometimes change during a project, the contractors have to keep multiple types of fixtures on hand. Lighting distributors must similarly make sure they carry the correct mix of fixtures that are compatible with the dimming control systems needed by the specifiers and contractors in order to meet compressed deadlines and increased customer expectations. At the same time, the distributors must minimize inventory to avoid being stuck with obsolete products that are based on old technology while LED technology continues to advance and LED fixtures continue to progress.
Thus, a need exists for an improved lighting fixture that is compatible with multiple types of dimmers, and particularly a dimmable driver for such lighting fixture that can operate with multiple dimming protocols.
The disclosed embodiments are directed to a method and system for dimming LEDs in a light fixture using a dimmable driver that can operate with multiple dimming protocols. The method and system is able to achieve expanded compatibility by combining several of the most widely used dimming protocols into one dimmable driver. This combining allows the dimmable driver to be disconnected from one type of dimmer and subsequently connected to another type of dimmer without having to replace or otherwise adjust the driver for each dimmer. Such a combination dimmable driver may be then installed in any LED or other solid-state lighting fixture to allow the lighting fixture to accommodate multiple types of dimmers. The resulting lighting fixture may thereafter be used in any number of lighting applications with high confidence that there will be no compatibility issues with the dimmer. This maximizes flexibility for lighting specifiers, contractors, and distributors while minimizing potential errors, costs, delays, and obsolete inventory.
In some embodiments, the combination dimmable driver may comprise an AC/DC power converter, a dimming controller, and a dimming signal converter. The AC/DC power converter and the dimming controller may be conventional components that are commonly employed in LED lighting applications. These components operate in their usual manner to provide power to the LEDs and to control the level of dimming of the LEDs, respectively, based on a dimming signal from a dimmer.
In accordance with the disclosed embodiments, the dimming signal converter operates to expand the compatibility of the dimming controller by allowing a dimming signal or dimming signals from several different types of dimmers to be used. The dimming signal converter converts the dimming signal(s) from the dimmer(s), whichever type is being used, into a common dimming level indicator and provides the dimming level indicator to the dimming controller. The dimming controller receives the dimming level indicator and uses it to control the level of dimming of the LEDs in the usual manner. In a typical scenario, only one type of dimmer is connected at a time to the combination dimmable driver. In other scenarios, multiple types of dimmers may be connected at the same time to the combination dimmable driver. In the latter case, the combination dimmable driver may look for a preset default type of dimmer and use the dimming signal from that dimmer before looking for dimming signals from other types of dimmers, or the combination dimmable driver may use dimming signals from all or several of the dimmers to generate the dimming signal indicator.
In some embodiments, the types of dimmers from which the dimming signal converter can receive and process dimming signals include a step dimmer, a 0-10 V dimmer, and a phase-cut dimmer. In one or more of these embodiments, the dimming signal converter may first look for a dimming signal from the 0-10 V dimmer and, if present, generate a dimming level indicator based on a dimming signal from the 0-10 V dimmer and provide the indicator to the dimming controller.
If the 0-10 V dimmer is not present, then in one or more of these embodiments the dimming signal converter may look for dimming signals from the phase-cut dimmer and the step dimmer, or vice versa. These latter types of dimmers typically provide two dimming signals, a first and a second dimming signal, that may be used as first and second logic signals by the dimming signal converter. The dimming signal converter may then generate an appropriate dimming level indicator based on these two logic signals. With a step dimmer, for example, if both first and a second dimming signals are logically asserted, then the dimming signal converter generates a minimum dimming level indicator (i.e., little or no dimming). If both dimming signals are logically unasserted, then the dimming signal converter generates a maximum dimming level indicator. If only one of the dimming signals is logically asserted, then the dimming signal converter generates a dimming level indicator that is between the minimum and maximum.
With a phase-cut dimmer, both the first and second dimming signals typically remain logically asserted at all times so the dimming level indicator generated by the dimming signal converter remains fixed at a minimum level. Dimming is then adjusted (i.e., increased) by using the phase delays imposed by the phase-cut dimmer on the voltage input from the AC/DC power converter. This arrangement has an added advantage in that there is no need for the dimming signal converter to determine whether the dimming signals came from the phase-cut dimmer or the step dimmer.
In some embodiments, the dimming signal converter may use dimming signals from all three types of dimmers at the same time. In these embodiments, the dimming signal converter may generate the dimming level indicator based on all three dimming signals using a predefined priority that specifies the order in which the dimming signals are applied. For example, the dimming signal converter may apply the dimming signal from the phase-cut dimmer first, then the step dimmer, and then the 0-10 V dimmer, or vice versa, or some other sequence, to generate the dimming level indicator.
Alternatively, the dimming signal converter may generate the dimming level indicator based on any two dimming signals using a predefined priority, or the dimming signal converter may generate the dimming level indicator based on only one dimming signal using a predefined priority.
In still other embodiments, the dimming signal converter may instead generate a dimming level indicator reflecting predefined defaults or programmed dimming levels when dimming signals from multiple types of dimmers are received at the same time. In these embodiments, one or more tables may be used to specify to the dimming signal converter which dimming level indicators should be generated when dimming signals from multiple types of dimmers are received at the same time.
In some embodiments, a comparator may be provided in the combination dimmable driver. The comparator may compare the two dimming signals from the phase-cut dimmer or the step dimmer to a reference voltage and provide either asserted or unasserted first and second logic dimming signals, as may be appropriate, to the dimming signal converter.
In general, in one aspect, the disclosed embodiments are directed to a combination dimmable driver for a light fixture. The combination dimmable driver comprises, among other things, an AC/DC power converter connected to the light fixture and configured to provide power to a plurality of LEDs in the light fixture, and a dimming controller connected to the AC/DC power converter, the dimming controller configured to control a level of dimming for the plurality of LEDs in the light fixture. The combination dimmable driver further comprises a dimming signal converter connected to the dimming controller and configured to provide a dimming level indicator to the dimming controller, the dimming controller controlling the level of dimming for the plurality of LEDs based on the dimming level indicator. The dimming signal converter is further configured to receive dimming signals from multiple types of dimmers and generate the dimming level indicator based on a dimming signal received from one of the multiple types of dimmers.
In general, in another aspect, the disclosed embodiments are directed to a method of dimming a plurality of LEDs in a light fixture. The method comprises, among other things, receiving a dimming signal from at least one of multiple types of dimmers, generating a dimming level indicator based on the dimming signal from said at least one of the multiple types of dimmers, and controlling a level of dimming for the plurality of LEDs in the light fixture based on the dimming level indicator.
In general, in still another aspect, the disclosed embodiments are directed to a light fixture. The light fixture comprises, among other things, a plurality of LEDs and a dimmable driver connected to the plurality of LEDs. The dimmable driver is compatible with three or more types of dimmers and configured to control dimming of the plurality of LEDs based on a dimming signal from at least one of said types of dimmers.
The foregoing and other advantages of the disclosed embodiments will become apparent upon reading the following detailed description and upon reference to the drawings, wherein:
As an initial matter, it will be appreciated that the development of an actual, real commercial application incorporating aspects of the disclosed embodiments will require many implementation specific decisions to achieve the developer's ultimate goal for the commercial embodiment. Such implementation specific decisions may include, and likely are not limited to, compliance with system related, business related, government related and other constraints, which may vary by specific implementation, location and from time to time. While a developer's efforts might be complex and time consuming in an absolute sense, such efforts would nevertheless be a routine undertaking for those of skill in this art having the benefit of this disclosure.
It should also be understood that the embodiments disclosed and taught herein are susceptible to numerous and various modifications and alternative forms. Thus, the use of a singular term, such as, but not limited to, “a” and the like, is not intended as limiting of the number of items. Similarly, any relational terms, such as, but not limited to, “top,” “bottom,” “left,” “right,” “upper,” “lower,” “down,” “up,” “side,” and the like, used in the written description are for clarity in specific reference to the drawings and are not intended to limit the scope of the invention.
Referring now to
In the lighting application 100 of
In the lighting application 100′ of
In the lighting application 100″ of
As can be seen in
In a similar manner,
In the lighting application 300 of
In accordance with the disclosed embodiments, the combination dimmable driver 302 may look for the presence of the 0-10 V dimmer 318 and, if detected, may default to using the dimming signal from the 0-10 V dimmer 318 to control dimming. Otherwise, the combination dimmable driver 302 looks for any dimming signals that may be present on Line 1 and Line 2 and uses these dimming signals, if detected, to control dimming. In this particular example, any dimming signals that may be present on Line 1 and/or Line 2 are provided by the step dimmer 310.
In accordance with the disclosed embodiments, the combination dimmable driver 402 may, like before, look for the presence of the 0-10 V dimmer 418 and, if detected, may default to using the dimming signal from the 0-10 V dimmer 418. Otherwise, the combination dimmable driver 402 again looks for any dimming signals that may be present on Line 1 and Line 2 and uses these dimming signals, if detected. In this example, any dimming signal that may be present on Line 1 and/or Line 2 may be provided by either the step dimmer 410 or the phase-cut dimmer 416.
It should also be noted that although
In general, the AC/DC power converter 514 operates in a known manner to convert AC current to DC current that may then be used to drive the LEDs 504. The dimming controller 516 similarly operates in a known manner to control dimming of the LEDs 504, typically by switching on and off the converted DC current at a particular frequency based on a desired level of dimming. The desired level of dimming and hence the specific switching frequency used by the dimming controller 516 is derived from a dimming level indicator generated by the dimming signal converter 518.
In accordance with the disclosed embodiments, the dimming level indicator (shown in
In some embodiments, the particular dimming level indicator signal generated is designed to cause the dimming controller 516 to control dimming of the LEDs 504 according to a specific dimming profile, such as the ones shown in
A dimming controller 614 in the combination dimmable driver 600 controls the operation of the power factor correction module 604 and the transformer 606, also in a known manner. Specifically, the dimming controller 614 receives power factor information from the power factor correction module 604 through a PFC current sense signal and provides feedback to the power factor correction module 604 through a PFC drive signal based on the PFC current sense signal. Similarly, the dimming controller 614 receives peak current information from the transformer 606 through a peak current detection signal and controls the switching frequency of the transformer 606 through a switch drive signal based on the peak current detection signal. By controlling (i.e., increasing, decreasing) the switching frequency of the transformer 606, and hence the amplitude of the rectified DC current, the dimming controller 614 is able to adjust the amount of dimming of the LEDs 612.
A dimming signal converter 616 in the combination dimmable driver 600 may be connected to the dimming controller 614 to provide a dimming level indicator signal to the dimming controller 614. The dimming level indicator signal gives the dimming controller 614 an indication of the level to adjust the dimming of the LEDs 612. In accordance with the disclosed embodiments, the particular dimming level indicator signal generated by the dimming signal converter 616 may be based on dimming signals from one or several of the different types of dimmers. In the embodiment shown here, for example, the dimming signal converter 616 may receive (and is compatible with) dimming signals from a step dimmer 618, a phase-cut dimmer 622, and a 0-10 V dimmer 624.
The 0-10 V dimmer 624 may be a conventional 0-10 V dimmer that, when present, may be connected to the dimming signal converter 616 through an isolation transformer 626. Operation (i.e., switching) of the isolation transformer 626 may be controlled by a transformer drive signal provided from the dimming controller 614 to the isolation transformer 626.
The step dimmer 618, when present, may be composed of conventional first and second switches 619, 620 that are connected to Line 1 and Line 2, respectively, from the line conductor. The first and second switches 619, 620 allow Line 1 and Line 2 to be switched on and off independently of each other to adjust dimming of the LEDs 612.
The phase-cut dimmer 622 may likewise be a conventional phase-cut dimmer, either a forward phase-cut dimmer or a reverse phase-cut dimmer. When present, the phase-cut dimmer 622 may be connected to essentially the same wiring as the step dimmer 618, but is positioned before the point where the line conductor splits into Line 1 and Line 2. It is also expected that both the switches 619, 620 will remain closed if they are present when the phase-cut dimmer 622 is connected.
In either case, AC current from Line 1 and/or Line 2 are provided to the bridge rectifier 602, which rectifies the AC current to a DC current. An EMI filter 628 reduces any electromagnetic interference that may be present on Lines 1 and 2 and a neutral (“Neutral”) line serves as a return path for current flowing through the LEDs 612.
The bridge rectifier 602 also taps or otherwise draws a small portion of the DC current converted from Lines 1 and 2 to provide two dimming signals, Dimming Signal 1 and Dimming Signal 2. These dimming signals correspond to whether current is flowing through Lines 1 and 2, respectively, meaning that either switch 619 and/or switch 620 are closed. The bridge rectifier 602 then provides these Dimming Signals 1 and 2 to a voltage comparator 630 in the combination dimmable driver 600. The voltage comparator 630 compares the Dimming Signals 1 and 2 to a reference voltage and outputs corresponding logic signals, Logic Signal 1 and Logic Signal 2, to the dimming signal converter 616. If the voltage comparator 630 determines that either Dimming Signals 1 and/or 2 are above the reference voltage, indicating that current is flowing respectively through either Line 1 and/or Line 2, then the comparator asserts Logic Signal 1 and/or Logic Signal 2 accordingly.
In general operation, the dimming signal converter 616 processes dimming signals from whichever dimmer or dimmers are present. Thus, if the 0-10 V dimmer 624 is present, the dimming signal converter 616 generates a dimming level indicator signal based on the 0-10 V dimming signal from the isolation transformer 626 and provides the dimming level indicator signal to the dimming controller 614. The dimming controller 614 thereafter uses the dimming level indicator signal to control dimming as depicted, for example, in
If the step dimmer 618 or the phase-cut dimmer 622 is present, then the dimming signal converter 616 processes the dimming signals from the step dimmer 618 or the phase-cut dimmer 622. As discussed above, these dimmers are wired to provide two dimming signals, Dimming Signals 1 and 2, that may be used as first and second Logic Signals 1 and 2, respectively, by the dimming signal converter 616 (via the voltage comparator 630). The dimming signal converter 616 may then generate an appropriate dimming level indicator based on the logic level of these Logic Signals 1 and 2.
With the step dimmer 618, for example, if both Logic Signals 1 and 2 are asserted, then the dimming signal converter 616 generates a minimum dimming level indicator (i.e., little or no dimming). If both Logic Signals 1 and 2 are unasserted, then the dimming signal converter 616 generates a maximum dimming level indicator. If only one of the Logic Signals 1 or 2 is asserted, then the dimming signal converter 616 generates a dimming level indicator that is between the minimum and maximum as depicted, for example, in
With the phase-cut dimmer 622, both the first and second dimming signals, Dimming Signals 1 and 2, typically remain logically asserted at all times, so the dimming level indicator generated by the dimming signal converter 616 remains fixed at a minimum level. Dimming is then adjusted (i.e., decreased, increased) by using the phase delays imposed by the phase-cut dimmer 622 on the input from the bridge rectifier 602 as depicted, for example, in
An advantage of the latter arrangements is that there is no need for the dimming signal converter 616 to determine whether Dimming Signals 1 and 2 came from the step dimmer 618 or the phase-cut dimmer 622. The dimming signal converter 616 just generates a dimming level indicator signal according to Logic Signals 1 and/or 2 and the desired dimming level simply follows.
In most applications, it is generally expected that only one type of dimmer will be connected at a time to the combination dimmable driver 600. However, in some applications, multiple types of dimmers may be simultaneously connected to the combination dimmable driver 600. When that happens, the combination dimmable driver 600 may add the amount of dimming provided by each type of dimmer on top of the amount of dimming provided by the other types of dimmers according to the exemplary dimming profiles shown
For example, in some applications, the phase-cut dimmer 622 and the 0-10 V dimmer 624 may both be connected to the combination dimmable driver 600 at the same time. In that case, both Logic Signals 1 and 2 are asserted, the dimming signal converter 616 generates a maximum dimming level indicator signal according to the dimming profile in
A result similar to the foregoing may be achieved when the step dimmer 618 and the 0-10 V dimmer 624 are simultaneously connected to the combination dimmable driver 600, or when all three types of dimmers are simultaneously connected to the combination dimmable driver 600.
In some embodiments, it is also possible to configure the combination dimmable driver 600 so that the dimming signal converter 616 automatically prioritizes or otherwise defaults to a particular type of dimmer if that dimmer is present. For example, the combination dimmable driver 600 may be programmed so that the dimming signal converter 616 automatically checks first to see whether the 0-10 V dimmer 624 is present. If the 0-10 V dimmer 624 is not present, then dimming signal converter 616 checks for the step dimmer 618 and/or the phase cut dimmer 622. Alternatively, the combination dimmable driver 600 may be programmed so that the dimming signal converter 616 automatically checks first to see whether the step dimmer 618 and/or the phase cut dimmer 622 are present before checking for the 0-10 V dimmer 624.
In some embodiments, the combination dimmable driver 600 may be programmed so that the dimming signal converter 616 automatically selects certain predefined defaults or programmed dimming levels when dimming signals from multiple types of dimmers are received at the same time. For example, if the combination dimmable driver 600 receives a dimming signal from both the 0-10 V dimmer 624 and the phase-cut dimmer 622, the dimming signal converter 616 may generate a dimming level indicator that reflects a specified default dimming scheme, such as a percentage of the dimming signals from both (or each) dimmer. In these embodiments, one or more tables may be used to specify the particular dimming level indicator to be generated by the dimming signal converter 616. An exemplary table is shown in Table 1 below. Of course, alternative default dimming behavior and/or number of dimmer types may be derived by those having ordinary skill in the art without departing from the scope of the disclosed embodiments.
Thus far, a number of specific implementations of a combination dimmable driver have been described. Following now in
The flow chart 700 generally begins with an initialization phase at block 702 where various components of the combination dimmable driver may be set and/or reset as needed. At block 704, if a 0-10 V dimming signal is present, the combination dimmable driver generates a dimming level indicator signal based on the 0-10 V dimming signal. The combination dimmable driver thereafter provides the dimming level indicator signal to the dimming controller at block 706. At about the same time or in parallel, if a first and/or second dimming signals are present, the combination dimmable driver generates a dimming level indicator signal based on the first and second dimming signals at block 708. The combination dimmable driver thereafter provides the dimming level indicator signal to the dimming controller at block 710.
The flow chart 800 generally begins with an initialization phase at block 802 where various components of the combination dimmable driver may be set and/or reset as needed. At block 804, the combination dimmable driver determines whether a 0-10 V dimming signal, indicating that a 0-10 V dimmer may be present or otherwise connected. If the determination is yes, then the combination dimmable driver proceeds to generate a dimming level indicator based on the 0-10 V dimming signal at block 806. The combination dimmable driver thereafter provides the dimming level indicator to a dimming controller at block 808.
If the determination at block 804 is no, then the combination dimmable driver determines at block 810 whether the first and second dimming signals are present, as may be the case if a step dimmer and/or a phase-cut dimmer is connected. If the determination is yes, then the combination dimmable driver proceeds to generate a dimming level indicator based on the first and second dimming signals at block 812 and provide the indicator to the dimming controller at block 814. If the determination is no, then the combination dimmable driver returns to block 804 to check for the presence the 0-10 V dimmer.
It should be noted that while a 0-10 V dimmer has been used as the default dimmer in the foregoing embodiment, the decision on which type of dimmer is used as the default dimmer, whether the 0-10 V dimmer, a step dimmer, or a phase-cut dimmer, can vary and may be chosen as needed for a particular application.
The combination dimmable driver may then generate a dimming level indicator signal at block 910 based on all or some of the dimming signals present using a predefined priority or a set of predefined defaults as explained above. For example, the combination dimmable driver may use the dimming signal from the phase-cut dimmer first, then the step dimmer, and then the 0-10 V dimmer, or vice versa, or some other sequence to generate the dimming level indicator. Or the combination dimmable driver may generate the dimming level indicators using a table similar to Table 1 in some embodiments. Alternatively, the combination dimmable driver may generate the dimming level indicator based on any two dimming signals using a predefined priority, such as the 0-10 V dimmer then the phase-cut dimmer, or the 0-10 V dimmer then the step dimmer, or the phase-cut dimmer then the step dimmer, and so forth, or vice versa. The combination dimmable driver may also generate the dimming level indicator based on only one dimming signal, whether the 0-10 V dimmer, the phase-cut dimmer, or the step dimmer, using a predefined priority.
The combination dimmable driver thereafter provides the dimming level indicator to a dimming controller at block 912 and the method 900 returns to blocks 904, block 906, and/or block 908 to continue checking for dimming signals from the different types of dimmers.
While particular aspects, implementations, and applications of the present disclosure have been illustrated and described, it is to be understood that the present disclosure is not limited to the precise construction and compositions disclosed herein and that various modifications, changes, and variations may be apparent from the foregoing descriptions without departing from the spirit and scope of the disclosed embodiments as defined in the appended claims.
This application for patent claims the benefit of priority to, and incorporates herein by reference, U.S. Provisional Application Ser. No. 62/264,310, entitled “Combination Dimmable Driver,” filed Dec. 7, 2015.
| Number | Date | Country | |
|---|---|---|---|
| 62264310 | Dec 2015 | US |
