Patent Grant
9282597
The present invention relates generally to lighting systems, and particularly to methods and systems of controlled LED lighting.
Light Emitting Diodes (LED)s have become a prevailing technology in the industry of lighting. However, an efficiently and flexibly controlled LED driving method and system is missing in the art.
Accordingly, it is a principal object of the present invention to provide improved methods and systems of controlled driving of LEDs. Thus, in accordance with an embodiment of the present invention, there is provided a Controlled Light Emitting Diode (LED) Driver comprising:
an AC/DC converter configured to convert an AC voltage at its input to a DC voltage at its output; at least one LED driver coupled to the output of the AC/DC converter and configured to convert the DC voltage to a pulsed output power for driving one or more LEDs that serve to provide lighting; and a local controller having a control interface for receiving control information from one or more control sources coupled to it. The local controller is coupled to the at least one LED driver and controls its operation by determining one or more LED driving parameters of the pulsed output power, based on the control information.
In an embodiment, a LED driver may operate as a voltage source or a current source. Principal LED driving parameters are maximum output power and output power duty cycle. A Pulse Width Modulation mechanism in the LED driver sets the duty cycle so as to result in a required LED lighting intensity.
In some embodiments, the LEDs are colored, and controlling the operation of the LED drivers comprises adjusting the pulsed output power of each of them so as to achieve a required resultant lighting color.
In an embodiment, the AC voltage is supplied by an external dimmer having a dimming angle, which the local controller senses and determines accordingly a maximum lighting intensity.
In embodiments of the present invention, various sensors are used for supplying control information to the local controller, either directly or through a remote controller. Examples of such sensors are: a motion detector, a light detector and a video camera. A sensor can be located close to the local controller and typically connected to it with a wire connection, or it can be remotely located and typically connected to it through a wireless link. The wireless link typically supports multiple access of control sources and in some embodiments it also supports a secure access.
In some embodiments, additional control sources can be used such as an external dimmer, a music player, a human voice and a smartphone.
In an embodiment, the local controller is further configured to send status information to the remote controller. Such status information may comprise command acknowledgement, the AC voltage dimming angle, parameters of the pulsed output power and output signaling of some control sources.
In accordance with an embodiment of the present invention, there is provided also a method of controlled LED driving comprising the steps of:
converting an AC voltage to a DC voltage; converting the DC voltage to one or more pulsed output power signals for driving one or more LEDs; receiving control information from one or more control sources; and determining one or more parameters of the pulsed output power signals based on the control information.
The present invention will be more fully understood from the following detailed description of the embodiments thereof, taken together with the drawings in which:
Embodiments of the present invention provide improved systems and methods for controlled driving of LEDs. In particular, the disclosed techniques help to provide efficient LED lighting in a given space, by controlling various LED driving parameters based on a variety of control sources, including sensors, which sense various environmental parameters such as lighting and motion in the vicinity of the LEDs.
Referring to
A LEDs block 124, which is, in an embodiment, external to CLD 104, typically comprises one or more LED chains coupled to LED drivers 116 and serve to provide lighting of a given space in the vicinity of LEDs 124. A LED driver 116 outputs a pulsed output power whose duty-cycle is modulated by a Pulse Width Modulation (PWM) technique for achieving a required lighting intensity. The amplitude of the pulsed output power is typically determined by LEDs 124 specification. V/I monitoring circuitry 120 coupled to LEDs 124 constitutes a monitoring means of the driving voltage and current supplied by each LED driver 116 to each LED chain 124.
A local controller 128 monitors and controls the operation of the aforementioned blocks through a control interface 130. In particular, local controller 128 controls driving parameters of LEDs 124, such as the duty-cycle and amplitude of the pulsed power at the output of each LED driver 116, for achieving required lighting of LEDs 124, based on control information received from various control sources that are described below.
In some embodiments, wherein AC voltage 108 is an output of an external dimmer, AC/DC converter 112 also constitutes a control source for local controller 128 by detecting the AC voltage dimming angle and providing this control information to local controller 128 through line 132. The local controller then determines accordingly the duty-cycle at the output of LED drivers 116.
In an alternative embodiment, wherein the lighting intensity is determined by a control source other than AC/DC converter 112, as described below, the local controller determines a maximum lighting intensity based on the dimming angle, so as to limit peak currents within AC/DC converter 112.
The control information flow on the inverse direction of line 132 serves local controller 128 for controlling the operation of AC/DC converter 112, e.g. turning it to idle mode when no lighting power is required.
In an embodiment, one or more remote controllers 144 constitute a control source for local controller 128 via control interface 130. As an example, remote controller 144 can be a smartphone, by which a user can command local controller 128 to turn on, turn off or dim LEDs 124. A user, or a computer application in remote controller 144, can, in the same manner, command any other characteristics of LEDs 124 lighting, e.g. a resultant color, as explained below. A link 140, which connects remote controller 144 to local controller 128 through control interface 130 within CLD 104, is typically a wireless link supporting one or more multiple access protocols. However, in some embodiments a wired link 140 may be used as well.
In an embodiment, link 140 is made bidirectional, thereby allowing local controller 128 to provide remote controller 144 with status information. Such status information typically comprises command acknowledgement, the dimming angle value if available, monitored parameters of the pulsed output power such as duty-cycle and amplitude, output signaling of control sources of local controller 128, specifically output signaling of sensors which are described below and the like.
In some embodiments, wherein remote controller 144 receives from local controller 128 the dimming angle detected by AC/DC converter 112, remote controller 144 determines the maximum lighting intensity, based on the dimming angle, instead of local controller 128.
In some embodiments, control interface 130 comprises an audio interface thereby allowing users to provide local controller 128 with control information in the form of vocal commands. In some embodiments, the above audio interface is adapted to receive control information in the form of sounds, specifically music coming from a music player or from playing music instruments, while local controller 128 is configured to vary LEDs 124 driving parameters according to the music played. In such an embodiment, LEDs 124 are typically colored with various colors, and controller 128 varies the driving parameters at the output of LED drivers 116 so as to provide variable lighting color and intensity synchronized with the music played.
In some embodiments, various types of sensors are used as control sources for local controller 128. Such sensors may be packaged within CLD 104, as depicted by local sensors 136 in
In an embodiment, a motion detection sensor indicates to local controller 128, upon detecting motion, that it should intensify the lighting level of LEDs 124 through LED drivers 116. As another example, a light detector sensor serves to measure and to indicate to local controller 128 the actual lighting intensity and optionally, the color of LEDs 124. Local controller 128 then adjusts the driving parameters at the output of LED drivers 116 so as to achieve a required lighting based on the light detector output signaling.
In an embodiment, a remote sensor 148 can send its output signaling to any of the local and remote controllers 128 and 144 respectively, as shown in
A remote sensor 148 may be, for example, a photographic means such as a video camera. In this case the video camera sends variable photographic information directly to local controller 128 as depicted by line 152 in
In another embodiment, local controller 128 analyses the actual lighting in various parts of the space and adjusts LED drivers 116 to provide required lighting characteristics in those parts, based on the analysis. In yet another embodiment, the video camera sends the above photo stream to remote controller 144, as depicted by line 156. In this case the above motion detection and/or lighting analysis is done in the remote controller. The remote controller then converts the analysis results to commands containing lighting parameters and sends these commands to local controller 128 through link 140.
In an embodiment, local controller 128 typically comprises a programmable processor, which is programmed in software to carry out the functions described herein. Software updates as well as required lighting characteristics may be downloaded to local controller 128 through link 140. In some embodiments link 140 comprises a secure access to avoid false or malicious control of CLD 104.
The above description has focused on the specific elements of CLD 104 and lighting system 100 that are essential for understanding certain features of the disclosed techniques. Conventional elements of CLD 104 that are not needed for this understanding have been omitted from
In a sending step 224, local controller 128 sends status information, such as dimming angle, to remote controller 144, which commands the local controller while taking into account this status information as explained above. This is depicted by a return loop from step 224 to step 212. In a sensing step 228, one or more sensors sense various parameters in the space to be lighted, as described above. The output signaling of these sensors constitutes part of the overall control information according to which local controller 128 controls LED drivers 116. This is depicted by a return loop from step 228 to step 212.
The flowchart shown in
Although the embodiments described herein mainly address LED lighting, the methods and systems exemplified by these embodiments can also be used in other lighting applications.
It will thus be appreciated that the embodiments described above are cited by way of example, and that the present invention is not limited to what has been particularly shown and described hereinabove. Rather, the scope of the present invention includes both combinations and sub-combinations of the various features described hereinabove, as well as variations and modifications thereof which would occur to persons skilled in the art upon reading the foregoing description and which are not disclosed in the prior art.
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| Number | Date | Country | |
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| 61807339 | Apr 2013 | US |
