Patent Application
20130141007
The invention pertains generally to the powering and control of solid state lighting systems, such as LED (Light Emitting Diode) lighting systems.
LED lighting systems are increasingly being used for illumination in business environments, such as stores, offices, and entertainment venues, as well as homes for general and decorative lighting purposes. LED lighting has many significant advantages over incandescent, fluorescent, and other lighting systems. For instance, they consume less power relative to the amount of light produced as compared to alternatives. Additionally, LEDs have a longer lifespan than most alternatives. Yet further, LEDs are sturdier than most other alternatives because there is no filament or other mechanically sensitive parts, as there are in incandescent and fluorescent light bulbs.
LED lighting systems operate on relatively low voltage compared to incandescent, fluorescent and other lighting systems. LED lights are powered by a regulated D/C current, rather than an A/C voltage.
Because LEDs generally output relatively small amounts of light per diode, most LED lighting systems use a plurality of LEDs to produce sufficient light. This may be accomplished in many forms, including (1) a linear array of LEDs to produce a long thin tube of relatively constant light output, looking much like a fluorescent tube light, (2) placing a cluster of LEDs in close proximity to each other within a bulb that resembles a conventional incandescent light bulb, and (3) stringing together a series of LED lights (like a string of holiday decorative lights).
Since LED lighting systems require regulated current and operate at relatively low voltages, a power system typically must be interfaced between the LEDs and the relatively high A/C voltage power typically available through the power grid in most countries, such as the 120 volt A/C power available in the United States and the 230 volt A/C power available throughout most of Europe. The power system must convert the incoming relatively high voltage A/C power to a regulated D/C current output tailored to the particular LED lighting system. The power system also must be able to adjust its output current responsive to a temperature signal from the LED Lighting Module (LLM) and to any control devices (e.g., dimmers or motion sensors) included in the lighting system.
The desired regulated D/C current for an LED lighting system depends on many different factors, such as the number of LEDs in the lighting system, the manner in which they are intercoupled (e.g., parallel and/or series), the control devices incorporated into the lighting system (e.g., dimming), and the temperature of the LEDs. Hence, different LED lighting systems require different power systems.
The following presents a simplified summary of the invention in order to provide a basic understanding of some aspects of the invention. This summary is not an extensive overview of the invention. It is not intended to identify key/critical elements of the invention or to delineate the scope of the invention. Its sole purpose is to present basic concepts in a simplified form as a prelude to the more detailed description that is presented later.
The invention is a modular system and apparatus for providing power for LED lighting modules. The power source of the present invention comprises (1) a power supply unit that outputs a regulated D/C voltage, (2) a configurable, intelligent gateway module that receives the regulated D/C voltage from the power supply and passes it to one or more power node modules on a power bus as well as to any control device or accessory in need of power, such as a motion detector or a cooling unit. The gateway module also receives control data from one or more control devices, such as a dimmer or a wireless controller, and instructs the power node to regulate the current according to any such control signals, and (3) an intelligent power node module that converts the regulated D/C voltage to a regulated D/C current to power the particular LED Light Module (LLM) and which also receives data from the LLM, such as temperature data, and adjusts the regulated output current accordingly.
As noted above, different LED lighting modules have different current requirements. Hence, every LED lighting system having a different current requirement must have a different power supply system. In fact, even lighting systems with the same power requirements may require different power supply systems as a result of different features or accessories included with the system. For instance, control devices, such as motion sensors and dimmers, and accessories, such as fans and other cooling accessories, may have their own unique power requirements. In addition, such control devices and accessories may output data that the power supply must be able to understand and respond to in order to provide the desired functionality.
Hence, power supplies for LED lighting systems are manufactured in small quantities, thus raising their cost. In addition, the design time to develop and implement a typical new power supply for a new LLM or to accommodate a new accessory or control device in an old LLM typically is on the order of eight to nine months.
The present invention substantially reduces or completely eliminates the cost and time of developing new power supplies for LLMs by providing a modular system that can work with a wide variety of LED lighting modules (LLMs), accessories, and control devices using virtually any off-the-shelf power source for generating a regulated D/C voltage output.
The power source may be any power source that outputs a regulated D/C voltage, including, but not limited to, batteries, solar panels, and A/C to D/C converters.
The next module is a gateway module 105. This module contains intelligence, such as a microprocessor, microcontroller, digital signal processor (DSP), field-programmable gate array (FPGA), complex programmable logic device (CPD), application-specific integrated circuit (ASIC) or any other form of digital processing apparatus. As will be discussed in more detail below, the intelligence in the gateway module 105 interfaces with control devices, such as dimmers, motion sensors, and wireless controllers to receive lighting control signals via either a communication bus 307 or a dedicated connection, and interfaces with the power node modules 107 via the communication bus 307 to control the LLM(s) 109. The gateway module 105 also places the regulated D/C voltage received from the power supply module 103 on a power bus 305, from which the power node modules 107 draw power. Any lighting accessories and control devices also may draw power from the power bus 305 either directly or through a power node. Finally, the gateway module maintains and controls the voltage power bus 305 and communication bus 307.
A word with regard to terminology in this specification is in order at this point. Herein, the term “power system” refers to the overall system for powering an LLM. For instance, this includes, but it not necessarily limited to, power supply node 303, gateway node 105, power node 107 and the power and communication buses 305, 307. The term “power supply” refers to the portion of the power system that outputs a regulated D/C voltage, e.g., power supply module 103. Finally, “power node” is a coined term to refer to the module in accordance with the present invention that converts the regulated D/C voltage to a regulated D/C current, among other things, e.g., power node module 107.
One or more power node modules 107 also are intelligent modules, containing microcontrollers (or other signal processing devices).
The power node module 107 receives the regulated D/C voltage on the power bus 305 from the power supply module 103 through the gateway module 105 and converts it to a regulated D/C current, which is provided to the LLM 109 on line 309 to produce light. In addition, the power node module 107 may receive instructions from the gateway module 105 over the communication bus 307, such as instructions generated responsive to control signals the gateway module 105 received from a dimmer or a motion sensor. The microcontroller in the power node module 107 interprets any instructions received from the gateway module 105 over communication bus 307 and controls the regulated D/C current output on line 309 to the LLM 109 accordingly. For instance, if a dimmer control device sends a signal to the gateway 105 indicating that fifty percent power is desired, the intelligence in the gateway 105, which is programmed to understand the language of the dimmer, interprets the command from the dimmer, generates a command to reduce current by fifty percent in the language of the communication bus 307 and addresses it to the proper power node module 107 on the communication bus. In response, the intelligence in the power node 107 regulates the regulated D/C current to the LLM 109 at the required level, e.g., fifty percent of its maximum amplitude.
The power node 107 can also receive local temperature or other data from the LLM 109 on line 311. More particularly, LED efficacy is dependent on local temperature. Thus, LLMs commonly generate a temperature signal that the power system uses to adjust the current applied to the LLM in order to keep it operating within a particular temperature range. This temperature signal is provided to the power node module 107 on line 311 and the intelligence in the power node module 107 adjusts the regulated D/C current output on line 309 responsive to the temperature signal (in addition to any control signal received from a control device, either directly or through the gateway module 105.) LLMs also may generate other information useful to the power node in terms of adjusting the output current, such as color temperature and flux level, which can be provided to the power node module on line 311.
In an alternative arrangement, the power node module 107 passes the temperature, color, flux, etc. information to the gateway module 105 via the communication bus 307. The intelligence in the gateway module 105 combines that information with any control information received from a control device and instructs the power node module 107 via the communication bus 307 of the proper current level it should output to the LLM 109 and the intelligence in the power node module regulates the output current 309 accordingly.
The number of power node/LLM units 110 that can be powered by a single power supply 103 is given by the following equation:
N<(Pout(supply)−Poverhead)/(Pllm/Effnode)
Since the power bus 305 directly carries the regulated D/C voltage output from the power supply module 103, a voltage for running voltage based accessories, such as cooling units and motion sensors, is available at each power nodes.
Further, by splitting the power source into three modules, namely, the power supply module 103, the gateway module 105, and the power node module 107, the power source for LLM units is highly adaptable at relatively low redesign and hardware costs. Particularly, with this configuration, the A/C to D/C power supply 103 can be almost any off-the-shelf power supply. Only the gateway module 105 and the power node module 107 need be adapted to the particular LLM, control devices, and/or accessories. Furthermore, the gateway module 105 and the power node module 107 typically will require only programming modifications, rather than hardware modifications, in order to be adapted to operate with different LLMs, control devices, and accessories.
In one embodiment, the power node module 107 is preprogrammed at the factory to the LLM to which it is coupled. For instance, its maximum D/C may be output current set according to the specification of the LLM. In operation however, the output D/C current can be adjusted downwardly therefrom as a function of the LLM temperature and any control devices.
In addition, however, a dimmer 113 is coupled to provide control signals to control input terminals 114 of the gateway module 105 on a dedicated line 313. When an end user 111 operates the dimmer 113 to set a desired illumination from the LLM 109, the dimmer outputs its control signals, (e.g., fifty percent power) to the gateway module 105, which may have been preprogrammed at the factory to interface with control devices using particular protocols. For instance, there is a widely used protocol for zero to ten volt dimmers. Other well known protocols include DALI (Digital Addressable Lighting Interface) having a protocol set forth in technical standard IEC 62386, DMX 512. Alternately, the intelligence in the gateway module may be equipped with programming to communicate using multiple protocols and include intelligence for determining on-the-fly the protocol being used by a control device that is coupled to it. The intelligence in the gateway node 105 may combine the control information from the dimmer 113 with any temperature information and send an instruction to the power node module 107 on communication bus 307 as to the proper regulated current to output to the LLM 109 to produce the desired illumination.
The gateway module in
Since the power node 107 has intelligence and also is coupled to the communication bus 307, in other embodiments, the power node 107 may receive the commands from the motion sensor directly via the communication bus and interpret them itself without the involvement of the gateway node 105; particularly if there is only one power node and LLM in the system, such that the motion sensor need not deal with addressing of the motion sensor control signals.
In one embodiment, the power node 107b may have the intelligence built into it to automatically adjust the current output on line 317 responsive to the thermal event 121, such as by shutting off the current to turn off the LLM 109b. In other embodiments, however, the intelligence for responding to temperature information and thermal events may reside in the gateway module 105, in which case the intelligence in the power node module 107b merely reports the thermal event 121 to the gateway module 105 via the communication bus 307 and receive instructions from gateway module 105 via the same communication bus 307.
Turning to the details, the gateway module 105 comprises four functional parts. The first is a communication protocol functional block 201. This block interprets the signals from the control module 125 to determine what the signals mean. This block 201 may be preprogrammed at the factory. Further, there is a power management integrated circuit 205 that powers all the circuitry in the gateway module 105 from the voltage from the constant voltage power supply module 103. The power management integrated circuit 205 monitors for under voltage or over voltage conditions and can shut off power in either case to prevent damage to the LLM. In addition, a microcontroller 203 receives the interpreted signals from the control device 125 and generates suitable commands for the power node module 107 and places them on the communication bus 307. Finally, the gateway module 105 includes a pass through block 207 for passing the regulated D/C voltage straight through to the power node module 107.
The power node module 107 comprises a constant current regulator 227 that receives the regulated D/C voltage and converts it into a regulated D/C current. A power management integrated circuit 223 manages power requirements on the power node module 107 as well as any accessories that might be coupled to receive power from the power node module. The power management integrated circuit 223 regulates the current for the microcontroller 225 and any other electronics in the power node module 107. Finally, a microcontroller 225 provides the intelligence for communicating with the gateway module 105, receiving and reading temperature information from the LLM 109, communicating with and controlling accessories, and the like. The power node module 107 is coupled to the LLM 109 by four lines, namely, the current supply line 309, comprising lines 309a and 309b, and the temperature data input lines 311, comprising differential signal lines 311a and 311b.
Finally, the LLM 109 comprises the LED array 211 as well as the thermal sensing circuitry 213. The current on lines 309a and 309b is provided to the LED array 211 while the thermal data generated by the thermal sensing circuitry 213 is provided to the power node module 107, via the thermal signaling lines 311a and 311b.
Power node modules 107 or combined power node/LLM units 141 can be designed generically with the communication and regulated D/C voltage pass through ports and/or one or more accessory ports incorporated therein. Then system designers can use such parts in virtually any of the aforedescribed embodiments, simply choosing to not use any of those ports that are unnecessary for the particular design in order to reduce part counts and maximize the benefits of mass production.
The system in the present invention is very flexible and eliminates much of the difficulty of customization of power sources for different LED lighting systems inherent in the prior art. For instance, in the prior art, integrated power supplies needed to be specifically built for operating with a particular dimmer or LLM. In the present invention, a generic power supply 103 can be used for multiple applications, and only the programming in the gateway module 105 (and may be the power node module 107, depending on the embodiment) would need to be adapted to operate with the particular dimmer.
Having thus described particular embodiments of the invention, various alterations, modifications, and improvements will readily occur to those skilled in the art. Such alterations, modifications, and improvements as are made obvious by this disclosure are intended to be part of this description though not expressly stated herein, and are intended to be within the spirit and scope of the invention. Accordingly, the foregoing description is by way of example only, and not limiting. The invention is limited only as defined in the following claims and equivalents thereto.
