WO2013039661A1

WO2013039661A1 - Multiple input dimming power supply for led illumination system

Info

Publication number: WO2013039661A1
Application number: PCT/US2012/051965
Authority: WO
Inventors: Peng Wang
Original assignee: GE Lighting Solutions, LLC
Priority date: 2011-09-16
Filing date: 2012-08-23
Publication date: 2013-03-21
Also published as: CN103002630A

Abstract

A LED lighting assembly includes a power source supplies power to a one or more LEDs and a dimming unit controls the power supplied to the one or more LEDs. The dimming unit includes a controller for determining an illumination and intensity of the one or more LEDs from a received a control signal and a dimming circuit in communication with the controller for controlling the amount of power supplied to the one or more LEDs to achieve the determined illumination and intensity.

Description

MULTIPLE INPUT DIMMING POWER SUPPLY FOR LED ILLUMINATION

SYSTEM

BACKGROUND

The present exemplary embodiment corresponds to the illumination arts, lighting arts, and related arts. It finds particular application in conjunction with multiple input dimming power supplies for light emitting diode (LED) based light sources, and will be described with particular reference thereto. However, it is to be appreciated that the present exemplary embodiment is also amenable to other like applications.

Systems for controlling electrical power to a load such as a light are well known. The systems include a dimming function that allows an individual or the system to customize the amount of power provided to a light to achieve a desired amount of illumination and intensity. For example, some systems automatically adjust the illumination of a light whereas some have a manual adjustor that allows an individual to select the illumination of a light. As LEDS become more popular and prevalent, it has become desirable to implement dimming functions in existing LED lighting units.

There are several challenges in implementing dimming functions in existing LED lighting units. For example, typical LED lighting units are not usually designed or suitable for implementation of a dimming function. The power supplies of typical lighting units are designed to convert and regulate AC line voltages and currents to appropriate LED voltages to power the LED lighting units. Adding a dimming function to an existing LED lighting unit requires the existing LED lighting fixture to be replaced resulting in a high cost for such implementation. Additionally, most LED power supplies are only able to receive either analog or digital control signals to operate the LED lighting unit. As the complexity of lighting control systems increase, and LED dimming strategies become more prevalent, it has become desirable to receive multiple types of control signals within the same LED drivers to control LED lighting units. This allows the end user the ability to use the same drivers and fixtures on multiple different dimming protocols using the same fixture. BRIEF DESCRIPTION

Various details of the present disclosure are hereinafter summarized to provide a basic understanding. This summary is not an extensive overview of the disclosure and is intended neither to identify certain elements of the disclosure, nor to delineate the scope thereof. Rather, the primary purpose of the summary is to present certain concepts of the disclosure in a simplified form prior to the more detailed description that is presented hereinafter.

According to one aspect of the present disclosure, a LED lighting assembly is provided. A power source supplies power to one or more LEDs. A dimming unit controls the power supplied to the LEDs. The dimming unit includes a controller for determining an illumination and intensity of the LEDs from a received control signal and a dimming circuit in communication with the controller for controlling the amount of power supplied to the LEDs to achieve the determined illumination and intensity.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of an LED source incorporating a multiple input dimming power supply in accordance with the present exemplary embodiment.

DETAILED DESCRIPTION

Referring now to the drawings which are provided for illustrating the exemplary embodiments only and not for purposes of limiting the claimed subject matter, FIGURE 1 shows a block diagram of a light source 2, such as an LED light fixture. The light source 2 includes an LED source 4 comprising one or more LEDs 6. Five LEDs 6 are illustrated in FIGURE 1 , but more or fewer LEDs are also contemplated. The set is typically formed of a plurality of subsets of LEDs, wherein the LEDs within each subset are serially interconnected. The subsets of serially interconnected LEDs are generally connected in parallel to form the set. A voltage supply 8 provides AC line voltage 10 to a power supply 12 for the LED source 2. The voltage supply 8 can include a wide range of voltages depending on the available line voltages. For example, 120 V and 277V are typically available in the U.S., however, other lines voltages can be utilized to supply the ballast circuit. Often for residential applications there may be an analog dimming circuit, or traditional wall-dimmer originally designed for dimming incandescent lamps, that uses a manual control setting to do 'phase-cut' or change the phase angle of the AC signal as a way or removing power from the input line. The power supply 12 converts and regulates the AC line voltage and current to the appropriate LED voltage to power the LED source 4. For example, the power supply 12 can dynamically adapt to an increased load such as an additional LED, convert alternating current voltage to a direct current voltage, correct for polarity of the incoming AC line voltage and current, and the like. The voltage and current from the AC line voltage 10 is rectified by a full wave rectifier bridge 14 and supplied to the LED source 4 through a power converter 16 and an output filter 18. The power converter 16 takes the AC voltage from the AC line voltage 10 and transforms it into DC voltage, with a regulated current, to power the LED source 4. The output filter 18 filters the power delivered to the LED source 4 to provide protection against output current ripples and the like.

To smooth out the AC current waveform and withdraw the switching high frequencies therefrom, an electromagnetic compatibility (EMC) input filter 20 may be added between the power supply 12 and the full wave rectifier bridge 14. The EMC input filter 20 typically contains an arrangement of capacitors, inductors and common mode chokes to reduce conducted electromagnetic emissions. Filtering is desirable due to the noise associated with a switching power supply. The current flowing through the EMC input filter 20 is proportional to the full-wave rectified voltage at the output of the rectifier bridge 14. The current waveform is sinusoidal and in phase with the voltage waveform so that the power factor is, if not equal to, close to unity.

The LED source 4 connects to the power supply 12 via a load input line 22 and a dimmer unit 24 via a load output line 26a. The dimmer unit 24 connects to the power supply 12 via a load output line 26b. The dimmer unit 24 controls the illumination and intensity of the LED source 4 in response to a dimming control signal 28. A controller 30 of the dimmer unit 24 receives the dimming control signal 28 and determines an appropriate illumination and intensity of the LED source 4. The controller 30 communicates with a dimming circuit 24 to control the amount of power supplied to the LED source 4. The dimming unit 24 includes inputs for digital dimming control signals 32 and analog dimming controls signals 34. For phase-cut analog dimming such as standard incandescent wall dimmers and ELV style dimmers, the input 34 is connected to the input line of the LED driver 10, or after an isolation transformer, to be able to read the waveform shape and power. A power converter 36 of the dimmer unit 24 takes the AC voltage from the analog dimming control signal 34 and converts it into a converted digital dimming control signal 38 to be inputted into the controller 30. The controller 30 receives the digital dimming control signals 32, 38 and determines the appropriate illumination and intensity of the LED source 4.

The digital dimming control signals 32 include signals implemented using the digital addressable lighting interface (DALI) protocol, DMX512 protocol, infrared sensor signals, optical sensor signals, temperature sensor signals, signals received from an external device, signals providing information pertaining to electrical parameters such as current and voltage of the power supply 12 and the LED source 4, and the like. The analog dimming control signal includes electronic low-voltage (ELV) and magnetic low- voltage (MLV) signals, conventional 0-10 V dimming signals, phase control dimming signals, a triac dimming signal, and the like.

It is also contemplated that the dimming unit 24 can determine the appropriate illumination and intensity of the LED source 4 from a combination of the digital dimming control signals 32 and the analog dimming controls signals 34. The dimming unit 24 can receive both digital dimming control signals 32 and the analog dimming controls signals 34 to determine the appropriate illumination and intensity of the LED source 4. For example, the dimming unit 24 receives an analog dimming control signal of 50% and digital dimming control signal of 30% and determines that the appropriate dimming level of the LED source is 40%. The controller 30 includes at least one processor, for example a microprocessor, a microcontroller, a digital signal processor (DSP), a general purpose processor, an application specific integrated circuit (ASIC), a dedicated processor, or other software controlled device configured to execute software for performing the operations described in further detail below. Typically, the software is carried on tangible memory or a computer readable medium for execution by the processor. Non-transitory computer readable media can include memory such as a hard disk drive, CD-ROM, DVD-ROM, internet servers, and the like. Other types of the processor are also contemplated. Display controllers, Application Specific Integrated Circuits (ASICs), FPGAs, and microcontrollers are illustrative examples of other types of components which may be used to provide the processor function. Embodiments may be implemented using software for execution by a processor, hardware, or some combination thereof.

The controller 30 of the dimmer unit 24 receives the dimming control signal 28 and determines an appropriate illumination and intensity of the LED source 4 and communicates with a dimming circuit 44 to control the amount of power supplied to the LED source 4. For example, the controller 30 provides timing information in the form of a timing signal derived from the dimming control signal 28 to the dimming circuit 44. The dimming circuit 44 activates one or more MOSFET switches to control the amount of power supplied to the LED source 4. In one example, the controller 30 uses known techniques for providing a pulse width modulation input to achieve a desired corresponding amount of dimming, or dimming can be achieved by lowering the current level output by the LED driver. It is also contemplated the dimming circuit 44 includes, but are not limited to, power MOSFETs, triacs, bipolar junction transistors, insulated gate bipolar transistors, and other like electrical devices.

As illustrated, the dimming unit 24 can be separate from the power supply 12 and the LED source 4. This enables dimming units 24 to be added to existing LED light fixtures that are not designed or suitable for implementation of a dimming function. For example, the dimming unit 24 can be connected in an existing LED light fixture between the LED source 4 and the power supply 12. The dimming unit 24 can be connected between the LED source 4 and the power supply 12 on either the input load line 22 or the output load line 26. It is also contemplated that the dimming unit 24 and the power supply 12 be embodied into a single light source 2. The light source 2, for example, may include a power supply 12 that controls the electrical power supplied to a load such as the LED source 4.

In another embodiment, the analog dimming signals are inputted into the power supply 12 through the voltage supply 8. The power supply 12 controls the illumination and intensity of the LED source 4 in response to the analog dimming control signal inputted to the power supply 12. The power supply 12 receives the analog dimming control signals and determines an appropriate illumination and intensity of the LED source 4 and regulates the AC line voltage and current to the appropriate LED voltage to power the LED source 4. It is also contemplated that the dimming of the LED source 4 can be controlled by a combination of the power supply 12 and the dimming unit 24. It is also contemplated that the appropriate illumination and intensity of the LED source 4 is controlled from a combination of the dimming control signals 32 inputted into dimming unit 24 and the analog dimming controls signals 34 inputted into the power supply 12. The appropriate illumination and intensity of the LED source 4 can also be determined from the dimming control signals 32 inputted into the dimming unit 24 and the analog dimming controls signals inputted into the power supply 12. For example, a 50% dimming control signal 32 inputted into the dimming unit 24 and a 40% analog dimming signal inputted into the power supply 12 can be combined to illuminate the LED source 4 to a dimming level of 40%.

The exemplary embodiment has been described with reference to the preferred embodiments. Obviously, modifications and alterations will occur to others upon reading and understanding the preceding detailed description. It is intended that the exemplary embodiment be construed as including all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.

Claims

CLAIMS:

1. A LED lighting assembly comprising: a power source for supplying power to one or more LEDs; and a dimming unit for controlling the power supplied to the one or more LEDs, the dimming unit comprising: a controller establishing a determined an illumination and intensity of the one or more LEDs from a received a control signal, and a dimming circuit in communication with the controller for controlling the amount of power supplied to the one or more LEDs to achieve the determined illumination and intensity.

2. The LED lighting assembly according to claim 1, wherein the control signal include either of an analog control signal or a digital control signal, with both signals capable of being interpreted by the controller in communication with the dimming circuit.

3. The LED lighting assembly according to claim 2, wherein the analog control signal includes at least one of a electronic low-voltage (ELV), a magnetic low-voltage (MLV) signals, conventional 0-10 V dimming signals, and a triac dimming signal, or other phase control dimming methods.

4. The LED lighting assembly according to claim 2, wherein the digital control signal includes at least one of signals implemented using the digital addressable lighting interface (DALI) protocol, DMX512 protocol, infrared sensor signals, optical sensor signals, temperature sensor signals, and signals providing information pertaining to electrical parameters such as current and voltage of the power supply and the one or more LEDs.

5. The LED lighting assembly according to claim 1, wherein the dimming unit further comprises: a power converter for converting received analog control signals to converted digital dimming control signals.

6. The LED lighting assembly according to claim 1, wherein the power supply and the dimming unit are separate components of the LED lighting assembly.

7. The LED lighting assembly according to claim 6, wherein the dimming unit is connected between the power supply and the one or more LEDs on a output-side of the one or more LEDs.