Light emitting diode (LED) lighting systems are becoming more prevalent as replacements for existing lighting systems. LEDs are an example of solid-state lighting (SSL) and have advantages over traditional lighting solutions such as incandescent and fluorescent lighting because they use less energy, are more durable, operate longer, can be combined in multiple color arrays that can be controlled to deliver virtually any color light, and generally contain no lead or mercury. In many applications, one or more LED dies (or chips) are mounted within an LED package or on an LED module, which may make up part of a lighting unit, lamp, “light bulb” or more simply a “bulb,” which includes one or more power supplies to power the LEDs.
An LED bulb may be made with a form factor that allows it to replace a standard incandescent bulb, or any of various types of fluorescent lamps. For example, an LED bulb may be made in the form of an A-series, or “Edison” style incandescent bulb with a threaded base. Such an LED bulb can be used in a floor lamp or a table lamp of the type that might be placed on an end table or bed-side table. Some such lamps include so-called “three-way” sockets intended to receive a “three-way” incandescent bulb of the type shown in
Embodiments of the present invention provide power supply circuitry that allows a solid-state lamp or light bulb to work in a manner similar to that of a common three-way incandescent light bulb. In at least some embodiments, circuitry is added to a driver (sometimes itself referred to as a power supply or a controller) to interpret the incoming AC line voltage and adjust the driver current for a solid-state emitter such as an LED.
In at least some embodiments, the power supply for the light bulb includes first and second inputs for receiving the line or input voltage relative to neutral, and a control circuit connected to the first and second inputs and a feedback input for a driver. The control circuit can selectively set a light output for the solid-state light emitter by influencing the feedback loop in accordance with the selective presence of the voltage at the first and second inputs. In a three-way lamp or bulb, the voltage inputs are connected to physical terminals, which along with a neutral terminal engage with terminals in a socket, lamp, light fixture, or the like.
In at least some embodiments, the control circuit selectively sets the light output by using a feedback input to set a regulation point for the driver. In at least some embodiments, the control circuit is operable to divert current from a feedback loop in accordance with the selective presence of the voltage at the first and second inputs. In at least some embodiments, the control circuit is operable to alter a current sense resistance for the solid-state emitter or LED in accordance with the selective presence of the voltage at the first and second inputs.
In some embodiments the circuit for setting light output in accordance with a selective presence of a voltage at a plurality of line inputs includes a feedback path for connection between a light emitter and a feedback input of a driver, a sensing circuit block connected to each of the plurality of line inputs to sense the voltage, and a control circuit block for each sensing block, each control circuit block connected to the feedback path to influence a regulation point for the driver in accordance with the presence of the voltage. A sensing circuit block and control circuit block can be used for each of as many line voltage inputs as desired to provide as many light levels as desired. If there are only two line inputs or the line inputs are otherwise organized in pairs, a pair of transistors can be provided, each transistor associated with the control circuit block and sensing circuit block for the input.
In some embodiments, transistors in the control circuit divert current in accordance with a sense voltage across a resistor. In some embodiments, transistors in the control circuit alter the current sense resistance. In some embodiments, transistors in the control circuit are connected in parallel. In some embodiments, transistors in the control circuit are connected in a cascode configuration.
In a three-way solid-state lamp according to at least some embodiments, the power supply selectively receives the input voltage, usually AC line voltage, on the first and second input terminals. The light output of the solid-state emitter or solid-state emitters is then set in accordance with a selective presence (for example, presence or absence on each input terminal) of the input voltage by causing the driver to supply power to enable the solid-state emitter or solid-state emitters to provide the light output in accordance with the input voltage.
Embodiments of the present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout.
It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of the present invention. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.
It will be understood that when an element such as a layer, region or substrate is referred to as being “on” or extending “onto” another element, it can be directly on or extend directly onto the other element or intervening elements may also be present. In contrast, when an element is referred to as being “directly on” or extending “directly onto” another element, there are no intervening elements present. It will also be understood that when an element is referred to as being “connected” or “coupled” to another element, it can be directly connected or coupled to the other element or intervening elements may be present. In contrast, when an element is referred to as being “directly connected” or “directly coupled” to another element, there are no intervening elements present.
Relative terms such as “below” or “above” or “upper” or “lower” or “horizontal” or “vertical” may be used herein to describe a relationship of one element, layer or region to another element, layer or region as illustrated in the figures. It will be understood that these terms are intended to encompass different orientations of the device in addition to the orientation depicted in the figures.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” “comprising,” “includes” and/or “including” when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms used herein should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
Unless otherwise expressly stated, comparative, quantitative terms such as “less” and “greater”, are intended to encompass the concept of equality. As an example, “less” can mean not only “less” in the strictest mathematical sense, but also, “less than or equal to.”
The terms “LED” and “LED device” as used herein may refer to any solid-state light emitter. The terms “solid-state light emitter” or “solid-state emitter” may include a light emitting diode, laser diode, organic light emitting diode, and/or other semiconductor device which includes one or more semiconductor layers, which may include silicon, silicon carbide, gallium nitride and/or other semiconductor materials, a substrate which may include sapphire, silicon, silicon carbide and/or other microelectronic substrates, and one or more contact layers which may include metal and/or other conductive materials. A solid-state lighting device produces light (ultraviolet, visible, or infrared) by exciting electrons across the band gap between a conduction band and a valence band of a semiconductor active (light-emitting) layer, with the electron transition generating light at a wavelength that depends on the band gap. Thus, the color (wavelength) of the light emitted by a solid-state emitter depends on the materials of the active layers thereof. In various embodiments, solid-state light emitters may have peak wavelengths in the visible range and/or be used in combination with lumiphoric materials having peak wavelengths in the visible range. Multiple solid-state light emitters and/or multiple lumiphoric materials (i.e., in combination with at least one solid-state light emitter) may be used in a single device, such as to produce light perceived as white or near-white in character. In certain embodiments, the aggregated output of multiple solid-state light emitters and/or lumiphoric materials may generate warm white light output having a color temperature range of from about 2700K to about 4000K.
Solid-state light emitters may be used individually or in combination with one or more lumiphoric materials (e.g., phosphors, scintillators, lumiphoric inks) and/or optical elements to generate light at a peak wavelength, or of at least one desired perceived color (including combinations of colors that may be perceived as white). Inclusion of lumiphoric (also called ‘luminescent’) materials in lighting devices as described herein may be accomplished by direct coating on solid-state light emitter, adding such materials to encapsulants, adding such materials to lenses, by embedding or dispersing such materials within lumiphor support elements, and/or coating such materials on lumiphor support elements. Other materials, such as light scattering elements (e.g., particles) and/or index matching materials may be associated with a lumiphor, a lumiphor binding medium, or a lumiphor support element that may be spatially segregated from a solid-state emitter.
For purposes of the discussion herein, the term “power supply” is used to refer to the circuitry that receives line input voltage and ultimately supplies power to solid-state emitters in a lamp or bulb. The term “driver” is used to refer to the portion of that circuitry that includes feedback compensation and a controller that is typically used in solid-state lamps. Thus, the term “power supply” is typically going to be used to refer to circuitry inclusive of the control circuit discussed in detail herein, whereas the term “driver” will be used to discuss circuitry exclusive of the control circuit. The terms “input” and “output” refer to input and output circuit paths. However, when used with the term “terminal” these terms are meant to refer to physical connections of a device such as a solid-state lamp or bulb.
Embodiments of the present invention provide power supply circuitry that allows a solid-state lamp or light bulb to work in a manner similar to that of a common three-way incandescent light bulb. In the case of the example LED light bulbs discussed herein, a control circuit is connected to an electronic LED driver (sometimes called a “controller”) to interpret the incoming AC line voltage (absence or presence) and adjust the LED current accordingly. The light output is adjusted depending on which AC input terminal(s) is (are) energized. This adjustment is accomplished by changing (manipulating) the LED driver's regulation point, either the voltage or current regulation point. With proper design of the circuitry, the LED bulb can mimic the light output of a traditional three-way incandescent light bulb as related to switch positions of a fixture or socket. Alternatively, the design can be altered to produce some other light output for specific combinations of voltages on the inputs. The table below illustrates the logic of adjusting the light output based on the presence or absence of AC line voltage on two input terminals, referred to as “AC Voltage #1” and “AC Voltage #2.”
The driver in the example of
The feedback control circuit 302 of
With control circuit 302a of
The control circuit 302a of
The control circuit 302b of
Staying with
The control circuit 302c of
As before, the control circuit 302d of
The example embodiments described can be “tuned” by alterations in resistor values, driver circuitry, and the like to create a three-way solid-state light bulb with various stepped light outputs to mimic various wattages of standard incandescent light bulbs, for example, bulbs providing 30/70/100, 40/60/100, or 50/100/150 watt equivalents. Non-standard lighting output configurations can also be created. For example, light output can be evenly stepped between the three settings as opposed to in the typical three-way incandescent bulb where the light outputs of two of the settings are fairly close together. It is also possible to have more than three settings by adding additional sense and control circuit blocks to the feedback control circuit.
The various portions of a solid-state lamp or bulb according to example embodiments of the invention can be made of any of various materials. Heat sinks can be made of metal or plastic, as can the various portions of the housings for the components of a lamp. A bulb according to embodiments of the invention can be assembled using varied fastening methods and mechanisms for interconnecting the various parts. For example, in some embodiments locking tabs and holes can be used. In some embodiments, combinations of fasteners such as tabs, latches or other suitable fastening arrangements and combinations of fasteners can be used which would not require adhesives or screws. In other embodiments, adhesives, screws, bolts, or other fasteners may be used to fasten together the various components.
Although specific embodiments have been illustrated and described herein, those of ordinary skill in the art appreciate that any arrangement which is calculated to achieve the same purpose may be substituted for the specific embodiments shown and that the invention has other applications in other environments. This application is intended to cover any adaptations or variations of the present invention. The following claims are in no way intended to limit the scope of the invention to the specific embodiments described herein.
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