Low-cost low-power lighting system and lamp assembly

Abstract

In accordance with embodiments of the present disclosure, a method and apparatus includes an input having a first input terminal and a second input terminal for receiving an input waveform. In one example, the apparatus includes a capacitor having a first capacitor terminal and a second capacitor terminal, wherein the first capacitor terminal is coupled to the first input terminal, and at least one light-emitting diode coupled in series with the capacitor between the second capacitor terminal and the second input terminal, such that the light-emitting diode generates light in conformity with at least one of an amplitude modulation and a frequency modulation of the input waveform.

Claims

1. An apparatus comprising: an input having a first input terminal and a second input terminal for receiving an input waveform; a capacitor having a first capacitor terminal and a second capacitor terminal, wherein the first capacitor terminal is coupled to the first input terminal; and at least one light-emitting diode coupled in series with the capacitor between the second capacitor terminal and the second input terminal, such that the light-emitting diode generates light in conformity with at least one of an amplitude modulation and a frequency modulation of the input waveform.

2. The apparatus of claim 1, wherein at least one of a frequency and an amplitude of the input waveform is based on a control setting of a dimmer.

3. The apparatus of claim 2, wherein the input waveform has a frequency substantially greater than a frequency of a signal received by the dimmer.

4. The apparatus of claim 1, further comprising a rectifier coupled between the capacitor and the at least one light-emitting diode, wherein the rectifier has a first rectifier terminal, a second rectifier terminal, a first output terminal, and a second output terminal, and further wherein: the first rectifier terminal is coupled to the second capacitor terminal; the second rectifier terminal is coupled to the second input terminal; and the at least one light-emitting diode is coupled between the first output terminal and the second output terminal.

5. The apparatus of claim 4, wherein the rectifier comprises a full-bridge rectifier.

6. The apparatus of claim 4, wherein the rectifier comprises at least one rectifying diode coupled between the first output terminal and the second output terminal with an opposite polarity to the at least one light-emitting diode.

7. The apparatus of claim 6, wherein the at least one rectifying diode comprises a light-emitting diode.

8. The apparatus of claim 1, comprising a second capacitor coupled in parallel with the at least one light-emitting diode.

9. The apparatus of claim 1, wherein the apparatus comprises a lamp assembly for housing the at least one light-emitting diode.

10. A method comprising: receiving an input waveform at an input having a first input terminal and a second input terminal; and generating light from at least one light-emitting diode in conformity with at least one of an amplitude modulation and a frequency modulation of the input waveform, wherein the at least one light-emitting diode is coupled in series with a capacitor having a first capacitor terminal and a second capacitor terminal, such that the first capacitor terminal is coupled to the first input terminal and the at least one light-emitting diode is coupled between the second capacitor terminal and the second input terminal.

11. The apparatus of claim 10, wherein at least one of a frequency and an amplitude of the input waveform is based on a control setting of a dimmer.

12. The apparatus of claim 11, wherein the input waveform has a frequency substantially greater than a frequency of a signal received by the dimmer.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) A more complete understanding of the present embodiments and advantages thereof may be acquired by referring to the following description taken in conjunction with the accompanying drawings, in which like reference numbers indicate like features, and wherein:

(2) FIG. 1 illustrates a lighting system that includes a triac-based leading-edge dimmer, as is known in the art;

(3) FIG. 2 illustrates example voltage and current graphs associated with the lighting system depicted in FIG. 1, as is known in the art;

(4) FIG. 3 illustrates a lighting system that includes a phase-cut trailing-edge dimmer, as is known in the art;

(5) FIG. 4 illustrates example voltage and current graphs associated with the lighting system depicted in FIG. 3, as is known in the art;

(6) FIG. 5 illustrates an example lighting system including a modulator for providing compatibility between a low-power lamp and other elements of a lighting system, in accordance with embodiments of the present disclosure;

(7) FIGS. 6A-6D illustrate example voltage graphs associated with the modulator illustrated in FIG. 5, in accordance with embodiments of the present disclosure;

(8) FIG. 7A illustrates an example voltage graph for a square wave output signal which is amplitude modulated based on a dimmer phase-cut angle;

(9) FIG. 7B illustrates an example voltage graph for a square wave output signal which is frequency modulated based on a dimmer phase-cut angle; and

(10) FIGS. 8A-8D illustrate additional example voltage graphs associated with the modulator illustrated in FIG. 5, in accordance with embodiments of the present disclosure.

DETAILED DESCRIPTION

(11) FIG. 5 illustrates an example lighting system 500 including a modulator 522 for providing compatibility between a low-power lamp assembly 532 and other elements of a lighting system, in accordance with embodiments of the present disclosure. As shown in FIG. 5, lighting system 500 may include a voltage supply 504, a dimmer 502, a modulator 522, and a plurality of lamp assemblies 532. Voltage supply 504 may generate a supply voltage V.sub.SUPPLY that is, for example, a nominally 60 Hz/110 V line voltage in the United States of America or a nominally 50 Hz/220 V line voltage in Europe.

(12) Dimmer 502 may comprise any system, device, or apparatus for generating a dimming signal V.sub..sub._.sub.DIM to other elements of lighting system 500, wherein the dimming signal V.sub..sub._.sub.DIM represents a dimming level that causes lighting system 500 to adjust power delivered to a lamp, and, thus, depending on the dimming level, increase or decrease the brightness of lamp 542. Thus, dimmer 502 may include a leading-edge dimmer similar or identical to that depicted in FIG. 1, a trailing-edge dimmer similar to that depicted in FIG. 3, or any other suitable dimmer.

(13) Modulator 522 may comprise any system, device, or apparatus for transferring energy from an input in the form of an input waveform (e.g., V.sub..sub._.sub.DIM) which is periodic at a first frequency, to an output waveform V.sub.OUT, wherein the output waveform V.sub.OUT is periodic at a second frequency substantially greater than (e.g., at least an order of magnitude greater) the first frequency. In some embodiments, the second frequency may be based on a phase-cut angle of the input waveform V.sub..sub._.sub.DIM indicative of a control setting of dimmer 502 providing the input waveform V.sub..sub._.sub.DIM. In these and other embodiments, the amplitude of the output waveform V.sub.OUT may be based on a phase-cut angle of the input waveform V.sub..sub._.sub.DIM indicative of a control setting of dimmer 502 providing the input waveform V.sub..sub._.sub.DIM. As described in greater detail below, modulator 522 may be configured to drive a plurality of parallel lamp assemblies 532, each of the parallel lamp assemblies 532 comprising a capacitor (e.g., capacitor 536) in series with a light source (e.g., lamp 542) for converting electrical energy of the output waveform V.sub.OUT into photonic energy.

(14) In some embodiments, a single assembly 506 (e.g., an enclosure, housing, package, etc.) may comprise both dimmer 502 and modulator 522, as shown in FIG. 5.

(15) The output waveform V.sub.OUT generated by modulator 522 may comprise any suitable signal having an amplitude, frequency, or both which is a function of a dimmer setting (e.g., phase-cut angle). For example, as shown in FIG. 6A, output waveform V.sub.OUT may comprise a square wave signal with an amplitude V.sub.AMP dependent upon the dimming signal V.sub..sub._.sub.DIM and/or a frequency f=1/t.sub.PER dependent upon the dimming signal V.sub..sub._.sub.DIM. As another example, as shown in FIG. 6B, output waveform V.sub.OUT may comprise a sinusoidal signal with an amplitude V.sub.AMP dependent upon the dimming signal V.sub..sub._.sub.DIM and/or a frequency f=1/t.sub.PER dependent upon the dimming signal V.sub..sub._.sub.DIM. As a further example, as shown in FIG. 6C, output waveform V.sub.OUT may comprise a triangle wave signal with an amplitude V.sub.AMP dependent upon the dimming signal V.sub..sub._.sub.DIM and/or a frequency f=1/t.sub.PER dependent upon the dimming signal V.sub..sub._.sub.DIM. As an additional example, as shown in FIG. 6D, output waveform V.sub.OUT may comprise a sawtooth signal with an amplitude V.sub.AMP dependent upon the dimming signal V.sub..sub._.sub.DIM and/or a frequency f=1/t.sub.PER dependent upon the dimming signal V.sub..sub._.sub.DIM.

(16) In operation, modulator 522 may modulate an amplitude and/or frequency of output waveform V.sub.OUT as shown in FIGS. 7A and 7B. FIG. 7A illustrates an example voltage graph for output waveform V.sub.OUT which is amplitude modulated based on a dimmer phase-cut angle of dimming signal V.sub..sub._.sub.DIM. FIG. 7B illustrates an example voltage graph for output waveform V.sub.OUT which is frequency modulated based on a dimmer phase-cut angle of dimming signal V.sub..sub._.sub.DIM. Although FIGS. 7A and 7B depict amplitude and frequency modulation of square wave waveforms, similar amplitude and frequency modulation may be applied to other types of waveforms, including sinusoidal waveforms, triangle wave signals, and sawtooth signals such as those depicted in FIGS. 6B-6D.

(17) In these and other embodiments, the output waveform V.sub.OUT generated by modulator 522 may comprise a waveform with an envelope function proportional to the dimming signal V.sub..sub._.sub.DIM. For example, as shown in FIG. 8A, output waveform V.sub.OUT may comprise a square wave signal with an envelope function proportional to the dimming signal V.sub..sub._.sub.DIM. As another example, as shown in FIG. 8B, output waveform V.sub.OUT may comprise a sinusoidal signal with an envelope function proportional to the dimming signal V.sub..sub._.sub.DIM. As a further example, as shown in FIG. 8C, output waveform V.sub.OUT may comprise a triangle wave signal with an envelope function proportional to the dimming signal V.sub..sub._.sub.DIM. As an additional example, as shown in FIG. 8D, output waveform V.sub.OUT may comprise a sawtooth signal with an envelope function proportional to the dimming signal V.sub..sub._.sub.DIM. It is noted with respect to FIGS. 8A-8D that the depicted proportionality between frequencies of example output waveforms V.sub.OUT and envelope functions thereof is for illustrative purposes, and in some embodiments of the present disclosure, frequencies of output waveforms V.sub.OUT may be at least an order of magnitude greater than the frequency of the corresponding envelope functions thereof.

(18) Turning again to FIG. 5, a lamp assembly 532 may comprise any system, device, or apparatus for converting electrical energy (e.g., delivered by modulator 522) into photonic energy. In some embodiments, a lamp assembly 532 may comprise a multifaceted reflector form factor (e.g., an MR16 form factor). As shown in FIG. 5, a lamp assembly 532 may comprise a capacitor 536, a rectifier 538, a capacitor 540, and a lamp 542. Lamp assembly 532 may have an input having a first input terminal and a second input terminal for receiving an input waveform (e.g., modulator output waveform V.sub.OUT). Capacitor 536 may have a first capacitor terminal and a second capacitor terminal such that the first capacitor terminal is coupled to the first input terminal of lamp assembly 532. Capacitor 536, rectifier 538, and lamp 542 may be arranged such that lamp 542 may be coupled in series with capacitor 536 between the second capacitor terminal and the second input terminal, via rectifier 538.

(19) Rectifier 538 may comprise any system, device, or apparatus for converting an AC signal into a DC signal. Rectifier 538 may comprise a first rectifier terminal, a second rectifier terminal, a first output terminal, and a second output terminal and may be coupled to lamp 542 and capacitor 536 such that the first rectifier terminal is coupled to the second capacitor terminal of capacitor 536, the second rectifier terminal is coupled to the second input terminal, and lamp 542 is coupled between the first output terminal and the second output terminal. In some embodiments, rectifier 538 may comprise a full-bridge rectifier. In embodiments in which lamp 542 comprises one or more LEDs, rectifier 538 may comprise at least one rectifying diode coupled between the first output terminal and the second output terminal with an opposite polarity to the one or more LEDs making up lamp 542. In such embodiments, the at least one rectifying diode may comprise one or more LEDs.

(20) Capacitor 540 may be coupled in parallel with lamp 542. In operation, capacitor 540 may store energy output by rectifier 538 which may be transferred to lamp 542.

(21) Lamp 542 may comprise any system, device, or apparatus for converting electrical energy (e.g., delivered by rectifier 538) into photonic energy. In some embodiments, lamp 542 may comprise an LED lamp. In operation of lamp assembly 532 in lighting system 500, lamp 542 may generate light in proportion to an amplitude and/or frequency of signal V.sub.OUT, and because the amplitude and/or frequency of signal V.sub.OUT may be a function of dimming signal V.sub..sub._.sub.DIM, lamp 542 may generate light in conformity with a control setting of a dimmer coupled to the input.

(22) Accordingly, by modulating the AC dimming signal V.sub..sub._.sub.DIM, a dimmable lamp assembly 532 as shown in FIG. 5 and described above may be realized which translates the delivery of current typically utilized in traditional lamps (e.g., incandescent bulbs) to a delivery of charge for LEDs. In addition, whereas in traditional approaches lamp assemblies often included complex circuitry for dimmer compatibility, the methods and systems described herein provide a solution in which dimmer compatibility is essentially performed by modulator 522, which may be provided externally to a lamp assembly 532 (e.g., mounted or installed in a housing separate from lamp assemblies 532 and/or separate from any socket or connector for coupling a lamp assembly 532 to lighting system 500), such that one or more lamp assemblies 532 may receive the modulated output signal V.sub.OUT from modulator 522. As a result, the complex dimmer compatibility circuitry present in each lamp assembly in a traditional low-power lighting system may effectively be replaced by a single dimmer compatibility circuit, which may lead to lower cost.

(23) As used herein, when two or more elements are referred to as coupled to one another, such term indicates that such two or more elements are in electronic communication whether connected indirectly or directly, with or without intervening elements.

(24) This disclosure encompasses all changes, substitutions, variations, alterations, and modifications to the example embodiments herein that a person having ordinary skill in the art would comprehend. Similarly, where appropriate, the appended claims encompass all changes, substitutions, variations, alterations, and modifications to the example embodiments herein that a person having ordinary skill in the art would comprehend. Moreover, reference in the appended claims to an apparatus or system or a component of an apparatus or system being adapted to, arranged to, capable of, configured to, enabled to, operable to, or operative to perform a particular function encompasses that apparatus, system, or component, whether or not it or that particular function is activated, turned on, or unlocked, as long as that apparatus, system, or component is so adapted, arranged, capable, configured, enabled, operable, or operative.

(25) All examples and conditional language recited herein are intended for pedagogical objects to aid the reader in understanding the disclosure and the concepts contributed by the inventor to furthering the art, and are construed as being without limitation to such specifically recited examples and conditions. Although embodiments of the present disclosure have been described in detail, it should be understood that various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the disclosure.