WO2019126584A1

WO2019126584A1 - Dimmer interface having reduced power consumption

Info

Publication number: WO2019126584A1
Application number: PCT/US2018/066956
Authority: WO
Inventors: Zhi Hua Song
Original assignee: Lumileds Llc
Priority date: 2017-12-20
Filing date: 2018-12-20
Publication date: 2019-06-27
Also published as: CN111869328A; TW202118347A; TW201931949A; TWI698153B; TWI771692B

Abstract

The disclosed subject matter includes an apparatus including a dimmer switch interface. The switch interface includes a transformer having a first winding that is magnetically coupled to a second winding, the first winding being electrically coupled to a pair of terminals. The switch interface also includes a current source configured to supply the second winding with an intermittent alternating current, the intermittent alternating current having a cyclical waveform, each cycle of the waveform including a first portion during which the current is fixed at a predetermined fixed low value and a second portion during which the current alternates between a high value and a low value.

Description

DIMMER INTERFACE HAVING REDUCED POWER CONSUMPTION

BACKGROUND

[0001] Light emitting diodes (“LEDs”) are commonly used as light sources in various applications. LEDs are more energy-efficient than traditional light sources, providing much higher energy conversion efficiency than incandescent lamps and fluorescent light, for example. Furthermore, LEDs radiate less heat into illuminated regions and afford a greater breadth of control over brightness, emission color and spectrum than traditional light sources. These characteristics make LEDs an excellent choice for various lighting applications ranging from indoor illumination to automotive lighting. Accordingly, the need exists for improved LED-based illumination systems that harness the advantages of LEDs to provide high-quality illumination.

SUMMARY

[0002] The present disclosure addresses this need. According to aspects of the disclosure, an illumination system is disclosed, comprising: a light fixture including a driver coupled to a light source; a dimmer switch; and a dimmer switch interface, including: (i) a transformer having a first winding that is magnetically coupled to a second winding, the first winding being electrically coupled to the dimmer switch, and the second winding being electrically coupled to the driver of the light fixture, and (ii) a current source configured to power the transformer with an intermittent alternating current when the current source is energized.

BRIEF DESCRIPTION OF THE DRAWINGS

[0003] The drawings described below are for illustration purposes only. The drawings are not intended to limit the scope of the present disclosure. Like reference characters shown in the figures designate the same parts in the various embodiments.

[0004] FIG. 1 is a schematic diagram of an example of an illumination system, according to aspects of the disclosure;

[0005] FIG. 2 is a graph of a current signal used to drive a transformer in a dimmer switch interface of the illumination system of FIG. 1 , according to aspects of the disclosure;

[0006] FIG. 3 is a schematic diagram of another example of an illumination system, according to aspects of the disclosure;

[0007] FIG. 4 is a graph of a current signal used to drive a transformer in a dimmer switch interface of the illumination system of FIG. 3, according to aspects of the disclosure; [0008] FIG. 5 is a graph of a control signal used to control the operation of a current source in the dimmer switch interface of the illumination system of FIG. 3, according to aspects of the disclosure;

[0009] FIG. 6 is a circuit diagram of an example of a current source that can be utilized in the dimmer switch interface of the illumination system of FIG. 3, according to aspects of the disclosure;

[0010] FIG. 7 is a flowchart of an example of a process performed by a controller that is part of the dimmer switch interface of the illumination system of FIG. 3, according to aspects of the disclosure;

[001 1] FIG. 8 is a plot illustrating a control signal and a corresponding current signal that can be generated by the current source in the dimmer switch interface of the illumination system of FIG. 3, according to aspects of the disclosure;

[0012] FIG. 9 is a plot illustrating another control signal and another corresponding current signal that can be generated by the current source in the dimmer switch interface of the illumination system of FIG. 3, according to aspects of the disclosure;

[0013] Fig. 10 is a top view of an electronics board for an integrated LED lighting system according to one embodiment;

[0014] Fig. 1 1 A is a top view of the electronics board with LED array attached to the substrate at the LED device attach region in one embodiment;

[0015] Fig. 1 1 B is a diagram of one embodiment of a two channel integrated LED lighting system with electronic components mounted on two surfaces of a circuit board;

[0016] FIG. 11 C is a diagram of an embodiment of an LED lighting system where the LED array is on a separate electronics board from the driver and control circuitry;

[0017] FIG. 1 1 D is a block diagram of an LED lighting system having the LED array together with some of the electronics on an electronics board separate from the driver circuit;

[0018] FIG. 1 1 E is a diagram of example LED lighting system showing a multi-channel

LED driver circuit;

[0019] FIG. 12 is a diagram of an example application system;

[0020] FIG. 13A is a diagram showing an LED device; and

[0021] FIG. 13B is a diagram showing multiple LED devices.

DETAILED DESCRIPTION

[0022] Examples of different light illumination systems and/or light emitting diode (“LED”) implementations will be described more fully hereinafter with reference to the accompanying drawings. These examples are not mutually exclusive, and features found in one example may be combined with features found in one or more other examples to achieve additional implementations. Accordingly, it will be understood that the examples shown in the accompanying drawings are provided for illustrative purposes only and they are not intended to limit the disclosure in any way. Like numbers refer to like elements throughout.

[0023] It will be understood that, although the terms first, second, third, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms may be used to distinguish one element from another. For example, a first element may be termed a second element and a second element may be termed a first element without departing from the scope of the present invention. As used herein, the term "and/or" may include any and all combinations of one or more of the associated listed items.

[0024] 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 may 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 may be 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 may be directly connected or coupled to the other element and/or connected or coupled to the other element via one or more intervening elements. In contrast, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intervening elements present between the element and the other element. It will be understood that these terms are intended to encompass different orientations of the element in addition to any orientation depicted in the figures.

[0025] Relative terms such as "below," "above," "upper,", "lower," "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.

[0026] Further, whether the LEDs, LED arrays, electrical components and/or electronic components are housed on one, two or more electronics boards may also depend on design constraints and/or application.

[0027] Semiconductor light emitting devices (LEDs) or optical power emitting devices, such as devices that emit ultraviolet (UV) or infrared (IR) optical power, are among the most efficient light sources currently available. These devices (hereinafter“LEDs”), may include light emitting diodes, resonant cavity light emitting diodes, vertical cavity laser diodes, edge emitting lasers, or the like.

Due to their compact size and lower power requirements, for example, LEDs may be attractive candidates for many different applications. For example, they may be used as light sources (e.g., flash lights and camera flashes) for hand-held battery-powered devices, such as cameras and cell phones. They may also be used, for example, for automotive lighting, heads up display (HUD) lighting, horticultural lighting, street lighting, torch for video, general illumination (e.g., home, shop, office and studio lighting, theater/stage lighting and architectural lighting), augmented reality (AR) lighting, virtual reality (VR) lighting, as back lights for displays, and IR spectroscopy. A single LED may provide light that is less bright than an incandescent light source, and, therefore, multi-junction devices or arrays of LEDs (such as monolithic LED arrays, micro LED arrays, etc.) may be used for applications where more brightness is desired or required.

[0028] Dimmer switches are devices used to control the brightness of light produced by light fixtures. On the outside, a manually operated dimmer switch may appear as a knob which a user can turn to increase or decrease the brightness of a light fixture. On the inside, the dimmer switch may include a variable resistor that is coupled to the knob. The variable resistor may be used to adjust the value of a voltage signal that is provided by the dimmer switch to the light fixture.

[0029] One dimming system that is often used in fluorescent and LED lighting is called 0-

10V dimming. According to this system, the voltage signal that is provided by a 0-10V dimming switch to a light fixture varies between 0V and 10V. When the value of the voltage signal is below a certain threshold close to 0V, the light fixture may operate at its lowest possible brightness or turn itself off completely. When the value of the voltage signal is above a certain threshold close to 10V, the light fixture may operate at its maximum brightness.

[0030] When the 0-10V system is used, dimmer switches are normally connected to light sources via dimmer switch interfaces. A dimmer switch interface is a device that may be interposed between a dimmer switch and a light fixture to electrically isolate the dimmer switch and suppress noise. To accomplish this function, the dimmer switch interface may include a transformer that is used to drive the dimmer switch and connect the dimmer switch to the light fixture.

[0031] One disadvantage of dimmer switch interfaces is that they are often energy- inefficient. A typical dimmer switch interface may often consume 100mW or more, which consumption is mostly due to the transformer in the dimmer switch interface. This consumption may be undesirable as it may increase the cost of operating the dimmer switch interface. Furthermore, the power consumption due to the transformer in the dimmer switch interface may prevent a lighting system utilizing a dimmer switch interface from complying with various present and future environmental regulations that mandate limits on the standby power of lighting systems.

[0032] According to aspects of the disclosure, a dimmer switch interface is disclosed that has reduced power consumption. The dimmer switch interface may include a transformer that is used to magnetically couple a dimmer switch to a light fixture. The transformer may be driven by a current source configured to supply the transformer with an intermittent current. When the transformer is driven with intermittent current, the current supplied to the transformer is switched between a high current value {e.g., 10mA) and low current value {e.g., OA). During periods in which the intermittent current is switched to the low value {e.g., OA), the transformer is turned off and does not consume any power. Accordingly, when the transformer is driven with intermittent current, the power consumption of the transformer can be significantly reduced.

[0033] According to aspects of the disclosure, a dimmer switch interface is disclosed, comprising: a pair of first terminals for connecting the dimmer switch interface to a dimmer switch; a pair of second terminals for connecting the dimmer switch to a driver of a light fixture; a transformer having a first winding that is magnetically coupled to a second winding, the first winding being electrically coupled to the pair of first terminals, and the second winding being electrically coupled to the pair of second terminals; and a current source configured to power the transformer with an intermittent alternating current when the current source is energized.

[0034] According to aspects of the disclosure, an apparatus is disclosed, comprising: a driver for a light fixture; and a dimmer switch interface for connecting the driver to a dimmer switch, the dimmer switch interface including: (i) a transformer having a first winding that is magnetically coupled to a second winding, the first winding being electrically coupled to a pair of terminals for connecting the dimmer switch interface to the dimmer switch, and the second winding being electrically coupled to the driver, and (ii) a current source configured to power the transformer with an intermittent alternating current when the current source is energized.

[0035] FIG. 1 is a diagram of an example of an illumination system 100, according to aspects of the disclosure. The illumination system 100 may include a dimmer switch 1 10, a light fixture 120, and a dimmer switch interface 130 coupling the dimmer switch 1 10 to the light fixture 120.

[0036] The dimmer switch 1 10 may be a 0-10V dimmer switch and/or any other suitable type of dimmer switch. The dimmer switch 1 10 may include a variable resistor (e.g., a potentiometer), and/or any suitable type of device that is capable of placing a variable load between terminals T 1 of the dimmer switch interface 130. Additionally or alternatively, the dimmer switch 1 10 may include any suitable type of semiconductor device that is capable of changing the voltage between the terminals T1 of the dimmer switch interface 130. Stated succinctly, according to aspects of the disclosure, the dimmer switch 110 may be any suitable type of device that is capable of generating a voltage signal that indicates a desired level of brightness for the light output from the light fixture 120. [0037] In some implementations, the dimmer switch 1 10 may include a light sensor that is configured to measure the level of ambient light in the vicinity of the light fixture 120 and generate a voltage signal based on the measured level of ambient light. Additionally or alternatively, in some implementations, the dimmer switch 1 10 may include a knob or a slider which can be used to actuate a potentiometer that is part of the dimmer switch 1 10. Additionally or alternatively, the dimmer switch 1 10 may include a wireless receiver {e.g., a ZigBee gateway, a WiFi receiver, a remote control receiver, etc.) that is capable of receiving an indication of a desired brightness level from a remote device {e.g., a user’s smartphone or remote control) and generating a corresponding voltage signal based on the indication.

[0038] The light fixture 120 may include any suitable type of light fixture. The light fixture 120 may include a driver 122 and a light source 124 that is powered using a signal PWR. The light source 124 may include any suitable type of light source, such as a fluorescent light source, an incandescent light source, and/or one or more light emitting diodes (LEDs). In the present example, the light source 124 includes one or more LEDs and the signal PWR is a DC or a pulse-width modulated (PWM) signal that is generated by the driver 122 based on a signal DIM received by the driver 122 from the dimmer switch interface 130. The driver 122 may include a DC/DC converter circuit, a tuning engine, or the like.

[0039] Signal DIM may be a voltage signal. The level of the signal DIM may determine the

DC magnitude and/or the duty cycle of the signal PWR. If the signal DIM has a first level (e.g., 2V), the driver 122 may impart a first DC magnitude and/or a first duty cycle on the signal PWR. By contrast, if the signal DIM has a second level (e.g., 5V), the driver 122 may impart a second DC magnitude and/or a second duty cycle on the signal PWR that are different from those for the first DIM level. As can be readily appreciated, the DC magnitude and/or the duty cycle of the signal PWR determines the amount of current delivered to the light source 124, which in turn may determine the brightness of the light output from the light source 124.

[0040] The dimmer switch interface 130 may provide isolation between the light fixture 120 and the dimmer switch 1 10 mainly to protect human beings operating the dimmer switch from electrical shock. The dimmer switch interface 130 may include a converter circuit 132 that is coupled to a converter circuit 134 via a transformer 136. The transformer 136 may be driven with a continuous current signal SO produced by a current source 138. As illustrated in FIG. 2, the signal SO may be an alternating current (AC) signal, and it may be shaped as a continuous square wave. In alternative implementations, however, the signal SO may be shaped as sinusoidal wave and/or any other suitable type of wave. In some implementations, a current signal may be continuous when the current signal has a constant current level. [0041] The transformer 136 may include a winding W1 and a winding W2 that is magnetically coupled to the winding W1. The winding W1 may be electrically coupled to the light fixture 120 {e.g., via the converter circuit 132). The winding W2 may be electrically coupled to the dimmer switch 110 {e.g., via the converter circuit 134). In some implementations, the winding W2 may be electrically coupled to the terminals T1 of the dimmer switch interface 130 (e.g., via the converter circuit 134). In such instances, the dimmer switch 1 10 may be also coupled to the terminals T1 to complete the electrical connection between the dimmer switch 1 10 and the winding W2. Additionally or alternatively, in some implementations, the winding W1 may be electrically coupled to the terminals T2 of the dimmer switch interface 130 (e.g., via the converter circuit 132). In such instances, the driver 122 may also be coupled to the terminals T2 of the dimmer switch interface 130 to receive the signal DIM for controlling the brightness of the light source 124.

[0042] In operation, the winding W2 carries the dimming control information from the dimmer switch 1 10 via the converter circuit 134, which also converts the voltage across the winding W2 into a DC current to supply the dimmer switch 1 10. As noted above, the voltage across the winding W2 may be generated, at least in part, by the dimmer switch 1 10. Furthermore, the voltage across the winding W2 may be transferred to the winding W1 of the transformer 136 through magnetic coupling, and converted by the converter circuit 132 into a DC current to produce the voltage signal DIM. The voltage signal DIM may then be used by the driver 122 of the light fixture 120 to adjust the brightness of the light fixture 120. According to aspects of the disclosure, the converter circuit 132 may include any suitable electronic circuit that is configured to produce a DC signal based on an AC signal received from the winding W1. Furthermore, according to aspects of the disclosure, the converter circuit 134 may include any suitable electronic circuit that is configured to form a desired AC signal on the winding W2.

[0043] FIG. 3 is a diagram of an example of an illumination system 300 which has improved power consumption. As is discussed further below, the improved power consumption is achieved by using a current source that intermittently switches on and off the transformer in the system’s dimmer switch interface in order to reduce the amount of power consumed to drive the transformer. According to the example of FIG. 3, the illumination system 300 may include a dimmer switch 310, a light fixture 120, and a dimmer switch interface 330 coupling the dimmer switch 310 to the light fixture 320.

[0044] The dimmer switch 310 may be a 0-10V dimmer switch and/or any other suitable type of dimmer switch. The dimmer switch 310 may include a variable resistor (e.g., a potentiometer), and or any suitable type of device that is capable of placing a variable load between terminals T 1 of the dimmer switch interface 330. Additionally or alternatively, the dimmer switch 310 may include any suitable type of semiconductor device that is capable of changing the voltage between the terminals T1 of the dimmer switch interface 330. Stated succinctly, according to aspects of the disclosure, the dimmer switch 310 may be any suitable type of device that is capable of generating a voltage signal that indicates a desired level of brightness for the light output from the light fixture 320.

[0045] In some implementations, the dimmer switch 310 may include a light sensor that is configured to measure the level of ambient light in the vicinity of the light fixture 320 and generate a voltage signal based on the measured level of ambient light. Additionally or alternatively, in some implementations, the dimmer switch 310 may include a knob or a slider which can be used to actuate a potentiometer that is part of the dimmer switch 310. Additionally or alternatively, the dimmer switch 310 may include a wireless receiver {e.g., a ZigBee gateway, a WiFi receiver, a remote control receiver, etc.) that is capable of receiving an indication of a desired brightness level from a remote device {e.g., a user’s smartphone or remote control) and generating a corresponding voltage signal based on the indication.

[0046] The light fixture 320 may include any suitable type of light fixture. The light fixture

320 may include a driver 322 and a light source 324 that is powered using a signal PWR. The light source 324 may include any suitable type of light source, such as a fluorescent light source, an incandescent light source, and/or one or more light emitting diodes (LEDs). In the present example, the light source 324 includes one or more LEDs and the signal PWR is a DC or a pulse-width modulated signal that is generated by the driver 322 based on a signal DIM received by the driver 322 from the dimmer switch interface 330.

[0047] Signal DIM may be a voltage signal. The level of the signal DIM may determine the

DC magnitude and/or the duty cycle of the signal PWR. If the signal DIM has a first level (e.g., 2V), the driver 322 may impart a first DC magnitude and/or a first duty cycle on the signal PWR. By contrast, if the signal DIM has a second level (e.g., 5V), the driver 322 may impart a second DC magnitude and/or a second duty cycle on the signal PWR that are different from those for the first DIM level. As can be readily appreciated, the DC magnitude and/or the duty cycle of the signal PWR determines the amount of current delivered to the light source 324, which in turn may determine the brightness of the light output from the light source 324.

[0048] The dimmer switch interface 330 may provide isolation between the light fixture 320 and the dimmer switch 310 mainly to protect human beings operating the dimmer switch from electrical shock. The dimmer switch interface 330 may include a converter circuit 332 that is coupled to a converter circuit 334 via a transformer 336. The transformer 336 may be driven with an intermittent current signal S1 produced by a current source 338. The operation of the current source 338 and the waveform of the intermittent current signal S1 are discussed in additional detail further below.

[0049] The transformer 336 may include a winding W1 and a winding W2 that is magnetically coupled to the winding W1. The winding W1 may be electrically coupled to the light fixture 320 {e.g., via the converter circuit 332). The winding W2 may be electrically coupled to the dimmer switch 310 {e.g., via the converter circuit 334). In some implementations, the winding W2 may be electrically coupled to the terminals T1 of the dimmer switch interface 330 (e.g., via the converter circuit 334). In such instances, the dimmer switch 310 may be also coupled to the terminals T1 to complete the electrical connection between the dimmer switch 310 and the winding W2. Additionally or alternatively, in some implementations, the winding W1 may be electrically coupled to the terminals T2 of the dimmer switch interface 330 (e.g., via the converter circuit 332). In such instances, the driver 322 may also be coupled to the terminals T2 of the dimmer switch interface 330 to receive the signal DIM for controlling the brightness of the light source 324.

[0050] In operation, the winding W2 carries the dimming control information from the dimmer switch 310 via the converter circuit 334, which also converts the voltage across the winding W2 into a DC current to supply the dimmer switch 310. As noted above, the voltage across the winding W2 may be generated, at least in part, by the dimmer switch 310. Furthermore, the voltage across the winding W2 may be transferred to the winding W1 of the transformer 336 through magnetic coupling, and converted by the converter circuit 332 into the voltage signal DIM. The voltage signal DIM may then be used by the driver 322 of the light fixture 320 to adjust the brightness of the light fixture 320. According to aspects of the disclosure, the converter circuit 332 may include any suitable electronic circuit that is configured to produce a DC signal based on an AC signal received from the winding W1. Furthermore, according to aspects of the disclosure, the converter circuit 334 may include any suitable electronic circuit that is configured to form a desired AC signal on the winding W2.

[0051] As noted above, the current source 338 may power the transformer 336 with an intermittent current signal S1. The signal S1 may be an alternating current signal. As illustrated in FIG. 4, the signal S1 may be cyclical in nature. Each cycle 419 of the signal S1 may include a portion 413 during which the signal S1 has a first current level, and a portion 417 during which the signal S1 has a second current level. The second current level may be higher than the first current level. For example, in some implementations, the first current level may be 0A and the second current level may have any value that is greater than 0A.

[0052] The frequency at which the signal S1 is switched to the second current level may be referred to as burst frequency. In some implementations, the signal S1 may have a burst frequency of 1 Hz. However, alternative implementations are possible in which the signal S1 has any suitable frequency {e.g, 5Hz, 10Hz, 0.5Hz, etc.)

[0053] When the signal S1 is at the first current level, the transformer 336 may be switched off (or operating in a reduced power consumption mode). When the signal S1 is at the second current level, the transformer 336 may be switched on and/or operating in a normal power consumption mode. In some implementations, by driving the transformer 336 with an intermittent current signal, the current source 338 may intermittently switch on and off the transformer 336. This in turn may cause the transformer 336 to be powered for only a fraction of the time for which the dimmer switch interface 330 is energized (or used), resulting in a reduced power consumption.

[0054] In some implementations, the signal S1 may be a PWM signal that is generated by intermittently changing its duty cycle. For example, during the portion 413 of each cycle 419, the current source 338 may switch the duty cycle of the signal S1 to a first value {e.g., 0%). As another example, during the portion 417 of each cycle 419, the current source 338 may switch the duty cycle of the signal S1 to a second value that is greater than the first value {e.g., 50%).

[0055] The duration of each cycle 419 of the signal S1 may determine the response time of the dimmer switch 310. As noted above, in some implementations, the duration of each cycle 419 may be 1 second. In such instances, the duration of each portion 413 of the cycle 419 may be 900 ms, and the duration of each portion 417 of the cycle 419 may be 100 ms. Alternatively, in some implementations, the duration of each portion 413 may be 980 ms and the duration of each portion 417 may be 20ms. Stated succinctly, the present disclosure is not limited to any specific duration for the portions 413 and 417 and/or the cycle 419.

[0056] In some implementations, the signal S1 may be generated based on a control signal CTRL that is supplied to the current source 338 by a control circuit 340. The control circuit 340 may include any suitable type of control circuit. For example, in some implementations, the control circuit may be a square wave generator and/or another type of signal generator. Additionally or alternatively, in some implementations, the control circuit 340 may be a low-power processor and/or a general purpose processor {e.g., an ARM-based processor) capable of executing logical operations, such as comparisons and branches. Additionally or alternatively, in some implementations, the control circuit 340 may include a Field-Programmable Gate Array (FPGA) or an Application-Specific Integrated Circuit (ASIC). Additionally or alternatively, in some implementations, the control circuit 340 may be configured to execute one or more processor- executable instructions which when executed by the control circuit 340 cause the control circuit 340 to perform the process 700, which is discussed further below with respect to FIG. 7. The processor- executable instructions may be stored in a memory (not shown) that is part of the dimmer switch interface 330 and/or the control circuit 340. Additionally or alternatively, the processor-executable instructions may be stored in a non-transitory computer-readable medium, such as a Secure Digital (SD) card. Although the control circuit 340 and the current source 338 are depicted separate elements, it will be understood that alternative implementations are possible in which the control circuit 340 and the current source 338 are integral with one another.

[0057] As illustrated in FIG. 5, the control signal CTRL may be a DC square wave having a cycle 510. Each cycle 510 may have a portion 512 in which the signal CTRL has a first duty cycle, and a portion 514 in which the signal CTRL has a second duty cycle that is greater than the first duty cycle. For example, in some implementations, the first duty cycle may be 0% and the second duty cycle may be 50%. In some implementations, each portion 512 of the control signal CTRL may have the same duration as each portion 413 of the current signal S1. Additionally or alternatively, in some implementations, each portion 514 of the control signal CTRL may have the same duration as each portion of the 417 of the current signal S1. The manner in which the control signal CTRL is used to generate the current signal S1 is discussed further below with respect to FIG. 6.

[0058] FIG. 6 is a diagram illustrating the internal structure of the current source 338 in further detail, according to aspects of the disclosure. As illustrated, the current source 338 may include a DC voltage source V1 and a Metal Oxide Semiconductor Field-Effect Transistor (MOSFET) Q3. The control signal CTRL, which is generated by the control circuit 340, may be applied at the gate of MOSFET Q3. The drain of MOSFET Q3 may be coupled to the respective bases of an NPN transistor Q1 and a PNP transistor Q2. Moreover, the collector of transistor Q1 may be coupled to the positive terminal of voltage source V1 {e.g., +12V), and the collector of transistor Q2 may be coupled to the negative terminal of the voltage source V1 {e.g., 0V). The emitters of transistors Q1 and Q2 may be coupled to one another at node N3. A resistor R5 and a capacitor C4 may be coupled in series to the node N3, as shown.

[0059] MOSFET Q3 may be switched on when the signal CTRL is high and switched off when the signal CTRL is low. When MOSFET Q3 is switched off, resistor R4 may forward-bias NPN transistor Q1 and reverse-bias PNP transistor Q2, turning on NPN transistor Q1 and tuning off PNP transistor Q2. When transistor Q1 is turned on and the PNP transistor Q2 is turned off, a high voltage close to the positive terminal voltage of V1 {e.g., +12V) may appear at the node N3, as a result of the electrical path spanning between the positive terminal of the voltage source V1 and node N3 becoming closed. When MOSFET Q3 is switched on, the common base of transistors Q1 and Q2 is pulled down, turning off NPN transistor Q1 and turning on PNP transistor Q2. When transistor Q1 is turned off and the PNP transistor Q2 is turned on, a low voltage close to the negative terminal voltage of V1 {e.g., 0V) may appear at the node N3, as a result of the electrical path spanning between the negative terminal of the voltage source V1 and node N3 becoming closed. In other words, by applying the signal CTRL at the gate of MOSFET Q3 gate, the control circuit 340 may cause a square wave DC voltage at the frequency of the control signal CTRL to appear at the node N3. Capacitor C4 may block the DC component of the DC square wave, turning it into a square AC voltage wave.

[0060] According to the example discussed with respect to FIGS. 3-6, the current source

338 may be configured to power the transformer 336 with intermittent current at all times. However, alternative implementations are possible, in which the current source 338 is configured to supply the transformer 336 with intermittent current only when the dimmer switch 310 is in standby mode. In such instances, when the dimmer switch 310 is not in standby mode, the current source 338 may be configured to supply the transformer 336 with continuous current.

[0061] According to aspects of the disclosure, the dimmer switch 310 may be in standby mode when it generates a voltage signal {e.g., 0V, 10V, etc.) which causes the driver 322 to turn off the light source 324 completely {e.g., by cutting the supply of current to the light source 324). Additionally or alternatively, the dimmer switch 310 may be considered to be in standby mode when it generates a voltage signal that is less than (or greater than) a predetermined threshold. For example, a manually operated dimmer switch may be in standby mode when the knob on the dimmer switch is turned all the way in one direction.

[0062] According to aspects of the disclosure, being able to supply the transformer 336 with intermittent current when the dimmer switch 310 is in standby mode may help improve the energy efficiency of the illumination system 300. For example, in some implementations, switching the transformer 336 with an intermittent current supply with a duty cycle of 10% may reduce the power consumption by 90%. This reduction may be significant in jurisdictions where the illumination system 300 is required to comply with laws and regulations that impose stringent standby power limits on illumination systems.

[0063] FIG. 7 is a flowchart of an example of a process 700 for selectively switching the transformer with an intermittent current supply when the dimmer switch 310 is put in standby mode, according to aspects of the disclosure.

[0064] At step 710, the control circuit 340 detects the voltage level of the signal DIM. In some implementations, the control circuit 340 may detect the voltage level of the signal DIM by using an analog-to-digital converter to sample the signal DIM.

[0065] At step 720, the control circuit 340 detects whether dimmer switch 310 is in standby mode based on the level of the signal DIM. In some implementations, the control circuit 340 may compare the level of the signal DIM to a predetermined threshold to detect whether the dimmer switch 310 is in standby mode. According to one particular example, when the level of the signal DIM is below a threshold, the control circuit 340 may detect that the dimmer switch 310 is in standby mode and proceed to step 740. According to the same example, when the level of the signal DIM is above the threshold, the control circuit 340 may detect that the dimmer switch 310 is not in standby mode, and proceed to step 730. Although in the present example the control circuit 340 detects that the dimmer switch 310 is in standby mode when the level of the signal DIM is below a threshold, alternative implementations are possible in which the control circuit 340 detects that the dimmer switch 310 is in standby mode when the level of the signal DIM is above a threshold.

[0066] At step 730, the control circuit 340 supplies a continuous current to the transformer

336. To supply intermittent current to the transformer 336, the control circuit 340 may provide a first control signal to the current source 338 which causes the current source 338 to output a continuous current. More particularly, the control circuit 340 may generate a control signal 810, which is shown in FIG. 8. As illustrated, the control signal 810 may be a square wave having a constant duty cycle. When the control signal 810 is supplied to the current source 338, the current source 338 may generate a continuous alternating current signal 820. As illustrated in FIG. 8, the current signal 820 may be the same or similar to the signal SO which is discussed above with respect to FIG. 2.

[0067] At step 740, the control circuit 340 supplies an intermittent current to the transformer 336. To supply continuous current to the transformer 336, the control circuit 340 may provide a second control signal to the current source 338 which causes the current source to output an intermittent current. More particularly, the control circuit 340 may supply the current source 338 with a control signal 910, which is shown in FIG. 9. As illustrated, the control signal 910 may be the same or similar to the control signal CTRL which is discussed above with respect to FIGS. 3-6. When the current source 338 is supplied with the control signal 910, the current source 338 may output to the transformer 336 an intermittent alternating current signal 920, which is also shown in FIG. 9. As illustrated, the alternating current signal 920 may be the same or similar to the signal S1 , which is discussed above with respect to FIGS. 3-6.

[0068] FIGS. 1-9 are provided as an example only. At least some of the elements discussed with respect to these figures can be arranged in different order, combined, and/or altogether omitted. For example, although in the example of FIG. 6, the transistors Q1 and Q2 are switched by a MOSFET transistor, alternative implementations are possible in which any other suitable type of switching devices is used instead, such as a solid-state relay, a PMOS transistor, etc. Furthermore, although in the present example, PNP and NPN transistors are used to close different electrical paths between voltage source V1 of the current source 338, alternative implementations are possible in which any other suitable type of switching device is used instead, such as a solid-state relay, a PMOS transistor, etc. The voltage source V1 may include any suitable type of voltage. For example, the voltage source may be a power connector. As another example, the voltage source may be a power adapter configured to convert AC mains voltage to DC voltage. Although the dimmer switch interface 330 and the driver 322 are represented as separate elements, it will be understood that in practice the dimmer switch interface 330 and the driver 322 may often be integral with one another.

[0069] FIG. 10 is a top view of an electronics board 31 1 for an integrated LED lighting system according to one embodiment. In alternative embodiments, two or more electronics boards may be used for the LED lighting system. For example, the LED array may be on a separate electronics board, or the sensor module may be on a separate electronics board. In the illustrated example, the electronics board 31 1 includes a power module 312, a sensor module 314, connectivity and control module 316 and an LED attach region 318 reserved for attachment of an LED array to a substrate 321. The dimmer switch interface 330 of Fig. 3 may be part of the power module 312 or may be external to the electronics board 318 and may provide input to the power module 312.

[0070] The substrate 321 may be any board capable of mechanically supporting, and providing electrical coupling to, electrical components, electronic components and/or electronic modules using conductive connecters, such as tracks, traces, pads, vias, and/or wires. The substrate 321 may include one or more metallization layers disposed between, or on, one or more layers of non-conductive material, such as a dielectric composite material. The power module 312 may include electrical and/or electronic elements. In an example embodiment, the power module 312 includes an AC/DC conversion circuit, a DC/DC conversion circuit, a dimming circuit, and an LED driver circuit.

[0071] The sensor module 314 may include sensors needed for an application in which the

LED array is to be implemented. Example sensors may include optical sensors (e.g., IR sensors and image sensors), motion sensors, thermal sensors, mechanical sensors, proximity sensors, or even timers. By way of example, LEDs in street lighting, general illumination, and horticultural lighting applications may be turned off/on and/or adjusted based on a number of different sensor inputs, such as a detected presence of a user, detected ambient lighting conditions, detected weather conditions, or based on time of day/night. This may include, for example, adjusting the intensity of light output, the shape of light output, the color of light output, and/or turning the lights on or off to conserve energy. For ARA/R applications, motion sensors may be used to detect user movement. The motion sensors themselves may be LEDs, such as IR detector LEDs. By way of another example, for camera flash applications, image and/or other optical sensors or pixels may be used to measure lighting for a scene to be captured so that the flash lighting color, intensity illumination pattern, and/or shape may be optimally calibrated. In alternative embodiments, the electronics board 31 1 does not include a sensor module.

[0072] The connectivity and control module 316 may include the system microcontroller and any type of wired or wireless module configured to receive a control input from an external device. By way of example, a wireless module may include blue tooth, Zigbee, Z-wave, mesh, WiFi, near field communication (NFC) and/or peer to peer modules may be used. The microcontroller may be any type of special purpose computer or processor that may be embedded in an LED lighting system and configured or configurable to receive inputs from the wired or wireless module or other modules in the LED system (such as sensor data and data fed back from the LED module) and provide control signals to other modules based thereon. The microcontroller may be part of or may include the control circuit 340 of Fig. 3, as disclosed herein. Algorithms implemented by the special purpose processor may be implemented in a computer program, software, or firmware incorporated in a non-transitory computer-readable storage medium for execution by the special purpose processor. Examples of non-transitory computer-readable storage mediums include a read only memory (ROM), a random access memory (RAM), a register, cache memory, and semiconductor memory devices. The memory may be included as part of the microcontroller or may be implemented elsewhere, either on or off the electronics board 31 1.

[0073] The term module, as used herein, may refer to electrical and/or electronic components disposed on individual circuit boards that may be soldered to one or more electronics boards 31 1. The term module may, however, also refer to electrical and/or electronic components that provide similar functionality, but which may be individually soldered to one or more circuit boards in a same region or in different regions.

[0074] FIG. 1 1 A is a top view of the electronics board 31 1 with an LED array 410 attached to the substrate 321 at the LED device attach region 318 in one embodiment. The electronics board 31 1 together with the LED array 410 represents an LED lighting system 400A. Additionally, the power module 312 receives a voltage input at Vin 497 and control signals from the connectivity and control module 316 over traces 418B, and provides drive signals to the LED array 410 over traces 418A. The LED array 410 is turned on and off via the drive signals from the power module 312. In the embodiment shown in Fig. 11 A, the connectivity and control module 316 receives sensor signals from the sensor module 314 over traces 418.

[0075] FIG. 1 1 B illustrates one embodiment of a two channel integrated LED lighting system with electronic components mounted on two surfaces of a circuit board 499. As shown in

FIG. 1 1 B, an LED lighting system 400B includes a first surface 445A having inputs to receive dimmer signals and AC power signals and an AC/DC converter circuit 412 mounted on it. The LED system 400B includes a second surface 445B with the dimmer interface circuit 415, DC-DC converter circuits 440A and 440B, a connectivity and control module 416 (a wireless module in this example) having a microcontroller 472, and an LED array 410 mounted on it. The LED array 410 is driven by two independent channels 41 1 A and 41 1 B. In alternative embodiments, a single channel may be used to provide the drive signals to an LED array, or any number of multiple channels may be used to provide the drive signals to an LED array. For example, FIG. 1 1 E illustrates an LED lighting system 400D having 3 channels and is described in further detail below. The dimmer switch interface 330 of FIG. 3 may be part of the dimmer interface circuit 415 and may provide input to the microcontroller 472.

[0076] The LED array 410 may include two groups of LED devices. In an example embodiment, the LED devices of group A are electrically coupled to a first channel 41 1 A and the LED devices of group B are electrically coupled to a second channel 41 1 B. Each of the two DC-DC converters 440A and 440B may provide a respective drive current via single channels 41 1 A and 41 1 B, respectively, for driving a respective group of LEDs A and B in the LED array 410. The LEDs in one of the groups of LEDs may be configured to emit light having a different color point than the LEDs in the second group of LEDs. Control of the composite color point of light emitted by the LED array 410 may be tuned within a range by controlling the current and/or duty cycle applied by the individual DC/DC converter circuits 440A and 440B via a single channel 41 1 A and 41 1 B, respectively. Although the embodiment shown n FIG. 1 1 B does not include a sensor module (as described in FIG. 10 and Fig. 1 1 A), an alternative embodiment may include a sensor module.

[0077] The illustrated LED lighting system 400B is an integrated system in which the LED array 410 and the circuitry for operating the LED array 410 are provided on a single electronics board. Connections between modules on the same surface of the circuit board 499 may be electrically coupled for exchanging, for example, voltages, currents, and control signals between modules, by surface or sub-surface interconnections, such as traces 431 , 432, 433, 434 and 435 or metallizations (not shown). Connections between modules on opposite surfaces of the circuit board 499 may be electrically coupled by through board interconnections, such as vias and metallizations (not shown).

[0078] FIG. 1 1 C illustrates an embodiment of an LED lighting system where the LED array is on a separate electronics board from the driver and control circuitry. The LED lighting system 400C includes a power module 452 that is on a separate electronics board than an LED module 490. The power module 452 may include, on a first electronics board, an AC/DC converter circuit

412, a sensor module 414, a connectivity and control module 416, a dimmer interface circuit 415 and a DC/DC converter 440. The LED module 490 may include, on a second electronics board, embedded LED calibration and setting data 493 and the LED array 410. Data, control signals and/or LED driver input signals 485 may be exchanged between the power module 452 and the LED module 490 via wires that may electrically and communicatively couple the two modules. The embedded LED calibration and setting data 493 may include any data needed by other modules within a given LED lighting system to control how the LEDs in the LED array are driven. In one embodiment, the embedded calibration and setting data 493 may include data needed by the microcontroller to generate or modify a control signal that instructs the driver to provide power to each group of LEDs A and B using, for example, pulse width modulated (PWM) signals. In this example, the calibration and setting data 493 may inform the microcontroller 472 as to, for example, the number of power channels to be used, a desired color point of the composite light to be provided by the entire LED array 410, and/or a percentage of the power provided by the AC/DC converter circuit 412 to provide to each channel. As disclosed herein, the dimmer switch interface 330 of Fig. 3 may be part of the dimmer interface circuit 415.

[0079] FIG. 1 1 D illustrates a block diagram of an LED lighting system having the LED array together with some of the electronics on an electronics board separate from the driver circuit. An LED system 400D includes a power conversion module 483 and an LED module 481 located on a separate electronics board. The power conversion module 483 may include the AC/DC converter circuit 412, the dimmer interface circuit 415 and the DC-DC converter circuit 440, and the LED module 481 may include the embedded LED calibration and setting data 493, LED array 410, sensor module 414 and connectivity and control module 416. The power conversion module 483 may provide LED driver input signals 485 to the LED array 410 via a wired connection between the two electronics boards.

[0080] FIG. 11 E is a diagram of an example LED lighting system 400D showing a multichannel LED driver circuit. In the illustrated example, the system 400D includes a power module 452 and an LED module 481 that includes the embedded LED calibration and setting data 493 and three groups of LEDs 494A, 494B and 494C. While three groups of LEDs are shown in Fig. 11 E, one of ordinary skill in the art will recognize that any number of groups of LEDs may be used consistent with the embodiments described herein. Further, while the individual LEDs within each group are arranged in series, they may be arranged in parallel in some embodiments.

[0081] The LED array 491 may include groups of LEDs that provide light having different color points. For example, the LED array 491 may include a warm white light source via a first group of LEDs 494A, a cool white light source via a second group of LEDs 494B and a neutral while light source via a third group of LEDs 494C. The warm white light source via the first group of LEDs 494A may include one or more LEDs that are configured to provide white light having a correlated color temperature (CCT) of approximately 2700K. The cool white light source via the second group of LEDs 494B may include one or more LEDs that are configured to provide white light having a CCT of approximately 6500K. The neutral white light source via the third group of LEDs 494C may include one or more LEDs configured to provide light having a CCT of approximately 4000K. While various white colored LEDs are described in this example, one of ordinary skill in the art will recognize that other color combinations are possible consistent with the embodiments described herein to provide a composite light output from the LED array 491 that has various overall colors.

[0082] The power module 452 may include a tunable light engine (not shown), which may be configured to supply power to the LED array 491 over three separate channels (indicated as LED1 +, LED2+ and LED3+ in Fig. 1 1 E). More particularly, the tunable light engine may be configured to supply a first PWM signal to the first group of LEDs 494A such as warm white light source via a first channel, a second PWM signal to the second group of LEDs 494B via a second channel, and a third PWM signal to the third group of LEDs 494C via a third channel. Each signal provided via a respective channel may be used to power the corresponding LED or group of LEDs, and the duty cycle of the signal may determine the overall duration of on and off states of each respective LED. The duration of the on and off states may result in an overall light effect which may have light properties (e.g., correlated color temperature (CCT), color point or brightness) based on the duration. In operation, the tunable light engine may change the relative magnitude of the duty cycles of the first, second and third signals to adjust the respective light properties of each of the groups of LEDs to provide a composite light with the desired emission from the LED array 491. As noted above, the light output of the LED array 491 may have a color point that is based on the combination (e.g., mix) of the light emissions from each of the groups of LEDs 494A, 494B and 494C.

[0083] In operation, the power module 452 may receive a control input generated based on user and/or sensor input and provide signals via the individual channels to control the composite color of light output by the LED array 491 based on the control input. In some embodiments, a user may provide input to the LED system for control of the DC/DC converter circuit by turning a knob or moving a slider that may be part of, for example, a sensor module (not shown). Additionally or alternatively, in some embodiments, a user may provide input to the LED lighting system 400D using a smartphone and/or other electronic device to transmit an indication of a desired color to a wireless module (not shown).

[0084] FIG. 12 shows an example system 550 which includes an application platform 560,

LED lighting systems 552 and 556, and secondary optics 554 and 558. The LED lighting system 552 produces light beams 561 shown between arrows 561 a and 561 b. The LED lighting system 556 may produce light beams 562 between arrows 562a and 562b. In the embodiment shown in FIG. 12, the light emitted from LED lighting system 552 passes through secondary optics 554, and the light emitted from the LED lighting system 556 passes through secondary optics 558. In alternative embodiments, the light beams 561 and 562 do not pass through any secondary optics. The secondary optics may be or may include one or more light guides. The one or more light guides may be edge lit or may have an interior opening that defines an interior edge of the light guide. LED lighting systems 552 and/or 556 may be inserted in the interior openings of the one or more light guides such that they inject light into the interior edge (interior opening light guide) or exterior edge (edge lit light guide) of the one or more light guides. LEDs in LED lighting systems 552 and/or 556 may be arranged around the circumference of a base that is part of the light guide. According to an implementation, the base may be thermally conductive. According to an implementation, the base may be coupled to a heat-dissipating element that is disposed over the light guide. The heat- dissipating element may be arranged to receive heat generated by the LEDs via the thermally conductive base and dissipate the received heat. The one or more light guides may allow light emitted by LED lighting systems 552 and 556 to be shaped in a desired manner such as, for example, with a gradient, a chamfered distribution, a narrow distribution, a wide distribution, an angular distribution, or the like.

[0085] In example embodiments, the system 550 may be a mobile phone of a camera flash system, indoor residential or commercial lighting, outdoor light such as street lighting, an automobile, a medical device, ARA/R devices, and robotic devices. The integrated LED lighting system 400A shown in FIG. 1 1 A, the integrated LED lighting system 400B shown in FIG. 1 1 B, the LED lighting system 400C shown in FIG. 1 1 C, and the LED lighting system 400D shown in FIG. 11 D illustrate LED lighting systems 552 and 556 in example embodiments.

[0086] In example embodiments, the system 550 may be a mobile phone of a camera flash system, indoor residential or commercial lighting, outdoor light such as street lighting, an automobile, a medical device, AR/VR devices, and robotic devices. The integrated LED lighting system 400A shown in FIG. 1 1 A, the integrated LED lighting system 400B shown in FIG. 1 1 B, the LED lighting system 400C shown in FIG. 1 1 C, and the LED lighting system 400D shown in FIG. 11 D illustrate LED lighting systems 552 and 556 in example embodiments.

[0087] The application platform 560 may provide power to the LED lighting systems 552 and/or 556 via a power bus via line 565 or other applicable input, as discussed herein. Further, application platform 560 may provide input signals via line 565 for the operation of the LED lighting system 552 and LED lighting system 556, which input may be based on a user input/preference, a sensed reading, a pre-programmed or autonomously determined output, or the like. One or more sensors may be internal or external to the housing of the application platform 560.

[0088] In various embodiments, application platform 560 sensors and/or LED lighting system 552 and/or 556 sensors may collect data such as visual data (e.g., LIDAR data, IR data, data collected via a camera, etc.), audio data, distance based data, movement data, environmental data, or the like or a combination thereof. The data may be related a physical item or entity such as an object, an individual, a vehicle, etc. For example, sensing equipment may collect object proximity data for an ADAS/AV based application, which may prioritize the detection and subsequent action based on the detection of a physical item or entity. The data may be collected based on emitting an optical signal by, for example, LED lighting system 552 and/or 556, such as an IR signal and collecting data based on the emitted optical signal. The data may be collected by a different component than the component that emits the optical signal for the data collection. Continuing the example, sensing equipment may be located on an automobile and may emit a beam using a vertical-cavity surface-emitting laser (VCSEL). The one or more sensors may sense a response to the emitted beam or any other applicable input.

[0089] In example embodiment, application platform 560 may represent an automobile and

LED lighting system 552 and LED lighting system 556 may represent automobile headlights. In various embodiments, the system 550 may represent an automobile with steerable light beams where LEDs may be selectively activated to provide steerable light. For example, an array of LEDs may be used to define or project a shape or pattern or illuminate only selected sections of a roadway. In an example embodiment, Infrared cameras or detector pixels within LED lighting systems 552 and/or 556 may be sensors that identify portions of a scene (roadway, pedestrian crossing, etc.) that require illumination.

[0090] FIG. 13A is a diagram of an LED device 200 in an example embodiment. The LED device 200 may include a substrate 202, an active layer 204, a wavelength converting layer 206, and primary optic 208. In other embodiments, an LED device may not include a wavelength converter layer and/or primary optics. Individual LED devices 200 may be included in an LED array in an LED lighting system, such as any of the LED lighting systems described above.

[0091] As shown in FIG. 13A, the active layer 204 may be adjacent to the substrate 202 and emits light when excited. Suitable materials used to form the substrate 202 and the active layer 204 include sapphire, SiC, GaN, Silicone and may more specifically be formed from a lll-V semiconductors including, but not limited to, AIN, AIP, AIAs, AlSb, GaN, GaP, GaAs, GaSb, InN, InP, InAs, InSb, ll-VI semiconductors including, but not limited to, ZnS, ZnSe, CdSe, CdTe, group IV semiconductors including, but not limited to Ge, Si, SiC, and mixtures or alloys thereof. [0092] The wavelength converting layer 206 may be remote from, proximal to, or directly above active layer 204. The active layer 204 emits light into the wavelength converting layer 206. The wavelength converting layer 206 acts to further modify wavelength of the emitted light by the active layer 204. LED devices that include a wavelength converting layer are often referred to as phosphor converted LEDs (“PCLED”). The wavelength converting layer 206 may include any luminescent material, such as, for example, phosphor particles in a transparent or translucent binder or matrix, or a ceramic phosphor element, which absorbs light of one wavelength and emits light of a different wavelength.

[0093] The primary optic 208 may be on or over one or more layers of the LED device 200 and allow light to pass from the active layer 204 and/or the wavelength converting layer 206 through the primary optic 208. The primary optic 208 may be a lens or encapsulate configured to protect the one or more layers and to, at least in part, shape the output of the LED device 200. Primary optic 208 may include transparent and/or semi-transparent material. In example embodiments, light via the primary optic may be emitted based on a Lambertian distribution pattern. It will be understood that one or more properties of the primary optic 208 may be modified to produce a light distribution pattern that is different than the Lambertian distribution pattern.

[0094] FIG. 13B shows a cross-sectional view of a lighting system 220 including an LED array 210 with pixels 201 A, 201 B, and 201 C, as well as secondary optics 212 in an example embodiment. The LED array 210 includes pixels 201 A, 201 B, and 201 C each including a respective wavelength converting layer 206B active layer 204B and a substrate 202B. The LED array 210 may be a monolithic LED array manufactured using wafer level processing techniques, a micro LED with sub-500 micron dimensions, or the like. Pixels 201 A, 201 B, and 201 C, in the LED array 210 may be formed using array segmentation, or alternatively using pick and place techniques.

[0095] The spaces 203 shown between one or more pixels 201 A, 201 B, and 201 C of the

LED devices 200B may include an air gap or may be filled by a material such as a metal material which may be a contact (e.g., n-contact).

[0096] The secondary optics 212 may include one or both of the lens 209 and waveguide

207. It will be understood that although secondary optics are discussed in accordance with the example shown, in example embodiments, the secondary optics 212 may be used to spread the incoming light (diverging optics), or to gather incoming light into a collimated beam (collimating optics). In example embodiments, the waveguide 207 may be a concentrator and may have any applicable shape to concentrate light such as a parabolic shape, cone shape, beveled shape, or the like. The waveguide 207 may be coated with a dielectric material, a metallization layer, or the like used to reflect or redirect incident light. In alternative embodiments, a lighting system may not include one or more of the following: the converting layer 206B, the primary optics 208B, the waveguide 207 and the lens 209.

[0097] Lens 209 may be formed form any applicable transparent material such as, but not limited to SiC, aluminum oxide, diamond, or the like or a combination thereof. Lens 209 may be used to modify the a beam of light input into the lens 209 such that an output beam from the lens 209 will efficiently meet a desired photometric specification. Additionally, lens 209 may serve one or more aesthetic purpose, such as by determining a lit and/or unlit appearance of the LED devices 201 A, 201 B and/or 201 C of the LED array 210.

[0098] Having described the embodiments in detail, those skilled in the art will appreciate that, given the present description, modifications may be made to the embodiments described herein without departing from the spirit of the inventive concept. Therefore, it is not intended that the scope of the invention be limited to the specific embodiments illustrated and described.

Claims

1. An apparatus, comprising:

a dimmer switch interface comprising:

(i) a transformer having a first winding that is magnetically coupled to a second winding, the first winding being electrically coupled to a pair of terminals, and

(ii) a current source configured to supply the second winding with an intermittent alternating current, the intermittent alternating current having a cyclical waveform, each cycle of the waveform including a first portion during which the current is fixed at a predetermined fixed low value and a second portion during which the current alternates between a high value and a low value.

2. The apparatus of claim 1 , wherein the transformer is intermittently switched on and off as a result of being powered with the intermittent alternating current.

3. The apparatus of claim 1 , wherein the first portion of any cycle has a longer duration than the second portion of the same cycle.

4. The apparatus of claim 1 , wherein the current source is configured to provide the intermittent alternating current to the transformer only when a dimmer switch is in a standby mode, the standby mode being one in which the dimmer switch at least in part generates a voltage signal having a value that falls within a predetermined range.

5. The apparatus of claim 1 , wherein the dimmer switch interface further includes a control circuit arranged to receive a signal over the pair of terminals for connecting the dimmer switch interface to a dimmer switch, the control circuit being configured to:

cause the current source to provide the intermittent alternating current to the transformer when the signal has a first value; and

cause the current source to provide a continuous alternating current to the transformer when the signal has a second value.

6. The apparatus of claim 1 , wherein an intermittent alternating current duty cycle of about 10% reduces the power consumption by at least 80%.

7. A system comprising:

a dimmer switch; and

a dimmer switch interface coupled to the dimmer switch, the dimmer switch interface comprising:

(i) a transformer having a first winding that is magnetically coupled to a second winding, the first winding being electrically coupled to the dimmer switch, and (ii) a current source configured to supply the second winding with an intermittent alternating current, the intermittent alternating current having a cyclical waveform, each cycle of the waveform including a first portion during which the intermittent alternating current is fixed at a predetermined fixed low value, and a second portion during which the intermittent alternating current alternates between a high value and a low value.

8. The system of claim 7, wherein the transformer is intermittently switched on and off as a result of being powered with the intermittent alternating current.

9. The system of claim 7, wherein the first portion of any cycle has a longer duration than the second portion of the same cycle.

10. The system of claim 7, wherein the current source is configured to provide the intermittent alternating current to the transformer only when the dimmer switch is in a standby mode, the standby mode being one in which the dimmer switch generates a voltage signal which causes a driver of a light fixture to turn off a light source of the light fixture.

1 1. The system of claim 7, wherein the dimmer switch interface further includes a control circuit arranged to receive a signal generated at least in part by the dimmer switch, the control circuit being configured to:

12. The system of claim 7, wherein an intermittent alternating current duty cycle of about 10% reduces the power consumption by at least 80%.

13. A system, comprising:

a light fixture comprising a driver coupled to a light source; and

a dimmer switch coupled to the driver via a dimmer switch interface, the dimmer switch interface including:

(i) a transformer having a first winding that is magnetically coupled to a second winding, the first winding being electrically coupled to the dimmer switch, and the second winding being electrically coupled to the driver of the light fixture, and

(ii) a current source configured to supply the second winding with an intermittent alternating current, the intermittent alternating current having a cyclical waveform, each cycle of the waveform including a first portion during which the intermittent alternating current is fixed at a predetermined fixed low value, and a second portion during which the intermittent alternating current alternates between a high value and a low value.

14. The system of claim 13, wherein the transformer is intermittently switched on and off as a result of being powered with the intermittent alternating current.

15. The system of claim 13, wherein the first portion of any cycle has a longer duration than the second portion of the same cycle.

16. The system of claim 13, wherein the current source is configured to provide the intermittent alternating current to the transformer only when the dimmer switch is in a standby mode, the standby mode being one in which the dimmer switch generates a voltage signal which causes the driver of the light fixture to turn off the light source of the light fixture.

17. The system of claim 13, wherein the dimmer switch interface further includes a control circuit arranged to receive a signal generated at least in part by the dimmer switch, the control circuit being configured to:

18. The system of claim 13, wherein an intermittent alternating current duty cycle of about 10% reduces the power consumption by at least 80%.

19. A method comprising:

detecting a voltage level of a DIM signal;

determining if a dimmer switch is in a standby mode;

supplying a transformer with an intermittent alternating current if the dimmer switch is determined to be in a standby mode; and

supplying the transformer with an continuous current if the dimmer switch is determined to not be in a standby mode.

20. The method of claim 19, wherein the intermittent alternating current comprises a cyclical waveform, each cycle of the waveform including a first portion during which the intermittent alternating current is fixed at a predetermined fixed low value, and a second portion during which the intermittent alternating current alternates between a high value and a low value.