KR20210112391A - Hybrid driving method for RGB color tuning - Google Patents

Abstract

The device provides an analog current dividing circuit configured to divide an input current into a first current and a second current, and a first current to a first color of the three colors of the LEDs simultaneously during a first portion of a period and the three colors of the LEDs provide a second current to a second color of the LEDs and provide a first current to a second color of the three colors of the LEDs and provide a second current to a third color of the three colors of the LEDs simultaneously during a second portion of the period of time and a plurality of switches for providing a first current to a first color of the three colors of the LEDs and a second current to a third color of the three colors of the LEDs simultaneously during a third portion of the period of time. contains an array.

Description

Hybrid driving method for RGB color tuning

This application claims the benefit of priority to U.S. Patent Application Serial No. 16/258,193, filed January 25, 2019, and claims priority to European Patent Application No. 19165527.3, filed March 27, 2019. Priority is claimed to U.S. Patent Application Serial No. 16/543,230, filed on August 16, 2019, which claims benefit, each of which is incorporated herein by reference in its entirety.

A light emitting diode (LED) is a semiconductor light source that emits light when an electric current flows through it. When an appropriate current is applied to the LED, electrons can recombine with electron holes in the LED, releasing energy in the form of photons. This effect is called electroluminescence. The color of the emitted light corresponding to the energy of the photon is determined by the energy bandgap of the semiconductor. White light is obtained by using multiple semiconductors or layers of wavelength converting material on semiconductor devices.

An LED circuit, also referred to as an LED driver, is an electrical circuit used to power an LED by providing an appropriate current. This circuit must provide enough current for the LED to emit light at the required brightness, but limit the current to prevent damage to the LED. Since the voltage drop across the LED is approximately constant over a wide range of operating currents, a balance is needed between sufficient current to power the LED and limiting the current to prevent damage. This causes a small increase in the applied voltage to greatly increase the current.

Combinations of LEDs are often used in Red-Green-Blue (RGB) color tuning schemes. The requirements of including additional LEDs and powering each LED within RGB color tuning add additional complexity to the driving scheme for RGB LEDs.

The device provides an analog current dividing circuit configured to divide an input current into a first current and a second current, and a first current to a first color of the three colors of the LEDs during a first portion of a period while simultaneously providing the three colors of the LEDs provide a second current to a second color of the LEDs and provide a first current to a second color of the three colors of the LEDs during a second portion of the period of time and simultaneously provide a second current to a third color of the three colors of the LEDs and a plurality of switches for providing a first current to a first color of the three colors of the LEDs during a third portion of the period of time and simultaneously providing a second current to a third color of the three colors of the LEDs. contains an array.

A more detailed understanding may be obtained from the following description given by way of example in connection with the accompanying drawings.
1A shows a CIE chromaticity diagram representing a color space.
1B shows a diagram showing different CCTs and their relationship to BBL.
1C shows an exemplary circuit of a hybrid drive circuit for RGB tuning.
1d shows a microcontroller for a computing device to handle complex signal processing with less PCB resources than analog circuits.
FIG. 1E shows a color chart for the circuit of FIG. 1 with a red LED (or an array of red LEDs) positioned at a central location.
FIG. 1F shows a color chart for the circuit of FIG. 1C with a green LED (or array of green LEDs) disposed in a central position.
1G shows a color chart for the circuit of FIG. 1C with a blue LED (or an array of blue LEDs) positioned at a central location.
1H shows another hybrid drive circuit.
FIG. 1I shows a color chart for the circuit of FIG. 1H with red and blue LEDs (or an array of red LEDs and an array of blue LEDs) driven by analog currents.
1J shows a color chart for the circuit of FIG. 1H with red and green LEDs (or an array of red LEDs and an array of green LEDs) driven by analog currents.
1K shows a color chart for the circuit of FIG. 1H with blue and green LEDs (or an array of blue LEDs and an array of green LEDs) driven by analog currents.
11 shows another hybrid drive circuit.
1M shows a color chart for the circuit of FIG. 1L providing full gamut coverage.
1N shows a hybrid driving method for RGB color tuning driving.
2 is a plan view of an electronic device board for an integrated LED lighting system according to an embodiment.
3A is a top view of an electronics board having an LED array attached to a substrate in an LED device attachment area in one embodiment.
3B 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.
3C is a diagram of an embodiment of an LED lighting system in which the LED array is on a separate electronics board from the driver and control circuitry.
3D is a block diagram of an LED lighting system with an LED array with some of the electronics on the electronics board separated from the driver circuitry.
3E is a diagram of an exemplary LED lighting system illustrating a multi-channel LED driver circuit.
4 is a diagram of an exemplary application system.
5A is a diagram illustrating an LED device.
5B is a diagram illustrating multiple LED devices.

Examples of different light illumination systems and/or light emitting diode (“LED”) implementations will be described more fully below 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 that they are not intended to limit the present disclosure in any way. Like numbers refer to like elements throughout.

Although the terms first, second, third, etc. may be used herein to describe various elements, it will be understood that 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 and listed items.

When an element, such as a layer, region, or substrate, is referred to as being “on” or extending “on” another element, it may be directly on or extend directly onto another element or intervening elements. (intervening elements) may also be present. In contrast, when an element is referred to as being "directly on" or extending "directly onto" another element, intervening elements may not be present. When an element is referred to as being “connected” or “coupled” to another element, one element may be directly connected or coupled to another element and/or another element via one or more intervening elements. It will also be understood that it may be connected to or coupled to In contrast, when an element is referred to as being “directly connected” or “directly coupled” to another element, there are no intervening elements between the element and the other element. It will be understood that these terms are intended to encompass different orientations of elements in addition to any orientation depicted in the figures.

Relative terms such as “below”, “above”, “upper”, “lower”, “horizontal” or “vertical” appear in the drawings. It may be used herein to describe the relationship of one element, layer, or region to another element, layer, or region as shown. 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.

Furthermore, whether the LEDs, LED arrays, electrical components and/or electronic components are housed on one or more than one electronic device board may also depend on design constraints and/or application.

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. Such devices may include light emitting diodes, resonant cavity light emitting diodes, vertical cavity laser diodes, edge emitting lasers, and the like. For example, due to their small size and lower power requirements, LEDs can be attractive candidates for many different applications. For example, they can be used as light sources (eg, flash light and camera flash) for hand-held battery-powered devices such as cameras and cell phones. . These include, for example, automotive lighting, heads up display (HUD) lighting, horticultural lighting, street lighting, torches for video, general lighting (eg home, shop, office and studio lighting, theater/stage lighting and architectural lighting). , augmented reality (AR) lighting, virtual reality (VR) lighting, backlighting for displays, and IR spectroscopy. A single LED can provide less bright light than an incandescent light source, so multi-junction devices or arrays of LEDs (eg, monolithic LED arrays, micro LED arrays, etc.) It can be used for applications where greater brightness is desired or required.

This description specifically describes color using phosphor-converted color LEDs by driving desaturated RGB color LEDs to produce white with high efficiency and high color rendering index (CRI). It relates to a hybrid drive scheme for handling mixing. The forward voltage of direct color LEDs decreases as the dominant wavelength increases. These LEDs are best driven by multi-channel DC/DC converters. A new phosphor-converted color LED targeting high efficiency and CRI has been created, offering new possibilities for correlated color temperature (CCT) tuning applications. The new color LEDs have desaturated (pastel) color points and can be mixed to achieve white with 90 + CRI over a wide CCT range. Other LEDs may have 80 CRI implementations, or even 70 CRI implementations may be used. These possibilities require LED circuits to realize and maximize this potential. At the same time, the control circuit can be compatible with single channel constant current drivers to promote market adoption.

Typically, LED drive circuits are formed using an analog approach or a pulse-width modulation (PWM) approach. In the analog driver, all colors are driven simultaneously. By providing a different current for each LED, each LED is driven independently. Analog drivers cause a color shift, and there is currently no way to shift the current in three ways. Analog drive often results in LEDs of certain colors being driven in a low current mode and other times being driven in a very high current mode. This wide dynamic range presents challenges to sensing and control hardware.

In PWM, each color is switched on sequentially at high speed. Each color is driven by the same current. The blended colors are controlled by changing the duty cycle of each color. That is, one color can be driven twice as long as another color is added to the mixed color. Human vision cannot perceive colors that change very quickly, so light appears to have one single color.

For example, a first LED is driven with current for a certain amount of time, then a second LED is driven with the same current for a certain amount of time, and then a third LED is driven with current for a certain amount of time. The blended colors are controlled by changing the duty cycle of each color. For example, if you have an RGB LED and want a specific output, red can be driven for part of a cycle, green can be driven for a different part of the cycle, and blue can be driven based on the human eye's perception. It is driven for another part of the cycle. Instead of driving the red LED at a lower current, it is driven at the same current for a shorter time. This example demonstrates the shortcomings of PWM where LEDs are poorly utilized resulting in inefficiencies.

Below, a comparison of the two driving schemes is summarized in Table 1 illustrating the advantages and disadvantages of each driving technique. As shown, analog driving provides good LED utilization, sharing of peak current by all colors, and generally good LED efficiency and overall efficiency. PWM provides good color point predictability because all LEDs are driven by peak current and by a relatively simple and efficient controller.

The present drive scheme includes a hybrid scheme to achieve the combined advantages of the analog and PWM approaches described above. The hybrid system splits the input current between the two colors each time, treating the set of two colors as virtual LEDs to overlay the PWM time slicing. This drive method uses the same number of LEDs to achieve the same level of overall efficiency as analog drive while preserving good color predictability. Compared to hybrid drive, PWM drive may require 50% more LEDs to achieve the same efficiency. The advantages of this hybrid drive method are presented in Table 2 below in addition to Table 1. Hybrid drive catches up with analog driver advantages in utilization of LEDs, current rating, LED efficiency and overall efficiency, and embedded PWM driver advantages in color point predictability and controller complexity.

1A shows a CIE chromaticity diagram 1 representing a color space. A color space is a three-dimensional space; That is, color is specified by a set of three numbers that specify the color and brightness of a particular uniform visual stimulus. The three numbers can be the International Commission on Illumination (CIE) coordinates X, Y, and Z, or other values such as hue, saturation, and luminance. Based on the fact that the human eye has three different types of color sensitive cones, the eye's response is best described in terms of these three "tristimulus values".

Chromaticity diagram 1 is a color space projected into a two-dimensional space ignoring brightness. For example, the standard CIE XYZ color space corresponds to a chromaticity space specified by two chromaticity coordinates x, y. Chromaticity is an objective specification of the quality of a color regardless of the luminance of the color. Chromaticity consists of two independent parameters, often designated as hue and saturation. Saturation may alternatively be referred to as saturation, chroma, intensity, or excitation purity. The chromaticity diagram 1 includes colors recognizable by the human eye. Chromaticity diagram 1 uses parameters based on the spectral power distribution (SPD) of light emitted from a colored object and is factorized by the measured sensitivity curves for the human eye. Any color can be precisely represented in two color coordinates x and y planes. The colors that can be matched by combining a given set of three primary colors, i.e., blue, green and red, are expressed in chromaticity by triangle 2 connecting the coordinates for the three colors, i.e. red coordinate 3, green coordinate 4, and blue coordinate 5. represented on the figure. Triangle 2 represents color gamut.

Chromaticity diagram 1 includes a Planckian locus or blackbody line (BBL) 6 . BBL6 is the path or trajectory that the color of an incandescent blackbody takes in a specific chromaticity space as the blackbody temperature changes. It progresses from deep red at low temperatures to orange, yellowish white, white, and finally bluish white at very high temperatures. Generally speaking, the human eye prefers white color points that are not too far from BBL6. The color points above the BBL6 will appear too green, while the color points below will appear too pink.

1B shows a diagram 10 showing different CCTs and their relationship to BBL6. When three primary colors (R, G, B) are used and the two colors are driven simultaneously, three virtual color points (R-G, R-B, G-B) are generated that generate a color gamut 2.1 of this driving method. The new gamut 2.1 is smaller than the old gamut 2. Between 2700K and 4000K, the color line runs below BBL6 in 3 STEP. This deviation is within the viewer's preference for slightly below BBL6 for warm color CCTs. As will be appreciated by those of ordinary skill in the art, the primary color points can be adjusted so that color gamut 2.1 completely surrounds the tunable band of interest. By forcing the current to split between the two colors, efficiency and utilization are improved.

1C shows an exemplary circuit 20 of a hybrid drive circuit for RGB tuning. Circuit 20 includes an LED driver 25 and an analog current divider circuit 21, a multiplexer array 22 and an LED array 23 electrically connected to a voltage regulator 24 that together produce a stabilized current lo do.

The LED array 23 includes one or a plurality of first color LEDs (color 1) 26, one or a plurality of second color LEDs (color 2) LEDs 27 designed to be tuned using a hybrid drive circuit. , and one or a plurality of third color LEDs (color 3) LEDs 28 . In one embodiment of circuit 20, color 1 is green, color 2 is red, and color 3 is blue, although any set of colors may be used for color 1, color 2, and color 3. As will be appreciated, the assignment of colors to particular channels is simply a design choice, and while other designs are contemplated, in order to provide a thorough understanding of the hybrid drive circuit described herein, the present description is Embodiments using 1 LED 26, color 2 LED 27 and color 3 LED 28 are also described, wherein color 1 is described as green, color 2 is described as red, and color 3 is described as blue. can be explained

The circuit 20 comprises an analog current dividing circuit 21 that divides the _{incoming current I 0} into two currents I ₁ , I _{2 .} Such an analog current divider circuit 21 is described in U.S. Patent Application No. 16/145,053 entitled AN ARBITRARY-RATIO ANALOG CURRENT DIVISION CIRCUIT, which is incorporated herein by reference as if set forth in its entirety. do. The analog current dividing circuit 21 may take the form of a drive circuit to provide the same current to each of the two colors. The analog current dividing circuit 21 can resolve any mismatch in forward voltage between different colors of LEDs while allowing precise control of the drive current of each color. Alternatively, the analog current dividing circuit 21 may allow for unequal division of current, which cannot be achieved by simply switching on both strings. As will be appreciated, other analog current dividing circuits may be utilized without departing from the spirit of the present invention. The analog current dividing circuit 21 is provided as an exemplary divider for a thorough understanding of the hybrid drive circuit described herein.

The analog current dividing circuit 21 may be mounted on a printed circuit board (PCB) to operate with the LED driver 25 and the LED array 23 . The LED driver 25 may be a conventional LED driver known in the art. The analog current dividing circuit 21 may allow the LED driver 25 to be used for applications utilizing two or more LED arrays 23 .

Each current channel of the analog current dividing circuit 21 may include a sense resistor. For example, in an embodiment having two current channels, the analog current dividing circuit 21 is a first sense resistor (Rs1) 29 that senses the first voltage of the first current channel 31 at Vsense1 and Vsense2 and a second sense resistor (Rs2) (30) for sensing the second voltage of the second current channel (32). The voltage at Vsense1 represents a current flowing through the first sense resistor Rs1 (29), and the voltage at Vsense2 represents a current flowing through the second sense resistor (Rs2) 30 .

The analog current dividing circuit 21 includes a calculating device 37 . The calculation device 37 is configured to compare the first sense voltage Vsense1 and the second sense voltage Vsense2 to determine the set voltage Vset. If the first sense voltage Vsense1 is lower than the second sense voltage Vsense2, the calculation device 37 is configured to increase Vset. When the first sense voltage Vsense1 device is greater than the second sense voltage Vsense2, the calculation device 37 is configured to decrease the set voltage Vset.

Specifically, the computing device 37 may include an operational amplifier (op amp) 38 , a capacitor 39 between the position of the set voltage Vset and ground, and a resistor 41 in parallel with the capacitor 39 . can The first sense voltage Vsense1 and the second sense voltage Vsense2 are supplied to the op amp 38 . The calculation device 37 may be configured to compare the first sense voltage Vsense1 with the second sense voltage Vsense2 by subtracting the first sense voltage Vsense1 from the second sense voltage Vsense2 . When the op amp 38 is in regulation, the computing device 37 converts the difference between the first sensed voltage Vsense1 and the second sensed voltage Vsense2 into a charging current so that the first sensed voltage Vsense1 becomes the second sensed voltage Vsense2 It may be configured to charge the capacitor 39 to increase the set voltage Vset when less than. The calculating device 37 is configured to convert the difference between the first sense voltage Vsense1 and the second sense voltage Vsense2 into the discharge resistor 41 to reduce the set voltage Vset when the first sense voltage Vsense1 is greater than the second sense voltage Vsense2 can be

Thus, when the first sense voltage Vsense1 is higher than the second sense voltage Vsense2 , the computing device 37 may decrease the set voltage Vset, which in turn powers the first current channel 31 , the first gate Decrease the voltage Vgate1. In other words, when the op amp 38 is in regulation, the first sense voltage Vsense1 is approximately equal to the second sense voltage Vsense2. Thus, during the steady state, the ratio of the current in the first current channel 31 to the current in the second current channel 32 is equal to the value of the second sense resistor Rs2 to the value of the first sense resistor Rs1, and then The equations of are satisfied:

Therefore, when the value of the first sense resistor Rs1 is equal to the value of the second sense resistor Rs2, the current flowing through the first resistor I_Rs1 is equal to the current flowing through the second resistor I_Rs2, and the current dividing circuit 20 is , assuming that the current drawn by the auxiliary circuits, such as supply voltage generation, is negligible, divides the current into two equal parts. It should be noted that, as one of ordinary skill in the art will recognize, the computing device 37 shown in FIG. 1C is one of many possible implementations.

The set voltage Vset may be supplied to a voltage controlled current source that may be implemented as the first op amp 33 . The first op amp 33 may provide a first gate voltage Vgate1 . The first gate voltage Vgate1 may be input to the first transistor 34 used to provide the _{driving current I 1 .} The first transistor 34 may be a conventional metal oxide semiconductor field effect transistor (MOSFET). The first transistor 34 may be an n-channel MOSFET.

The second transistor 35 may provide a driving current 12 . The second transistor 35 may be a conventional MOSFET. The second transistor 35 may be an n-channel MOSFET. The second transistor may be switched on only when the first current channel 31 is in regulation. A second gate voltage Vgate2 may flow through the second transistor 35 .

A second gate voltage Vgate2 may be supplied to the REF input of a shunt regulator 36 . In an embodiment, shunt regulator 36 has an internal reference voltage of 2.5V. When the voltage applied at the REF node is higher than 2.5V, the shunt regulator 36 can sink a large current. When the voltage applied to the REF node is lower than 2.5V, the shunt regulator 36 can sink a very small quiescent current.

A large sink current may pull the gate voltage of the second transistor 35 down to a level below its threshold, which may switch off the second transistor 35 . The shunt regulator 36 may not be able to pull the cathodes more than the forward voltage (Vf) of the diode below their REF nodes. Accordingly, the second transistor 35 may have a threshold voltage higher than 2.5V. Alternatively, a shunt regulator with a lower internal reference voltage, such as 1.24V, may be used.

Circuit 20 includes a multiplexer array 22 that electrically connects _two of three LEDs 26 , 27 , 28 to two current sources I ₁ , I 2 generated by analog current divider circuit 21 . . Multiplexer array 22 may include four MOSFETs S1 ( 11 ), S2 ( 12 ), S3 ( 13 ), S4 ( 14 ), also referred to as switches, as shown in circuit 20 . . The multiplexer array 22 directs I ₁ and I ₂ per hour to two of the colors of the LED array 23 . As the table below shows, since MOSFET S2(12) and MOSFET S3(13) are the inverted values of MOSFET S1(11) and MOSFET S4(14) (i.e. S2=INVERTED S1 and S3=INVERTED S4), Control of MOSFET S1 (11) and MOSFET S4 (14) is required. As defined in the following equations,

Operationally, the hybrid driving method utilizes the analog current dividing circuit 21 to simultaneously drive two colors of the LED array 23 and then overlay the PWM time slicing with the third color of the LED array 23 . The utilization of LEDs in array 23 for an embodiment that is color 1 green, color 2 red and color 3 blue is shown in Table 3.

In driving two colors simultaneously, virtual color points are created. The ratio between the currents I1 and I2 can be predefined (ie any ratio can be used but 1:1 or slightly different to maximize efficiency). Using the three colors of the LED array 23, three virtual color points (RG, R-B, G-B) can be created by adding the primary colors R/G/B (the fourth color point for blending). A triangle formed by three virtual color points (R-G, R-B, G-B) defines a color gamut of a new driving method. Table 4 summarizes the timing sequence of the operation of the hybrid driving scheme for 3-channel LED driving. As will be understood by one of ordinary skill in the art, the particular sequence of colors is not necessarily critical. In implementations of the hybrid drive scheme, the color duplets may be arranged or rearranged in a manner that minimizes the complexity of implementing the PWM logic. To provide a sample timing sequence, Table 4 is presented below. During the sub-interval T1, power may be supplied to the red-green color duplet. During the sub-interval T2, power may be supplied to the green-blue color duplet. During the sub-interval T3, power may be supplied to the red-blue color duplet. The sum of the subintervals T1 , T2 , and T3 is combined to substantially cover the switching period T .

1D shows a microcontroller 40 in which the computing device 37 may be utilized to handle complex signal processing with fewer PCB resources than the analog circuitry described above. The microcontroller 40 handles the input signals and the operation of S1 and S4. The microcontroller 40 can monitor the absolute value of the input current by sensing VSENSE1 at the input 15 and sensing the board temperature with the NTC 17 . These two reads, VSENSE1 at input 15, NTC 17 can be used to compensate for color shift due to drive current and temperature. 0-10V represents the control input 16 . The microcontroller 40 may be mapped to the CCT tuning curve. The microcontroller 40 converts incoming commands into operations of the multiplexer array 23 . Specifically, the microcontroller 40 may provide the first output signal 11 to the control switch S1 and the second output signal 14 to the control switch S4 .

1E shows a color chart 42 for a circuit 20 with a red LED (or an array of red LEDs) positioned in a central position. A color chart 42 is overlaid on the color chart of FIG. 1B . Color chart 42 shows the reachable gamut 43 from the use of RB-RG-BG in circuit 20 for 2700K to 6000K (matched gamut 2.1 from FIG. 1B) and for 2500K and below. Color gamut 44 from the use of RG-RB-R in circuit 20 is depicted. The color gamut 43 can be provided with high efficiency. Color gamut 44 can be provided with reduced efficiency. The combination of gamut 43 and gamut 44 from circuit 20 approximates gamut 2 described above with respect to FIG. 1A . Although the combination of gamut 43 and 44 does not completely cover all of the gamut 2 , the combination of gamut 43 and 44 may be sufficient for many applications, and the hybrid circuit 20 . may be a reasonable compromise for the increased efficiency achieved by

1F shows a color chart 45 for circuit 20 with a green LED (or an array of green LEDs) located in a central position. A color chart 45 is overlaid on the color chart of FIG. 1B . Color chart 45 shows the reachable gamut 43 from the use of RB-RG-BG in circuit 20 for 2700K to 6000K (matching gamut 2.1 from FIG. 1B ) and over BBL 6 A color gamut 46 from the use of RG-GB-G in circuit 20 is depicted. The color gamut 43 can be provided with high efficiency. Color gamut 46 can be provided with reduced efficiency. The combination of gamut 43 and gamut 46 from circuit 20 approximates gamut 2 described above with respect to FIG. 1A . Although the combination of gamut 43 and gamut 46 does not completely cover all of gamut 2, the combination of gamut 43 and gamut 46 may be sufficient for many applications, and hybrid circuit 20 may be a reasonable compromise for the increased efficiency achieved by

1G shows a color chart 47 for a circuit 20 with a blue LED (or an array of blue LEDs) located in a central position. A color chart 47 is overlaid on the color chart of FIG. 1B . Color chart 47 shows the reachable color gamut 43 from the use of RB-RG-BG in circuit 20 for 2700K to 6000K (matching region 2.1 from FIG. 1B) and circuits beyond 6500K. A color gamut (48) from the use of GB-RB-B in (20) is depicted. The color gamut 43 can be provided with high efficiency. Color gamut 48 can be provided with reduced efficiency. The combination of gamut 43 and gamut 48 from circuit 20 approximates gamut 2 described above with respect to FIG. 1A . Although the combination of gamut 43 and 48 does not completely cover all of the gamut 2 , the combination of gamut 43 and 48 may be sufficient for many applications, and the hybrid circuit 20 . may be a reasonable compromise for the increased efficiency achieved by

It is clear from Figures 1e, 1f, 1g that all parts of the color gamut 2 can be reached by simply changing the LED located in the center of the circuit 20 . In each configuration of the LEDs gamut 2.1 is covered, plus an additional portion of gamut 2 as well. Such coverage may be sufficient for many applications, and may be a compromise for increased efficiency.

1H shows another hybrid drive circuit 50 . Circuit 50 may provide increased color gamut from circuit 20 . Circuit 50 includes analog current division circuit 21 , LED array 23 , voltage regulator 24 , and LED driver 25 as described herein above with respect to FIG. 1C . As in FIG. 1C , the LED array 23 includes one or a plurality of color 1 LEDs 26 , one or a plurality of color 2 LEDs 27 , and one or a plurality of color 3 designed to be tuned using a hybrid drive circuit. LEDs 28 may be included. A multiplexer array 52 is utilized in circuit 50 . In one embodiment of circuit 50, color 1 is green, color 2 is red, and color 3 is blue, although any set of colors may be used for color 1, color 2, and color 3. As will be appreciated, the assignment of colors to particular channels is simply a design choice, and while other designs are contemplated, in order to provide a thorough understanding of the hybrid drive circuit described herein, the present description is Embodiments using 1 LED 26, color 2 LED 27 and color 3 LED 28 are also described, wherein color 1 is described as green, color 2 is described as red, and color 3 is described as blue. can be explained

A multiplexer array (52) electrically connecting two of the three LEDs (26, 27, 28) to two current sources (11, b) generated by an analog current dividing circuit (21). As shown in the circuit 50, the multiplexer array 52 includes five MOSFETs S1 (51), S2 (53), S3 (54), S4 (56), and S5 (57), which are also referred to as switches. may include The multiplexer array 52 directs I ₁ and I ₂ per hour to two of the colors of the LED array 23 . Since MOSFET S2(53) and MOSFET S3(54) are the inverted values of MOSFET S1(51) and MOSFET S4(56) and MOSFET S5(57) is the inverted combination of MOSFET S1(51) and MOSFET S2(53), , MOSFET S1 (51), MOSFET S4 (56) and control of X are required. Specifically,

Table 5 shows possible combinations provided by circuit 50 . The utilization of LEDs in array 23 for an embodiment that is color 1 green, color 2 red, and color 3 blue is shown in Table 5.

1I shows a color chart 55 for a circuit 50 having red and blue LEDs (or an array of red LEDs and an array of blue LEDs) driven by analog currents. A color chart 55 is overlaid on the color chart of FIG. 1B . Color chart 55 depicts gamut 43 (matched to gamut 2.1 from FIG. 1B ), gamut 44 , and gamut 48 . The color gamut 43 can be provided with high efficiency. Color gamuts 44 and 48 can be provided with reduced efficiency. The combination of gamuts 43 , 44 , 48 from circuit 50 approximates gamut 2 described above with respect to FIG. 1A . Although the combination of color gamuts 43 , 44 , 48 does not completely cover the entirety of color gamut 2 , the combination of color gamuts 43 , 44 , 48 may be sufficient for many applications, and hybrid circuit 50 . may be a reasonable compromise for the increased efficiency achieved by

1J shows a color chart 60 for a circuit 50 having red and green LEDs (or an array of red LEDs and an array of green LEDs) driven by analog currents. A color chart 60 is overlaid on the color chart of FIG. 1B . The color chart 60 depicts the reachable gamut 43 (matching gamut 2.1 from FIG. 1B ), gamut 44 , and gamut 46 . The color gamut 43 can be provided with high efficiency. Color gamuts 44 and 46 can be provided with reduced efficiency. The combination of gamuts 43 , 44 , 46 from circuit 50 approximates the gamut described above with respect to FIG. 1A . Although the combination of color gamut 43 , 44 , 46 does not completely cover all of color gamut 2 , the combination of color gamut 43 , 44 , 46 may be sufficient for many applications and can be achieved by hybrid circuit 50 . It may be a reasonable trade-off for the increased efficiency achieved.

1K shows a color chart 65 for a circuit 50 having blue and green LEDs (or an array of blue LEDs and an array of green LEDs) driven by analog currents. A color chart 65 is overlaid on the color chart of FIG. 1B. Color chart 65 depicts gamut 43 (matched to gamut 2.1 from FIG. 1B ), gamut 46 , and gamut 48 . The color gamut 43 can be provided with high efficiency. Color gamuts 46 and 48 can be provided with reduced efficiency. The combination of gamuts 43 , 46 , 48 from circuit 50 approximates gamut 2 described above with respect to FIG. 1A . Although the combination of color gamuts 43 , 46 , 48 does not completely cover the entirety of color gamut 2 , the combination of color gamuts 43 , 46 , 48 may be sufficient for many applications, and hybrid circuit 50 . may be a reasonable compromise for the increased efficiency achieved by

11 shows another hybrid drive circuit 70 . Circuit 70 may provide increased color gamut from circuits 20 and 50 . Circuit 70 includes analog current dividing circuit 21 , LED array 23 , voltage regulator 24 , and LED driver 25 as described in the specification above with respect to FIG. 1C . As in FIG. 1C , the LED array 23 includes one or a plurality of color 1 LEDs 26 , one or a plurality of color 2 LEDs 27 , and one or a plurality of color 3 designed to be tuned using a hybrid drive circuit. LEDs 28 may be included. Multiplexer array 72 is utilized in circuit 70 . In one embodiment of circuit 70, color 1 is green, color 2 is red, and color 3 is blue, although any set of colors may be used for color 1, color 2, and color 3. As will be appreciated, the assignment of colors to particular channels is simply a design choice, and while other designs are contemplated, in order to provide a thorough understanding of the hybrid drive circuit described herein, the present description is Embodiments using 1 LED 26, color 2 LED 27 and color 3 LED 28 are also described, wherein color 1 is described as green, color 2 is described as red, and color 3 is described as blue. can be explained

A multiplexer array 72 electrically connecting _two of the three LEDs 26 , 27 , 28 to the two current sources I ₁ , I 2 generated by the analog current dividing circuit 21 . Multiplexer array 72 may include six MOSFETs S1 , S2 , S3 , S4 , S5 , S6 , also referred to as switches, as shown in circuit 70 . Multiplexer array 72 directs I ₁ and I ₂ per hour to two of the colors of LED array 23 . Since MOSFET S2, MOSFET S3 and MOSFET S5 are the inverted values of MOSFET S1 and MOSFET S4, and MOSFET S6 is the inverted combination of MOSFET S4 and MOSFET S5, it is necessary to control _{MOSFET S1, MOSFET S4 and X 1} , X _{2 .} . Specifically,

Table 6 illustrates possible combinations provided by circuit 70 . The utilization of LEDs in array 23 for an embodiment that is color 1 green, color 2 red, and color 3 blue is shown in Table 6.

By alternating the same color between I1 and I2, any mismatch between I1 and I2 can be averaged out, such as by chopping, for example.

1M shows a color chart 75 for circuit 70 that provides full color gamut 2 coverage. A color chart 75 is overlaid on the color chart of FIG. 1B . Color chart 75 depicts the total reachable gamuts 43 , 44 , 46 , 48 matching the gamut described above with respect to FIG. 1A .

1N shows a method 80 of hybrid driving for RGB color tuning driving. Method 80 may be used by circuit 20 , circuit 50 , or circuit 70 to produce 1/2 gamut, 3/4 gamut and full gamut outputs as described herein. Method 80 divides the input current into a first current and a second current through the analog current dividing circuit in step 82 . In step 84 , the method 80 simultaneously generates a first current for a first color of three colors of LEDs and a second current for a second color of three colors of LEDs through the multiplexer array during a first portion of a period of time. to provide. In step 86, the method 80 generates, through the multiplexer array, a first current for a second color of three colors of LEDs and a second current for a third color of three colors of LEDs, during a second portion of the time period. at the same time provide In step 88, method 80 includes; During a third portion of the period of time, a first current to a first color of the three colors of LEDs and a second current to a third color of the three colors of LEDs are simultaneously provided through the multiplexer array. In method 80, splicing of the first current and the second current into different dulets of the LEDs is performed using pulse width modulation (PWM) time slicing to provide driving for a third one of the three colors of the LEDs. can occur In method 80, the PWM is substantially equal between the combination of a first color of the three colors of the LEDs and a second color of the three colors of the LEDs and a third color of the three colors of the LEDs, or a desired driving characteristic of the LEDs may differ depending on the

2 is a plan view of an electronic device board 310 for an integrated LED lighting system according to an embodiment. In alternative embodiments, two or more electronic device 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 310 has a power module 312 , a sensor module 314 , a connection and control module 316 , and an LED attachment area 318 reserved for attachment of the LED array to the substrate 320 . ) is included.

The substrate 320 mechanically supports and electrically connects electrical components, electronic components and/or electronic modules using conductive connectors such as tracks, traces, pads, vias, and/or wires. It can be any board capable of providing bonding. Substrate 320 may include one or more metallization layers disposed between or on one or more layers of a non-conductive material, such as a dielectric composite material. Power module 312 may include electrical and/or electronic components. In an exemplary embodiment, the power module 312 includes an AC/DC conversion circuit, a DC/DC conversion circuit, a dimming circuit, and an LED driver circuit. One of the circuits 20 , 50 , 70 may be included within the power module 312 .

The sensor module 314 may include the necessary sensors for the application in which the LED array is implemented. Exemplary sensors may include optical sensors (eg, IR sensors and image sensors), motion sensors, thermal sensors, mechanical sensors, proximity sensors, or even timers. For example, LEDs in street lighting, general lighting, and horticultural lighting applications may be based on a number of different sensor inputs, such as detected user presence, detected ambient lighting conditions, detected weather conditions, or day/ It may be turned off/on and/or adjusted based on the time of night. This may include, for example, adjusting the light output intensity, the shape of the light output, the color of the light output, and/or turning the light on or off to save energy. For AR/VR applications, motion sensors can be used to detect user movement. The motion sensor itself may be LEDs, such as IR detector LEDs. As another example, for a camera flash application, the image and/or other optical sensors or pixels may be used to measure illumination for the scene to be captured, so that the flash illumination color, intensity illumination pattern, and/or shape is can be optimally calibrated. In alternative embodiments, the electronic device board 310 does not include a sensor module.

The connection and control module 316 may include any type of wired or wireless module configured to receive control inputs from a system microcontroller and external devices. For example, a wireless module may include Bluetooth, ZigBee, Z-Wave, mesh, WiFi, near field communication (NFC) and/or peer-to-peer modules may be used. A microcontroller may be embedded in an LED lighting system and configured or configured to receive inputs (such as sensor data and data fed back from the LED module) from a wired or wireless module or other modules in the LED system. and may be any type of special purpose computer or processor capable of providing control signals to other modules based thereon. The algorithms implemented by the special-purpose processor may be implemented in a computer program, software, or firmware included in a non-transitory computer-readable storage medium for execution by the special-purpose processor. Examples of non-transitory computer-readable storage media include read only memory (ROM), random access memory (RAM), registers, cache memory, and semiconductor memory devices. The memory may be included as part of the microcontroller, or implemented elsewhere on or off the electronic device board 310 . One of the circuits 20 , 50 , 70 may be included within the connection and control module 316 .

The term module as used herein may refer to electrical and/or electronic components disposed on separate circuit boards that may be soldered to one or more electronic device boards 310 . However, the term module may 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 the same area or in different areas.

3A is a top view of an electronics board 310 having an LED array 410 attached to a substrate 320 in an LED device attachment area 318 in one embodiment. Electronics board 310 represents LED lighting system 400A with LED array 410 . Additionally, power module 312 receives a voltage input at Vin 497 and control signals from connection and control module 316 via traces 418B, and LED array 410 via traces 418A. ) to provide driving signals. The LED array 410 is turned on and off through drive signals from the power module 312 . 3A , the connection and control module 316 receives sensor signals from the sensor module 314 via traces 418 . One of the circuits 20 , 50 , 70 may be included within a power module 312 and/or a connection and control module 316 .

3B shows 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. 3B , the LED lighting system 400B includes a first surface 445A having inputs for receiving dimmer signals and AC power signals and an AC/DC converter circuit 412 mounted thereon. do. The LED system 400B includes a second surface 445B and has a connection and control module 416 having a dimmer interface circuit 415, DC-DC converter circuits 440A and 440B, and a microcontroller 472 thereon. (a wireless module in this example), and an LED array 410 are mounted. LED array 410 is driven by two independent channels 411A and 411B. In alternative embodiments, a single channel may be used to provide drive signals to the LED array, or any number of multiple channels may be used to provide drive signals to the LED array. For example, FIG. 3E shows an LED lighting system 4000 having three channels, which is described in more detail below.

The LED array 410 may include two groups of LED devices. In an exemplary embodiment, the LED devices of group A are electrically coupled to the first channel 411A and the LED devices of group B are electrically coupled to the second channel 411B. Each of the two DC-DC converter circuits 440A and 440B provides a respective drive current through single channels 411A and 411B to drive respective groups A and B of LEDs in LED array 410, respectively. can do. 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 LEDs in the second group. Control of the complex color point of the light emitted by the LED array 410 controls the current and/or duty cycle applied by the individual DC/DC converter circuits 440A and 440B via a single channel 411A and 411B, respectively. By doing so, it can be tuned within the range. Although the embodiment shown in FIG. 3B does not include a sensor module (as described in FIGS. 2 and 3A ), alternative embodiments may include a sensor module.

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

3C shows an embodiment of an LED lighting system in which the LED array is on a separate electronics board from the driver and control circuitry. The LED lighting system 400C includes an LED module 490 and a power module 452 on a separate electronics board. One of the circuits 20 , 50 , 70 may be included within the power module 452 . The power module 452 is, on the first electronic device board, an AC/DC converter circuit 412 , a sensor module 414 , a connection and control module 416 , a dimmer interface circuit 415 and a DC/DC converter circuit 440 may be included. The LED module 490 may include the LED calibration and setting data 493 and the LED array 410 embedded on the second electronic device board. Data, control signals and/or LED driver input signals 485 may be exchanged between power module 452 and LED module 490 via wires that may electrically and communicatively couple the two modules. have. Embedded LED calibration and setup data 493 may include any data needed by other modules in a given LED lighting system to control how the LEDs in the LED array are driven. In one embodiment, the embedded calibration and setup data 493 provides a control signal that instructs the driver to power each group A and B of LEDs using, for example, pulse width modulation (PWM) signals. It may contain data needed by the microcontroller to create or modify it. In this example, calibration and setup data 493 is sent to microcontroller 472 , for example, the number of power channels to be used, the desired color point of the composite light provided by the overall LED array 410 , and/or each It may notify about the percentage of power provided by the AC/DC converter circuit 412 to provide to the channel.

3D shows a block diagram of an LED lighting system with an LED array with some of the electronics on the electronics board separated from the driver circuitry. The LED system 400D includes a power conversion module 483 and an LED module 481 located on separate electronics boards. One of the circuits 20 , 50 , 70 may be included in the power conversion module 483 . The power conversion module 483 may include an AC/DC converter circuit 412 , a dimmer interface circuit 415 and a DC-DC converter circuit 440 , and the LED module 481 has built-in LED calibration and setting data 493 , an LED array 410 , a sensor module 414 , and a connection and control module 416 . The power conversion module 483 may provide the LED driver input signals 485 to the LED array 410 through a wired connection between the two electronic device boards.

3E is a diagram of an exemplary LED lighting system 400D illustrating a multi-channel LED driver circuit. In the illustrated example, system 400D includes a power module 452 and an LED module 481 that includes embedded LED calibration and setup data 493 and three groups of LEDs 494A, 494B, and 494C. include Although three groups of LEDs are shown in FIG. 3E , 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. Also, although the individual LEDs in each group are arranged in series, they may be arranged in parallel in some embodiments.

LED array 491 may include groups of LEDs that provide light with different color points. For example, LED array 491 may include a warm white light source through a first group of LEDs 494A, a cool white light source through a second group of LEDs 494B, and a neutral white light source through a third group of LEDs 494C. It may include a light source. The warm white light source through the first group of LEDs 494A may include one or more LEDs configured to provide white light having a CCT of approximately 2700K. The cool white light source through the second group of LEDs 494B may include one or more LEDs configured to provide white light having a CCT of approximately 6500K. The neutral white light source through the third group of LEDs 494C may include one or more LEDs configured to provide light having a CCT of approximately 4000K. Although various white colored LEDs are described in this example, one of ordinary skill in the art would be able to provide a composite light output from an LED array 491 having a variety of overall colors consistent with the embodiments described herein. It will be appreciated that other color combinations are possible.

Power module 452 includes a tunable light engine (not shown) that can be configured to power LED array 491 across three separate channels (represented by LED1+, LED2+, and LED3+ in FIG. 3E). may include More specifically, the tunable light engine supplies a first PWM signal to a first group of LEDs 494A, such as a warm white light source, via a first channel, and to a second group of LEDs 494B via a second channel. supply a second PWM signal and supply a third PWM signal to a third group of LEDs 494C via a third channel. Each signal provided through a respective channel can be used to power a corresponding LED or group of LEDs, and the duty cycle of the signal can determine the overall duration of the on and off states of each respective LED. have. The duration of the on and off states can result in an overall optical effect that can have optical properties based on duration (eg, correlated color temperature CCT, color point or luminance). In operation, the tunable light engine performs the duty of the first, second and third signals to adjust respective optical properties of each of the groups of LEDs to provide composite light having a desired emission from the LED array 491 . You can change the relative size of the cycles. As noted above, the light output of the LED array 491 may have a color point that is based on a combination (eg, a mixture) of light emissions from each of the groups 494A, 494B, and 494C of LEDs.

In operation, the power module 452 receives control inputs generated based on user and/or sensor inputs, and controls individual channels to control a composite color of light output by the LED array 491 based on the control inputs. signals can be provided. In some embodiments, the user provides an input to the LED system for control of the DC/DC converter circuit by turning a knob or moving a slider, which may be, for example, part of a sensor module (not shown). can do. Additionally or alternatively, in some embodiments, a user can connect to LED lighting system 4000 using a smartphone and/or other electronic device to transmit an indication of a desired color to a wireless module (not shown). You can provide input.

4 shows an example system 550 that includes an application platform 560 , LED lighting systems 552 and 556 , and auxiliary optics 554 and 558 . LED lighting system 552 produces light beams 561 shown between arrows 561A and 561B. The LED lighting system 556 can generate light beams 562 between the arrows 562A and 562B. 4 , light emitted from LED lighting system 552 passes through auxiliary optics 554 , and light emitted from LED lighting system 556 passes through auxiliary optics 558 . In alternative embodiments, light beams 561 and 562 do not pass through any auxiliary optics. The auxiliary optics may be or include one or more light guides. The one or more light guides may be edge lits or may have interior openings defining an inner edge of the light guides. The LED lighting systems 552 and/or 556 are inserted into the interior openings of the one or more light guides such that they inject light into an inner edge (inner opening light guide) or an outer edge (edge lit light guide) of the one or more light guides. can be The LEDs in LED lighting systems 552 and/or 556 may be arranged around the perimeter of a base that is part of a light guide. According to one implementation, the base may be thermally conductive. According to one implementation, the base may be coupled to a heat-dissipating element disposed above the light guide. The heat dissipation element may be arranged to receive heat generated by the LEDs through the thermally conductive base and dissipate the received heat. The one or more light guides determine that the light emitted by the LED lighting systems 552 and 556 has, for example, a gradient, a chamfered distribution, a narrow distribution, a wide distribution, an angular distribution, or the like. may be allowed to be molded in any desired manner, such as

In example embodiments, system 550 may be a mobile phone of a camera flash system, indoor residential or commercial lighting, outdoor lighting such as street lighting, automotive, medical devices, AR/VR devices, and robotic devices. The integrated LED lighting system 400A shown in FIG. 3A, the integrated LED lighting system 400B shown in FIG. 3B, the LED lighting system 400C shown in FIG. 3C, and the LED lighting system 400C shown in FIG. 3D ( 400D shows LED lighting systems 552 and 556 in example embodiments.

In example embodiments, system 550 may be a mobile phone of a camera flash system, indoor residential or commercial lighting, outdoor lighting such as street lighting, automotive, medical devices, ARNR devices, and robotic devices. The integrated LED lighting system 400A shown in FIG. 3A, the integrated LED lighting system 400B shown in FIG. 3B, the LED lighting system 400C shown in FIG. 3C, and the LED lighting system 400C shown in FIG. 3D ( 400D shows LED lighting systems 552 and 556 in example embodiments.

Application platform 560 may provide power to LED lighting systems 552 and/or 556 via a power bus via line 565 or other applicable input, as discussed herein. Application platform 560 may also provide input signals over line 565 for operation of LED lighting system 552 and LED lighting system 556, which inputs include user input/preference, sensed reading. , pre-programmed or autonomously determined outputs, etc. The one or more sensors may be inside or outside the housing of the application platform 560 .

In various embodiments, application platform 560 sensors and/or LED lighting system 552 and/or 556 sensors include visual data (eg, LIDAR data, IR data, data collected via a camera, etc.); Data may be collected, such as audio data, distance-based data, motion data, environmental data, or the like or a combination thereof. Data may relate to physical items or entities such as objects, individuals, vehicles, and the like. For example, sensing equipment may collect object proximity data for an ADAS/AV based application, which may prioritize detection and subsequent actions based on detection of a physical item or entity. Data may be collected, for example, based on emitting an optical signal, such as an IR signal, by the LED lighting system 552 and/or 556 and collecting data based on the emitted optical signal. The data may be collected by a different component than the component emitting the optical signal for data collection. Continuing the example, sensing equipment may be positioned 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.

In an exemplary 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, system 550 may represent an automobile having steerable light beams, wherein LEDs may be selectively activated to provide steerable light. For example, an array of LEDs may be used to define or project or shape or pattern or illuminate only selected sections of a roadway. In an exemplary embodiment, the infrared cameras or detector pixels in LED lighting systems 552 and/or 556 may be sensors that identify portions of the scene (roads, crosswalks, etc.) that require illumination. .

5A is a diagram of an LED device 200 in an exemplary embodiment. The LED device 200 can include a substrate 202 , an active layer 204 , a wavelength converting layer 206 , and primary optics 208 . In other embodiments, the LED device may not include a wavelength converting 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.

As shown in FIG. 5A , the active layer 204 may be adjacent the substrate 202 and emit light when excited. Suitable materials used to form the substrate 202 and the active layer 204 include sapphire, SiC, GaN, silicon, and more specifically, AlN, AlP, AlAs, AlSb, GaN, GaP, GaAs, GaSb. Group III-V semiconductors including but not limited to, InN, InP, InAs, InSb, Group II-VI semiconductors including but not limited to ZnS, ZnSe, CdSe, CdTe, Ge, Si, SiC Group IV semiconductors, including but not limited to, and mixtures or alloys thereof.

The wavelength converting layer 206 may be remote from, proximate to, or directly over the active layer 204 . The active layer 204 emits light into the wavelength converting layer 206 . The wavelength converting layer 206 serves to further modify the wavelength of the light emitted by the active layer 204 . LED devices that include a wavelength converting layer are often referred to as phosphor converted LEDs (“PCLEDs”). The wavelength converting layer 206 may be any light emitting such as, for example, a transparent or translucent binder or phosphor particles in a matrix, or a ceramic phosphor element that absorbs light of one wavelength and emits light of a different wavelength. material may be included.

Primary optics 208 may be on or over one or more layers of LED device 200 , such that light passes through primary optics 208 from active layer 204 and/or wavelength converting layer 206 . allow to do The primary optics 208 may be a lens or encapsulate device configured to protect one or more layers and at least partially shape the output of the LED device 200 . Primary optics 208 may include transparent and/or translucent materials. In example embodiments, light through the primary optics may be emitted based on a Lambertian distribution pattern. It will be appreciated that one or more properties of the primary optics 208 may be modified to produce a light distribution pattern that is different from a Lambertian distribution pattern.

5B shows a cross-sectional view of a lighting system 220 including an auxiliary optics 212 as well as an LED array 210 having pixels 201A, 201B, and 201C in an exemplary embodiment. The LED array 210 includes pixels 201A, 201B, and 201C each including a respective wavelength converting layer 206B, an active layer 204B, and a substrate 202B. The LED array 210 may be a monolithic LED array fabricated using wafer level processing techniques, micro LEDs having dimensions of 500 microns or less, and the like. Pixels 201A, 201B, and 201C in LED array 210 may be formed using array partitioning, or alternatively may be formed using pick and place techniques.

The spaces 203 shown between one or more pixels 201A, 201B, and 201C of the LED devices 200B may include an air gap, or may be a contact (eg, an n-contact). It may be filled with a material such as a metallic material.

Secondary optics 212 may include one or both of lens 209 and waveguide 207 . Although secondary optics are discussed according to the example shown, in illustrative embodiments, secondary optics 212 may be used to diffuse incoming light (diverging optics) or to collect incoming light into a collimated beam (collimating optics). It will be appreciated that they may be used. In exemplary embodiments, the waveguide 207 may be a light collector and may have any applicable shape for focusing light, such as a parabolic shape, a conical shape, a beveled shape, and the like. The waveguide 207 may be coated with a dielectric material, metallization layer, or the like used to reflect or redirect incident light. In alternative embodiments, the illumination system may not include one or more of the conversion layer 206B, the primary optics 208B, the waveguide 207 , and the lens 209 .

Lens 209 may be formed of any applicable transparent material, such as, but not limited to, SiC, aluminum oxide, diamond, or the like, or combinations thereof. The lens 209 may be used to modify the light beam input into the lens 209 so that the output beam from the lens 209 can efficiently meet the desired optical measurement specifications. Additionally, the lens 209 may serve one or more aesthetic purposes, such as by determining the lit and/or unlit appearance of the LED devices 201A, 201B, and/or 201C of the LED array 210 .

Although embodiments have been described in detail, those skilled in the art will recognize that, given this 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 only to the specific embodiments shown and described.

Claims (20)

A light emitting diode (LED) color tuning device comprising:
A hybrid drive circuit coupled to a multi-color LED array, the hybrid drive circuit comprising:
an analog current dividing circuit that generates current for at least two LED current drive sources; and
a switching array coupled between the analog current dividing circuit and the multi-color LED array, wherein the switching array is configured to, for a predetermined amount of time, transmit current from at least one of the at least two LED current drive sources to at least one of the multi-color LED arrays. configured to periodically provide two colors substantially simultaneously. According to claim 1,
further comprising an LED driver electrically coupled to a voltage regulator, the voltage regulator providing a voltage signal for the multi-color LED array, the combination of the LED driver and the voltage regulator being an input to the analog current dividing circuit LED color tuning device that provides a stabilized current as a According to claim 1,
The switching array is an LED color tuning device including a multiplexer array. According to claim 1,
and a voltage controlled current source configured to supply current to the analog current dividing circuit to generate current for the at least two LED current drive sources. According to claim 1,
The switching array comprises:
provide a first current from a first of the at least two LED current drive sources to a first color of three colors in the multi-color LED array substantially simultaneously during a first portion of the time period, the at least two LEDs provide a second current from a second of the current drive sources to a second of three colors in the multi-color LED array;
provide the first current to a second color of three colors in the multi-color LED array substantially simultaneously during the second portion of the time period and apply the second current to a third color of three colors in the multi-color LED array 2 provide a current, and
provide the first current to a first of three colors in the multi-color LED array and provide the second current to a third of three colors in the multi-color LED array substantially simultaneously during the third portion of the time period 2 LED color tuning device configured to provide current. 6. The method of claim 5,
wherein the first portion, the second portion, and the third portion of the time period are selectable using pulse width modulation (PWM) time slicing. 6. The method of claim 5,
wherein the sum of the first current and the second current is substantially equal to an input current supplied from an LED driver to the analog current dividing circuit. 6. The method of claim 5,
wherein each of the at least two LED current drive sources is configured to supply substantially the same amount of current to the multi-color LED array. 6. The method of claim 5,
wherein each of the at least two LED current drive sources is configured to supply an unequal amount of current to the multi-color LED array. According to claim 1,
wherein the multi-color LED array comprises at least one red color LED, at least one green color LED and at least one blue color LED. According to claim 1,
wherein the multi-color LED array comprises at least one desaturated red LED, at least one desaturated green LED, and at least one desaturated blue LED. According to claim 1,
wherein the switching array comprises at least four switching devices. According to claim 1,
and the hybrid drive circuit is further configured to supply a pulse width modulated (PWM) time slicing signal to selected ones of the multi-color LED array. A light emitting diode (LED) color tuning device comprising:
a multi-color LED array comprising at least one desaturated red LED, at least one desaturated green LED, and at least one desaturated blue LED; and
A hybrid drive circuit coupled to the multi-color LED array, the hybrid drive circuit comprising:
an analog current dividing circuit that generates current for at least two LED current drive sources; and
a switching array coupled between the analog current dividing circuit and the multi-color LED array, wherein the switching array is configured to, for a predetermined amount of time, transmit current from at least one of the at least two LED current drive sources to at least one of the multi-color LED arrays. An LED color tuning device comprising: - configured to periodically provide two colors substantially simultaneously. 15. The method of claim 14,
and a voltage controlled current source configured to supply current to the analog current dividing circuit to generate current for the at least two LED current drive sources. 16. The method of claim 15,
and a computing device configured to compare the first sense voltage V _SENSE1 and the second sense voltage V _SENSE2 to determine and supply a set voltage V _SET , wherein the set voltage is an input voltage to the voltage controlled current source. tuning device. 15. The method of claim 14,
and the hybrid drive circuit is further configured to supply a pulse width modulated (PWM) time slicing signal to selected ones of the multi-color LED array. 15. The method of claim 14,
further comprising an LED driver electrically coupled to a voltage regulator, the voltage regulator providing a voltage signal for the multi-color LED array, the combination of the LED driver and the voltage regulator being an input to the analog current dividing circuit LED color tuning device that provides a stabilized current as a A method for tuning a multi-color light emitting diode (LED) array comprising:
determining and supplying a set voltage as an input voltage to a voltage controlled current source;
dividing the input current into a first current and a second current; and
Based on the determination of color temperature:
providing the first current to a first color of three colors of the multi-color LED array and providing the second current to a second color of three colors of the multi-color LED array substantially simultaneously during a first portion of a period of time do;
provide the first current to a second one of three colors of the multi-color LED array substantially simultaneously during the second portion of the time period and the second current to a third one of the three colors of the multi-color LED array to provide;
providing the first current to a first of three colors of the multi-color LED array and applying the second current to a third of three colors of the LED multi-color array substantially simultaneously during a third portion of the period of time A method comprising the step of providing. 20. The method of claim 19,
wherein the providing of the first current and the providing of the second current to different dulets of the LED multi-color array occurs using pulse width modulation (PWM) time slicing.

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