Color control technology for dimmable lighting devices and related systems and methods

Abstract

A technique for controlling the color of a light source during dimming is provided. A current control circuit may be disposed within a light source module and configured to adjust a current path through some of the lamps (e.g., LEDs) in the module according to a driving input current. If the multiple current paths through the lamps have different impedances, a change in the current path will result in an increase or decrease in the amount of current through the lamps. If the adjusted lamp has a different color temperature than other lamps of the light source module, a change in the current path along with adjusting the driving current may affect a change in color temperature when the light source module is dimmed.

Description

Technical Field

[0001] The present invention relates to a lighting device (eg, an LED) comprising a system (eg, a light source module) for controlling the color of the lighting device during dimming of the lighting device. Background Art

[0002] Light emitting diodes (LEDs) can generally provide light in a more efficient manner than incandescent and / or fluorescent light sources. Therefore, LED lamps and light fixtures are desirable to consumers as a means of reducing energy usage while providing light in a home or business.

[0003] In addition to energy usage, the correlated color temperature (CCT) of the light produced by the light source is often considered when selecting a light source. CCT (hereinafter referred to as "color temperature") is a measure of the color appearance of "white" light emitted from an electric light source. Color temperature provides a general indication of the degree to which white light has a "cool" color (referring to more blue tones) or a "warm" color (referring to more yellow tones). The terms warm and cool are often used because traditional incandescent lamps produce a soft white (sometimes with a slight yellow tint), and because warm light has long been regarded as desirable in a light source because it tends to make the colors in an environment feel warm and comfortable.

[0004] Some light sources may be configured to be dimmable, meaning that they may be controlled to increase or decrease the intensity of the light produced. Dimmable light sources are often used in home or commercial environments. The color temperature of the light produced at each of the different available light intensities may be of interest, so that a desired one or more hues may be produced when the light source is dimmed. Summary of the invention

[0005] The present application relates to a lighting device (eg, an LED) including a system (eg, a light source module) for controlling the color of the lighting device during dimming of the lighting device.

[0006] According to some aspects, a light source module circuit is provided, comprising: a plurality of first LEDs connected in series, the first LEDs being configured to generate light having a first color temperature; one or more control units, the one or more control units being connected in series with the plurality of first LEDs; a plurality of second LEDs connected in series, the second LEDs being configured to generate light having a second color temperature different from the first color temperature, wherein the plurality of second LEDs are connected in parallel with the plurality of first LEDs and the one or more control units; and a current control circuit, the current control circuit being connected in parallel to the one or more control units and being configured to adjust a ratio of a current passing through the plurality of first LEDs to a current passing through the plurality of second LEDs according to a driving current input to the plurality of first LEDs and the plurality of second LEDs.

[0007] The above-mentioned device and method embodiments can be implemented by any suitable combination of the aspects, features and actions described in further detail above or below. These and other aspects, embodiments and features of the present teaching can be more fully understood according to the following description in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Various aspects and embodiments will be described with reference to the following drawings. It should be understood that the drawings are not necessarily drawn to scale. In the drawings, each identical or nearly identical component shown in the various figures is represented by a similar reference numeral. For clarity, not every component may be labeled in every figure.

[0009] Figure 1 shows illustrative circuitry of a light source module configured to control the color of light generated during dimming according to some embodiments;

[0010] Figure 2 shows illustrative circuitry of a light source module configured to control the color of light generated during dimming using a first illustrative current control circuit configuration in accordance with some embodiments;

[0011] Figure 3 shows illustrative circuitry of a light source module configured to control the color of light generated during dimming using a second illustrative current control circuit configuration in accordance with some embodiments;

[0012] Figure 4 is a diagram showing an illustrative relationship between a drive current of a light source module and current through various components of the module according to some embodiments;

[0013] Figure 5 shows an illustrative circuit of a light source module configured to control the color of light generated during dimming according to some embodiments, wherein a parallel control unit is provided;

[0014] Figure 6 An illustrative circuit of a light source module configured to control the color of light generated during dimming according to some embodiments is shown, wherein a diode is arranged in parallel with a control unit;

[0015] Figure 7 is a graph showing illustrative dimming color curves for two different light source modules according to some embodiments; and

[0016] FIG. 8A to FIG. 8B An illustrative color tunable point light source on a single substrate is shown in accordance with some embodiments. DETAILED DESCRIPTION

[0017] Techniques are provided for controlling the color of a light emitting device during dimming of the light emitting device. As discussed above, warm light has long been considered desirable in a light source because it tends to make the colors in an environment feel warm and comfortable. In particular, incandescent lamps naturally emit warm-colored light, and the color of the light can become even warmer when the lamp is dimmed, even tending to be orange or reddish in some cases. LED light sources produce light differently than incandescent lamps, however, dimming an LED light source by reducing the amount of current supplied to the LED generally has the effect of reducing the brightness of the light produced with little or no effect on the color temperature of the light.

[0018] In order to control the color of the LED light source during dimming, the traditional light source module contains LEDs of different color temperatures, and as the driving current of the light source module decreases, the amount of current passing through each of the different LEDs is controlled. However, the traditional method requires many complex electronic components to produce this balance, such as a microcontroller for the control circuit and a memory that defines the way the microcontroller performs the control. In some cases, the light source module may also include a current detection sensor, a current regulator and / or a switching circuit to control the current to the different LEDs.

[0019] During dimming, some conventional light sources may bypass portions of a circuit containing one or more LEDs to reduce the current flowing through the bypassed LEDs and thus reduce the light produced by the bypassed LEDs. As a result of changes in the relative brightness of the LEDs of the light source, the color temperature of the light source can be controlled if the LEDs have different color temperatures. However, such approaches may result in non-uniformities in the light. For example, in a lighting tube with an even distribution of warm and cool LEDs, at some point during dimming, the bypassed LEDs may receive a sufficiently low current that they go out while the other LEDs remain lit. The result is that the light source contains dark areas during dimming, which is undesirable.

[0020] The inventors have recognized and understood a technique for controlling the color of an LED light source during dimming that does not require complex electronic components such as a microcontroller. A current control circuit may be disposed within a light source module and configured to adjust the current path through some of the LEDs in the module according to a driving input current. If the multiple current paths through these LEDs have different impedances (or different forward voltages), the change in the current path will result in an increase or decrease in the amount of current through these LEDs. If the adjusted LED has a different color temperature than other LEDs of the light source module, the change in the current path as the current driving current is adjusted when the light source module is dimmed can affect the change in color temperature. Although in some cases, the current can be completely switched between paths, this is not necessary because any change in the relative extent to which the current flows through various paths may result in a change in color temperature. In addition, it is important to smoothly change the current through each LED of the circuit when the light source is dimmed to avoid the aforementioned dark zone during dimming. In other words, the technology described herein allows a change in the color temperature of the LED light source during dimming so that all LEDs of the light source are extinguished at substantially the same driving current.

[0021] As an example of the application of the technology described herein, consider a light source module including two groups of LEDs with different color temperatures. One of the two groups of LEDs is connected to two current paths parallel to each other. At a relatively high drive current, the current control circuit can operate so that the current passes through the first group of LEDs and the first current path in addition to the second group of LEDs. This higher drive current can produce a specific color temperature as a result of the relative brightness of the two groups of LEDs. However, at a relatively low drive current, the current control circuit can switch the current through the first group of LEDs to follow the second current path instead, while the current also flows through the second group of LEDs as before. However, now, a larger or smaller portion of the current can pass through the first group of LEDs compared to the second group of LEDs, because there is now a greater or reduced impedance to the current flowing through the first group of LEDs, respectively, compared to the second group of LEDs. Therefore, the ratio of the current flowing through the first group of LEDs and the second group of LEDs can be changed, and therefore their relative brightness and the perceived color temperature of the light can be changed. By adjusting the way the current control circuit switches the current in this way, and by adjusting the characteristics of the two current paths, the desired color temperature of the light source module can be produced when the light source module is dimmed. Again, it is important that the switching of the current through the current control circuit does not stop current from flowing through the LEDs of the circuit, as this would create dark areas in the light source.

[0022] According to some embodiments, the current control module can control the color temperature of the light generated by the light source module by providing a bypass for the driving current. In particular, the current control module can include at least one transistor that switches modes when the driving current decreases, thereby opening and / or closing a current path for the driving current to follow.

[0023] According to some embodiments, the light source module may include one or more control units connected along alternative current paths, and the current control module may perform switching as described above between the alternative current paths. A suitable control unit may include any non-luminous component for changing the way current flows through one of the alternative current paths compared to another alternative current path. In some cases, a control unit may be selected to change the way the current flowing through the control unit varies according to the drive current to produce the desired behavior. For example, selecting another control unit relative to one control unit can affect the amount of current flowing through the control unit (and / or through a different one of the alternative current paths) when the drive current changes. In this way, the selection of the control unit can affect how the color temperature of the light source module changes with the drive current.

[0024] Although the use of a light-emitting component in place of a control unit may produce current changes during dimming, as discussed above, this may result in dark areas in the light source when the current through the light-emitting component is low enough that the component is extinguished while other areas of the light source module are still emitting light during dimming. It may be true that a circuit that includes a light-emitting component in place of a control unit has higher efficiency because more light will be produced in the circuit for the same current when compared to the same circuit that includes a control unit. However, the techniques described herein can achieve the benefits of smooth transitions in light intensity and color temperature during dimming (a benefit that would not be produced by a circuit that includes a light-emitting component in place of a control unit), albeit at the expense of reduced efficiency.

[0025] The following is a more detailed description of various embodiments of the technology for controlling the color of an LED light source during dimming and various related concepts. It should be understood that the various aspects described herein can be implemented in any of a variety of ways. The examples of specific implementations provided herein are for illustrative purposes only. In addition, the various aspects described in the following embodiments can be used alone or in any combination, and are not limited to the combinations explicitly described herein.

[0026] Figure 1 An illustrative circuit of a light source module configured to control the color of light generated during dimming according to some embodiments is shown. Figure 1In the example of FIG. 1 , the circuit 100 includes a driving current source 105 and two groups of LEDs 101a to 101h and 102a to 102h, each group of LEDs being connected in series. In addition, the group of LEDs 101a to 101h is connected in series with two control units 111 and 112, and the group of LEDs 101a to 101h is connected in series to a current control circuit 120, which is connected in parallel with the control units 111 and 112. A circuit ground 106 is provided.

[0027] supply Figure 1 As an illustrative circuit, the current control circuit can control the color of the light source module by changing the path of the current through some (but not all) of the LEDs according to the driving input current. In the illustrative circuit 100, the current control circuit 120 can be configured to adjust the degree to which the current flows through the current control circuit compared to the control unit 111 and the control unit 112 according to the driving current 105.

[0028] exist Figure 1 In the example of FIG. 1 , there are two alternative current paths connected to the first group of LEDs 101a to 101h: a first path, i.e., a path from LED 101h to ground 106 via current control circuit 120; and a second path, i.e., a path from LED 101h to ground 106 via control unit 111 and control unit 112. As discussed above, if these paths differ in impedance (or forward voltage), then changing the degree to which current flows through each of the two paths will result in changes in the relative amounts of current flowing through LEDs 101a to 101h and 102a to 102h.

[0029] For example, assume that current flows along the second path via control unit 111 and control unit 112, and the amount of current flowing through LEDs 101a to 101h and the control unit is equal to the amount of current flowing through LEDs 102a to 102h. In addition, current control circuit 120 operates to cause at least some current to flow along the first path through the current control circuit rather than the second path through control unit 111 and control unit 112. Assuming that the impedance (or forward voltage) of the two paths is not equal, this operation may result in more or less current flowing through LEDs 101a to 101h than in the case of LEDs 102a to 102h. If the color temperature of LEDs 101a to 101h is different from the color temperature of LEDs 102a to 102h, the color temperature of the combined light generated by the LEDs of circuit 100 may be changed by the operation of current control circuit 120.

[0030] According to some embodiments, LEDs 101a to 101h may be configured to generate light having a different color temperature than that of LEDs 102a to 102h. For simplicity, this characteristic of an LED is hereinafter referred to as the color temperature of the LED. Furthermore, for the purpose of comparing the color temperature of one LED with the color temperature of another LED, it is assumed that the comparison is made with the same current input to the LED, because in some cases, the color temperature of the LED may vary with the input current.

[0031] In some embodiments, the color temperature of the LEDs 101a to 101h is each greater than or equal to 1000K, 1500K, 2000K, 2500K, or 3000K. In some embodiments, the color temperature of the LEDs 101a to 101h is each less than or equal to 4000K, 3500K, 3000K, 2500K, 2000K, 1500K. Any suitable combination of the above reference ranges is also possible (e.g., the color temperature of each of the LEDs 101a to 101h is greater than or equal to 1500K and less than or equal to 2500K, etc.). The preferred range of each of the color temperatures of the LEDs 101a to 101h is between 1500K and 3000K.

[0032] In some embodiments, the color temperature of the LEDs 102a to 102h is each greater than or equal to 3000K, 3500K, 4000K, 4500K, or 5000K. In some embodiments, the color temperature of the LEDs 102a to 102h is each less than or equal to 8000K, 7500K, 7000K, 6500K, 6000K, 5500K, 5000K, 4500K, 4000K, 3500K, or 3000K. Any suitable combination of the above reference ranges is also possible (e.g., the color temperature of each of the LEDs 102a to 102h is greater than or equal to 3500K and less than or equal to 4500K, etc.). The preferred range of each of the color temperatures of the LEDs 102a to 102h is between 3500K and 7500K.

[0033] In some embodiments, all of LEDs 101a to 101h may have a first color temperature, and all of LEDs 102a to 102h may have a second, different color temperature. In other cases, the two groups of LEDs may present a range of color temperatures; these two ranges may or may not overlap.

[0034] According to some embodiments, LEDs 101a to 101h and LEDs 102a to 102h may be intermediate white LEDs, such as but not limited to commercially available LEDs with model numbers 3030, 3014, 2016, 2835, 5630, or combinations thereof. In some embodiments, one or more of LEDs 101a to 101h and LEDs 102a to 102h may have a frameless light emitting surface, such as but not limited to CSP (chip scale package) LEDs, CubeTM LEDs (e.g., models MP1616, MP1919), and / or LED packages in which all or substantially all of the package size is the light emitting surface. These types of packages may enable the LEDs to be arranged in high-density lighting arrays.

[0035] According to some embodiments, control unit 111 and control unit 112 can each be a non-luminous component, such as a non-luminous semiconductor diode, resistor or transistor. In addition, any number of control units can be included along the current path between the group of LEDs 101a to 101h and ground. In some embodiments, one or more control units can be connected in series with LEDs 102a to 102h.

[0036] According to some embodiments, the control unit 111 and the control unit 112 may each be a pure resistance component having a linear IV characteristic curve. According to some embodiments, the control unit 111 and the control unit 112 may each be a component having a nonlinear IV characteristic curve, such as a photoresistor, a thermistor, a varistor, a diode, a transistor, or a thyristor. According to some embodiments, one or both of the control unit 111 and the control unit 112 may include a semiconductor PN junction.

[0037] According to some embodiments, the current control circuit 120 can be configured to open or close one or more circuit paths when the drive current 105 decreases. In some embodiments, these changes in the structure of the current control circuit 120 can be achieved by including one or more transistors in the current control circuit, and the operation mode of the one or more transistors changes as the drive current 105 changes. In some embodiments, the voltage across the transistors of the current control circuit 120 (e.g., the base collector voltage and / or the base emitter voltage) can exceed a critical value, thereby causing the operation mode of the transistor to change. This operation mode change can open and / or close the current path from the LED 101h to the ground through the current control circuit 120, thereby causing a change in the amount of current flowing through the LEDs 101a to 101h.

[0038] In some embodiments, the current control circuit can be connected to portions of circuit 100 in other ways than shown; for example, current control circuit 120 can be connected in parallel with LEDs 101a to 101h, or can be connected to ground 106 via other paths, it can include one or more components, etc.

[0039] In some embodiments, all components in circuit 100 can be arranged on a single printed circuit board (PCB). For example, circuit 100 can be arranged on a FR4 board, a MCPCB board, or a ceramic board. Current control circuit 120 can be a discrete control circuit module or an integrated circuit (IC). Arranging the components of circuit 100 on a single board can have the advantages of making the lighting fixture including circuit 100 more compact, lower cost, simple manufacturing process, and / or reducing power loss.

[0040] In some embodiments, the current control circuit 120 may include one or more variable resistors. Such a resistor may be external, meaning that it may be adjusted separately from the rest of the current control circuit (which may be an integrated circuit). The variable resistor may allow control of the dimming curve of the circuit 100, which is the relationship between the color temperature of the light produced from the circuit and the drive current 105. For example, changing the amount of resistance at one or more portions of the current control circuit may change the shape of the dimming curve. Examples of this behavior are described below with respect to Figure 7 Have a discussion.

[0041] It should be understood that providing Figure 1 The example is intended to illustrate how the current control circuit 120 can control the flow of current between multiple paths and therefore how to control the relative amount of current flowing between two groups of LEDs during dimming, and other configurations of such a circuit may be possible. For example, it should be understood that additional components can be arranged within the circuit 100 without changing the functionality of the circuit. In addition, more than two current paths connected to a group of LEDs can also be considered, and the more than two current paths can even include more than one current control circuit, each current control circuit having an effect on the path that the current through the first group of LEDs subsequently follows. In addition, although two groups of LEDs are shown, any number of such groups may be included, including multiple groups with control units and / or multiple groups connected to current control circuits.

[0042] Figure 2 Illustrative circuitry is shown of a light source module configured to control the color of light generated during dimming using a first illustrative current control circuit configuration in accordance with some implementations. Figure 2 An example of a circuit 100 with an illustrative design for a current control circuit 120 is shown.

[0043] exist Figure 2 In the example of FIG. 2 , the circuit 200 includes a driving current source 205 and two groups of LEDs 201a to 201h and 202a to 202h, each group of LEDs being connected in series. In addition, the group of LEDs 201a to 201h is connected in series with two control units 211 and 212, and the group of LEDs 201a to 201h is connected in series to a current control circuit 220, which is connected in parallel with the control units 211 and 212. A circuit ground 206 is provided.

[0044] exist Figure 2 In the example of FIG. 2 , the current control circuit 220 includes a transistor 221 and resistors 222 and 223. Under a relatively high drive current 205, the potential difference V between the emitter of the transistor 221 and the base of the transistor BE , and the potential difference V between the base and collector of the transistor BC The transistor can be operated in cutoff mode (for example, V BE is less than about 0.7V and V BC Thus, at this higher drive current, no current will flow from the LEDs 201a to 201h through the current control circuit 220, but current will flow through the control units 211 and 212.

[0045] As the driving current is reduced to dim the light source module (of which the circuit 200 is a component), V BE 21. The current generated by the circuit 200 may rise to about 0.7V or more, causing the transistor 221 to transition to a saturated mode of operation or a forward active mode of operation. When this occurs, current will begin to flow through the current control circuit 220, and less through the control units 211 and 212. Eventually, the drive current may become low enough that little or no current flows through the control units 211 and 212, and all or nearly all of the current flowing through the LEDs 201a to 201h also flows through the current control circuit 220. As the current transitions between these paths, the current through the LEDs 201a to 201h and the current control circuit 220 will increase, resulting in a greater portion of the light generated by the circuit 200 being output from the LEDs 201a to 201h rather than from the LEDs 202a to 202h than the relative portion of the light generated from the two groups of LEDs at the higher drive current.

[0046] By way of example and not limitation, illustrative values ​​for resistor 222 and resistor 223 may be 100 kΩ and 350 Ω, respectively.

[0047] Figure 3Illustrative circuitry is shown for a light source module configured to control the color of light generated during dimming using a second illustrative current control circuit configuration in accordance with some implementations. Figure 3 An example of a circuit 100 with an illustrative design for a current control circuit 120 is shown.

[0048] exist Figure 3 In the example of FIG. 3 , the circuit 300 includes a driving current source 305 and two groups of LEDs 301a to 301h and 302a to 302h, each group of LEDs being connected in series. In addition, the group of LEDs 301a to 301h is connected in series with two control units 311 and 312, and the group of LEDs 301a to 301h is connected in series to a current control circuit 320. A circuit ground 306 is provided.

[0049] exist Figure 3 In the example of FIG. 3 , in addition to resistors 323, 324, 325, 326, and 327, the current control circuit 320 also includes transistors 321 and 322. Under a relatively high drive current 305, the potential difference V between the emitter of transistor 321 and the base of transistor 321 is BE1 It may be above about 0.7V, so that transistor 321 is in a forward active mode or saturation mode. Resistor 327 may be configured to facilitate this behavior. For example, if the drive current is about 900mA, resistor 327 may have a resistance of about 1Ω.

[0050] exist Figure 3 In the example of FIG. 1 , resistor 321 and resistor 322 may be configured such that: when transistor 321 is active at a relatively high drive current, the potential difference V between the emitter of transistor 322 and the base of transistor 322 is BE2 is lower than about 0.7 V. Therefore, the transistor 322 can operate in a cut-off operation mode at a higher drive current, and no current will pass through the current control circuit 320 from the LEDs 301 a to 301 h , but the current will pass through the control units 311 and 312 .

[0051] As the driving current is reduced to dim the light source module (of which the circuit 300 is a component), V BE1 can drop below about 0.7V, causing transistor 321 to transition to the cutoff mode of operation. This in turn causes the voltage at the base of transistor 322 to drop rapidly, which can cause V BE2302a to 302h.

[0052] By way of example and not limitation, illustrative values ​​for resistors 323 - 327 may be as follows: resistor 323 = 5 kΩ; resistor 324 = 1 kΩ; resistor 325 = 36 kΩ; resistor 326 = 10 kΩ; resistor 327 = 0.8 Ω.

[0053] Figure 4 is a graph showing an illustrative relationship between a drive current of a light source module and current through various components of the module according to some embodiments. For example, graph 400 can show the relative amount of current through different LEDs and through a control unit in any of circuits 100, 200, or 300 according to a drive current (e.g., 105, 205, or 305, respectively). Figure 4 In the example of FIG. 1 , the LED associated with the current control circuit that controls the amount of current flowing through the LED, such as any of the LEDs 101a to 101h, 201a to 201h, or 301a to 301h, is referred to as a "bypass LED." Additionally, the LED not associated with the current control circuit, such as any of the LEDs 102a to 102h, 202a to 202h, or 302a to 302h, is referred to as a "non-bypass LED."

[0054] As in Figure 4 As shown in the example of , the currents through the bypass LED, the non-bypass LED and the control unit, shown by lines 401, 402 and 403 respectively, are the same above a certain critical value of the drive current (as shown in the upper right of the graph 400). Figure 4 An example may relate to a light source module in which the same number of LEDs are arranged in each of the bypass group and the non-bypass group.

[0055] Below this critical drive current, which may be, for example, the drive current at which the alternative current path begins to open, the current through the control unit begins to drop, and at the same time the amount of current through the bypass LED becomes greater than the amount of current through the non-bypass LED. As discussed above, assuming that the bypass LED has a different color temperature than the non-bypass LED, Figure 4 The behavior shown in illustrates how the color temperature of the combined light can be controlled during dimming of the light source module due to a reduced drive current being supplied to the light source module. Figure 4 It can be noted in the example of that the brightness of the non-bypassed LED can be expected to drop to zero or near zero at low drive currents, while the bypassed LED remains efficient in generating light. This can allow, for example, warm light to be generated from the light source module at low brightness.

[0056] Figure 5 An illustrative circuit of a light source module configured to control the color of light generated during dimming is shown, wherein a parallel control unit is provided, according to some embodiments. Figure 5 An example of a circuit 100 is shown in which a control unit is connected in series with a second set of LEDs.

[0057] exist Figure 5 In the example of FIG. 5 , the circuit 500 includes a driving current source 505 and two groups of LEDs 501a to 501h and 502a to 502h, each group of LEDs being connected in series. In addition, the group of LEDs 501a to 501h is connected in series with two control units 511 and 512, and the group of LEDs 501a to 501h is connected in series to a current control circuit 520. The group of LEDs 502a to 502h is connected in series with two control units 513 and 514. A circuit ground 506 is provided.

[0058] As discussed above, in some cases, the control unit can be connected in series with LEDs whose current is not directly controlled by the current control circuit. This configuration can have the advantage of equalizing the behavior of multiple groups of LEDs at certain drive currents by simulating components along one of the current paths connected to the non-current controlled LEDs (e.g., LEDs 502a to 502h) along another path connected to the current controlled LEDs (e.g., LEDs 501a to 501h).

[0059] Figure 6 An illustrative circuit of a light source module configured to control the color of light generated during dimming is shown, in accordance with some embodiments, wherein diodes are arranged as parallel control units. Figure 6 An example of a circuit 100 is shown in which the control unit is a diode (eg, a semiconductor diode) and is connected in series with four groups of LEDs, two of which are current controlled by a current control circuit 620 .

[0060] exist Figure 6 In the example of FIG. 6 , the circuit 600 includes a driving current source 605 and four groups of LEDs 601a to 601h, 602a to 602h, 603a to 603h, and 604a to 604h, each group of LEDs being connected in series. In addition, the group of LEDs 601a to 601h is connected in series with three control units 611a to 611c (the control units 611a to 611c are diodes), and the group of LEDs 601a to 601h is connected in series to a current control circuit 620. The group of LEDs 602a to 602h is connected in series with three control units 612a to 612c (the control units 612a to 612c are diodes), and the group of LEDs 602a to 602h is connected in series to a current control circuit 620. The group of LEDs 603a to 603h is connected in series with three control units 613a to 613c (control units 613a to 613c are diodes), and the group of LEDs 604a to 604h is connected in series with three control units 614a to 614c (control units 614a to 614c are diodes). A circuit ground 606 is provided.

[0061] As in Figure 6 In the example of , using a diode as a control unit can have the advantage that the forward voltage varies with the current through the control unit. In particular, it can be desirable that diodes 611a to 611c and diodes 612a to 612c have nonlinear IV characteristic curves so that when the current through the control unit becomes sufficiently low, the forward voltage across the diode drops rapidly. Current control circuit 620 can be configured in any suitable manner, including as in Figure 2 and Figure 3 The current control circuit 220 or 320 shown in and discussed above.

[0062] Figure 7 7 is a diagram showing illustrative dimming color curves for two different light source modules according to some embodiments. Graph 700 shows two illustrative dimming curves, which are the relationship between the color temperature of light generated from a light source module and the drive current to the module. For example, a first light source module can exhibit a dimming curve 710, where the color temperature becomes significantly warmer (lower color temperature) at a drive current below about 100 mA. A second light source module can alternatively exhibit a dimming curve 720, where the color temperature gradually becomes warmer as the drive current decreases.

[0063] As discussed above, based on the desired dimming curve, the current control circuit can be configured, for example, by selecting components and / or component parameters to produce a specific dimming curve. Figure 3 The resistor 327) can at least partially determine the shape of the dimming curve of the light source module including the circuit. In some embodiments, such a resistor can be variable, so that a user may be able to change a single light source module to produce a dimming curve by changing the resistance of the variable resistor. Figure 7 Different dimming curves 710 and 720 (other dimming curves are also possible) are shown in FIG.

[0064] FIG. 8A to FIG. 8B An illustrative color tunable point light source on a single substrate is shown according to some embodiments. Fig. 8A and Figure 8B In the example of , a plurality of LEDs with "warm" white or "cold" white colors, labeled "W" and "C", are arranged on substrate 801 / 802. For example, according to the above circuit example, a current control circuit labeled "CCC" and a control unit labeled "CU" are coupled to the LED array.

[0065] According to some embodiments, substrate 801 and substrate 802 may include a metal core printed circuit board (MCPCB) that can provide good heat dissipation. In some embodiments, one or more of the LEDs (also marked as "C" or "W") can be a frameless LED - such as a cubic LED, so that the light emitting area can be tightly assembled on the substrate. The number of LEDs can be selected to provide the desired light source light emitting surface diameter of the array package (e.g., 6mm, 9mm, 14mm, 18mm, etc.). In some embodiments, the light source can be alternatively configured in a linear plate for cove ceiling lighting, linear tubes, linear fixtures and / or panel applications, or configured in a circular plate with a suitable diameter for application in A bulbs, BR lamps, ceiling lamps and / or downlight applications.

[0066] Having thus described several aspects of at least one embodiment of this invention, it is to be appreciated various alterations, modifications, and improvements will readily occur to those skilled in the art.

[0067] Such changes, modifications and improvements are intended to be part of the present disclosure and are intended to fall within the spirit and scope of the present invention. In addition, although the advantages of the present invention are pointed out, it should be understood that not every embodiment of the technology described herein will include each described advantage. Some embodiments may not implement any feature described as advantageous herein, and in some cases, one or more of the described features may be implemented to implement further embodiments. Therefore, the above description and accompanying drawings are only examples.

[0068] For example, it should be understood that the light source modules described herein can be arranged in any suitable lighting device, including but not limited to light bulbs (e.g., A19-type bulbs, raised reflector (BR) bulbs, or parabolic aluminized reflector (PAR) bulbs), track lighting, spotlighting, downlights, etc.

[0069] The various aspects of the present invention may be used alone, in combination, or in a variety of arrangements not specifically discussed in the embodiments described in the foregoing, and therefore its application is not limited to the details and arrangements of the components set forth in the foregoing description or shown in the drawings. For example, aspects described in one embodiment may be combined in any manner with aspects described in other embodiments.

[0070] In addition, the present invention can be implemented as a method, examples of which have been provided. The actions performed as part of the method can be ordered in any suitable manner. Thus, embodiments can be constructed in which the actions are performed in an order different from the order shown, and even if shown as sequential actions in an illustrative embodiment, the embodiment can also include performing some actions simultaneously.

[0071] Additionally, some actions are described as being taken by a “user.” It should be understood that a “user” need not be a single individual, and in some implementations, actions attributed to a “user” may be performed by a group of individuals and / or individuals in conjunction with computer-assisted tools or other devices.

[0072] The use of ordinal terms such as "first", "second", "third", etc. in the claims to modify claim elements does not itself imply any priority, precedence or sequence of one claim element relative to another claim element, or the temporal order of the actions of performing the method, but is merely used as a mark to distinguish one claim element with a certain name from another element with the same name (only for the use of ordinal terms), thereby distinguishing the claim elements.

[0073] In addition, the words and terms used herein are for descriptive purposes and should not be considered limiting. The use of "includes," "comprising," or "having," "containing," "involving," and variations thereof herein is intended to include the items listed thereafter and their equivalents as well as additional items.

Claims

1. A light source module circuit, comprising: a plurality of first LEDs connected in series, the first LEDs being configured to generate light having a first color temperature; a first current path connected in series with the plurality of first LEDs and comprising one or more control units; a plurality of second LEDs connected in series, the second LEDs being configured to generate light having a second color temperature different from the first color temperature, wherein the plurality of first LEDs are connected in series with the one or more control units, and the plurality of second LEDs are connected in parallel with the plurality of first LEDs and the one or more control units; and a second current path connected in parallel to the one or more control units and comprising a current control circuit, The current control circuit is configured to adjust the impedance and / or the forward voltage of the first current path and / or the second current path according to the driving current input to the plurality of first LEDs and the plurality of second LEDs, thereby adjusting the amount of current passing through the plurality of first LEDs when the current passes through the plurality of second LEDs at the same time. wherein the current control circuit comprises a transistor, and wherein the impedance and / or the forward voltage of the first current path and / or the second current path is adjusted at least in part according to whether the transistor is in an off mode or an off mode, The light source module circuit also includes one or more resistors connecting the base of the transistor to the input drive current, and one or more resistors connecting the base of the transistor to the circuit ground. The one or more resistors connecting the base of the transistor to the input drive current are connected to the input drive current via the second transistor.

2. The light source module circuit according to claim 1, wherein: The one or more control units include one or more diodes.

3. The light source module circuit according to claim 2, wherein: The one or more control units are diodes.

4. The light source module circuit according to claim 1, wherein: All of the first color temperatures are lower than any of the second color temperatures.

5. The light source module circuit according to claim 4, wherein: The first color temperatures are each between 1500K and 3000K, and wherein the second color temperatures are each between 3500K and 7500K.

6. The light source module circuit according to claim 1, wherein: The plurality of first LEDs and the plurality of second LEDs include the same number of LEDs. 7 . The light source module circuit of claim 1 , further comprising one or more control units connected in series with the plurality of second LEDs.

8. The light source module circuit according to claim 1, wherein: The first plurality of LEDs includes at least 3 LEDs, and wherein the second plurality of LEDs includes at least 3 LEDs.

9. The light source module circuit according to claim 1 further comprises at least one variable resistor, wherein the at least one variable resistor is configured to adjust the relationship between the driving current and the color temperature of the light generated by the light source module circuit according to the resistance of the at least one variable resistor.

10. The light source module circuit according to claim 1, wherein: The plurality of first LEDs, the one or more control units, the plurality of second LEDs, and the current control circuit are manufactured on a single printed circuit board.

11. The light source module circuit according to claim 10, wherein: The current control circuit includes an integrated circuit coupled to an external resistor.

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