A lighting device based on light-emitting diodes (LEDs), comprising at least two strings of light-emitting diodes (LEDs) for emitting light, and a corresponding method.

Abstract

A lighting device based on a light-emitting diode (LED) includes: a power supply; a first LED string comprising a plurality of first LEDs connected in series, wherein the first LED string is connected to the power supply; a second LED string comprising a plurality of second LEDs connected in series, wherein the output of the second LED string is connected to the output of the first LED string; and a 1:N one-to-many switch, wherein the input of the switch is connected to the power supply, and wherein the output of the switch is connected to the input of subsequent LEDs in the second LED string, such that the position of the 1:N one-to-many switch determines the number of LEDs in the second LED string powered by the power supply.

Description

Technical Field

[0001] This disclosure generally relates to the field of lighting, and more specifically, to an LED-based lighting device comprising at least two strings of light-emitting diodes (LEDs) and whose light output can be controlled. Background Technology

[0002] In recent years, the lighting industry has undergone a transformation with the adoption of light-emitting diode (LED) technology. Among the many innovations in this specific technological field, LED-based lighting devices with multiple parallel LED strings have been developed as efficient solutions for various application scenarios. Compared to traditional light sources, these devices offer higher performance, greater flexibility, and higher reliability.

[0003] The basic concept behind these LED-based lighting devices relates to the design of parallel LED strings. In this configuration, multiple LED strings are connected in parallel to a common power supply. Each LED string consists of several individual LEDs, and these strings share the same power supply while distributing the total current provided by the power supply.

[0004] One of the advantages of this parallel arrangement is its redundancy. If one LED string fails or malfunctions, the other strings can continue to operate, ensuring uninterrupted lighting. This robustness makes parallel LED configurations particularly suitable for critical applications requiring continuous illumination.

[0005] LED-based lighting devices with parallel LED strings offer advanced functionality, allowing users to customize the color temperature of the emitted light. Color temperature refers to the perceived warmth or coolness of light, measured in Kelvin. By adjusting the current flowing through each LED string, users can change the color temperature to achieve the desired atmosphere or lighting for a specific task. This flexibility makes these devices suitable for a wide range of environments, from comfortable living spaces to those requiring clinical-grade lighting.

[0006] Another feature of these LED lighting devices is the ability to control the ratio of uplighting to downlighting. Uplighting refers to the portion of light beams directed upwards, typically used for ambient or indirect lighting. Downlighting, on the other hand, refers to the portion of light beams directed downwards, providing focused illumination. Users can manipulate the ratio of uplighting to downlighting by adjusting the intensity of specific LED strings. This controllability allows architects and designers to fine-tune the lighting environment, enhancing aesthetics, comfort, and functionality.

[0007] LED-based lighting fixtures with parallel LED strings represent a significant advancement in the lighting industry. Their parallel configuration provides redundancy, ensuring reliability, while the ability to customize color temperature and uplight / downlight ratios makes it possible to create tailored lighting experiences in different environments.

[0008] One of the driving forces behind innovators is to reduce the complexity and / or size of these LED-based lighting devices without sacrificing functionality too much. Summary of the Invention

[0009] This disclosure aims to provide a light-emitting diode (LED) based lighting device comprising two LED strings, wherein the LED-based lighting device is implemented such that the number of LEDs powered by a power supply can be controlled.

[0010] According to a first aspect of this disclosure, a lighting device based on a light-emitting diode (LED) is provided, comprising:

[0011] power supply;

[0012] A first LED string includes a plurality of first LEDs connected in series, wherein the first LED string is connected to the power supply;

[0013] The second LED string includes a plurality of second LEDs connected in series, wherein the output terminal of the second LED string is connected to the output terminal of the first LED string;

[0014] A 1:N one-to-many switch, wherein the input of the switch is connected to the power supply, and wherein the output of the switch is connected to the subsequent input of each LED in the second LED string, such that the position of the 1:N one-to-many switch determines the number of LEDs in the second LED string powered by the power supply.

[0015] The inventors discovered that it is beneficial to design LED-based lighting devices in a way that allows control over the number of LEDs actually powered by the power source.

[0016] This control can be achieved by introducing a 1:N one-to-many switch. The input of this switch is directly or indirectly connected to the power supply, while its output is connected to the subsequent inputs of the LEDs in the second LED string. In this way, the position of the 1:N one-to-many switch determines the actual number of LEDs in the second LED string that are powered by the power supply.

[0017] This can be illustrated with a simple example.

[0018] The first LED string consists of five LEDs connected in series. The input terminal (i.e., its anode) of the first LED is connected to a power source. The output terminal (i.e., its cathode) of the first LED is connected to the input terminal of the second LED. The output terminal of the second LED is connected to the input terminal of the third LED. The output terminal of the third LED is connected to the input terminal of the fourth LED. The output terminal of the fourth LED is connected to the input terminal of the fifth LED. The output terminal of the fifth LED is connected to a power source.

[0019] The second LED string comprises five LEDs connected in series. The input terminal (i.e., its anode) of the first LED is connected to one of the output terminals of a 1:N switch. The output terminal (i.e., its cathode) of the first LED is connected to the input terminal of the second LED. The input terminal of the second LED is also connected to one of the output terminals of the 1:N switch. The output terminal of the second LED is connected to the input terminal of the third LED. The input terminal of the third LED is also connected to one of the output terminals of the 1:N switch. The output terminal of the third LED is connected to the input terminal of the fourth LED. The output terminal of the fourth LED is connected to the input terminal of the fifth LED. The output terminal of the fifth LED is connected to the output terminal of the fifth LED in the first LED string.

[0020] In this specific example, the 1:N switch is actually a 1:3 switch. The switch has three possible states. First state: Power is connected to the input of the first LED via the switch. Second state: Power is connected to the input of the second LED via the switch. Third state: Power is connected to the input of the third LED via the switch. If power is connected to the input of the third LED via the switch, then the first and second LEDs will be in a floating state. This means that only the third, fourth, and fifth LEDs are actually powered and illuminated.

[0021] The example above shows that the state of the switch determines the number of LEDs activated in the second string.

[0022] In one example, the power supply is a constant current-based power supply.

[0023] A voltage source provides a constant voltage difference, or voltage potential, between its terminals to maintain a fixed voltage output, such as 5 volts or 12V. However, the current flowing through a circuit connected to the voltage source varies depending on the impedance in the circuit. Higher impedance results in lower current, and lower impedance results in higher current. Essentially, a voltage source maintains its output voltage constant but allows the current to fluctuate according to the circuit impedance.

[0024] In contrast, a current source provides a constant current regardless of the voltage across its terminals. It maintains a fixed current output, such as 1 amp or 10 amps. The voltage across a circuit connected to a current source will vary depending on the circuit's impedance. It automatically adjusts the voltage across its terminals to maintain the specified current, and is therefore load-independent. Essentially, a current source keeps the current constant while allowing the voltage to vary as needed.

[0025] In one example, LED-based lighting devices also include:

[0026] - A third LED string, comprising a plurality of third LEDs, wherein the output of the third LED string is connected to the output of the first LED string; and

[0027] - A second 1:N one-to-many switch, wherein the input of the second switch is connected to the power supply, and wherein the output of the second switch is connected to the subsequent input of the LEDs in the third LED string, such that the position of the second 1:N one-to-many switch determines the number of LEDs in the third LED string powered by the power supply.

[0028] The advantage of this particular example is that it allows control of multiple LED strings. The number of LEDs in both the second and first LED strings can be controlled. This provides greater flexibility and more tuning capabilities compared to embodiments that can only control the number of LEDs in a single LED string.

[0029] In another example, the second LED string further includes one or more diodes connected in series with the plurality of second LEDs, and at least one output of the 1:N one-to-many switch is connected to the input of the one or more diodes.

[0030] In some cases, replacing some LEDs with diodes, or adding diodes to a second LED string, can make the light emission surface of the luminaire more uniform. This will only slightly reduce efficiency. For example, this can be used for calibration purposes, such as in uplight / downlight applications.

[0031] In yet another example, LED-based lighting devices also include:

[0032] - An N:1 many-to-one switch, wherein the output of the switch is connected to the power supply, and wherein the input of the switch is respectively connected to the subsequent input of an LED in the second LED string and the input of a corresponding subsequent LED in the first LED string, such that the position of the 1:N one-to-many switch and the position of the N:1 many-to-one switch together determine the number of LEDs in the first and second LED strings powered by the power supply.

[0033] The advantage of this particular example is that the N:1 switch can be used as a dimmer. The same number of LEDs can be enabled / activated, for example, two LEDs in each of the first and second LED strings. This effectively achieves the dimming function.

[0034] In another example, the first LED string and the second LED string consist of the same type of LEDs.

[0035] In this particular application, the first LED string can be guided downwards, the second LED string can be guided upwards, and vice versa.

[0036] In another example, the power supply is a current-based power supply, and the LED device further includes:

[0037] A control mechanism for controlling the amount of current supplied by the current-based power supply based on the voltage on the first LED string.

[0038] In another example, the device includes:

[0039] - Voltage absorption units are respectively arranged between the output terminal of the switch and the subsequent input terminal of the LED in the second LED string.

[0040] The voltage absorption unit may include a non-LED-based diode.

[0041] The switch can be a mechanical switch.

[0042] A mechanical switch is a device that enables or disables LEDs in various LED-based lighting fixtures. Such switches are designed to physically connect or disconnect a circuit, thereby allowing or interrupting the flow of current to the LED. When the switch is in a specific position, the input is connected to one of several outputs; that is, the circuit is closed, current flows, and the LED is lit.

[0043] In a second aspect of this disclosure, a method for operating a light-emitting diode (LED) based lighting device is provided, wherein the method includes the following steps:

[0044] - By connecting the input terminal of the 1:N one-to-many switch to the power supply and connecting one of the output terminals of the switch to the input terminal, the position of the 1:N one-to-many switch determines the number of LEDs in the second LED string powered by the power supply.

[0045] It should be noted that the advantages described with reference to the first aspect of this disclosure (i.e., lighting devices based on light-emitting diodes (LEDs)) also apply to the second aspect of this disclosure (i.e., methods of operating such LED-based lighting devices).

[0046] In one example, the LED-based lighting device further includes a third LED string comprising a plurality of third LEDs, wherein the output of the third LED string is connected to the output of the first LED string, and a second 1:N one-to-many switch, wherein the input of the second switch is connected to the power supply, and the output of the second switch is respectively connected to the subsequent inputs of the LEDs in the third LED string, wherein the method further includes the following steps:

[0047] - By connecting the input terminal of the second switch to the power supply through the 1:N one-to-many switch, and connecting one of the output terminals of the second switch to the input terminal, the position of the second 1:N one-to-many switch determines the number of LEDs in the third LED string powered by the power supply.

[0048] In other examples, the method also includes:

[0049] - The amount of current supplied by the current-based power supply is controlled by a control mechanism based on the voltage on the first LED string.

[0050] In another example, the device also includes a voltage absorption unit, which is respectively arranged between the output of the switch and the subsequent input of the LEDs in the second LED string.

[0051] In yet another example, the method also includes the following steps:

[0052] – The user receives tactile input from the switch regarding the position of the switch.

[0053] This disclosure is described in conjunction with the accompanying drawings. It should be emphasized that, according to industry standards, the various features are not drawn to scale. In fact, for clarity, the dimensions of the various features can be arbitrarily increased or decreased.

[0054] In the accompanying drawings, similar parts and / or features may have the same reference numerals. Furthermore, various parts of the same type can be distinguished by adding a dash after the reference numeral and a second reference numeral. If only the first reference numeral is used in the description, the description applies to any similar parts having the same first reference numeral, regardless of the second reference numeral.

[0055] The above and other aspects of this disclosure will become apparent and readily understood through the examples described below with reference to the accompanying drawings. Attached Figure Description

[0056] Figure 1 An example of a light-emitting diode (LED) based lighting device according to the present disclosure is disclosed;

[0057] Figure 2 Another example of an LED-based lighting device according to this disclosure is disclosed;

[0058] Figure 3 Another example of an LED-based lighting device according to this disclosure is disclosed;

[0059] Figure 4 Another example of an LED-based lighting device according to this disclosure is disclosed;

[0060] Figure 5 An example of the method according to this disclosure is disclosed. Detailed Implementation

[0061] It should be noted that in the description of the accompanying drawings, the same reference numerals refer to the same or similar parts that perform the same or substantially similar functions.

[0062] The following description will be more detailed with reference to specific examples shown in the accompanying drawings to provide a more thorough understanding of the features of this disclosure. It should be noted that the drawings illustrate only typical examples and should not be construed as limiting the scope of the claims. The drawings are intended to facilitate understanding of this disclosure and are not necessarily drawn to scale. Those skilled in the art will appreciate the advantages of the claimed subject matter upon reading this specification and in conjunction with the accompanying drawings.

[0063] The above description provides only preferred examples and is not intended to limit the scope, applicability, or configuration of this disclosure. Rather, the following description of preferred examples will provide those skilled in the art with a feasible description of how to implement the preferred examples of this disclosure. It should be understood that various changes can be made to the function and arrangement of the elements, including combining features of different embodiments, without departing from the scope of this disclosure.

[0064] Unless the context explicitly requires otherwise, throughout the specification and claims, the words “comprising,” “including,” and variations thereof shall be understood as inclusive, not exclusive or exhaustive; that is, meaning “including but not limited to.” The terms “connection” or “coupling,” or any variations thereof, as used herein, refer to any direct or indirect connection or coupling between two or more elements; the connection or coupling between elements may be physical, logical, electromagnetic, or a combination thereof. Additionally, when used in this application, the words “this article,” “above,” “below,” and similar terms refer to the entire application and not any particular part thereof. Where the context permits, singular or plural terms used in the detailed description may also include the plural or singular, respectively. The word “or,” when referring to a series of items, covers all of the following interpretations: any one item in the list, all items in the list, and any combination of items in the list.

[0065] These and other changes to the technology may be made after reading the following detailed description. While this description describes certain examples of the technology and envisions best practices, the technology can be practiced in many ways, no matter how detailed the description may be. The details of the system may vary considerably in its specific implementation, but are still covered by the technology disclosed herein. As noted above, specific terms used in describing certain features or aspects of the technology should not be construed as implying that the term is redefined herein to limit any particular feature or aspect associated with that term. In general, unless these terms are expressly defined in the detailed description section, the terms used in the appended claims should not be construed as limiting the technology to the specific examples disclosed in the specification. Therefore, the actual scope of the technology includes not only the disclosed examples but also all equivalent ways of practicing or implementing the technology under the claims.

[0066] Figure 1 An example 1 of a light-emitting diode (LED) based lighting device according to the present disclosure is disclosed.

[0067] The LED-based lighting device 1 includes a power supply 3. In this particular example, the power supply 3 is a current source, meaning it is arranged to provide a constant current. The voltage on the power supply may fluctuate, i.e., it depends on the impedance of the components connected to the current source.

[0068] The LED-based lighting device 1 also includes a first LED string 2, which comprises a plurality of LEDs connected in series, wherein the first LED string 2 is connected to the power supply 3.

[0069] This disclosure is not limited to the number of LEDs in the second LED string 2. The number of LEDs may be between 10 and 40. In some cases, the number of LEDs may even reach hundreds or thousands—depending entirely on the specific application of the LED-based lighting device.

[0070] A second LED string 4 is provided, comprising a plurality of LEDs connected in a second series connection, wherein the output terminal 8 of the second LED string 4 is connected to the output terminal 9 of the first LED string 2.

[0071] In addition, a 1:N one-to-many switch 5 is provided, wherein the input terminal 7 of the switch is connected to the power supply 3, and the output terminal 6 of the switch is respectively connected to the subsequent input terminals of the LEDs in the second LED string 4, such that the position of the 1:N one-to-many switch determines the number of LEDs in the second LED string powered by the power supply.

[0072] For example, one example of a mechanical 1:N switch is a selector switch with multiple positions. In a three-position rotary switch, the switch can be mechanically rotated to connect to one of the inputs of three different LEDs in a second LED string of four. Such switches can be used in a variety of applications, such as selecting different sound sources in audio equipment or selecting different operating modes in industrial control systems.

[0073] Figure 2 Another example 18 of an LED-based lighting device according to this disclosure is disclosed.

[0074] It should be noted that the same reference numerals are used in all figures to represent the same or similar features and / or functions.

[0075] In this particular example, an additional LED string 11 is also shown, which is connected to the power supply 4 via a different LED input terminal using another switch 12. The input terminal 13 of this switch 12 is thus connected to the power supply 3, while the output terminal 14 of the switch 12 is connected to the subsequent input terminal of the LED in the additional LED string 11.

[0076] Therefore, multiple switches can be used, each of which can be used to control the number of LEDs in a specific LED string, that is, to enable / disable certain LEDs in a specific LED string.

[0077] Figure 3 Another example 21 of an LED-based lighting device according to this disclosure is disclosed.

[0078] and Figure 1 The difference in the example shown lies in the diodes labeled 22 and 23 in the attached figure. In this specific case, diodes 22 and 23 are non-LED-based diodes. These diodes 22 and 23 can perform a certain calibration process. For example, if it is desired that the current ratio between the first LED string and the second LED string is 50:50, and the first LED string has 20 LEDs and the second LED string has 18 LEDs, then introducing non-LED-based diodes into the second LED string can be useful. This will make the total impedance of the two LED strings the same. Then, depending on the state of the switch, one or more diodes or LEDs in the second LED string can be disabled / activated.

[0079] Figure 4 Another example 31 of an LED-based lighting device according to this disclosure is disclosed.

[0080] and Figure 1The difference in the illustrated embodiment is that an N:1 many-to-one switch 32 is introduced at the output end of the LED string, i.e., between the output end of the LED string and the power supply. The input end of this N:1 many-to-one switch 32 is connected to the subsequent input ends of LEDs in different LED strings, as shown by reference numeral 32 in the figure.

[0081] Based on the position of switch 32, multiple LEDs in the LED string can be disabled / activated, thus switch 32 can act as a dimmer.

[0082] Figure 5 An example of a method according to this disclosure is disclosed.

[0083] This method is intended to operate a light-emitting diode (LED) based lighting device according to any of the foregoing examples.

[0084] The first step involves operating switch 41. In other words, by connecting the input terminal of the 1:N one-to-many switch to the power supply and connecting one of the output terminals of the switch to the input terminal, the position of the 1:N one-to-many switch determines the number of LEDs powered by the power supply in the second LED string.

[0085] The second step includes supplying current 42 to the LED string from the power source, and the third step includes providing illumination 43 from the different LEDs in the LED string.

[0086] To reduce the number of claims, certain aspects of the technology are presented below in certain claim forms, but the applicant has conceived of various aspects of the technology in any number of claim forms. For example, while some aspects of the technology may be formulated as computer-readable medium claims, others may also be embodied as computer-readable medium claims, or in other forms, such as apparatus plus function claims.

[0087] In the above description, numerous specific details have been set forth for illustrative purposes to provide a thorough understanding of the disclosed technical implementations. However, it will be apparent to those skilled in the art that embodiments of the disclosed technology can be practiced without some of these specific details.

[0088] Those skilled in the art, upon studying the accompanying drawings, the disclosure, and the appended claims, will be able to understand and implement other variations of the disclosed embodiments. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite articles "a" or "an" do not exclude multiple. The mere fact that certain measures are recited in mutually different dependent claims does not mean that a combination of these measures cannot be used advantageously. Any reference numerals in the claims should not be construed as limiting their scope.

Claims

1. A lighting device based on a light-emitting diode (LED), comprising: - power supply; - A first LED string, comprising a plurality of first LEDs connected in series, wherein the first LED string is connected to the power supply; - A second LED string, comprising a plurality of second LEDs connected in series, wherein the output of the second LED string is connected to the output of the first LED string; - A 1:N one-to-many switch, wherein the input of the switch is connected to the power supply, and wherein the output of the switch is connected to the subsequent input of each LED in the second LED string, such that the position of the 1:N one-to-many switch determines the number of LEDs in the second LED string powered by the power supply. The 1:N one-to-many switch mentioned above is a mechanical switch.

2. The LED-based lighting device according to claim 1, wherein the power supply is a constant current power supply.

3. The LED-based lighting device according to any one of the preceding claims, wherein the LED-based lighting device further comprises: - A third LED string, comprising multiple third LEDs, wherein the output of the third LED string is connected to the output of the first LED string. - A second 1:N one-to-many switch, wherein the input of the second switch is connected to the power supply, and wherein the output of the second switch is connected to the subsequent input of the LEDs in the third LED string, such that the position of the second 1:N one-to-many switch determines the number of LEDs in the second LED string powered by the power supply.

4. The LED-based lighting device according to any one of the preceding claims, wherein the second LED string further comprises one or more diodes connected in series with the plurality of second LEDs, and wherein at least one output terminal of the 1:N one-to-many switch is connected to the input terminal of the one or more diodes.

5. The LED-based lighting device according to any one of the preceding claims, wherein the LED-based lighting device further comprises: An N:1 many-to-one switch, wherein the output of the switch is connected to the power supply, and wherein the input of the switch is respectively connected to the subsequent input of an LED in the second LED string and the subsequent input of a corresponding LED in the first LED string, such that the position of the 1:N one-to-many switch and the position of the N:1 many-to-one switch together determine the number of LEDs in the first LED string and the second LED string powered by the power supply.

6. The LED-based lighting device according to any one of the preceding claims, wherein the first LED string and the second LED string comprise LEDs of the same type.

7. The LED-based lighting device according to any one of the preceding claims, wherein the power supply is a current-based power supply, and wherein the LED device further comprises: - A control mechanism for controlling the amount of current supplied by the current-based power supply based on the voltage on the first LED string.

8. The LED-based lighting device according to any one of the preceding claims, wherein the device comprises: Voltage absorption units are respectively arranged between the output terminal of the switch and the subsequent input terminal of the LED in the second LED string.

9. The LED-based lighting device according to claim 6, wherein the voltage absorption unit comprises a non-LED-based diode.

10. A method of operating a lighting device based on a light-emitting diode (LED) according to any one of the preceding claims, wherein the method comprises the following steps: - By connecting the input terminal of the 1:N one-to-many switch to the power supply and connecting one of the output terminals of the switch to the input terminal, the position of the 1:N one-to-many switch determines the number of LEDs in the second LED string powered by the power supply.

11. The method according to any one of claims 10, wherein the LED-based lighting device further comprises: A third LED string, comprising a plurality of third LEDs, wherein the output of the third LED string is connected to the output of the first LED string; And a second 1:N one-to-many switch, wherein the input of the second switch is connected to the power supply, and wherein the output of the second switch is respectively connected to the subsequent inputs of the LEDs in the third LED string, wherein the method further includes the following steps: - The input terminal of the second switch is connected to the power supply by the 1:N one-to-many switch, and one of the output terminals of the second switch is connected to the input terminal, such that the position of the second 1:N one-to-many switch determines the number of LEDs in the third LED string powered by the power supply.

12. The method according to any one of claims 10 to 11, wherein the method further comprises: - The control mechanism controls the amount of current supplied by the current-based power supply based on the voltage on the first LED string.

13. The method according to any one of claims 10 to 12, wherein the device further comprises voltage absorption units respectively disposed between the output terminal of the switch and the subsequent input terminals of the LEDs in the second LED string.

14. The method according to any one of claims 10 to 13, wherein the method further comprises the following step: - Tactile input about the position of the switch is received from the user by the switch.

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