LED lighting system, LED lighting device and dimming control method thereof

Abstract

The present disclosure proposes an LED lighting system, an LED lighting device and a dimming control method thereof. The LED lighting system includes a rectifier circuit, a filter circuit, a drive circuit, an LED module and a demodulation circuit. The demodulation circuit is coupled to a first connection end and a second connection end, and is used to capture the signal characteristics in the input power supply, and demodulate the signal characteristics to extract the corresponding dimming information. The demodulation circuit generates a dimming control signal according to the dimming information, and provides the dimming control signal to the drive circuit. The drive circuit adjusts the power conversion action based on the dimming control signal, so as to change the size of the driving power supply in response to the dimming information. The signal characteristic is a phase tangent angle, and when the LED module emits light at the lowest brightness, the phase tangent angle is not greater than 90 degrees.

Description

Technical Field

[0001] The present disclosure relates to the field of lighting fixtures, and in particular to an LED lighting system, an LED lighting device and a dimming control method thereof. Background Art

[0002] LED lighting technology is rapidly developing and replacing traditional incandescent and fluorescent lamps. Compared with fluorescent lamps filled with inert gas and mercury, LED straight tube lamps do not need to be filled with mercury. Therefore, in various lighting systems for home or workplaces dominated by lighting options such as traditional fluorescent bulbs and tubes, various LED lamps such as LED straight tube lamps, LED bulbs, LED filament lamps, high-power LED lamps or integrated LED lamps have unsurprisingly gradually become highly anticipated lighting options. The advantages of LED lamps include improved durability and lifespan as well as lower energy consumption. Therefore, after considering all factors, LED lamps will be the best lighting option.

[0003] In general LED lighting solutions, how to achieve dimming control is a widely discussed topic. In existing dimming technologies, the effective value of the input voltage is usually adjusted by phase cutting / chopping to achieve the dimming effect. However, this dimming control method significantly affects the integrity of the voltage waveform, which inevitably causes various problems such as reduced LED lamp luminous efficiency and flickering.

[0004] In view of the above problems, the present disclosure and its embodiments are proposed below. Summary of the invention

[0005] However, the term "the present invention" is only used to describe certain embodiments disclosed in this specification (whether or not in the claims), rather than a complete description of all possible embodiments. In order to avoid confusion caused by unnecessary distinctions between possible inventions during the preparation of this specification, multiple possible inventions are collectively referred to as "the present invention".

[0006] Many embodiments of the "invention" are described herein in a summary, which term is used to describe certain embodiments currently disclosed, whether or not protection is claimed, and is not necessarily an exhaustive description of all possible embodiments, but merely an overview of certain embodiments. Certain embodiments of the various features or aspects described below as "the invention" can be combined in different ways to form an LED straight tube lamp or a portion thereof.

[0007] According to some specific embodiments, the present disclosure proposes an LED lighting system, characterized in that it includes a dimmer and at least one LED lighting device; the dimmer is used to receive input power from an external power grid, and modulate the phase angle of the input power within a dimming phase interval according to a dimming signal to generate a modulated input power; the LED lighting device receives the modulated input power as the input power of the LED lighting device, and is driven and illuminated accordingly, wherein the upper limit phase angle of the dimming phase interval is less than 90 degrees.

[0008] In some embodiments of the present disclosure, when the LED lighting device receives the modulated input power with the upper limit phase-tangent angle, the LED lighting device emits light at the highest brightness or the lowest brightness.

[0009] In some embodiments of the present disclosure, an upper limit tangent angle of the dimming phase interval is less than 45 degrees.

[0010] In some embodiments of the present disclosure, the dimming phase interval is a phase interval of 15 degrees to 20 degrees.

[0011] According to some specific embodiments, the present disclosure provides an LED lighting device that lights up in response to an input power supply, characterized in that: the LED lighting device includes: a power module for receiving the input power supply to generate a driving power supply; and an LED module that lights up in response to the driving power supply; the power module includes: a demodulation circuit for receiving the input power supply and demodulating the input power supply to generate a dimming control signal for controlling the brightness of the LED module, wherein the demodulation circuit demodulates based on a phase tangent angle of the input power supply and generates the dimming control signal indicating the brightness of the LED module.

[0012] In some embodiments of the present disclosure, the demodulation circuit extracts dimming information corresponding to the phase-cut angle, and generates the dimming control signal according to the dimming information.

[0013] In some embodiments of the present disclosure, when the LED module reaches minimum brightness, the tangent angle is less than 90 degrees.

[0014] In some embodiments of the present disclosure, when the LED module reaches minimum brightness, the tangent angle is less than 45 degrees.

[0015] In some embodiments of the present disclosure, the phase range of the phase tangent angle is: 0 degrees to 45 degrees; 5 degrees to 45 degrees; 5 degrees to 20 degrees; 15 degrees to 20 degrees; or 15 degrees to 45 degrees.

[0016] In some embodiments of the present disclosure, the dimming level of the LED module is related to the phase-cutting angle.

[0017] In some embodiments of the present disclosure, the dimming level of the LED module is related to the phase cut angle, but is substantially unrelated to the peak value of the voltage of the external power grid.

[0018] In some embodiments of the present disclosure, the dimming level of the LED module is substantially independent of the effective value of the input power.

[0019] In some embodiments of the present disclosure, the dimming level of the LED module is not directly proportional to the effective value of the input power.

[0020] In some embodiments of the present disclosure, the effective value of the input power refers to a root mean square (RMS) value.

[0021] In some embodiments of the present disclosure, the effective value range ratio of the input power supply is smaller than the brightness range ratio of the LED module, wherein the effective value range ratio is defined as the ratio of the maximum value to the minimum value of the effective value of the input power supply, and the brightness range ratio is defined as the ratio of the maximum value to the minimum value of the brightness of the LED module.

[0022] In some embodiments of the present disclosure, the effective value range ratio of the input power source is less than or equal to 2, and the brightness range ratio of the LED module is greater than or equal to 10.

[0023] In some embodiments of the present disclosure, the phase angle is selected within a default phase interval so that the total harmonic distortion of the power module is less than 25% and / or the power factor of the power module is greater than 0.9.

[0024] In some embodiments of the present disclosure, the brightness range ratio of the LED module is greater than or equal to 10.

[0025] In some embodiments of the present disclosure, the brightness of the LED module is negatively correlated to the phase tangent angle of the input power.

[0026] In some embodiments of the present disclosure, the brightness of the LED module is negatively correlated to the level of the dimming control signal.

[0027] In some embodiments of the present disclosure, the level of the dimming control signal is positively correlated to the phase-cutting angle.

[0028] In some embodiments of the present disclosure, the phase angle is selected within a default phase interval so that the total harmonic distortion of the power module is less than 25% and / or the power factor of the power module is greater than 0.9.

[0029] In some embodiments of the present disclosure, when the phase-tangent angle of the input power signal corresponds to minimum brightness, the total harmonic distortion of the power module is less than 25%.

[0030] In some embodiments of the present disclosure, when the phase-tangent angle of the input power signal corresponds to minimum brightness, the power factor of the power module is greater than 0.9.

[0031] In some embodiments of the present disclosure, the demodulation circuit samples and counts the input power to demodulate a phase angle of the input power, and generates the dimming control signal according to the demodulated phase angle of the input power.

[0032] In some embodiments of the present disclosure, the dimming control signal performs corresponding analog dimming or digital dimming on the LED module.

[0033] In some embodiments of the present disclosure, the analog dimming is current control dimming.

[0034] In some embodiments of the present disclosure, the digital dimming is pulse width modulation (PWM) controlled dimming.

[0035] In some embodiments of the present disclosure, the dimming control signal has a default number of different signal states corresponding to the phase-cutting angle, so as to control the LED module to dim at the default number of dimming levels.

[0036] In some embodiments of the present disclosure, the power module further includes: a rectifier circuit for rectifying the input power to generate a rectified signal; and a filter circuit coupled to the rectifier circuit for filtering the rectified signal to generate a filtered signal.

[0037] In some embodiments of the present disclosure, the power module further includes a dimming switch, which turns on or off the driving power supply according to the dimming control signal to dim the LED module.

[0038] In some embodiments of the present disclosure, the power module further includes: a driving circuit coupled to the filtering circuit for performing power conversion on the filtered signal to generate the driving power.

[0039] In some embodiments of the present disclosure, the driving circuit adjusts the power conversion action based on the dimming control signal, so as to change the driving power size in response to the phase cut angle to dim the LED module.

[0040] In some embodiments of the present disclosure, the driving circuit includes a power switch and an energy storage circuit, wherein the power switch is used to switch the energy storage circuit to perform power conversion on the filtered signal to generate the driving power; wherein the power switch adjusts the size of the driving power in response to the dimming control signal to dim the LED module.

[0041] In some embodiments of the present disclosure, the input power phase angle is a leading edge phase angle or a trailing edge phase angle.

[0042] In some embodiments of the present disclosure, the dimming control signal is not in the power supply loop between the LED module and the driving power supply.

[0043] According to some specific embodiments, the present disclosure provides an LED lighting system, which includes a dimmer and an LED lighting device. The dimmer is used to receive input power from an external power grid, and modulate the phase angle of the input power within a dimming phase interval according to a dimming signal to generate a modulated input power. The LED lighting device receives the modulated input power and is driven and illuminated accordingly.

[0044] In some embodiments of the present disclosure, the dimmer includes a controllable electronic component for adjusting a phase angle in response to the dimming signal to generate a modulated input power signal, wherein the controllable electronic component includes a bidirectional triode thyristor, a single-chip microprocessor or a transistor.

[0045] According to some specific embodiments, the present disclosure provides an LED lighting system, which includes a dimmer and an LED lighting device. The dimmer is used to receive an input power supply from an external power grid, and modulate the phase angle of the input power supply within a dimming phase interval according to a dimming signal to generate a modulated input power supply. The LED lighting device receives the modulated input power supply and is driven and illuminated accordingly. The dimming degree of the LED lighting device varies with the phase angle of the modulated input power supply. The effective value range ratio of the input power supply is smaller than the brightness range ratio of the LED module, wherein the definition of the effective value range ratio is the ratio of the maximum value to the minimum value of the effective value of the input power supply, and the definition of the brightness range ratio is the ratio of the maximum value to the minimum value of the brightness of the LED module.

[0046] In some embodiments of the present disclosure, the effective value range ratio of the input power source is less than or equal to 2, and the brightness range ratio of the LED module is greater than or equal to 10.

[0047] In some embodiments of the present disclosure, the phase angle is selected within a default phase interval so that the total harmonic distortion of the power module is less than 25% and / or the power factor of the power module is greater than 0.9.

[0048] In some embodiments of the present disclosure, the brightness range ratio of the LED module is greater than or equal to 10.

[0049] According to some specific embodiments, the present disclosure provides an LED lighting system, which includes a dimmer and an LED lighting device. The dimmer is used to receive input power from an external power grid, and modulate the phase angle of the input power within a dimming phase interval according to a dimming signal to generate a modulated input power. The LED lighting device receives the modulated input power and is driven and illuminated accordingly. The phase angle is selected within a default phase interval so that the total harmonic distortion of the power module is less than 25% and / or the power factor of the power module is greater than 0.9.

[0050] In some embodiments of the present disclosure, when the phase-tangent angle of the input power signal corresponds to minimum brightness, the total harmonic distortion of the power module is less than 25%.

[0051] In some embodiments of the present disclosure, when the phase-tangent angle of the input power signal corresponds to minimum brightness, the power factor of the power module is greater than 0.9.

[0052] According to some specific embodiments, the present disclosure provides an LED lighting system, which includes a dimmer and at least one LED lighting device. The dimmer is used to receive input power from an external power grid, and modulate the phase angle of the input power within a dimming phase interval according to a dimming signal to generate a modulated input power. The LED lighting device receives the modulated input power and is driven and illuminated accordingly, wherein the upper limit phase angle of the dimming phase interval is less than 90 degrees.

[0053] In some embodiments of the present disclosure, when the LED lighting device receives the modulated input power with the upper limit phase-tangent angle, the LED lighting device emits light at the highest brightness or the lowest brightness.

[0054] In some embodiments of the present disclosure, an upper limit tangent angle of the dimming phase interval is less than 45 degrees.

[0055] In some embodiments of the present disclosure, the dimming phase interval is a phase interval of 15 degrees to 20 degrees.

[0056] According to some specific embodiments, the present disclosure provides an LED lighting system, which includes a dimmer and at least one LED lighting device. The dimmer is used to receive input power from an external power grid, and modulate the phase angle of the input power within a dimming phase interval according to a dimming signal to generate a modulated input power. The at least one LED lighting device receives the modulated input power and is driven and illuminated accordingly, wherein the upper limit phase angle of the dimming phase interval is less than 90 degrees.

[0057] In some embodiments of the present disclosure, an upper limit tangent angle of the dimming phase interval is less than 45 degrees.

[0058] In some embodiments of the present disclosure, the dimming phase interval is a phase interval of 15 degrees to 20 degrees.

[0059] According to some specific embodiments, the present disclosure provides an LED lighting device, which includes a rectifier circuit, a filter circuit, a driver circuit, an LED module, and a demodulator circuit. The rectifier circuit receives an input power supply from a first connection terminal and a second connection terminal, and rectifies the input power supply to generate a rectified signal. The filter circuit is coupled to the rectifier circuit to filter the rectified signal to generate a filtered signal. The driver circuit is coupled to the filter circuit to perform power conversion on the filtered signal to generate a driving power supply. The LED module is coupled to the driver circuit, and is lit and emits light in response to the driving power supply. The demodulator circuit is coupled to the first connection terminal and the second connection terminal to capture the signal characteristics in the input power supply, and demodulate the signal characteristics to extract the corresponding dimming information. The demodulator circuit generates a dimming control signal according to the dimming information, and provides the dimming control signal to the driver circuit. The driver circuit adjusts the power conversion action based on the dimming control signal, thereby changing the size of the driving power supply in response to the dimming information.

[0060] The beneficial effect of the dimming control method disclosed herein is that dimming control can be achieved while maintaining the power conversion efficiency of the LED lighting device. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1A is a schematic block diagram of an LED lighting system according to an embodiment of the present disclosure;

[0062] Figure 1B is a schematic block diagram of an LED lighting system according to another embodiment of the present disclosure;

[0063] Figure 2 It is a dimming waveform diagram of an LED lighting system;

[0064] Figure 3 is a schematic block diagram of an LED lighting device according to an embodiment of the present disclosure;

[0065] Figure 4 is a schematic block diagram of a driving circuit according to an embodiment of the present disclosure;

[0066] FIG5 is a schematic diagram of a dimming waveform according to an embodiment of the present disclosure;

[0067] Figure 6 is a schematic diagram of the corresponding relationship among the phase cutting angle, the demodulation signal and the brightness of the LED module according to an embodiment of the present disclosure;

[0068] Figure 7 is a schematic diagram of the corresponding relationship among the phase cutting angle, the demodulation signal and the brightness of the LED module according to another embodiment of the present disclosure;

[0069] Figure 8 is a schematic diagram of input power waveforms of an LED lighting device under different grid voltages according to an embodiment of the present disclosure;

[0070] Fig. 9 is a flowchart of the steps of a dimming control method of an LED lighting system according to an embodiment of the present disclosure; and

[0071] Fig.10 It is a flowchart of the steps of a dimming control method of an LED lighting device according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0072] The present disclosure proposes a new LED lighting system, LED lighting device and dimming control method. Now, the specific embodiments of the present disclosure will be described in detail in conjunction with the accompanying drawings. The descriptions in the following different embodiments of the present invention are only used to illustrate the present invention and are only examples. The present disclosure is not an exhaustive enumeration, and the disclosed content does not constitute a limitation on the specific implementation method. The embodiments listed below are only examples, and there may be many implementation methods and variations that do not require the details provided here. It should also be emphasized that the present disclosure provides technical details of alternative examples, but these listed alternatives are not exhaustive of all possible implementations. In addition, even if the technical details described in different examples are consistent, it should not be understood that the technical details are necessary. Here, it is impractical to list various possible variations of each technical feature. The technical features required for the present invention should be determined with reference to the description in the claims.

[0073] In the drawings of the specification, the size or relative size of each component may be exaggerated for clarity. Like reference numerals in each part represent like elements.

[0074] The terms used herein are only used to describe specific embodiments and are not intended to limit the present invention. The singular description used herein is also intended to include the plural form of the components, unless the context clearly indicates otherwise; the term "and / or" used herein includes all possible combinations of the listed items and may sometimes be simply represented by " / ".

[0075] It should be understood that although the terms "first", "second" or "third" etc. may be used herein to describe different elements, components, regions, layers or steps, etc., these elements, components, regions, layers and / or steps, etc. are not limited by these terms. As an example of a common naming method, unless the context clearly indicates otherwise, these terms are only used to distinguish one element, component, region, layer or step from another element, component, region, layer or step. Therefore, without departing from the teachings of the present invention, a first element, component, region, layer or step discussed in one part of the specification may be referred to as a second element, component, region, layer or step in another part of the specification or in the claims. In addition, in some cases, even if a word is not described as "first" or "second" in the specification, the word may still be expressed as "first" or "second" in the claims to distinguish different technical features in the claims.

[0076] It should be further understood that the terms "comprising" or "including" used in this specification specify the listed technical features, regions, quantities, steps, operations, elements and / or devices, but do not exclude other or additional technical features, regions, quantities, steps, operations, elements, devices and / or their combinations.

[0077] It should be understood that when an element is referred to as being "connected," "coupled," or "on" another element, the two may be directly connected or coupled, or indirectly connected or coupled through an intermediate element. Conversely, when an element is referred to as being "directly connected" or "directly coupled" to another element, there is no intermediate element. Other words used to describe the relationship between two elements should be understood similarly (e.g., "between" and "directly between," "adjacent" and "directly adjacent," etc.). However, the term "contact" used herein should be understood as a direct connection (e.g., contacting each other) unless the context specifies otherwise.

[0078] Each embodiment will be described here based on the plan view and / or cross-sectional view as an ideal schematic diagram. Accordingly, the exemplary views may change due to production technology and / or tolerances. Therefore, the embodiments disclosed herein are not limited to the views shown, but also include configuration changes based on the production process. Therefore, the characteristics of the areas shown in the accompanying drawings are exemplary in nature, and the shapes of the local areas shown in the figures are only examples of elements of specific shapes, but the present invention is not limited to these aspects.

[0079] Terms that indicate relative spatial position relationships (such as "below", "lower than", "below", "above", "above", etc.) may be used herein to describe the relationship between one element or technical feature and other elements or technical features in the drawings. It should be understood that these terms that indicate relative spatial position relationships, in addition to covering the directions shown in the drawings, also cover different directions of the device shown in use or operation. For example, if the device shown in the figure is flipped, the elements that were originally described as "lower than" other elements or "below" other elements will be located "above" other elements or technical features. Therefore, the term "lower than" can cover both the directions of "above" and "lower than". The above-mentioned device can also be in other directions (rotated 90 degrees or in other directions), and the spatial position description terms used here should also be understood accordingly.

[0080] Here, terms such as "same", "equal", "planar", and "coplanar" used to describe directions, layouts, positions, shapes, sizes, quantities, or other characteristics do not necessarily mean completely identical directions, layouts, positions, shapes, sizes, quantities, or other characteristics, but rather cover approximately identical directions, layouts, positions, shapes, sizes, quantities, or other characteristics within a possible and acceptable range of variation, such as some variations in the production process. This may be emphasized by the term "substantially", unless the context or other instructions indicate otherwise. For example, the terms "substantially the same", "substantially equal", or "substantially planar" may actually mean "same", "equal", or "planar", or may actually mean "same", "equal", or "planar" within a possible and acceptable range (such as errors caused by the production process).

[0081] For example, the terms "approximately" and "about" may reflect that the size, direction or layout is different only within a small range, and / or the operation, function or structure of certain components will not be significantly affected. For example, the range of "about 0.1 to about 1" may cover a deviation of 0%-5% around the value 0.1 and a deviation of 0%-5% around the value 1, especially when the corresponding deviation value also has the same effect as the listed numerical range, that is, it means that the corresponding deviation value is also included in the range of "about 0.1 to about 1".

[0082] For example, the term "transistor" may refer to a field effect transistor (FET), such as an N-type half field effect transistor (MOSFET), a P-type MOSFET, a gallium nitride (GaN) FET, a silicon carbide (SiC) FET, a bipolar junction transistor (BJT), a Darlington transistor, a heterojunction bipolar transistor (HBT), etc.

[0083] Unless otherwise defined, all terms (including technical and scientific terms) used herein are generally understood by those skilled in the art to which the present invention belongs. It should be further understood that terms such as those defined in commonly used dictionaries should be consistent with their meanings in the context of the relevant technical field and / or this application, and should not be understood in an idealized or overly formal manner if not clearly defined herein.

[0084] Here, an object described as being "electrically connected" is configured so that an electrical signal can be transmitted from one object to another object. Therefore, when a passive conductive device (e.g., a wire, a pad, an internal power line, etc.) is physically connected to another passive electrically insulating device (e.g., a prepreg of a printed circuit board, an electrically insulating adhesive connecting two devices, an electrically insulating bottom fill or molded layer, etc.), the conductive device is not electrically connected to the other device. In addition, "directly electrically connected" to each other means that the components are electrically connected via one or more passive devices (e.g., wires, pads, internal power lines, resistors, etc.). In other words, directly electrically connected devices do not include devices electrically connected through active devices (e.g., transistors or diodes). Directly electrically connected elements are directly physically connected as well as directly electrically connected.

[0085] Components described as being thermodynamically connected or in heat transfer are configured so that heat can be transferred along a path between the components, thereby transferring heat from the first component to the second component. Two components are not thermodynamically connected simply because they are part of the same device or the same board. In general, components that conduct heat and are directly connected to other heat-conducting or heat-producing components (or connected to other components through intermediate heat-conducting components, or are in close proximity to other components so that heat can be transferred in large quantities) will be described as being thermodynamically connected to these components, or in heat transfer with these components. Conversely, two components that have insulating materials between them that significantly prevent heat transfer, or components that only conduct heat in small amounts, are not described as being thermodynamically connected or in heat transfer with each other. The terms "thermally transferable" or "thermally conductive" do not apply to all materials that can provide small amounts of heat conduction, but only refer to materials that are generally known to be good conductors of heat or known to be used for heat transfer, or components that have similar thermal conductivity properties to these materials.

[0086] Embodiments of the present invention may be described from the perspective of functional blocks, units and / or modules and shown in the accompanying drawings. It should be understood by those skilled in the art that these functional blocks, units and / or modules can be implemented by physical means of electronic (or optical) circuits (e.g., logic circuits, discrete devices, analog circuits, hardware connection lines, storage elements, line connections, etc.), which may be formed based on semiconductor manufacturing processes or other manufacturing processes. In the case of implementation by a microprocessor or similar method, these functional blocks, units and / or modules may be programmed with software (e.g., microcode) to implement the various functions discussed in the present disclosure, and may be optionally driven by hardware and / or software. Alternatively, to implement other functions, each functional block, unit and / or module may be implemented by dedicated hardware, or by a combination of dedicated hardware and a processor (e.g., one or more programmed microprocessors and related circuits). At the same time, each functional block, unit and / or module in each embodiment may be physically divided into two or more interactive and discrete blocks, units and / or modules. Furthermore, these functional blocks, units and / or modules in different embodiments may be physically combined into more complex functional blocks, units and / or modules.

[0087] If any term in this application conflicts with any patent application to which this application claims priority, or conflicts with terms referenced and contained in this application, or terms referenced and contained in any patent application to which this application claims priority, the term shall be interpreted based on the terms used or defined in this application.

[0088] It should be noted that the description of the following embodiments in the present disclosure is only intended to clearly illustrate the creative features of the disclosed content. However, each embodiment is not limited to being implemented separately. In fact, in the final product, multiple different embodiments can and tend to be implemented simultaneously, and these embodiments can be combined in different ways to achieve a variety of final products. Therefore, those skilled in the art can combine possible embodiments, or replace components / modules in different embodiments according to design requirements. The embodiments disclosed herein are not limited to the following examples, and any possible replacement and arrangement between multiple embodiments is also included here.

[0089] Figure 1A is a schematic block diagram of an LED lighting system according to an embodiment of the present disclosure. Figure 1A The LED lighting system 10 of this embodiment includes a dimmer 50 and an LED lighting device 100, wherein the LED lighting device 100 further includes a power module PM and an LED module LM.

[0090] In the LED lighting system 10, the input end of the dimmer 50 is electrically connected to the external power grid EP to receive the input power Pin from the external power grid EP. The output end of the dimmer 50 is electrically connected to the LED lighting device 100 through the first connection end 101 and the second connection end 102 of the LED lighting device 100, so as to provide the input power Pin_C after dimming processing (also referred to as the modulated input power Pin_C) to the LED lighting device 100. In other words, the external power grid EP is electrically connected to the LED lighting device 100 through the dimmer 50 to supply power to the LED lighting device 100. Among them, the input power Pin or the input power Pin_C can be an AC power supply or a DC power supply, and can refer to at least any one of the input voltage, input current and input power. In addition, in the LED lighting system 10, the power supply circuit formed between the external power grid EP and the LED lighting device 100 can be defined as a bus.

[0091] The LED lighting device 100 receives an input power supply Pin_C from a first connection terminal 101 and a second connection terminal 102, wherein the power module PM generates a driving power supply Sdrv based on the input power supply Pin_C and provides it to the LED module LM, so that the LED module LM is illuminated in response to the driving power supply Sdrv. In some embodiments, the LED lighting device 100 can be any type of LED lamp, such as an LED spotlight, an LED downlight, an LED bulb, an LED track light, an LED panel light, an LED ceiling light, an LED straight tube lamp, or an LED filament lamp, etc., and the present disclosure is not limited to this. In an embodiment where the LED lighting device 100 is an LED straight tube lamp, the LED lighting device 100 can be a ballast-compatible (Type-A) straight tube lamp, a ballast bypass type (Type-B) straight tube lamp, or an external power supply type (Type-C) straight tube lamp.

[0092] From the overall operation of the LED lighting system 10, the dimmer 50 performs dimming processing on the input power Pin according to a dimming signal Sdim, and generates the input power Pin_C accordingly. The user can give the corresponding dimming signal Sdim to the dimmer 50 through a control interface (not shown). The control interface can be implemented in various forms such as a switch, a knob or a wireless signal receiver, and the present disclosure is not limited to this. In addition, depending on the selected dimming method, the dimming processing can be to change the signal characteristics of the input power Pin, such as the conduction angle, frequency, amplitude, phase or a combination thereof. In the dimmer 50, it includes at least one controllable electronic component (not shown) connected to the bus, such as a thyristor, a single-chip microcomputer, a transistor, etc. The controllable electronic component can adjust the signal characteristics of the input power Pin in response to the dimming signal Sdim, so that the input power Pin is converted to the input power Pin_C.

[0093] When the LED lighting device 100 receives the input power Pin_C, the power module PM will further convert the input power Pin_C into a stable driving power Sdrv for use by the LED module LM, wherein the power module PM will generate driving power Sdrv with different voltages (which may be called driving voltages) and / or currents (which may be called driving currents) based on the signal characteristics of different input power Pin_C. After the driving power Sdrv is generated, the LED module LM will be lit and emit light in response to the driving power Sdrv. The luminous brightness of the LED module LM is related to the magnitude of the driving voltage and / or the driving current, which is adjusted based on the signal characteristics of the input power Pin_C, and the signal characteristics of the input power Pin_C are controlled by the dimming signal Sdim. In other words, the dimming signal Sdim is directly related to the luminous brightness of the LED module LM. The operation of the power module PM to convert the input power Pin_C into the driving power Sdrv may include but is not limited to signal processing processes such as rectification, filtering, and DC-to-DC conversion. Further description of this part will be given in other embodiments later.

[0094] Figure 1B This is a schematic block diagram of an LED lighting system according to another embodiment of the present disclosure. This embodiment is a system configuration diagram of multiple LED lighting devices with a dimmer. Please refer to Figure 1B The LED lighting system 20 of this embodiment includes a dimmer 50 and a plurality of LED lighting devices 100_1-100_n, wherein n is a positive integer greater than or equal to 2. In the LED lighting system 20, the configuration and function of the dimmer 50 and each LED lighting device 100_1 are the same as those described above. Figure 1A The LED lighting systems of the single LED lighting devices 100 of the embodiment are the same. The main difference between the two is that the LED lighting devices 100_1-100_n of the embodiment are arranged in parallel, that is, the first connection ends 101 of each LED lighting device 100_1-100_n are electrically connected together, and the second connection ends 102 of each LED lighting device 100_1-100_n are electrically connected together.

[0095] Under the configuration of this embodiment, the input power Pin_C is simultaneously provided to the LED lighting devices 100_1-100_n, so that the LED lighting devices 100_1-100_n are lit together. Therefore, in some embodiments, when the dimming signal Sdim is applied / adjusted, the luminous brightness of the LED lighting devices 100_1-100_n will change synchronously. Since the LED lighting system 20 implements dimming control by adjusting the signal characteristics of the input power Pin, it is not necessary to pull out an independent signal line on each LED lighting device 100_1-100_n to receive the dimming signal, which greatly simplifies the wiring and installation complexity in a multi-lamp control application environment.

[0096] Specifically, there are many possible implementations for dimming control by adjusting the signal characteristics of the input power Pin. The general conventional implementation is to adjust the effective value (RMS) of the input power Pin by adjusting the conduction angle of the input power Pin, thereby adjusting the size of the driving power Sdrv. Figure 1A and Figure 2 The conventional dimming control method and the corresponding circuit operation are described. Figure 2 This is a schematic diagram of the dimming waveform of an LED lighting system. Please also refer to Figure 1A and Figure 2 In this embodiment, the external power grid EP provides AC power as the input power Pin, and Figure 2 The half-cycle voltage waveform of the input power Pin with an amplitude of VPK is shown in FIG. Figure 2 In the figure, from top to bottom are the voltage waveforms WF1, WF2 and WF3 under three different dimming control states, namely, the luminous brightness Lux is the maximum brightness Lmax, the luminous brightness Lux is 50% of the maximum brightness Lmax, and the luminous brightness Lux is 17% of the maximum brightness Lmax. Among them, the dimmer 50 can adjust the phase tangent angle / conduction angle of the input power Pin by controlling the on or off state of the controllable electronic component connected in series to the bus. For example, if the input power Pin is to be modulated with a 90-degree phase tangent angle, the dimmer 50 can turn off the controllable electronic component within 1 / 4 cycle of the input power Pin, and keep the controllable electronic component turned on during the remaining period of the half cycle. In this way, the voltage waveform of the input power Pin can be zero during the period from 0 to 90 degrees of phase, and the waveform of the sine wave can be re-formed during the period from 90 degrees to 180 degrees of phase (taking the leading edge phase tangent as an example, but not limited to this). The input power Pin after phase cutting is the input power Pin_C with a conduction angle of 90 degrees. The principle of using other phase cutting angles to modulate the input power Pin is similar to the above.

[0097] First, let's look at the voltage waveform WF1. When the dimmer 50 modulates the input power Pin at a tangent angle of 0 degrees in response to the dimming signal Sdim (i.e., the conduction angle of the input power Pin is 180 degrees), the dimmer 50 will directly provide the input power Pin to the LED lighting device 100, i.e., the input power Pin is equal to the input power Pin_C. In this case, the effective value of the input power Pin_C is Vrms1, and the power module PM will generate a corresponding driving power Sdrv based on the input power Pin_C having an effective value of Vrms1 to drive the LED module LM, so that the light luminance Lux of the LED module LM is the maximum luminance Lmax.

[0098] From the voltage waveform WF2, when the dimmer 50 modulates the input power Pin at a 90-degree phase angle in response to the dimming signal Sdim (i.e., the conduction angle of the input power Pin is 90 degrees), the dimmer 50 disconnects the bus when the phase of the input power Pin is from 0 degrees to 90 degrees, and conducts the bus when the phase is from 90 degrees to 180 degrees. In this case, the effective value of the input power Pin_C is Vrms2, wherein Vrms2 is less than Vrms1, and makes the luminous brightness Lux equal to 50% of the maximum brightness Lmax.

[0099] From the voltage waveform WF3, when the dimmer 50 modulates the input power Pin at a 90-degree phase angle in response to the dimming signal (i.e., the conduction angle of the input power Pin is 30 degrees), the dimmer 50 disconnects the bus when the phase of the input power Pin is between 0 degrees and 150 degrees, and conducts the bus when the phase is between 150 degrees and 180 degrees. In this case, the effective value of the input power Pin_C is Vrms3, wherein Vrms3 is less than Vrms2, and makes the luminous brightness Lux equal to 17% of the maximum brightness Lmax.

[0100] According to the dimming control method described above, the dimmer 50 can modulate the phase tangent angle / conduction angle of the input power Pin so that the effective value of the input power Pin_C (such as Vrms1, Vrms2, Vrms3) changes accordingly, wherein the change in the effective value of the input power Pin_C is basically positively correlated with the change in the conduction angle of the input power Pin_C, that is, the larger the conduction angle of the input power Pin_C, the larger the effective value of the input power Pin_C. In other words, the change in the effective value of the input power Pin_C is basically negatively correlated with the phase tangent angle of the input power Pin_C. In general, the conventional dimming control method described above actually realizes the dimming function by modulating the effective value of the input power. The advantage of this dimming method is that because the driving power Sdrv will directly reflect the effective value of the input power Pin_C and change accordingly, the LED lighting device 100 does not need to change the hardware configuration, and only needs to add the dimmer 50 to the system to realize the dimming function.

[0101] More specifically, in this dimming mode, in order to allow the effective value of the input power Pin to have a sufficient amplitude change so that the luminous brightness can be changed by a corresponding amplitude, when the dimmer 50 controls the phase angle / conduction angle to modulate the effective value of the input power Pin, it is bound to have a larger phase adjustment range. For example, dimming is usually performed between a phase of 0 degrees and 180 degrees, similar to Figure 2 However, when the conduction angle of the input power source Pin_C is small to a certain extent, the total harmonic distortion (THD) and power factor (PF) characteristics of the power module PM will be significantly affected, thereby greatly reducing the power conversion efficiency and possibly causing the LED module LM to flicker. In other words, under this dimming method, the efficiency of the power module PM is limited by the dimmer 50 and is difficult to improve.

[0102] On the other hand, since the effective value of the input power Pin_C is directly affected by the amplitude VPK, the dimmer 50 using the above dimming method cannot be compatible with various grid voltage specifications (such as 120V, 230V or 277V AC voltage). The designer needs to adjust the parameters or hardware design of the dimmer 50 according to the application environment of the LED lighting system 10, which will increase the overall production cost of the product.

[0103] In response to the above problems, the present disclosure proposes a new dimming control method and an LED lighting system and an LED lighting device using the same, which can use the phase-cut angle / conduction angle change of the input power Pin as a modulation signal, obtain the actual dimming information by demodulating the modulation signal, and control the circuit operation of the power module PM to generate the driving power Sdrv accordingly. Since the change of the phase-cut angle / conduction angle is only to carry the dimming information corresponding to the dimming signal Sdim, rather than to directly adjust the effective value of the input power Pin_C, the dimmer 50 can adjust the phase-cut angle / conduction angle of the input power Pin within a smaller phase interval, so that the effective value of the processed input power Pin_C will not have a large difference with the input power Pin provided by the external power grid EP. With this dimming control method, no matter what the brightness state is, the conduction angle of the input power Pin_C will be similar to the input power Pin, so that the THD and PF characteristics can be maintained. This means that the conversion efficiency of the power module PM will not be suppressed by the dimmer 50. The following is a further description of the dimming control method taught by the present disclosure and the structure and operation of the corresponding LED lighting device.

[0104] Figure 3 is a schematic block diagram of an LED lighting device according to an embodiment of the present disclosure. Figure 3 The LED lighting device 200 of this embodiment can be used in Figure 1A or Figure 1B In the LED lighting system 10 or 20 shown, the LED lighting device 200 includes a power module PM and an LED module LM, wherein the power module PM further includes a rectifier circuit 210 , a filter circuit 220 , a drive circuit 230 and a demodulation circuit 240 .

[0105] The rectifier circuit 210 receives the input power Pin_C through the first connection terminal 101 and the second connection terminal 102, rectifies the input power Pin_C, and then outputs the rectified signal Srec through the first rectifier output terminal 211 and the second rectifier output terminal 212. The input power Pin_C can be an AC signal or a DC signal, which does not affect the operation of the LED lighting device 200. When the LED lighting device 200 is designed to be lit based on a DC signal, the rectifier circuit 210 in the power module PM can be omitted. In the configuration where the rectifier circuit 210 is omitted, the first connection terminal 101 and the second connection terminal 102 are directly coupled to the input terminal (i.e., 211, 212) of the filter circuit 220. In some embodiments, the rectifier circuit 210 can be a full-wave rectifier circuit, a half-wave rectifier circuit, a bridge rectifier circuit, or other types of rectifier circuits, but the present disclosure is not limited thereto.

[0106] The filter circuit 220 is electrically connected to the rectifier circuit 210 to filter the rectified signal Srec; that is, the input end of the filter circuit 220 is coupled to the first rectifier output end 211 and the second rectifier output end 212 to receive the rectified signal Srec and filter the rectified signal Srec. The filtered signal Sflr is output from the first filter output end 221 and the second filter output end 222. Among them, the first rectifier output end 211 can be regarded as the first filter input end of the filter circuit 220, and the second rectifier output end 212 can be regarded as the second filter input end of the filter circuit 220. In this embodiment, the filter circuit 220 can filter out the ripple in the rectified signal Srec, so that the waveform of the generated filtered signal Sflr is smoother than the waveform of the rectified signal Srec. In addition, the filter circuit 220 can be configured by selecting the circuit to filter a specific frequency to filter out the response / energy of the external driving power supply at the specific frequency. In some embodiments, the filter circuit 220 may be a circuit composed of at least one of a resistor, a capacitor, and an inductor, such as a parallel capacitor filter circuit or a π-type filter circuit, but the present disclosure is not limited thereto.

[0107] The driving circuit 230 is electrically connected to the filter circuit 220 to receive the filtered signal Sflr and perform power conversion on the filtered signal Sflr to generate a driving power Sdrv; that is, the input end of the driving circuit 230 is coupled to the first filter output end 221 and the second filter output end 222 to receive the filtered signal Sflr, and then generate a driving power Sdrv for driving the LED module LM to emit light. Among them, the first filter output end 221 can be regarded as the first driving input end of the driving circuit 230, and the second filter output end 222 can be regarded as the second driving input end of the driving circuit 230. The driving power Sdrv generated by the driving circuit 230 will be provided to the LED module LM through the first driving output end 231 and the second driving output end 232, so that the LED module LM can light up in response to the received driving power Sdrv. The following is Figure 4 The embodiment of the driving circuit 230 is further described.

[0108] Figure 4 This is a schematic block diagram of a driving circuit according to an embodiment of the present disclosure. Figure 3 and Figure 4 , the driving circuit 330 is the aforementioned Figure 3An embodiment of the driving circuit 230 includes a switching control circuit 331 and a conversion circuit 332, which performs power conversion in a current source mode to drive the LED module LM to emit light. The conversion circuit 332 includes a switch circuit (also called a power switch) PSW and an energy storage circuit ESE. The conversion circuit 332 is coupled to the first filter output terminal 221 and the second filter output terminal 222, receives the filtered signal Sflr, and according to the control of the switching control circuit 331, converts the filtered signal Sflr into a driving power Sdrv and outputs it from the first driving output terminal 231 and the second driving output terminal 232 to drive the LED module LM. Under the control of the switching control circuit 331, the driving power output by the conversion circuit 332 is a stable current, so that the LED filament module emits light stably. In addition, the driving circuit 330 may also include a bias circuit 333, which can generate an operating voltage Vcc based on the bus voltage of the power module, and the operating voltage Vcc is provided to the switching control circuit 331, so that the switching control circuit 331 can be started and operated in response to the operating voltage.

[0109] The switching control circuit 331 of this embodiment can adjust the duty cycle of the output lighting control signal Slc in real time according to the current working state of the LED module LM, so that the switch circuit PSW is turned on or off in response to the lighting control signal Slc. The switching control circuit 331 can determine the current working state of the LED module LM by detecting at least one or more of the input voltage (which can be the level on the first connection terminal 101 / the second pin 102, the level on the first rectifier output terminal 211 or the level on the first filter output terminal 221), the output voltage (which can be the level on the first driver output terminal 231), the input current (which can be the bus current, that is, the current flowing through the rectifier output terminal 211 / 212, the filter output terminal 221 / 222) and the output current (which can be the current flowing through the driver output terminal 231 / 232, the current flowing through the energy storage circuit ESE or the current flowing through the switch circuit PSW). The energy storage circuit ESE will repeatedly charge / discharge energy according to the on / off state of the switch circuit PSW, so that the driving power Sdrv received by the LED module LM can be stably maintained at a preset current value Ipred.

[0110] The input end of the demodulation circuit 240 is electrically connected to the first connection end 101 and the second connection end 102 to receive the input power Pin_C, and the output end of the demodulation circuit 240 is electrically connected to the driving circuit 230 to provide a dimming control signal Sdc. The demodulation circuit 240 generates a corresponding dimming control signal Sdc according to the phase tangent angle / conduction angle of the input power Pin_C in each cycle or half cycle, wherein the switching control circuit 331 adjusts the output of the lighting control signal Slc according to the dimming control signal Sdc, thereby causing the driving power Sdrv to change in response to the change of the lighting control signal Slc. For example, the switching control circuit 331 can adjust the duty cycle of the lighting control signal Slc according to the dimming control signal Sdc, so that the driving power Sdrv increases or decreases in response to the brightness information indicated by the lighting control signal Slc. When the dimming control signal Sdc indicates a higher luminous brightness or color temperature, the switching control circuit 331 will increase the duty cycle based on the dimming control signal Sdc, thereby causing the conversion circuit ESE to output a higher driving power Sdrv to the LED module LM; conversely, when the dimming control signal Sdc indicates a lower luminous brightness or color temperature, the switching control circuit 331 will decrease the duty cycle based on the dimming control signal Sdc, thereby causing the conversion circuit ESE to output a lower driving power Sdrv to the LED module LM. In this way, the dimming control effect can be achieved.

[0111] More specifically, the demodulation process performed by the demodulation circuit 240 on the input power Pin_C may be, for example, a signal conversion method such as sampling, counting and / or mapping. For example, the demodulation circuit 240 may sample and count the zero-level duration of the input power Pin_C in each cycle or half cycle of the input power Pin_C, wherein the counted zero-level duration may be linearly or nonlinearly mapped to a level, and the mapped level may be provided to the switching control circuit 331 as the dimming control signal Sdc. The mapped level range may be selected based on the processable range of the switching control circuit 331, which may be, for example, 0V-5V. Figure 5A To further illustrate the signal waveform and circuit operation of the LED lighting system of the present disclosure under different dimming states, Figure 5A FIG. 4 is a schematic diagram of a dimming waveform according to an embodiment of the present disclosure.

[0112] Please refer to Figures 3 to 5A In this embodiment, the dimmer can, for example, modulate the phase angle of the input power Pin within the dimming phase interval D_ITV. Figure 5A In the figure, from top to bottom are the voltage waveform WF4 of the dimming phase interval D_ITV, the voltage waveform WF5 when the luminous brightness Lux is the maximum brightness Lmax, and the voltage waveform WF6 when the luminous brightness Lux is the minimum brightness Lmin.

[0113] First, from the voltage waveform WF4, the dimming phase interval D_ITV is composed of the phase interval between the lower limit phase tangent angle C1 and the upper limit phase tangent angle C2. The lower limit phase tangent angle C1 can be, for example, any value in the range of 0 to 15 degrees (such as 1, 2, 3... and so on), but the present disclosure is not limited to this. In addition, the upper limit phase tangent angle C2 can be, for example, any value in the range of 20 to 45 degrees (such as 21, 22, 23... and so on), but the present disclosure is not limited to this. In other words, the dimming phase interval D_ITV can be, for example, a phase interval of 0 to 45 degrees, a phase interval of 5 to 45 degrees, a phase interval of 5 to 20 degrees, a phase interval of 15 to 20 degrees, or a phase interval of 15 to 45 degrees, etc., which can be selected according to design requirements. In the present disclosure, the selection of the upper limit phase-tangent angle C2 is mainly based on two principles: first, the width of the dimming phase interval D_ITV can have sufficient resolution during mapping; second, when the dimmer adjusts the phase-tangent angle of the input power Pin_C to the upper limit phase-tangent angle C2, the THD and PF characteristics of the power module PM can still be maintained (for example, not less than 80% of the THD and PF when dimming at the lower limit phase-tangent angle C1, preferably making the THD less than 25% and / or making the PF greater than 0.9).

[0114] From the voltage waveform WF5, when the dimmer 50 modulates the input power Pin at the phase angle C1 in response to the dimming signal Sdim (i.e., the conduction angle of the input power Pin is 180-C1 degrees), the dimmer 50 disconnects the bus during the period when the phase of the input power Pin is from 0 degrees to C1, and conducts the bus during the period when the phase is from C1 to 180 degrees. In this case, the demodulation circuit 240 generates a dimming control signal Sdc indicating that the luminous brightness Lux is adjusted to the maximum brightness Lmax according to the input power Pin_C with the phase angle C1. The switching control circuit 331 uses the dimming control signal Sdc as a reference for controlling the switching of the power switch PSW, thereby causing the conversion circuit 332 to generate a corresponding driving power Sdrv to drive the LED module LM, and maintain the luminous brightness Lux of the LED module LM at the maximum brightness Lmax.

[0115] From the voltage waveform WF6, when the dimmer 50 modulates the input power Pin at the phase angle C2 in response to the dimming signal (i.e., the conduction angle of the input power Pin is 180-C2 degrees), the dimmer 50 disconnects the bus during the period when the phase of the input power Pin is from 0 degrees to C2, and conducts the bus during the period when the phase is from 150 degrees to 180 degrees. In this case, the demodulation circuit 240 generates a dimming control signal Sdc indicating that the luminous brightness Lux is adjusted to the minimum brightness Lmin according to the input power Pin_C with the phase angle C2. The switching control circuit 331 uses the dimming control signal Sdc as a reference for controlling the switching of the power switch PSW, thereby causing the conversion circuit 332 to generate a corresponding driving power Sdrv to drive the LED module LM, and reduce the luminous brightness Lux of the LED module LM to the minimum brightness Lmin. In this embodiment, the minimum brightness Lmin can be, for example, 10% of the maximum brightness Lmax.

[0116] Compared to Figure 2 As for the dimming control method shown in the figure, although the present embodiment also adopts the method of adjusting the phase cut angle / conduction angle to realize dimming control, since the present embodiment only uses the phase cut angle / conduction angle change of the input power source Pin_C as a reference signal indicating the dimming information, and does not intend to make the effective value change of the input power source Pin_C directly reflected in the change of the luminous brightness, the dimming phase interval D_ITV selected in the dimming control method of the present embodiment will be significantly smaller than that in Figure 2 From another perspective, under the dimming control method of this embodiment, no matter which phase cut angle within the dimming phase range is used by the dimmer to modulate the input power Pin, the effective value of the input power Pin_C generated will not be much different. For example, in some embodiments, the effective value of the input power Pin_C generated by the upper limit phase cut angle C2 modulation (such as the effective value under the voltage waveform WF6) will not be lower than the effective value of the input power Pin_C generated by the lower limit phase cut angle C1 modulation (such as the effective value under the voltage waveform WF5) by more than 50%.

[0117] From another perspective, in the aforementioned generally conventional implementation, since the luminous brightness of the LED module is directly related to the effective value of the input power Pin_C after modulation, therefore, in the generally conventional implementation, the effective value range ratio of the input power Pin_C is substantially the same as the brightness range ratio of the LED module. The definition of the effective value range ratio described herein is the ratio of the maximum value to the minimum value of the effective value of the input power Pin_C, and the definition of the brightness range ratio is the ratio of the maximum value to the minimum value of the luminous brightness of the LED module. Relatively speaking, according to the present disclosure, as described above, the effective value range ratio of the input power Pin_C may be unrelated to the brightness range ratio of the LED module. In some preferred embodiments, the effective value range ratio of the input power Pin_C may be smaller than the brightness range ratio of the LED module. In some preferred embodiments, the effective value range ratio of the input power Pin_C after modulation is less than or equal to 2, and the brightness range ratio of the LED module is greater than or equal to 10.

[0118] It should be noted that the correlation between the luminous brightness Lux of the above-mentioned LED module LM and the phase tangent angle change is only an example and not a limitation. For example, in other embodiments, the brightness of the LED module may be negatively correlated with the phase tangent angle of the input power Pin_C.

[0119] Please refer to Figure 5B In this embodiment, from the voltage waveform WF7, when the dimmer 50 modulates the input power Pin at the phase angle C1 in response to the dimming signal Sdim (i.e., the conduction angle of the input power Pin is 180-C1 degrees), the dimmer 50 disconnects the bus during the period when the phase of the input power Pin is from 0 degrees to C1, and conducts the bus during the period when the phase is from C1 to 180 degrees. In this case, the demodulation circuit 240 generates a dimming control signal Sdc indicating that the luminous brightness Lux is adjusted to the minimum brightness Lmin according to the input power Pin_C with the phase angle C1. The switching control circuit 331 uses the dimming control signal Sdc as a reference for controlling the switching of the power switch PSW, thereby causing the conversion circuit 332 to generate a corresponding driving power Sdrv to drive the LED module LM, and maintain the luminous brightness Lux of the LED module LM at the minimum brightness Lmin.

[0120] From the voltage waveform WF8, when the dimmer 50 modulates the input power Pin at the phase angle C2 in response to the dimming signal (that is, the conduction angle of the input power Pin is 180-C2 degrees), the dimmer 50 will disconnect the bus during the period when the phase of the input power Pin is from 0 degrees to C2, and turn on the bus during the period when the phase is from 150 degrees to 180 degrees. In this case, the demodulation circuit 240 will generate a dimming control signal Sdc indicating that the luminous brightness Lux is adjusted to the maximum brightness Lmax according to the input power Pin_C with a phase angle of C2. The switching control circuit 331 will use the dimming control signal Sdc as a reference to control the switching of the power switch PSW, thereby causing the conversion circuit 332 to generate a corresponding driving power Sdrv to drive the LED module LM, and reduce the luminous brightness Lux of the LED module LM to the maximum brightness Lmax. Incidentally, Figure 5A and Figure 5B In the embodiment, the tangent angle C2 is greater than the tangent angle C1.

[0121] From one perspective, Figure 5A In the embodiment, the luminance Lux of the LED module LM is negatively correlated to the tangent angle of the input power source Pin_C, and Figure 5B In the embodiment of the present invention, the luminance Lux of the LED module LM is positively correlated with the tangent angle of the input power source Pin_C. From another perspective, Figure 5A In the embodiment of the present invention, the luminance Lux of the LED module LM is positively correlated with the effective value of the input power Pin_C, and Figure 5B In the embodiment, the luminous brightness Lux of the LED module LM is negatively correlated with the effective value of the input power Pin_C. In contrast, in the aforementioned general conventional implementation, the luminous brightness Lux of the LED module LM can only be positively correlated with the effective value of the input power Pin_C. However, in the present disclosure, it is preferable to freely select the correlation between the luminous brightness Lux of the LED module LM and the effective value or tangent angle of the input power Pin_C according to actual needs, that is, according to the present disclosure, the luminous brightness Lux of the LED module LM may not be directly proportional to the effective value of the input power Pin_C.

[0122] Below Figure 6 and Figure 7 To further illustrate the specific circuit operation and signal generation mechanism of the demodulation circuit 240 in different embodiments. Figure 6 and Figure 7 Schematic diagrams of the corresponding relationship among the phase cutting angle, the demodulation signal and the brightness of the LED module according to different embodiments of the present disclosure.

[0123] Please refer to the reference first Figure 3 , Figure 4 and Figure 6The demodulation circuit 240 of this embodiment uses a signal processing method similar to an analog circuit to realize the acquisition and conversion of dimming information. Figure 6 It can be seen that when the phase angle ANG_pc of the input power Pin_C is adjusted within the interval of C1 and C2, the level of the dimming control signal Sdc will change within the interval of V1 and V2 accordingly. In other words, the phase angle ANG_pc of the input power Pin_C will have a positive linear correlation with the level of the dimming control signal Sdc within the dimming phase interval. From the perspective of the operation of the demodulation circuit 240, when the demodulation circuit 240 determines that the phase angle of the input power Pin_C is C1, it will correspondingly generate a dimming control signal Sdc with a level of V1; similarly, when the demodulation circuit 240 determines that the phase angle of the input power Pin_C is C2, it will correspondingly generate a dimming control signal Sdc with a level of D2.

[0124] Then, the dimming control signal Sdc which is positively correlated with the phase angle ANG_pc is given to the switching control circuit 331, so that the conversion circuit 332 generates a corresponding driving power Sdrv to drive the LED module LM, and the LED module LM has a corresponding luminous brightness Lux. In some embodiments, the luminous brightness Lux of the LED module LM is in a linear relationship with a negative correlation with the level of the dimming control signal Sdc. Figure 6 As shown in FIG. 1 , when the dimming control signal Sdc received by the switching control circuit 331 is at a level Va between the levels V1 and V2, the switching control circuit 331 will adjust the lighting control signal Slc accordingly, so that the LED module LM emits light at a brightness La after being driven by the driving power source Sdrv. The brightness La is inversely proportional to the level Va, and can be expressed as However, the disclosure is not limited thereto.

[0125] It is worth noting that the above-mentioned mechanism for generating the dimming control signal Sdc and the luminous brightness Lux is only to illustrate that the demodulation circuit 240 of the present disclosure extracts the signal characteristics (such as the phase angle) of the input power source Pin_C and converts / maps it into a dimming control signal Sdc, so that the driving circuit 230 can adjust the luminous brightness Lux of the LED module LM based on the dimming control signal Sdc, which is a signal conversion implementation similar to an analog circuit, but it is not used to limit the scope of the present disclosure. In some embodiments, Figure 6 The corresponding relationship between the phase-cut angle ANG_pc and the dimming control signal Sdc shown in FIG. 1 may also be a nonlinear relationship. For example, the corresponding relationship between the phase-cut angle ANG_pc and the dimming control signal Sdc is an exponential relationship. Similarly, Figure 6The corresponding relationship between the dimming control signal Sdc and the luminous brightness Lux shown can also be a nonlinear relationship, and the present disclosure is not limited thereto. In addition, in some embodiments, the phase angle ANG_pc and the level of the dimming control signal Sdc can also be negatively correlated. In some embodiments, the brightness La and the level Va can also be positively correlated.

[0126] Please refer to Figure 3 , Figure 4 and Figure 7 The demodulation circuit 240 of this embodiment uses a signal processing method similar to a digital circuit to realize the acquisition and conversion of dimming information. Specifically, when the phase angle of the input power source Pin_C is adjusted within a default range, the dimming control signal will have a default number of different signal states corresponding to the change of the phase angle, so as to control the dimming of the LED module to a default number of dimming levels. For example, Figure 7 It can be seen that when the phase angle ANG_pc of the input power Pin_C is adjusted within the interval between C1 and C2, the dimming control signal Sdc will have 8 different signal states, such as D1 to D8, corresponding to the change of the phase angle ANG_pc. In other words, the phase angle ANG_pc of the input power Pin_C will be divided into 8 sub-intervals within the dimming phase interval, and each sub-interval will correspond to a signal state D1-D8 of the dimming control signal Sdc. In some embodiments, the signal state can be indicated by a high or low level; for example, the dimming control signal Sdc in state D1 corresponds to a 1V level, and the dimming control signal Sdc in state D8 corresponds to a 5V level. In some embodiments, the signal state can be indicated by a multi-bit logic level; for example, the dimming control signal Sdc in state D1 corresponds to a logic level of "000", and the dimming control signal Sdc in state D8 corresponds to a logic level of "111".

[0127] Then, the dimming control signal Sdc with the signal state D1-D8 is given to the switching control circuit 331, so that the conversion circuit 332 generates the corresponding driving power Sdrv to drive the LED module LM, and the LED module LM has the corresponding luminous brightness Lux. In some embodiments, the signal states D1-D8 can correspond one-to-one to the different luminous brightness Lux of the LED module LM. Figure 6 As shown, the signal states D1-D8 may correspond to the luminance Lux being 100%, 87.5%, 75%, 62.5%, 50%, 37.5%, 25%, and 10% of the maximum luminance Lmax, respectively. It is mentioned here that the present embodiment takes the demodulation circuit 240 designed with a 3-bit resolution as an example (i.e., 8-segment dimming), but the present disclosure is not limited thereto.

[0128] Figure 8This is a schematic diagram of the input power waveform of the LED lighting device under different grid voltages according to an embodiment of the present disclosure. Figure 1A , Figure 3 and Figure 8 As can be seen from the diagram, no matter the peak voltage of the input power Pin is a1 or a2, if the dimmer 50 modulates the input power with the phase-cut angle C3, the input power Pin_C generated by the dimmer 50 will still have the same zero-level period (i.e., the period from the phase 0 to C3). Therefore, no matter what the peak voltage of the input power Pin is, the demodulation circuit 240 can still demodulate the input power Pin_C with the same phase-cut angle to produce the same dimming control signal Sdc. In other words, no matter which external power grid EP specification the LED lighting system 10 is applied to, the LED lighting system 10 can make the LED lighting device 100 have the same luminous brightness or color temperature when receiving the same dimming signal Sdim, so it can be compatible with applications with various power grid EP voltage specifications.

[0129] From another perspective, in the present disclosure, the dimming of the LED module (eg, luminous brightness or color temperature) is related to the phase-cut angle of the input power source Pin_C, but is substantially unrelated to the voltage peak of the external power grid EP.

[0130] In contrast, if we use Figure 2 The dimming control method described in the embodiment has a significant difference in effective value even if the same phase angle is used for modulation under input power sources with different peak voltages. Figure 2 The dimming control method described in the embodiment can only be individually designed according to the actual application environment of the LED lighting system 10 and is not compatible with various grid voltage specifications.

[0131] It should be noted that due to the parasitic effects of the circuit components themselves or the matching between the components is not necessarily ideal, therefore, although it is intended that the dimming of the LED module does not respond to the peak value of the voltage of the external power grid, in fact, the dimming effect of the LED module may still slightly respond to the peak value of the voltage of the external power grid. That is, according to the present disclosure, it is acceptable that the dimming of the LED module slightly responds to the peak value of the voltage of the external power grid due to the non-ideality of the circuit. This is the meaning of the aforementioned "substantially" not responding to the peak value of the voltage of the external power grid, and the same applies to other places mentioned in this article. The word "slightly" here, in one embodiment, may mean that when the peak value of the voltage of the external power grid is twice, the dimming of the LED module is only affected by, for example, less than 5%.

[0132] Fig. 9 This is a flowchart of the dimming control method of an LED lighting system according to an embodiment of the present disclosure. Figure 1A and Fig. 9 , the overall dimming control method is described here from the perspective of the LED lighting system 10. First, the dimmer 50 modulates the input power Pin according to the dimming signal Sdim, and generates the input power Pin_C accordingly (step S110), wherein the input power Pin_C carries a signal feature indicating dimming information, and the signal feature can be, for example, the phase tangent angle / conduction angle of the input power Pin_C. The input power Pin_C is provided to the LED lighting device 100, so that the LED lighting device 100 performs power conversion based on the input power Pin_C and lights up the internal LED module (step S120). On the other hand, the LED lighting device 100 captures the signal feature from the input power Pin_C (step S130), and demodulates the captured signal feature to extract the corresponding dimming information (step S140). Then, the LED lighting device 100 adjusts the power conversion operation with reference to the demodulated dimming information to change the luminous brightness or color temperature of the LED module (step S150).

[0133] More specifically, with Figure 3 From the above, the above-mentioned signal feature acquisition (step S130) and the action of demodulating the input power Pin_C (step S140) can be realized by the demodulation circuit 240 in the LED lighting device 100 / 200. In one embodiment, the LED lighting device 100 performs power conversion based on the input power Pin_C and lights up the internal LED module (step S120) and adjusts the power conversion operation based on the dimming information to adjust the luminous brightness of the LED module (step S150) can be realized by the driving circuit 230 in the LED lighting device 100 / 200.

[0134] The overall dimming control method is further described below from the perspective of the LED lighting device 100. Fig.10 shown. Fig.10 This is a flowchart of the dimming control method of an LED lighting device according to an embodiment of the present disclosure. Figure 1A , Figure 3 and Fig.10. When the LED lighting device 100 receives the input power Pin_C, the rectifier circuit 210 and the filter circuit 220 will sequentially rectify and filter the input power Pin_C, and generate a filtered signal Sflr to the driver circuit 230 (step S210). The driver circuit 230 will perform power conversion on the received filtered signal Sflr, and generate a driving power Sdrv to provide to the rear LED module (step S220). On the other hand, the demodulation circuit 240 will capture the signal characteristics of the input power Pin_C (step S230), and then demodulate the captured signal characteristics to extract dimming information (such as the size of the angle corresponding to the tangent angle), and generate a corresponding dimming control signal Sdc (step S240). The driver circuit 230 will refer to the dimming control signal Sdc to adjust the power conversion operation, so as to adjust the size of the generated driving power Sdrv in response to the dimming information (step S250), thereby changing the luminous brightness or color temperature of the LED module LM.

[0135] Furthermore, the method of using the dimming control signal Sdc to adjust the power conversion operation of the driving circuit 230 can be an analog control method in some embodiments. For example, the level of the dimming control signal Sdc can be used to analogically control, for example, the voltage or current reference value of the driving circuit 230, thereby analogically adjusting the size of the driving power Sdrv.

[0136] In some embodiments, the power conversion operation of the driving circuit 230 is adjusted by a dimming control signal Sdc. In one embodiment, optionally, a digital control method can be used. For example, the dimming control signal Sdc can have different duty cycles in response to the phase-cutting angle. In such embodiments, the dimming control signal Sdc can have, for example, a first state (e.g., a high logic state) and a second state (e.g., a low logic state). In one embodiment, the first state and the second state are used to digitally control the size of the driving power Sdrv of the driving circuit 230. For example, the output current is output in the first state, and the output current is stopped in the second state, thereby dimming the LED module LM.

[0137] It should be noted that the dimming control signal Sdc (eg Figure 3 11), is not in the power loop of the LED module LM and the driving power source Sdrv. In other words, the dimming control signal Sdc is not used to directly drive the power source of the LED module LM. From another perspective, the current or power of the dimming control signal Sdc is much smaller than the current or power of the driving power source Sdrv. Specifically, in some embodiments, the current or power of the dimming control signal Sdc is much smaller than 1 / 10, 1 / 100 or less than 1 / 100 of the current or power of the driving power source Sdrv.

[0138] It is worth mentioning that although the above embodiments of the present disclosure regarding the use of phase cutting angle / conduction angle to modulate the input power supply are all based on the leading edge phase cutting as an example (the input voltage is chopped from the phase 0 degree), the present disclosure is not limited to this. In some embodiments, the dimmer can also use the trailing edge phase cutting (the input voltage is chopped from a specific phase until the phase is 180 degrees) to modulate the input power supply.

[0139] In addition, although the above embodiments are all based on adjusting the brightness of the LED module, they can also be applied to adjusting the color temperature of the LED module. For example, if the above dimming control method is applied to only adjust the driving power provided to the red LED lamp beads (that is, only the brightness of the red LED lamp beads is adjusted), the color temperature of the LED lighting device can be adjusted through the above dimming control method.

[0140] According to the design of the rectifier circuit in the power module, it can be a dual rectifier circuit. The first and second rectifier circuits in the dual rectifier circuit are respectively coupled to the lamp holders arranged at both ends of the LED lighting device. The dual rectifier circuit architecture can be applied to a dual-end power input drive architecture.

[0141] The dual rectification circuit may, for example, include two half-wave rectification circuits, two full-wave bridge rectification circuits, or one half-wave rectification circuit plus one full-wave bridge rectification circuit.

[0142] According to the design of the pins in the LED lamp tube, two pins can be set at a single end (with no pins at the other end), two pins can be set at two opposite ends correspondingly, or four pins can be set at two opposite ends correspondingly. The design of setting two pins at a single end and the design of setting two pins at two opposite ends correspondingly are suitable for the single rectifier circuit design of the rectifier circuit. The design of setting four pins at two opposite ends correspondingly is suitable for the double rectifier circuit design of the rectifier circuit, and the external drive signal is received only through the two pins at one end or through any one of the two pins at the two ends.

[0143] According to the design of the filter circuit of the power module, a single capacitor can be set, or a π-type filter circuit can be set. The filter circuit filters out the high-frequency part of the rectified signal to provide a DC signal with a low-frequency ripple voltage as the filtered signal. The filter circuit further includes an LC filter circuit, which has a high impedance to a specific high frequency to comply with the current restrictions on a specific frequency in the UL standard. In addition, according to some embodiments, the filter circuit further includes a filter unit, which is coupled between a filter circuit and the pin to reduce the electromagnetic radiation (EMI) caused by the circuit in the LED lamp tube. When the external drive signal is a DC signal, the filter circuit in the power supply module of the LED lamp tube can be omitted.

[0144] The exemplary features mentioned above in the present invention can be combined arbitrarily to improve the LED lamp, and the above embodiments are described only as examples. The present invention is not limited thereto, and there may be many variations without departing from the spirit of the present invention and the scope of protection of the claims.

Claims

1. An LED lighting device, characterized in that: It includes a rectifier circuit, a filter circuit, a drive circuit, an LED module, and a demodulation circuit, wherein: The rectifier circuit is used to receive an input power signal through the first connection terminal and the second connection terminal to rectify the input power signal to generate a rectified signal; The filter circuit is coupled to the rectifier circuit to electrically filter the rectified signal to generate a filtered signal; The driving circuit is coupled to the filtering circuit, and is used to perform power conversion on the filtered signal to generate a driving power signal; The LED module is coupled to the driving circuit to be lit and emit light according to the driving power signal; The demodulation circuit is coupled to the first connection end and the second connection end, and is used to capture the signal characteristics in the input power signal, and is used to demodulate the signal characteristics to obtain corresponding dimming information; The demodulation circuit is used to generate a dimming control signal according to the dimming information, and to provide the dimming control signal to the driving circuit; and The driving circuit includes a switching control circuit and a conversion circuit, wherein the switching control circuit controls the conversion circuit according to the received dimming control signal, so as to change or adjust the magnitude of the driving power supply signal in response to the dimming information. The signal characteristic is a tangent angle of the input power signal, and when the LED module is lit at the lowest brightness, the tangent angle is not greater than 90 degrees. When the tangent angle is between 0 and 15 degrees, the LED module is dimmed to the highest brightness, and when the tangent angle is between 15 and 20 degrees, the LED module is dimmed to the lowest brightness, so that the total harmonic distortion of the LED lighting device is less than 25% and the power factor of the LED lighting device is greater than 0.

9. Wherein, the minimum brightness is 10% of the maximum brightness of the LED, wherein the tangent angle is formed by the front tangent, and The demodulation circuit samples and counts the zero-level duration of the input power signal in each cycle or half cycle of the input power signal, and maps the counted zero-level duration to a level, which is provided to the switching control circuit as the dimming control signal to adjust the driving power signal.

2. The LED lighting device according to claim 1, characterized in that: The dimming level of the LED module is not related to the peak voltage of the input power signal.

3. The LED lighting device according to claim 1, characterized in that: The dimming level of the LED module is not related to the effective value of the input power signal.

4. The LED lighting device according to claim 1, characterized in that: The dimming level of the LED module is not directly proportional to the effective value of the input power signal.

5. The LED lighting device according to claim 4, characterized in that: The effective value refers to the root mean square (RMS) value.

6. The LED lighting device according to claim 5, characterized in that: The effective value range ratio of the input power signal is smaller than the brightness range ratio of the LED module, wherein the effective value range ratio refers to the ratio of the maximum value to the minimum value of the effective value of the input power signal, and the brightness range ratio refers to the ratio of the maximum value to the minimum value of the brightness of the LED module.

7. The LED lighting device according to claim 6, characterized in that: The effective value range ratio of the modulated input power signal is less than or equal to 2, and the brightness range ratio of the LED module is greater than or equal to 10.

8. The LED lighting device according to claim 1, characterized in that: The phase tangent angle is selected between a maximum phase degree and a minimum phase degree; and when the input power signal has a maximum phase degree of the phase tangent angle or a minimum phase degree of the phase tangent angle, the total harmonic distortion and power factor characteristics of the LED lighting device are degraded by no more than 20%.

9. The LED lighting device according to claim 1, characterized in that: The effective value of the input power at the maximum phase tangent angle is not less than 50% of the effective value at the minimum phase tangent angle.

10. The LED lighting device according to claim 1, characterized in that: When the phase tangent angle of the input power signal remains unchanged, the brightness of the LED module remains unchanged when the amplitude of the input power signal changes.

11. An LED lighting system, characterized in that: Include: One or more LED lighting devices according to any one of claims 1 to 10; as well as The dimmer is electrically connected to the external power grid, and is used to receive a mains power signal, and to change the phase angle of the mains power signal according to the dimming signal, so as to generate the input power signal to the LED lighting device.

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