Light-emitting device

Abstract

To achieve a power supply unit with reduced radiation noise.SOLUTION: A power supply unit (2) for lighting an LED light source (3) includes: an input unit (21); a noise filter (22); an output unit (25); an impedance element (26) and a first capacitor (27) connected in series; and a second capacitor (28) whose one end is connected to the output unit (25) and whose other end is connected to a ground terminal. One end of either impedance element (26) or first capacitor (27) is connected to the noise filter (22) and the other end is connected to the ground terminal.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a power supply unit for lighting a light emitting diode element. [Background technology]

[0002] Patent Document 1 discloses an LED lighting device consisting of a power supply unit that receives input from an AC power supply and an LED (Light Emitting Diode) element connected to the power supply unit via wiring. The power supply unit in this cited reference is equipped with a capacitor between the output line and a ground terminal and an inductor on the output line to prevent malfunction due to radiation noise from the LED element or cable, while solving problems such as common mode noise from the input power supply. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2013-143807 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, noise regulation standards are becoming stricter every year, and in addition to preventing malfunctions, the emission of radiated noise is also being regulated. Specifically, the PSE noise regulation standards are scheduled to be revised to CISPRJ15, which defines the frequency band of noise field strength as 30MHz to 300MHz. Therefore, reducing the frequency band of radiated noise is necessary to comply with PSE.

[0005] In addition, when a power supply unit has Y capacitors connected to the ground terminal on both the AC and DC sections, most common mode noise can be removed through the ground terminal by the Y capacitor on the AC section. However, if noise removal from the ground terminal is not ideal, noise that cannot be removed by the Y capacitor on the AC section will propagate to the DC section as noise through the Y capacitor on the DC section. This causes radiated noise to be emitted from the LED elements or cables.

[0006] In particular, if the total length of the connection path, including the cables and boards connecting the Y capacitor on the AC side and the LED element, is long, such as 1200 mm, the total connection path functions as an antenna and becomes a noise source. As a result, the LED element emits radiated noise between 100 MHz and 300 MHz according to the antenna length.

[0007] Therefore, one aspect of the present invention is to provide a method for reducing radiation noise. 、 Power supply unit A light emitting device comprising: The purpose is to achieve the following. [Means for solving the problem]

[0008] In order to solve the above problems, according to one aspect of the present invention, Light-emitting device is a light emitting diode element and the light emitting diode element Power supply unit for lighting the A light emitting device comprising: And, The power supply unit includes: an input section for receiving AC power, a conversion section for converting the AC power into DC power, a noise filter disposed between the input section and the conversion section, an output section for outputting the DC power to the light-emitting diode element, an impedance element and a first capacitor connected in series, and a second capacitor having one end connected to the output section and the other end connected to a ground terminal; a substrate on which the light emitting diode element is disposed, and a second dummy wiring that is wired on the substrate, the second dummy wiring having one end connected to the output section and the other end electrically floating, One end of either the impedance element or the first capacitor is connected to the noise filter, and the other end of the other is connected to a ground terminal. Effect of the Invention

[0009] According to one aspect of the present invention, a method for reducing radiation noise is provided. Light-emitting device It is possible to achieve this. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing a circuit diagram of an LED lighting device according to a first embodiment. [Diagram 2] FIG. 11 is a circuit diagram of an LED lighting device according to a second embodiment. [Diagram 3] FIG. 11 is a diagram showing a circuit diagram of an LED lighting device according to a third embodiment. [Figure 4] FIG. 11 is a diagram showing a circuit diagram of an LED lighting device according to embodiment 4. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] [Embodiment 1] Hereinafter, one embodiment of the present invention will be described in detail.

[0012] (LED lighting device configuration) 1 is a diagram showing a circuit diagram of an LED lighting device 1 (light emitting device) according to embodiment 1. As shown in this figure, the LED lighting device 1 includes a power supply unit 2 and an LED light source 3.

[0013] The power supply unit 2 includes an input section 21, a noise filter 22, a conversion section 23, a line filter 24, an output section 25, an impedance element 26, a first capacitor 27, and a second capacitor .

[0014] The input unit 21 receives AC power from an AC power supply 41. The input unit 21 outputs the received AC power to the noise filter 22.

[0015] The noise filter 22 removes noise of an AC component in the input AC power by filtering out noise contained in the input AC power. Furthermore, the noise filter 22 removes noise from the conversion unit 23 so as to prevent noise from leaking to the AC power supply 41. The noise filter 22 outputs the filtered AC power to the conversion unit 23.

[0016] The noise filter 22 may be configured as a single-phase two-stage filter circuit or a single-phase one-stage filter circuit using a common mode choke coil. Specifically, the noise filter 22 includes a first common mode choke coil and a second common mode choke coil connected in order between the AC power supply 41 and the conversion unit 23. Furthermore, a first X capacitor is connected between the connection points of the AC power supply 41 and the first common mode choke coil, a second X capacitor is connected between the connection points of the first common mode choke coil and the second common mode choke coil, and a third X capacitor is connected between the connection points of the second common mode choke coil and the conversion unit 23. Here, the secondary side of the first common mode choke coil, one pole of the second X capacitor, and the primary side of the second common mode choke coil are connected to the first capacitor 27.

[0017] The conversion unit 23 converts the input AC power into DC power. The conversion unit 23 may be a switching power supply including a transformer and a switching element. The conversion unit 23 outputs the converted DC power to the line filter 24.

[0018] The line filter 24 is disposed between the conversion unit 23 and the output unit 25. The line filter 24 removes switching noise contained in the input DC power by filtering the switching noise contained in the DC power. The line filter 24 outputs the filtered DC power to the output unit 25.

[0019] The line filter 24 may be a common mode choke coil. As the line filter 24, a third common mode choke coil is connected between the conversion unit 23 and the output unit 25. Also, a third capacitor may be connected between the connection point of the conversion unit 23 and the third common mode choke coil, and a fourth capacitor may be connected between the connection point of the third common mode choke coil and the output unit 25. Furthermore, a second capacitor 28 is connected to the secondary side of the third common mode choke coil and one pole of the fourth capacitor.

[0020] The output unit 25 outputs the input DC power to the LED light source 3 .

[0021] The impedance element 26 and the first capacitor 27 are connected in series. The impedance element 26 may be configured with at least one of a coil and a resistor. In this embodiment, the impedance element 26 is configured with a coil. The first capacitor 27 may be a Y capacitor.

[0022] In the power supply unit 2, one end of either the impedance element 26 or the first capacitor 27 may be connected to the noise filter 22, and the other end of the other may be connected to a ground terminal. In the example shown in Fig. 1, one end of the impedance element 26 is connected to the noise filter 22, and the other end of the impedance element 26 is connected to one end of the first capacitor 27. The other end of the first capacitor 27 is connected to the ground terminal.

[0023] Alternatively, the positions of the impedance element 26 and the first capacitor 27 may be interchanged. That is, one end of the first capacitor 27 may be connected to the noise filter 22, and the other end of the first capacitor 27 may be connected to one end of the impedance element 26. In this configuration, the other end of the impedance element 26 is connected to the ground terminal. Even if the connection order of the impedance element 26 and the first capacitor 27 is interchanged, the impedance element 26 and the first capacitor 27 can perform the same role as before the connection order is interchanged.

[0024] The second capacitor 28 is connected between the output section 25 and the ground terminal. That is, one end of the second capacitor 28 is connected to the output section, and the other end is connected to the ground terminal. The second capacitor 28 may be a Y capacitor.

[0025] The ground terminal may be a metal housing of the power supply unit 2. The ground terminal is also connected to the ground terminal of the AC power supply 41 inputted through the input section 21.

[0026] The LED light source 3 includes a light emitting diode element (LED element) therein, and emits light with DC power input from the power supply unit 2. In other words, the power supply unit 2 is a unit for lighting the LED element of the LED light source 3.

[0027] (LED lighting device operation) When the first capacitor 27 and the second capacitor 28 are Y capacitors, the Y capacitor is generally effective against noise of 1 MHz or more, and has the effect of reducing common mode noise.

[0028] However, as described above, common mode noise that is mixed in from the conversion unit 23, typically via the capacitor connected to the AC side and the capacitor connected to the DC side, may be emitted from the light-emitting device as radiated noise.

[0029] 1, the propagation of the noise from the AC part side to the DC part side is inhibited or the noise energy is reduced by impedance element 26. Therefore, by connecting impedance element 26 and first capacitor 27 in series, it is possible to suppress the generation of radiation noise.

[0030] [Embodiment 2] Other embodiments of the present invention will be described below. For ease of explanation, the same reference numerals are given to components having the same functions as those described in the above embodiment, and the description thereof will not be repeated.

[0031] 2 shows a circuit diagram of an LED lighting device 1a according to embodiment 2. Unlike the LED lighting device 1, the LED lighting device 1a includes, instead of the impedance element 26, a coil 26a and a resistor 26b connected in parallel with each other.

[0032] When low-frequency noise of 100 MHz or less (30 MHz to 100 MHz) is present, the coil 26a can release the noise to the ground terminal without suppressing the current change because of the low frequency. On the other hand, when high-frequency noise of more than 100 MHz (100 MHz to 300 MHz) is present, the coil 26a does not let the noise through because of the high frequency, and the resistor 26b reduces the noise current while releasing the noise to the ground terminal.

[0033] If the structure were such that noise could not be released completely to the ground terminal, the noise would flow to AC power supply 41 in the device into which the noise was mixed or in which the noise was generated. Therefore, it is necessary to release the mixed-in noise or generated noise to the ground terminal.

[0034] Therefore, by configuring impedance element 26 as a parallel structure of coil 26a and resistor 26b, low-frequency noise (30 MHz to 100 MHz) can be released to the ground terminal. Therefore, the function of reducing the noise current flowing to the AC power line can be obtained without impairing the noise reduction function of the first capacitor. Furthermore, this effect does not impair the noise reduction function of the first capacitor. Note that the coil referred to here includes not only a general coil but also chip inductors, ferrite beads, and chip ferrite beads, and may be any element that has the function of allowing low-frequency current to pass through without suppressing changes.

[0035] [Embodiment 3] Other embodiments of the present invention will be described below. For ease of explanation, the same reference numerals are given to members having the same functions as those described in the above embodiment, and the description thereof will not be repeated.

[0036] 3 shows a circuit diagram of an LED lighting device 1b according to embodiment 3. The LED lighting device 1b differs from the LED lighting device 1 in that the power supply unit 2 includes a first dummy wiring 29.

[0037] The first dummy wiring 29 is a wiring having one end connected to the output section 25 and the other end electrically floating. The electrically floating wiring may be a copper foil pattern or wire on a substrate. Therefore, since an antenna separate from the antenna of the LED light source 3 is formed inside the power supply unit 2, it is possible to reduce the noise energy that generates the radiation noise. By reducing the noise energy, it is possible to suppress the generation of the radiation noise.

[0038] Therefore, by providing the power supply unit 2 with the first dummy wiring 29, it is possible to reduce radiation noise.

[0039] [Embodiment 4] Other embodiments of the present invention will be described below. For ease of explanation, the same reference numerals are given to members having the same functions as those described in the above embodiment, and the description thereof will not be repeated.

[0040] 4 shows a circuit diagram of an LED lighting device 1c according to embodiment 4. The LED lighting device 1c is different from the LED lighting device 1 in that the LED light source 3 is provided with a second dummy wiring 31. That is, the LED lighting device 1c further includes a substrate (not shown) on which the LED elements of the LED light source 3 are arranged, and a second dummy wiring 31 wired on the substrate of the LED light source 3.

[0041] The second dummy wiring 31 is a wiring having one end connected to the substrate of the LED light source 3 and the other end electrically floating. The electrically floating wiring may be a copper foil pattern or wire on the substrate. Therefore, the second dummy wiring forms an antenna separate from the antenna of the LED light source 3 inside the power supply unit 2, and thus can reduce the noise energy that generates the radiation noise by distributing it. The reduction in noise energy can suppress the generation of radiation noise.

[0042] Therefore, by providing the second dummy wiring 31 in the LED light source 3, it is possible to reduce radiation noise.

[0043] 〔summary〕 The power supply unit according to aspect 1 of the present invention is a power supply unit for lighting a light-emitting diode element, and comprises an input section to which AC power is input, a conversion section to convert the AC power into DC power, a noise filter arranged between the input section and the conversion section, an output section to output the DC power to the light-emitting diode element, an impedance element and a first capacitor connected in series, and a second capacitor having one end connected to the output section and the other end connected to a ground terminal, and one end of either the impedance element or the first capacitor is connected to the noise filter, and the other end of the other is connected to the ground terminal.

[0044] According to the above configuration, it is possible to reduce the radiation noise emitted from the power supply unit.

[0045] A power supply unit according to a second aspect of the present invention is the power supply unit according to the first aspect, wherein the impedance element is configured by at least one of a coil and a resistor.

[0046] According to the above configuration, the impedance element is formed of at least one of a coil and a resistor, so that noise energy can be reduced.

[0047] A power supply unit according to a third aspect of the present invention is configured in the above-mentioned second aspect, wherein the impedance element is configured with the coil and the resistor connected in parallel to each other.

[0048] According to the above configuration, the impedance element is formed by a coil and a resistor connected in parallel with each other, so that noise energy can be reduced in a frequency band in which radiation noise occurs.

[0049] The power supply unit according to a fourth aspect of the present invention may be any of the first to third aspects described above, further comprising a first dummy wiring having one end connected to the output section and the other end electrically floating.

[0050] According to the above configuration, the first dummy wiring can reduce noise energy that generates radiation noise emitted by the power supply unit.

[0051] The power supply unit according to a fifth aspect of the present invention may be any of the first to fourth aspects described above, further comprising a line filter disposed between the conversion section and the output section.

[0052] According to the above configuration, it is possible to filter out noise mixed in the DC power converted by the conversion unit, which leads to a reduction in radiation noise.

[0053] A light emitting device according to a sixth aspect of the present invention includes the power supply unit according to any one of the first to fifth aspects and the light emitting diode element.

[0054] According to the above configuration, by connecting the light emitting device to the power supply unit with reduced radiation noise, the light emitting device can be used in a state in which the emission of radiation noise is reduced.

[0055] The light emitting device according to aspect 7 of the present invention may be the same as in aspect 6 above, further comprising a substrate on which the light emitting diode elements are arranged, and a second dummy wiring wired on the substrate, the second dummy wiring having one end connected to the output section and the other end electrically floating.

[0056] According to the above configuration, the second dummy wiring can reduce noise energy that causes radiation noise emitted by the light emitting device.

[0057] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. The technical scope of the present invention also includes embodiments obtained by appropriately combining the technical means disclosed in the different embodiments. Furthermore, new technical features can be formed by combining the technical means disclosed in the respective embodiments. [Explanation of symbols]

[0058] 1, 1a, 1b, 1c LED lighting device (light emitting device) 2 Power supply units 3 LED light source 21 Input section 22 Noise Filter 23 Conversion section 24 Line Filter 25 Output section 26 Impedance Element 26a Coil 26b resistance 27 First Capacitor 28 Second Capacitor 29 First dummy wiring 31 Second dummy wiring 41 AC power supply

Claims

1. A light emitting diode element; A light-emitting device comprising: a power supply unit for lighting the light-emitting diode element, The power supply unit includes: an input unit to which AC power is input; A conversion unit that converts the AC power into DC power; a noise filter disposed between the input unit and the conversion unit; an output section that outputs the DC power to the light emitting diode element; an impedance element and a first capacitor connected in series; a second capacitor having one end connected to the output section and the other end connected to a ground terminal; A substrate on which the light emitting diode elements are disposed; a second dummy wiring that is wired on the substrate, the second dummy wiring having one end connected to the output section and the other end electrically floating; a first end of the impedance element or the first capacitor is connected to the noise filter, and the other end of the impedance element or the first capacitor is connected to a ground terminal.

2. 2. The light emitting device according to claim 1, wherein the impedance element is composed of at least one of a coil and a resistor.

3. 3. The light emitting device according to claim 2, wherein the impedance element is formed by the coil and the resistor connected in parallel with each other.

4. 4. The light emitting device according to claim 1, further comprising a first dummy wiring having one end connected to the output section and the other end electrically floating.

5. 5. The light emitting device according to claim 1, further comprising a line filter disposed between the conversion section and the output section.

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