Power supply device and lighting apparatus

Abstract

To provide a power supply device and a lighting apparatus, capable of suppressing a radiation noise.SOLUTION: A power supply device comprises: a substrate; an output terminal part that is provided to the substrate and is used for a connection with a light source unit; a switching circuit that is provided to the substrate, includes a switching element, converts a power to be input into a power corresponding to the light source unit by a switching of a switching element, and turns on the light source unit connected to the output terminal part by supplying the power after the conversion to the output terminal part; and a noise filter that is provided to the substrate, is electrically connected to the output terminal part and the switching circuit, and suppresses noises overlapped to the power supplied to the output terminal part from the switching circuit. A distance between the noise filter and the output terminal part is shorter than that between the switching circuit and the output terminal part.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] SUMMARY OF THE DISCLOSURE The present invention relates to a power supply device and a lighting fixture. [Background technology]

[0002] There is a lighting fixture that includes a light source unit and a power supply device for lighting the light source unit. The power supply device has a switching circuit that converts input power into another power corresponding to the light source unit and supplies the converted power to the light source unit to light the light source unit. The switching circuit has a switching element and performs power conversion by switching the switching element.

[0003] In such lighting fixtures, it is desirable to suppress the radiated noise emitted from the entire lighting fixture in order to comply with radiated electric field strength standards (for example, CISPRJ 15). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2018-57069 A Summary of the Invention [Problem to be solved by the invention]

[0005] The object is to provide a power supply device and a lighting fixture capable of suppressing radiation noise. [Means for solving the problem]

[0006] According to an embodiment of the present invention, there is provided a power supply device comprising: a substrate; an output terminal portion provided on the substrate and used for connecting to a light source unit; a switching circuit provided on the substrate and having a switching element, which converts input power into power corresponding to the light source unit by switching the switching element and supplies the converted power to the output terminal portion, thereby lighting the light source unit connected to the output terminal portion; and a noise filter provided on the substrate, electrically connected between the output terminal portion and the switching circuit, and suppressing noise superimposed on the power supplied from the switching circuit to the output terminal portion, wherein the distance between the noise filter and the output terminal portion is shorter than the distance between the switching circuit and the output terminal portion. Effect of the Invention

[0007] According to the embodiments of the present invention, it is possible to provide a power supply device and a lighting fixture capable of suppressing radiation noise. [Brief description of the drawings]

[0008] [Figure 1] 1 is a block diagram illustrating a lighting device according to an embodiment of the present invention; [Diagram 2] FIG. 1 is a block diagram illustrating a switching circuit according to an embodiment of the present invention. [Diagram 3] FIG. 2 is a plan view illustrating a schematic view of a portion of a substrate according to an embodiment. [Figure 4] FIG. 11 is a plan view illustrating a modified example of a portion of the substrate according to the embodiment. [Diagram 5] FIG. 11 is a block diagram illustrating a modification of the switching circuit according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Each embodiment will be described below with reference to the drawings. The drawings are schematic or conceptual, and the relationship between the thickness and width of each part, the size ratio between parts, etc. are not necessarily the same as in reality. Even when the same part is shown, the dimensions and ratios of each part may be different depending on the drawing. In this specification and each drawing, elements similar to those described above with reference to the previous drawings are given the same reference numerals and detailed descriptions thereof will be omitted as appropriate.

[0010] FIG. 1 is a block diagram illustrating a lighting device according to an embodiment. As shown in FIG. 1, the lighting fixture 2 includes a light source unit 4 and a power supply device 10.

[0011] The light source unit 4 has a light source 4a. The light source unit 4 is connected to the power supply device 10 via wiring or the like, and receives a supply of power from the power supply device 10 to emit light from the light source 4a. The lighting fixture 2 is attached to, for example, a ceiling in a room, and illuminates a space such as a room by emitting light from the light source unit 4 (light source 4a). However, the installation position of the lighting fixture 2 is not limited to the ceiling in a room, and may be any position. The space illuminated by the lighting fixture 2 may be any space.

[0012] The light source 4a is, for example, a light emitting diode (LED). In other words, the light source unit 4 is an LED unit (LED module). However, the light source 4a may be, for example, an organic light emitting diode (OLED), an inorganic electroluminescence light emitting element, an organic electroluminescence light emitting element, or other electroluminescence type light emitting element. The light source 4a may be, for example, a light bulb. The light source 4a may be any light source that irradiates light in response to the supply of power. The number of light sources 4a provided in the light source unit 4 is not limited to one. The light source unit 4 may have, for example, a plurality of light sources 4a connected in series or in parallel.

[0013] The power supply device 10 includes a substrate 12, a pair of input terminal units 14a, 14b, a pair of output terminal units 16a, 16b, a conversion circuit 18, a switching circuit 20, a control circuit 22, and a noise filter 24.

[0014] More specifically, the substrate 12 is a printed wiring board, and has, for example, a wiring pattern.

[0015] The pair of input terminal portions 14a, 14b are provided on the substrate 12. The pair of input terminal portions 14a, 14b are mounted on the substrate 12 and electrically connected to a wiring pattern provided on the substrate 12, for example.

[0016] The pair of input terminals 14a, 14b are used for connection to the power source PS. The pair of input terminals 14a, 14b are, for example, a connector or a terminal block. The power supply device 10 is connected to the power source PS via the pair of input terminals 14a, 14b. The power supply device 10 is, for example, detachably connected to the power source PS via the pair of input terminals 14a, 14b. The power supplied by the power source PS is, for example, AC power. The power source PS is, for example, a commercial power source. The power source PS may be a private generator or the like. However, the power supplied by the power source PS is not limited to AC power, and may be DC power or the like. The power supplied by the power source PS may be any power.

[0017] The pair of output terminal portions 16a, 16b are provided on the substrate 12. Similarly to the pair of input terminal portions 14a, 14b, the pair of output terminal portions 16a, 16b are, for example, mounted on the substrate 12 and electrically connected to a wiring pattern provided on the substrate 12.

[0018] The pair of output terminals 16a, 16b are used for connection to the light source unit 4. The pair of output terminals 16a, 16b are, for example, a connector or a terminal block. The power supply device 10 is connected to the light source unit 4 via the pair of output terminals 16a, 16b. The power supply device 10 is detachably connected to the light source unit 4 via, for example, the pair of output terminals 16a, 16b.

[0019] The conversion circuit 18 is provided on the substrate 12. The conversion circuit 18 is mounted on the substrate 12 and connected to the pair of input terminal units 14a, 14b via the wiring pattern of the substrate 12. The conversion circuit 18 is connected to the power source PS via the pair of input terminal units 14a, 14b, and converts AC power supplied from the power source PS into DC power. The conversion circuit 18 is, for example, an AC-DC conversion circuit.

[0020] The conversion circuit 18 has, for example, a rectifier circuit that rectifies AC power supplied from the power source PS, and a converter that converts the power rectified by the rectifier circuit into DC power. The converter has a switching element and converts the rectified power into DC power by switching the switching element. More specifically, the converter is a boost converter that converts the rectified power into DC power of an arbitrary voltage level. In other words, the converter is a power factor improvement circuit that brings the power factor on the power source PS side closer to 1.

[0021] The conversion circuit 18 inputs the converted DC power to the switching circuit 20. For example, when the power supplied from the power source PS is DC power, the conversion circuit 18 may be omitted. The power supplied from the power source PS may be input to the switching circuit 20 as is.

[0022] The switching circuit 20 is provided on the substrate 12. The switching circuit 20 is mounted on the substrate 12 and connected to the conversion circuit 18 and the pair of output terminal portions 16a, 16b via the wiring pattern of the substrate 12. The switching circuit 20 converts input power into power corresponding to the light source unit 4 and supplies the converted power to the pair of output terminal portions 16a, 16b, thereby lighting up the light source unit 4 connected to the pair of output terminal portions 16a, 16b.

[0023] The switching circuit 20 is, for example, a DC-DC conversion circuit that converts the DC power supplied from the conversion circuit 18 into DC power having a voltage magnitude corresponding to the light source unit 4. The switching circuit 20 is, for example, a step-down converter that steps down the DC power boosted by the conversion circuit 18 to DC power having a voltage magnitude corresponding to the light source unit 4. The switching circuit 20 may have a dimming function that changes the brightness of the light irradiated from the light source unit 4 by changing the voltage magnitude in response to a dimming signal input from the outside, for example.

[0024] When the power supplied from the switching circuit 20 to the pair of output terminals 16a, 16b is DC power, the output terminal 16a is a high-potential output terminal, and the output terminal 16b is a low-potential output terminal. The potential of the output terminal 16b is, for example, a reference potential (ground potential).

[0025] However, the power supplied from the switching circuit 20 to the light source unit 4 is not limited to DC power and may be AC ​​power, etc. The switching circuit 20 may have any configuration capable of converting input power into power suitable for the light source unit 4.

[0026] The control circuit 22 controls the operation of the conversion circuit 18 and the switching circuit 20. The control circuit 22 controls the conversion of AC power to DC power by the conversion circuit 18, and also controls the conversion of DC power to another DC power by the switching circuit 20.

[0027] The control circuit 22 is provided, for example, on the substrate 12. The control circuit 22 is connected to the conversion circuit 18 and the switching circuit 20, for example, via a wiring pattern on the substrate 12. However, the control circuit 22 does not necessarily have to be provided on the substrate 12 on which the conversion circuit 18 and the switching circuit 20 are provided. The control circuit 22 may be provided, for example, on a substrate separate from the substrate 12, and electrically connected to the conversion circuit 18 and the switching circuit 20.

[0028] The noise filter 24 is provided on the substrate 12. The noise filter 24 is mounted on the substrate 12 and electrically connected between the output terminal unit 16a and the switching circuit 20 via the wiring pattern of the substrate 12. The noise filter 24 suppresses noise superimposed on the power supplied from the switching circuit 20 to the output terminal unit 16a.

[0029] When the power supplied from the switching circuit 20 to the pair of output terminals 16a, 16b is DC power, the noise filter 24 is electrically connected between the high-potential output terminal 16a and the switching circuit 20 as described above. This makes it possible to more appropriately suppress noise superimposed on the power supplied from the switching circuit 20 to the light source unit 4 via the pair of output terminals 16a, 16b. However, the noise filter 24 may be electrically connected between the low-potential output terminal 16b and the switching circuit 20. Alternatively, two noise filters 24 may be provided, one between the output terminal 16a and the switching circuit 20 and the other between the output terminal 16b and the switching circuit 20.

[0030] For example, ferrite beads, a common mode choke coil, or the like is used as the noise filter 24. However, the noise filter 24 is not limited to these, and may be any element capable of appropriately suppressing noise superimposed on the power supplied from the switching circuit 20.

[0031] The power supply device 10 further includes, for example, a housing 26. The housing 26 houses therein the board 12 and each of the components provided on the board 12, such as the input terminal units 14a, 14b, the output terminal units 16a, 16b, the conversion circuit 18, the switching circuit 20, the control circuit 22, and the noise filter 24. In other words, the housing 26 covers the periphery of each component such as the board 12.

[0032] The housing 26 has, for example, four openings, and at least a part of the input terminal units 14a, 14b and the output terminal units 16a, 16b are exposed to the outside from each of the four openings. In this way, the housing 26 covers the periphery of each unit, while enabling connection (wiring) between the input terminal units 14a, 14b and the power source PS, and connection between the output terminal units 16a, 16b and the light source unit 4.

[0033] The housing 26 is made of a metal material such as aluminum. The housing 26 is conductive. The housing 26 is electrically connected to the wiring pattern of the substrate 12 so as to have the same potential as the reference potential (ground potential) of the substrate 12. By covering each part with the housing 26 and setting the housing 26 to the reference potential in this manner, it is possible to suppress radiation noise emitted from the power supply device 10 to the outside.

[0034] FIG. 2 is a block diagram illustrating a switching circuit according to the embodiment. 2, the switching circuit 20 has a first input terminal 20a, a second input terminal 20b, a first output terminal 20c, and a second output terminal 20d. The first input terminal 20a is electrically connected to a high potential side output terminal of the conversion circuit 18. The second input terminal 20b is electrically connected to a low potential side output terminal of the conversion circuit 18. This allows power to be input from the conversion circuit 18 to the switching circuit 20. In this example, DC power is input from the conversion circuit 18 to the switching circuit 20.

[0035] The first input terminal 20a is the high potential input terminal of a pair of input terminals that receive input of DC power. The second input terminal 20b is the low potential input terminal of a pair of input terminals that receive input of DC power. The first input terminal 20a may be electrically connected to, for example, the input terminal unit 14a. The second input terminal 20b may be electrically connected to, for example, the input terminal unit 14b.

[0036] The switching circuit 20 includes a switching element 30, a diode 32, and an inductor .

[0037] The switching element 30 has a first main terminal 30a, a second main terminal 30b, and a control terminal 30c. The first main terminal 30a is electrically connected to the first input terminal 20a. The second main terminal 30b is electrically connected to the cathode of the diode 32.

[0038] The switching element 30 is, for example, an n-channel FET. For example, the first main terminal 30a is a drain, the second main terminal 30b is a source, and the control terminal 30c is a gate. The switching element 30 may be, for example, a p-channel FET or a bipolar transistor.

[0039] The anode of the diode 32 is electrically connected to the second input terminal 20b. The diode 32 is, for example, a freewheeling diode. One end of the inductor 34 is electrically connected to the second main terminal 30b. More specifically, one end of the inductor 34 is electrically connected to a connection point between the second main terminal 30b and the cathode of the diode 32. The other end of the inductor 34 is electrically connected to the first output terminal 20c. The second output terminal 20d is electrically connected to the second input terminal 20b.

[0040] The switching circuit 20 is a step-down chopper circuit. The switching circuit 20 converts the input DC power into another DC power corresponding to the light source unit 4 by stepping down the voltage of the DC power input from the conversion circuit 18 by switching the switching element 30. The switching circuit 20 is, for example, a constant current circuit. The switching circuit 20 supplies, for example, a substantially constant DC current to the light source unit 4 (light source 4a).

[0041] The first output terminal 20c is a high-potential output terminal, and the second output terminal 20d is a low-potential output terminal The potential of the first output terminal 20c is higher than the potential of the second output terminal 20d.

[0042] The switching circuit 20 is electrically connected to a pair of output terminals 16a, 16b via a first output terminal 20c and a second output terminal 20d. The first output terminal 20c is electrically connected to the output terminal 16a. The second output terminal 20d is electrically connected to the output terminal 16b. In other words, the switching circuit 20 is electrically connected to the light source unit 4 via the first output terminal 20c and the second output terminal 20d. For example, when the light source 4a of the light source unit 4 is an LED, the first output terminal 20c is connected to the anode of the light source 4a, and the second output terminal 20d is connected to the cathode of the light source 4a. As a result, the light source 4a is turned on by the DC power output from the first output terminal 20c and the second output terminal 20d.

[0043] The power supply device 10 further includes, for example, an output capacitor 36. The output capacitor 36 has a first electrode 36a and a second electrode 36b. The first electrode 36a is electrically connected to the first output terminal 20c. The second electrode 36b is electrically connected to the second output terminal 20d. The output capacitor 36 is connected in parallel between the first output terminal 20c and the second output terminal 20d. The potential of the first electrode 36a is set higher than the potential of the second electrode 36b. The first electrode 36a is, for example, an anode, and the second electrode 36b is, for example, a cathode.

[0044] The output capacitor 36 smoothes the current flowing between the first main terminal 30a and the second main terminal 30b of the switching element 30 due to switching of the switching element 30. This makes it possible to suppress fluctuations in the current of the DC power supplied from the switching circuit 20 to the light source unit 4.

[0045] The noise filter 24 is electrically connected between the output terminal section 16a and the first output terminal 20c of the switching circuit 20. More specifically, the noise filter 24 is electrically connected between the output terminal section 16a and a connection point between the first output terminal 20c and a first electrode 36a of the output capacitor 36.

[0046] The control circuit 22 is electrically connected to the control terminal 30c of the switching element 30. The control circuit 22 controls the switching of the switching element 30. That is, the control circuit 22 switches the switching element 30 on and off. The control circuit 22 switches the switching element 30 on and off by a voltage (drive signal) input to the control terminal 30c. In this way, the control circuit 22 is connected to the control terminal 30c of the switching element 30, and controls the conversion of power by the switching circuit 20 by controlling the switching of the switching element 30. As a result, DC power is supplied from the switching circuit 20 to the light source unit 4. In other words, the switching circuit 20 converts the input power into power corresponding to the light source unit 4 by switching the switching element 30.

[0047] The control circuit 22 stops the supply of DC power from the switching circuit 20 to the light source unit 4, for example, by turning off the switching element 30. In addition, the control circuit 22 can change the voltage value and current value of the DC power supplied to the light source unit 4, for example, by changing the on / off cycle (duty ratio) of the switching element 30. This makes it possible to change, for example, the brightness of the light irradiated from the light source 4a.

[0048] The configuration of the switching circuit 20 is not limited to the above circuit. The switching circuit 20 may be any circuit that has at least a switching element 30 and can convert input power into power corresponding to the light source unit 4 by switching the switching element 30.

[0049] FIG. 3 is a plan view that illustrates a schematic view of a portion of the substrate according to the embodiment. For ease of illustration, FIG. 3 conveniently illustrates only some of the components (elements) mounted on the substrate 12.

[0050] 3, a distance D1 between the noise filter 24 and the output terminal portion 16a is shorter than a distance D2 between the switching circuit 20 and the output terminal portion 16a. That is, the noise filter 24 is provided on the substrate 12 so as to be located closer to the output terminal portion 16a than the switching circuit 20. The distance D2 between the switching circuit 20 and the output terminal portion 16a is preferably, for example, 15 mm or more.

[0051] More specifically, the distance D2 between the switching circuit 20 and the output terminal portion 16a is the shortest distance between any of the components (elements) constituting the switching circuit 20 and the output terminal portion 16a. In this example, the distance D2 is, for example, the distance between the inductor 34 and the output terminal portion 16a.

[0052] Also, each component mounted on the board 12 may be mounted on both sides of the plate-shaped board 12. For example, the noise filter 24 may be mounted on the side opposite to the output terminal portion 16a. More specifically, the distance D1 is the shortest distance between the noise filter 24 and the output terminal portion 16a when the noise filter 24 and the output terminal portion 16a are projected onto the same surface of the board 12. Similarly, each component constituting the switching circuit 20 may be mounted on both sides of the plate-shaped board 12. More specifically, the distance D2 is the shortest distance between any of the components constituting the switching circuit 20 and the output terminal portion 16a when the components constituting the switching circuit 20 and the output terminal portion 16a are projected onto the same surface of the board 12. Note that the distance D1 may be the shortest straight-line distance between the noise filter 24 and the output terminal portion 16a. The distance D2 may be the shortest straight-line distance between any of the components constituting the switching circuit 20 and the output terminal portion 16a.

[0053] The state where two components are projected onto the same surface of the substrate 12 means, in other words, when two components are mounted on both surfaces of the substrate 12, the component mounted on the other surface of the substrate 12 is projected onto one surface of the substrate 12. In other words, it means the state where the component mounted on the other surface of the substrate 12 is seen through from the one surface side of the substrate 12.

[0054] 3, the noise filter 24 is provided on the substrate 12 so as to be located, for example, between the switching circuit 20 and the output terminal portion 16a. For example, the noise filter 24 is provided on the substrate 12 so as to be located at least a portion of the noise filter 24 between the switching circuit 20 and the output terminal portion 16a.

[0055] A distance D1 between the noise filter 24 and the output terminal portion 16a is, for example, shorter than a distance D3 between the noise filter 24 and the switching circuit 20. In other words, the noise filter 24 is provided on the substrate 12 so as to be located between the switching circuit 20 and the output terminal portion 16a and closer to the output terminal portion 16a than the switching circuit 20.

[0056] The distance D3 between the noise filter 24 and the switching circuit 20 is, for example, 1.5 times or more the distance D1 between the noise filter 24 and the output terminal portion 16a. More specifically, the distance D3 is the shortest distance between the noise filter 24 and any of the components constituting the switching circuit 20 when the components constituting the switching circuit 20 and the noise filter 24 are projected onto the same surface of the substrate 12.

[0057] 3, the noise filter 24 is provided on the substrate 12 so as to be located, for example, between the switching element 30 and the output terminal portion 16a. For example, the noise filter 24 is provided on the substrate 12 so as to be located at least a portion of the noise filter 24 between the switching element 30 and the output terminal portion 16a.

[0058] A distance D1 between the noise filter 24 and the output terminal portion 16a is, for example, shorter than a distance D4 between the noise filter 24 and the switching element 30. In other words, the noise filter 24 is provided on the substrate 12 so as to be located between the switching element 30 and the output terminal portion 16a and closer to the output terminal portion 16a than the switching element 30.

[0059] The distance D4 between the noise filter 24 and the switching element 30 is, for example, 1.5 times or more the distance D1 between the noise filter 24 and the output terminal portion 16a. More specifically, the distance D4 is the shortest distance between the switching element 30 and the noise filter 24 in a state in which the switching element 30 and the noise filter 24 are projected onto the same surface of the substrate 12.

[0060] The switching circuit 20 can be a noise source for the power supply device 10. In the switching circuit 20, noise may be generated due to switching of the switching element 30. The noise generated in the switching circuit 20 may be emitted from the power supply device 10 to the outside as radiation noise, and may also propagate to the light source unit 4 via the output terminals 16a, 16b and wiring, and may be emitted from the light source unit 4 to the outside as radiation noise.

[0061] As a result of intensive investigation, the inventors of the present application have found that it is possible to suppress noise propagating from the power supply device 10 to the light source unit 4 by providing a noise filter 24 electrically connected between the output terminal portion 16a and the switching circuit 20. The inventors of the present application have also found that it is possible to more appropriately suppress noise propagating from the power supply device 10 to the light source unit 4 by devising a physical arrangement on the substrate 12 so as to separate the switching circuit 20, which is a noise source, as far as possible from the output terminal portions 16a, 16b and to provide the noise filter 24 closer to the output terminal portions 16a, 16b than the switching circuit 20.

[0062] As described above, in the lighting fixture 2 and power supply device 10 according to this embodiment, a noise filter 24 is provided that is electrically connected between the output terminal unit 16a and the switching circuit 20, and the distance D1 between the noise filter 24 and the output terminal unit 16a is made shorter than the distance D2 between the switching circuit 20 and the output terminal unit 16a. As a result, in the lighting fixture 2 and power supply device 10 according to this embodiment, the radiation noise emitted from the entire lighting fixture 2 can be suppressed.

[0063] The radiated noise emitted from the lighting fixture 2 is measured, for example, by a measurement method specified in a radiated electric field strength standard such as CISPRJ 15. In the lighting fixture 2 according to the present embodiment, for example, the radiated noise measured by a measurement method specified in the radiated electric field strength standard can be suppressed to a level lower than that specified in the radiated electric field strength standard. The lighting fixture 2 according to the present embodiment can easily comply with the radiated electric field strength standard.

[0064] In the lighting fixture 2 and power supply device 10 according to this embodiment, the noise filter 24 is provided on the substrate 12 so as to be located between the switching circuit 20 and the output terminal portion 16a. This makes it possible, for example, to easily separate the switching circuit 20 from the output terminal portion 16a and to effectively utilize the space between the switching circuit 20 and the output terminal portion 16a. For example, even when the switching circuit 20 is separated from the output terminal portion 16a, an increase in the size of the substrate 12 can be suppressed.

[0065] In addition, the distance D1 between the noise filter 24 and the output terminal portion 16a is shorter than the distance D3 between the noise filter 24 and the switching circuit 20. This makes it possible to more appropriately suppress noise incident on the output terminal portion 16a. In other words, it is possible to more appropriately suppress noise propagating to the light source unit 4 via the output terminal portion 16a. Therefore, it is possible to more appropriately suppress the radiation noise emitted from the entire lighting fixture 2. It is preferable to make the distance D1 between the noise filter 24 and the output terminal portion 16a as short as possible.

[0066] Furthermore, the distance D3 between the noise filter 24 and the switching circuit 20 is 1.5 times or more the distance D1 between the noise filter 24 and the output terminal unit 16a. This makes it possible to, for example, ensure an appropriate distance between the switching circuit 20 and the output terminal unit 16a, and more appropriately suppress the noise incident on the output terminal unit 16a. The radiation noise emitted from the entire lighting fixture 2 can be more appropriately suppressed.

[0067] The largest noise source in the switching circuit 20 is the switching element 30. Therefore, the noise filter 24 is provided on the substrate 12 so as to be located between the switching element 30 and the output terminal portion 16a. This makes it possible, for example, to easily separate the switching element 30 from the output terminal portion 16a, and also makes it possible to effectively utilize the space between the switching element 30 and the output terminal portion 16a and to prevent the substrate 12 from becoming larger.

[0068] A distance D1 between the noise filter 24 and the output terminal portion 16a is shorter than a distance D4 between the noise filter 24 and the switching element 30. This makes it possible to more appropriately suppress the radiation noise emitted from the entire lighting fixture 2.

[0069] The distance D4 between the noise filter 24 and the switching element 30 is 1.5 times or more the distance D1 between the noise filter 24 and the output terminal portion 16a. This makes it possible to more appropriately suppress the radiation noise emitted from the entire lighting fixture 2.

[0070] However, the distance D1 does not necessarily have to be shorter than the distances D3 and D4. The distances D3 and D4 do not necessarily have to be 1.5 times or more the distance D1. The distances D3 and D4 may be set to any distances that can appropriately suppress the radiation noise.

[0071] FIG. 4 is a plan view illustrating a schematic modification of a portion of the substrate according to the embodiment. 3, for ease of illustration, Fig. 4 conveniently shows only some of the components (elements) mounted on the substrate 12. Furthermore, components that are substantially the same in function and configuration as those in the above embodiment are given the same reference numerals, and detailed description thereof will be omitted.

[0072] 4, in this example, the switching circuit 20 is located on the left side of the output terminal portion 16a, whereas the noise filter 24 is located on the lower side of the output terminal portion 16a. That is, in this example, the noise filter 24 is not located between the switching circuit 20 and the output terminal portion 16a.

[0073] On the other hand, also in this example, the distance D1 between the noise filter 24 and the output terminal portion 16a is shorter than the distance D2 between the switching circuit 20 and the output terminal portion 16a.

[0074] In this way, the noise filter 24 does not necessarily have to be located between the switching circuit 20 and the output terminal portion 16a. The noise filter 24 may be located in any position as long as the distance D1 between the noise filter 24 and the output terminal portion 16a is shorter than the distance D2 between the switching circuit 20 and the output terminal portion 16a.

[0075] In this case, as in the above embodiment, it is possible to suppress the radiation noise emitted from the entire lighting fixture 2. However, as in the above embodiment, it is more preferable to provide the noise filter 24 on the substrate 12 so as to be located between the switching circuit 20 and the output terminal portion 16a. This makes it easier to separate the switching circuit 20 from the output terminal portion 16a as described above, and also makes it possible to effectively utilize the space between the switching circuit 20 and the output terminal portion 16a and suppress an increase in the size of the substrate 12.

[0076] FIG. 5 is a block diagram illustrating a modified example of the switching circuit according to the embodiment. 5, in this example, the switching circuit 20 has a switching element 40 and a rectifying element 42. The switching element 40 is connected in parallel to the light source unit 4. The switching element 40 has a first main terminal 40a, a second main terminal 40b, and a control terminal 40c. The switching element 40 may be the same as that described for the switching element 30.

[0077] The first main terminal 40a is electrically connected to the first input terminal 20a. The second main terminal 40b is electrically connected to the second input terminal 20b. This connects the switching element 40 in parallel with the light source unit 4. The control terminal 40c is electrically connected to the control circuit 22. The switching element 40 switches in response to a signal from the control circuit 22.

[0078] The rectifying element 42 is provided between the switching element 40 and the light source unit 4. The rectifying element 42 is, for example, a diode. One end (anode) of the rectifying element 42 is electrically connected to the first main terminal 40a of the switching element 40 and the first input terminal 20a. The other end (cathode) of the rectifying element 42 is electrically connected to the first output terminal 20c. In other words, the rectifying element 42 is provided between the first input terminal 20a and the first output terminal 20c. The rectifying element 42 rectifies in the direction from the first input terminal 20a to the first output terminal 20c.

[0079] In this example, one end of the light source 4a of the light source unit 4 is electrically connected to the output terminal of the conversion circuit 18 via the output terminal section 16a, the noise filter 24, the first output terminal 20c, the rectifying element 42, and the first input terminal 20a.

[0080] The switching circuit 20 and the control circuit 22 switch the switching element 40 on and off in response to a dimming signal input from outside, and periodically switch between outputting and stopping the output of the DC current input from the conversion circuit 18, thereby performing pulse width modulation control on the DC current. In other words, the switching element 40 generates a modulated current from the DC current by switching between outputting and stopping the output of the DC current to the light source unit 4.

[0081] In this way, the switching circuit 20 switches the switching element 40 on and off to generate a modulated current (PWM current) from a direct current, and supplies the modulated current to the light source unit 4. In this example, the switching circuit 20 is, for example, a DC / PWM conversion circuit.

[0082] The control circuit 22 changes the pulse width of the modulation current in response to the dimming signal. In other words, the control circuit 22 changes the on time of the switching element 40 in response to the dimming signal. This makes it possible to change the brightness of the light emitted from the light source unit 4 by switching the switching element 40 on and off. In other words, it is possible to perform dimming control of the light emitted from the light source unit 4. The pulse width of the modulation current is, in other words, the dimming degree of the light emitted from the light source unit 4.

[0083] In the switching circuit 20, by turning off the switching element 40 connected in parallel to the light source unit 4, a direct current can be supplied to the light source unit 4. On the other hand, when the switching element 40 is turned on, a current flows through the switching element 40, and the supply of direct current to the light source unit 4 is stopped.

[0084] The rectifying element 42 rectifies in the direction from the first input terminal 20a to the first output terminal 20c, thereby suppressing the current flowing from the light source unit 4 to the switching element 40 when the switching element 40 is switched from the OFF state to the ON state. In this way, the rectifying element 42 is provided between the switching element 40 and the light source unit 4, and suppresses the reverse flow of the current from the light source unit 4 to the switching element 40. This makes it possible to quickly cut off the current flowing to the light source unit 4 when the switching element 40 is turned on. For example, when the switching element 40 is turned on, it is possible to suppress the current flowing from the light source unit 4 to the switching element 40, which causes the modulated current that changes in a pulse shape to not have a desired shape. In other words, it is possible to suppress the desired dimming level from being achieved.

[0085] In this manner, the switching circuit 20 may be a DC / PWM conversion circuit. In this case, too, by making the distance D1 between the noise filter 24 and the output terminal unit 16a shorter than the distance D2 between the switching circuit 20 and the output terminal unit 16a, it is possible to suppress the radiation noise emitted from the entire lighting fixture 2, as described above.

[0086] The configuration of the switching circuit 20 is not limited to the above, and may be any configuration that has a switching element, converts input power into power corresponding to the light source unit 4 by switching the switching element, and supplies the converted power to the output terminal portions 16a, 16b, thereby lighting the light source unit 4 connected to the output terminal portions 16a, 16b.

[0087] Although some embodiments and examples of the present invention have been described, these embodiments or examples are presented as examples and are not intended to limit the scope of the invention. These novel embodiments or examples can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the gist of the invention. These embodiments or examples and their modifications are included in the scope and gist of the invention, and are included in the scope of the invention and its equivalents described in the claims. [Explanation of symbols]

[0088] 2...Lighting equipment, 4...Light source unit, 4a...Light source, 10...Power supply device, 12...Board, 14a, 14b...Input terminal section, 16a, 16b...Output terminal section, 18...Conversion circuit, 20...Switching circuit, 22...Control circuit, 24...Noise filter, 26...Housing, 30...Switching element, 32...Diode, 34...Inductor, 36...Output capacitor, 40...Switching element, 42...Rectifier element, PS...Power supply

Claims

1. A substrate; an output terminal portion provided on the substrate and used for connection to a light source unit; a switching circuit provided on the substrate, having a switching element, converting input power into power corresponding to the light source unit by switching the switching element, and supplying the converted power to the output terminal unit, thereby lighting the light source unit connected to the output terminal unit; a noise filter that is provided on the substrate, electrically connected between the output terminal unit and the switching circuit, and suppresses noise superimposed on the power supplied from the switching circuit to the output terminal unit; Equipped with A power supply device, wherein a distance between the noise filter and the output terminal portion is shorter than a distance between the switching circuit and the output terminal portion.

2. 2. The power supply device according to claim 1, wherein the noise filter is provided on the substrate so as to be located between the switching circuit and the output terminal portion.

3. 3. The power supply device according to claim 2, wherein a distance between the noise filter and the output terminal portion is shorter than a distance between the noise filter and the switching circuit.

4. 4. The power supply device according to claim 3, wherein the distance between the noise filter and the switching circuit is 1.5 times or more the distance between the noise filter and the output terminal portion.

5. 2. The power supply device according to claim 1, wherein the noise filter is provided on the substrate so as to be located between the switching element and the output terminal portion.

6. 6. The power supply device according to claim 5, wherein a distance between the noise filter and the output terminal portion is shorter than a distance between the noise filter and the switching element.

7. 7. The power supply device according to claim 6, wherein the distance between the noise filter and the switching element is 1.5 times or more the distance between the noise filter and the output terminal portion.

8. A light source unit; A power supply device according to any one of claims 1 to 7; A lighting fixture comprising:

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