Power source device and illumination equipment

Abstract

To provide a power source device and illumination equipment that can reduce electric noise more suitably.SOLUTION: A power source device includes a substrate, a power source circuit that is provided at the substrate and converts input AC power into DC power corresponding to a light source module, an output unit that outputs the DC power to the light source module, a ground electrode set to the ground potential, and a ground circuit that suppresses electric noise radiated from the substrate to the outside. The power source circuit includes a rectifying circuit that converts the AC power to rectifying power, and a conversion circuit that converts the rectifying power to the DC power. The ground circuit includes a first capacitor provided between the ground electrode and a first path between a high-potential output terminal of the rectifying circuit and a first output terminal of the output unit, and a second capacitor provided between the ground electrode and a second path between a low-potential output terminal of the rectifying circuit and a second output terminal of the output unit.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] Embodiments of the present invention relate to a power supply device and a lighting fixture.

Background Art

[0002] There is known a lighting fixture including a light source module having a light source such as an LED, and a power supply device that supplies DC power to the light source module to turn on the light source module. The power supply device has a power supply circuit that converts AC power into DC power and supplies it to the light source module. In such a power supply device, electrical noise may be radiated to the outside along with the operation of power conversion in the power supply circuit. As a method for reducing the radiated electrical noise, there is a technique of adding a grounding circuit using a capacitor to the input section of the AC power.

[0003] However, in a configuration in which a grounding circuit is provided at the input section of the AC power, the noise reduction effect may be insufficient. For this reason, in the power supply device and the lighting fixture, it is desired to more appropriately reduce electrical noise.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Embodiments of the present invention provide a power supply device and a lighting fixture that can more appropriately reduce electrical noise.

Means for Solving the Problems

[0006] According to an embodiment, a substrate, a power supply circuit provided on the substrate, which converts input AC power into DC power corresponding to a light source module and lights up the light source module by supplying the converted DC power to the light source module, an output unit provided on the substrate and having a pair of output terminals, namely, a first output terminal on the high potential side and a second output terminal on the low potential side, for outputting the DC power converted by the power supply circuit to the light source module, a ground electrode provided on the substrate and set to the ground potential by being electrically connected to a portion of an external ground potential, and a ground circuit provided on the substrate for suppressing electrical noise radiated from the substrate to the outside. The power supply circuit has a pair of input terminals, a high potential output terminal, and a low potential output terminal, and includes a rectification circuit that converts AC power input through the pair of input terminals into rectified power and outputs the converted rectified power from the high potential output terminal and the low potential output terminal, and a conversion circuit that converts the rectified power converted by the rectification circuit into DC power corresponding to the light source module and outputs the converted DC power to the output unit. The ground circuit includes a first capacitor provided between a first path between the high potential output terminal and the first output terminal and the ground electrode, and a second capacitor provided between a second path between the low potential output terminal and the second output terminal and the ground electrode. A power supply device is provided.

Effect of the Invention

[0007] A power supply device and a lighting fixture that can more appropriately reduce electrical noise can be provided.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0009] Hereinafter, each embodiment will be described with reference to the drawings. Note that the drawings are schematic or conceptual, and the relationship between the thickness and width of each part, the ratio of the sizes between parts, etc. are not necessarily the same as the actual ones. Also, even when representing the same part, there are cases where their dimensions and ratios are represented differently in the drawings. In the present specification and each drawing, the same elements as those described above with respect to the previously shown drawings are denoted by the same reference numerals, and detailed descriptions thereof are omitted as appropriate.

[0010] Fig. 1 is a block diagram schematically showing a lighting fixture according to the embodiment. As shown in Fig. 1, the lighting fixture 2 includes a power supply device 10 and a light source module 12. The light source module 12 is connected to the power supply device 10. The light source module 12 is detachably connected to the power supply device 10, for example, via a connector or the like. However, the light source module 12 may be provided integrally with the power supply device 10, for example.

[0011] The power supply device 10 receives an input of AC power, converts the input AC power into DC power, and supplies the converted DC power to the light source module 12 to turn on the light source module 12.

[0012] The light source module 12 has a light source 12a. The light source 12a is, for example, a Light Emitting Diode (LED). The light source 12a may be, for example, an Organic Light Emitting Diode (OLED), an Inorganic ElectroLuminescence light emitting element, an Organic ElectroLuminescence light emitting element, or other field emission type light emitting elements. The light source 12a may be, for example, a light bulb. The light source 12a may be any light source capable of irradiating light based on the DC power supplied from the power supply device 10. The light source module 12 may have, for example, a plurality of light sources 12a connected in series. The number of light sources 12a provided in the light source module 12 may be any number.

[0013] The power supply device 10 has a substrate 20 and a power supply circuit 22 provided on the substrate 20. The substrate 20 is, more specifically, a printed wiring board. The power supply circuit 22 is composed of a plurality of elements mounted on the substrate 20 and converts AC power into DC power. The power supply circuit 22 converts the input AC power into DC power corresponding to the light source module 12 and supplies the converted DC power to the light source module 12 to turn on the light source module 12.

[0014] The power supply device 10 further has, for example, a case 23. The case 23 houses the substrate 20 inside. In other words, the case 23 covers the periphery of the substrate 20. The case 23 has conductivity. For example, a steel plate is used for the case 23. The case 23 only needs to have conductivity at least in part. For example, the surface of the case 23 may have insulation properties by surface treatment, painting, etc. However, the case 23 does not necessarily have to have conductivity. The material of the case 23 may be any material capable of covering at least the periphery of the substrate 20.

[0015] The lighting fixture 2 further includes, for example, a support plate 14 and a terminal block 16. The support plate 14 supports the power supply device 10. The support plate 14 supports, for example, the case 23 of the power supply device 10. The support plate 14 has conductivity. The support plate 14 supports the case 23 and is electrically connected to the case 23. The case 23 is attached to the support plate 14, for example, by screwing. The support plate 14 is electrically connected to the case 23 by supporting the case 23 in contact with the case 23. The support plate 14 may be electrically connected to the case 23 via, for example, a conductive screw. The method of electrically connecting the support plate 14 and the case 23 is not limited to the above, and any method that can appropriately electrically connect the support plate 14 and the case 23 in a state where the case 23 is supported by the support plate 14 may be used.

[0016] For example, a steel plate is used for the support plate 14. However, the material of the support plate 14 is not limited to this. The support plate 14 does not necessarily have to have conductivity. The material of the support plate 14 may be any material that can at least appropriately support the power supply device 10.

[0017] The terminal block 16 is attached to the support plate 14. The terminal block 16 is used for connecting a pair of AC power lines and a ground line. One end of each of the pair of AC power lines is connected to the terminal block 16. The other end of each of the pair of AC power lines is connected to, for example, a building distribution board. Thereby, the lighting fixture 2 receives supply of AC power from the pair of AC power lines. In other words, the lighting fixture 2 receives supply of AC power from an AC power source via the pair of AC power lines. The AC power source is, for example, a commercial power source or a home generator. The AC power source may be any power source that can appropriately supply AC power to the lighting fixture 2. The AC power supplied from the pair of AC power lines (AC power source) is more specifically single-phase AC power. The AC voltage of the AC power is, for example, 100V to 242V (effective value).

[0018] A pair of connection points of the terminal block 16 with a pair of AC power lines are electrically connected to the substrate 20 of the power supply device 10 via a pair of wirings or the like. Thereby, the AC power supplied from the pair of AC power lines is input to the substrate 20 (power supply circuit 22) via the terminal block 16 and the wirings or the like. However, the method of inputting AC power to the substrate 20 is not limited to the above, and any method capable of appropriately inputting AC power to the substrate 20 may be used.

[0019] One end of the ground wire is connected to the terminal block 16. The other end of the ground wire is electrically connected to, for example, a portion of the building at the ground potential. In other words, the lighting fixture 2 is electrically connected to a portion of the building at the ground potential via the ground wire. The connection point of the terminal block 16 with the ground wire is electrically connected to the support plate 14. Thereby, the potential of the support plate 14 is set to be substantially the same potential as the ground potential. In other words, the potential of the support plate 14 is set to be substantially the same potential as the reference potential of the building.

[0020] Also, as described above, the support plate 14 is electrically connected to the case 23. Therefore, the potential of the case 23 is also set to be substantially the same potential as the ground potential. Thus, by setting the potential of the case 23 that houses the substrate 20 to the ground potential, it is possible to suppress the electrical noise generated in accordance with the operation of power conversion by the power supply circuit 22 from being radiated to the outside. However, the potential of the case 23 does not necessarily have to be set to the ground potential. In this case, the case 23 and the support plate 14 do not have to be conductive.

[0021] The power supply device 10, the support plate 14, and the terminal block 16 are installed, for example, in the space above the ceiling. The light source module 12 is attached to the ceiling portion of the building through, for example, an opening provided in the ceiling, thereby irradiating light toward the interior of the room. However, the configuration of the lighting fixture 2 is not limited to the above. For example, the power supply device 10 may be configured to be attached to the ceiling portion of the building together with the light source module 12. Further, the attachment position of the lighting fixture 2 is not limited to the ceiling and may be any position where it is necessary to irradiate light. The lighting fixture 2 may be attached to, for example, an outdoor outer wall or a support column. The configuration of the lighting fixture 2 is not limited to the above and may be any configuration including at least the power supply device 10 and the light source module 12. The support plate 14 and the terminal block 16 are provided as necessary and can be omitted.

[0022] FIG. 2 is a block diagram schematically showing a power supply device according to an embodiment. As shown in FIG. 2, the power supply device 10 further includes an input unit 24, an output unit 26, and a control circuit 28. The input unit 24 has a pair of input terminals 24a and 24b for receiving an input of AC power. The input unit 24 is provided on the substrate 20. The input unit 24 is, for example, an input connector provided on the substrate 20. The pair of input terminals 24a and 24b may be, for example, electrodes (pads) provided on the substrate 20. The pair of input terminals 24a and 24b are connected to the terminal block 16 via, for example, a pair of wirings. Thereby, the AC power supplied from the AC power source is supplied to the substrate 20 via the pair of AC power lines, the terminal block 16, and the pair of wirings.

[0023] The output unit 26 is provided on the substrate 20. The output unit 26 has a pair of output terminals, namely a first output terminal 26a and a second output terminal 26b, for outputting the DC power converted by the power supply circuit 22 to the light source module 12. The first output terminal 26a is the output terminal on the high potential side among the pair of output terminals. The second output terminal 26b is the output terminal on the low potential side among the pair of output terminals. The output unit 26 is, for example, an output connector provided on the substrate 20. The first output terminal 26a and the second output terminal 26b may be, for example, electrodes (pads) provided on the substrate 20. The first output terminal 26a and the second output terminal 26b are connected to the light source module 12 via wiring or the like. Thereby, the DC power converted by the power supply circuit 22 is supplied to the light source module 12. Note that the output unit 26 does not necessarily have to be directly connected to the light source module 12. The output unit 26 may be configured to be connected to the light source module 12 via, for example, a connector provided on another substrate.

[0024] The control circuit 28 controls the operation of converting AC power to DC power by the power supply circuit 22. The control circuit 28 is provided on the substrate 20. However, the control circuit 28 does not necessarily have to be provided on the same substrate as the substrate 20 on which the power supply circuit 22 is provided. The control circuit 28 may be configured to be provided on a substrate different from the substrate 20 and electrically connected to the power supply circuit 22 via wiring or the like.

[0025] As shown in FIG. 2, the power supply circuit 22 includes a rectifier circuit 30 and a conversion circuit 32. The rectifier circuit 30 rectifies the AC power input to the input unit 24 and converts it into rectified power. For example, a diode bridge formed by combining four rectifier elements is used for the rectifier circuit 30. That is, the rectifier circuit 30 is a full-wave rectifier. The rectified power is, for example, pulsating DC power.

[0026] The rectifier circuit 30 has a pair of input terminals 30a, 30b, a high-potential output terminal 30c, and a low-potential output terminal 30d. The input terminals 30a, 30b are electrically connected to the input section 24. For example, the input terminal 30a is electrically connected to the input terminal 24a of the input section 24, and the input terminal 30b is electrically connected to the input terminal 24b of the input section 24. The rectifier circuit 30 receives an input of AC power from the input section 24 via the pair of input terminals 30a, 30b. The rectifier circuit 30 converts the AC power input via the pair of input terminals 30a, 30b into rectified power, and outputs the converted rectified power from the high-potential output terminal 30c and the low-potential output terminal 30d. The potential of the high-potential output terminal 30c is set to a potential higher than the potential of the low-potential output terminal 30d.

[0027] The rectifier circuit 30 may be a half-wave rectifier or the like. The rectified voltage may be a full-wave rectified pulsating current or a half-wave rectified pulsating current. For example, a Schottky barrier diode is used for the rectifier circuit 30. Thereby, for example, good responsiveness can be obtained.

[0028] The conversion circuit 32 is provided between the rectifier circuit 30 and the output section 26. The conversion circuit 32 is electrically connected to the rectifier circuit 30 and is also electrically connected to the output section 26. The conversion circuit 32 converts the rectified power converted by the rectifier circuit 30 into DC power corresponding to the light source module 12, and outputs the converted DC power to the output section 26. In other words, the conversion circuit 32 supplies the converted DC power to the light source module 12 connected to the output section 26.

[0029] The conversion circuit 32 has a first converter 41, a second converter 42, a high-frequency removal capacitor 43, and a smoothing capacitor 44. The high-frequency removal capacitor 43 is provided between the high-potential output terminal 30c and the low-potential output terminal 30d, and suppresses high-frequency components superimposed on the rectified power after being rectified by the rectifier circuit 30.

[0030] The first converter 41 has, for example, a switching element 51, an inductor 52, and a diode 53. The switching element 51 has electrodes 51a to 51c. One end of the inductor 52 is electrically connected to the high potential output terminal 30c. The other end of the inductor 52 is electrically connected to the electrode 51a. The electrode 51b is electrically connected to the low potential output terminal 30d. The anode of the diode 53 is electrically connected to the electrode 51a. The cathode of the diode 53 is electrically connected to one end of the smoothing capacitor 44. The other end of the smoothing capacitor 44 is electrically connected to the low potential output terminal 30d.

[0031] That is, in this example, the first converter 41 is a boost chopper circuit. The first converter 41 converts, for example, an AC voltage of 100V to 242V (rms value) input to the input section 24 into a DC voltage of 420V.

[0032] In other words, the first converter 41 is a power factor improvement circuit. The first converter 41 suppresses the generation of harmonics that are integer multiples of the power supply frequency in the input current of the rectifier circuit 30 by converting the rectified power converted by the rectifier circuit 30 by the switching of the switching element 51 into another power. Thereby, the first converter 41 improves the power factor of the input power.

[0033] The electrode 51c is electrically connected to the control circuit 28. The electrode 51c is a so-called control electrode. The switching element 51 switches according to a signal from the control circuit 28. The first converter 41 improves the power factor, for example, by switching the switching element 51 to make the input current approach a half-wave waveform of a sine wave. Note that the configuration of the first converter 41 is not limited to the above, and may be any configuration that has at least one switching element and can improve the power factor of the input power by the switching of the switching element.

[0034] The switching element 51 is, for example, an n-channel FET. For example, the electrode 51a is the drain, the electrode 51b is the source, and the electrode 51c is the gate. The switching element 51 may be, for example, a p-channel FET or a bipolar transistor or the like.

[0035] The smoothing capacitor 44 converts the power output from the first converter 41 into DC power by smoothing the power output from the first converter 41. In other words, the smoothing capacitor 44 converts the power after power factor improvement into DC power by smoothing the output voltage after power factor improvement. The smoothing capacitor 44 supplies DC power to the second converter 42.

[0036] The second converter 42 has a pair of input terminals 42a, 42b and a pair of output terminals 42c, 42d. The input terminal 42a is electrically connected to one end of the smoothing capacitor 44 on the high potential side. The input terminal 42b is electrically connected to one end of the smoothing capacitor 44 on the low potential side. In other words, the input terminal 42b is electrically connected to the low potential output terminal 30d. Thereby, DC power is supplied from the smoothing capacitor 44 to the second converter 42.

[0037] The second converter 42 has, for example, a switching element 55, a diode 56, an inductor 57, and an output capacitor 58. The switching element 55 has electrodes 55a to 55c. The electrode 55a is electrically connected to the input terminal 42a. The electrode 55b is electrically connected to the cathode of the diode 56. The anode of the diode 56 is electrically connected to the low potential output terminal 30d. One end of the inductor 57 is electrically connected to the electrode 55b. The other end of the inductor 57 is electrically connected to the output terminal 42c. The output terminal 42d is electrically connected to the low potential output terminal 30d (input terminal 42b).

[0038] The output capacitor 58 has a first electrode 58a and a second electrode 58b. The first electrode 58a is electrically connected to the output terminal 42c. The second electrode 58b is electrically connected to the output terminal 42d. The output capacitor 58 is connected in parallel between the output terminal 42c and the output terminal 42d. The output capacitor 58 smoothes the current flowing between the electrodes 55a and 55b of the switching element 55 by the switching of the switching element 55. Thereby, DC power is output from the output terminal 42c and the output terminal 42d.

[0039] The potential of the first electrode 58a is set higher than the potential of the second electrode 58b. The first electrode 58a is, for example, an anode, and the second electrode 58b is, for example, a cathode. The output terminal 42c is the output terminal on the high potential side, and the output terminal 42d is the output terminal on the low potential side. The potential of the output terminal 42c is higher than the potential of the output terminal 42d. The output terminal 42c is electrically connected to the first output terminal 26a of the output unit 26. The output terminal 42d is electrically connected to the second output terminal 26b of the output unit 26. Thereby, the DC power converted by the second converter 42 (conversion circuit 32) is output to the output unit 26.

[0040] In this example, the second converter 42 is a buck chopper circuit. The second converter 42 converts the DC power supplied from the smoothing capacitor 44 into another DC power according to the light source module 12 by stepping down the voltage of the input power. The second converter 42 converts, for example, the DC voltage of the first converter 41 of 420V into a DC voltage of 50V to 300V. The second converter 42 is, for example, a constant current circuit. The second converter 42 supplies, for example, a substantially constant DC current to the light source module 12.

[0041] The switching element 55 is, for example, an n-channel FET. For example, the electrode 55a is a drain, the electrode 55b is a source, and the electrode 55c is a gate. The switching element 55 may be, for example, a p-channel FET or a bipolar transistor or the like.

[0042] Note that the configuration of the second converter 42 is not limited to the above circuit. The second converter 42 may have at least one switching element, and any circuit capable of converting the converted power of the first converter 41 into DC power corresponding to the light source module 12 by switching the switching element is acceptable.

[0043] The control circuit 28 is electrically connected to the electrode 51c of the switching element 51. The electrode 51c is a so-called control electrode. The control circuit 28 controls the switching of the switching element 51. That is, the control circuit 28 switches the on / off state of the switching element 51. The control circuit 28 switches the on / off state of the switching element 51 according to the voltage (control signal) input to the electrode 51c. For example, the control circuit 28 controls the improvement of the power factor of the input power by the first converter 41 by switching the switching element 51.

[0044] The control circuit 28 is electrically connected to the electrode 55c of the switching element 55. The electrode 55c is a so-called control electrode. The control circuit 28 controls the switching of the switching element 55. That is, the control circuit 28 switches the on / off state of the switching element 55. The control circuit 28 switches the on / off state of the switching element 55 according to the voltage (control signal) input to the electrode 55c. For example, the control circuit 28 generates a DC voltage between the electrodes 58a and 58b of the output capacitor 58 by switching the switching element 55. Thereby, DC power is supplied from the second converter 42 (power supply circuit 22, conversion circuit 32) to the light source module 12.

[0045] For example, the control circuit 28 stops the supply of DC power from the second converter 42 to the light source module 12 by turning off the switching element 55. Also, for example, the control circuit 28 changes the voltage value and current value of the DC power supplied to the light source module 12 by changing the on / off period (duty ratio) of the switching element 55.

[0046] Here, the off state of the switching element 51 means, for example, a state in which substantially no current flows between the electrodes 51a and 51b which are the main electrodes. In the off state, for example, a weak current that does not affect the operation of the first converter 41 may flow between the electrodes 51a and 51b. That is, the on state of the switching element 51, in other words, is the first state in which current flows between the electrodes 51a and 51b, and the off state is the second state in which the current flowing between the electrodes 51a and 51b is smaller than that in the first state. The on state and the off state of the switching element 55 are the same as the on state and the off state of the switching element 51.

[0047] Note that the configuration of the conversion circuit 32 is not limited to the above. The conversion circuit 32 may have any configuration capable of converting the rectified power converted by the rectification circuit 30 into DC power corresponding to the light source module 12 and outputting the converted DC power to the output unit 26. The configuration of the conversion circuit 32 may be, for example, any configuration having at least one switching element and capable of converting rectified power into DC power by switching of the switching element.

[0048] The power supply device 10 further includes a ground electrode 60 and a ground circuit 62. The ground electrode 60 is set to the ground potential by being electrically connected to a portion of an external ground potential. The ground electrode 60 is set to the ground potential, for example, by being electrically connected to a ground wire connected to the terminal block 16.

[0049] The ground electrode 60 is provided on the substrate 20. The ground electrode 60 is attached to the substrate 20 by, for example, screwing. The ground electrode 60 is electrically connected to the case 23. The case 23 supports the substrate 20 while accommodating it inside, and is electrically connected to the ground electrode 60 of the supported substrate 20. The case 23 supports the substrate 20 and is electrically connected to the ground electrode 60, for example, by supporting the substrate 20 in a state of being in contact with the ground electrode 60. The substrate 20 is supported by the case 23 in a state where the ground electrode 60 is in contact with the case 23, for example, by screwing the ground electrode 60 to the case 23. Note that the method of electrically connecting the ground electrode 60 and the case 23 is not limited to this, and any method may be used. The method of supporting the substrate 20 by the case 23 is not limited to the above, and any method may be used.

[0050] As described above, the potential of the case 23 is set to the ground potential via the support plate 14, the terminal block 16, and the ground wire. Therefore, the ground electrode 60 is set to the ground potential via the case 23, the support plate 14, the terminal block 16, and the ground wire by being electrically connected to the case 23.

[0051] The method of setting the potential of the ground electrode 60 to the ground potential is not limited to the above, and any method that can appropriately set the potential of the ground electrode 60 to the ground potential may be used. For example, by attaching the substrate 20 to the support plate 14 so that the ground electrode 60 contacts the support plate 14, the potential of the ground electrode 60 may be set to the ground potential via the support plate 14. In this case, the power supply device 10 may not have the case 23. Alternatively, the potential of the ground electrode 60 may be set to the ground potential by connecting a wiring or the like connected to the ground wire or the terminal block 16 to the ground electrode 60.

[0052] Note that the ground potential set for the ground electrode 60 does not have to be exactly the same as the potential of the ground. The ground potential set for the ground electrode 60 may have an error based on, for example, the respective resistance components of the ground electrode, ground wiring provided in the building, and the ground wire connected to the terminal block 16 with respect to the potential of the ground. The ground electrode 60 may be any electrode for electrically connecting to an external ground potential portion, such as a portion of the ground potential of the building.

[0053] The ground electrode 60 is provided, for example, at a position closer to the output portion 26 than the rectifier circuit 30 in the physical arrangement on the substrate 20. In other words, the rectifier circuit 30 is provided at a position closer to the input portion 24 than the ground electrode 60. The shortest distance between the ground electrode 60 and the output portion 26 is shorter than the shortest distance between the rectifier circuit 30 and the output portion 26. More specifically, the shortest distance between the rectifier circuit 30 and the output portion 26 is the shortest distance between each component (e.g., rectifying element) constituting the rectifier circuit 30 and the output portion 26 (the first output terminal 26a or the second output terminal 26b).

[0054] The substrate 20 is, for example, rectangular. The input portion 24 is provided at one end side in the longitudinal direction of the substrate 20, and the output portion 26 is provided at the other end side in the longitudinal direction of the substrate 20. The rectifier circuit 30 is provided, for example, between the input portion 24 and the output portion 26 in the longitudinal direction of the substrate 20. The ground electrode 60 is provided, for example, between the rectifier circuit 30 and the output portion 26 in the longitudinal direction of the substrate 20. However, the shape of the substrate 20 is not limited to a rectangular shape and may be any shape.

[0055] The grounding electrode 60 is provided, for example, in the vicinity of the switching element 51 of the first converter 41. The grounding electrode 60 is thermally coupled to the switching element 51, for example. The grounding electrode 60 is thermally coupled to the switching element 51 by contacting the switching element 51, for example. The grounding electrode 60 may be thermally coupled to the switching element 51 via, for example, a heat dissipation sheet or heat dissipation grease without directly contacting the switching element 51. A metal material having high electrical conductivity and high thermal conductivity, such as aluminum or copper, is used for the grounding electrode 60, for example.

[0056] The grounding electrode 60 is electrically connected to the case 23 and thermally coupled to the case 23 by contacting the case 23, for example. Thereby, the grounding electrode 60 is used for setting the ground potential and also used as a heat dissipation plate for the switching element 51. The grounding electrode 60 dissipates the heat generated in the switching element 51 to the case 23 and the support plate 14 connected to the case 23 by being thermally coupled to the switching element 51 and the case 23. Thus, by also using the grounding electrode 60 as a heat dissipation plate for the switching element 51, an increase in the number of components of the power supply device 10 can be suppressed. However, the position of the grounding electrode 60 is not limited to the above and may be any position on the substrate 20.

[0057] The grounding circuit 62 includes a first capacitor 71 and a second capacitor 72. The grounding circuit 62 is provided on the substrate 20. The first capacitor 71 and the second capacitor 72 are mounted on the substrate 20. One end of the first capacitor 71 is electrically connected to a first path between the high-potential output terminal 30c of the rectifier circuit 30 and the first output terminal 26a of the output unit 26. The other end of the first capacitor 71 is electrically connected to the ground electrode 60. In other words, the first capacitor 71 is provided between the first path between the high-potential output terminal 30c and the first output terminal 26a and the ground electrode 60. One end of the second capacitor 72 is electrically connected to a second path between the low-potential output terminal 30d of the rectifier circuit 30 and the second output terminal 26b of the output unit 26. The other end of the second capacitor 72 is electrically connected to the ground electrode 60. In other words, the second capacitor 72 is provided between the second path between the low-potential output terminal 30d and the second output terminal 26b and the ground electrode 60.

[0058] The grounding circuit 62 is provided on the rectified path of the rectifier circuit 30. The grounding circuit 62 electrically connects the first path between the high-potential output terminal 30c and the first output terminal 26a to the ground electrode 60 via the first capacitor 71, and electrically connects the second path between the low-potential output terminal 30d and the second output terminal 26b to the ground electrode 60 via the second capacitor 72, thereby suppressing the generation of electrical noise accompanying the operation of converting the rectified power by the conversion circuit 32 into DC power. By providing the grounding circuit 62, for example, the electrical noise radiated from the power supply device 10 to the outside can be suppressed. The grounding circuit 62 is provided on the substrate 20 and suppresses the electrical noise radiated from the substrate 20 to the outside.

[0059] In the conversion circuit 32, for example, the switching element 51 of the first converter 41 can become a noise source. The grounding circuit 62 suppresses the flow of the direct current component of the current after being rectified by the rectifier circuit 30 to the grounding path by the first capacitor 71 and the second capacitor 72, and allows the current of the alternating current component (high-frequency component) accompanying the switching of the switching element 51 to flow to the grounding path. Thereby, the grounding circuit 62 suppresses the generation of electrical noise accompanying the operation of the conversion circuit 32.

[0060] The grounding circuit 62 is provided, for example, on the path between the rectifier circuit 30 and the first converter 41. One end of the first capacitor 71 is electrically connected to the path between the high potential output terminal 30c and the first converter 41 (inductor 52), for example. One end of the second capacitor 72 is electrically connected to the path between the low potential output terminal 30d and the connection point of the first converter 41 (electrode 51b), for example. Thereby, for example, the electrical noise radiated (propagated) from the conversion circuit 32 to the input unit 24 side can be suppressed.

[0061] The capacitance value of the second capacitor 72 is substantially the same as the capacitance value of the first capacitor 71, for example. The capacitance value of the second capacitor 72 is, for example, 90% or more and 110% or less of the capacitance value of the first capacitor 71.

[0062] The grounding circuit 62 connects the first path and the grounding electrode 60 via the first capacitor 71 and connects the second path and the grounding electrode 60 via the second capacitor 72 so that the impedance between the first path and the grounding electrode 60 is equal to the impedance between the second path and the grounding electrode 60. The grounding circuit 62 adjusts the impedance between the first path and the grounding electrode 60 and the impedance between the second path and the grounding electrode 60 so that the impedance between the first path and the grounding electrode 60 is equal to the impedance between the second path and the grounding electrode 60.

[0063] This can further suppress the generation of electrical noise accompanying the operation of the conversion circuit 32. However, the capacitance value of the second capacitor 72 does not necessarily have to be the same as that of the first capacitor 71. For example, when the magnitudes of the parasitic capacitance components of each path are different, the capacitance value of the second capacitor 72 may be made different from that of the first capacitor 71 in order to adjust the impedances of the respective paths to be equal.

[0064] The grounding circuit 62 further includes a third capacitor 73. The third capacitor 73 is provided between the first capacitor 71 and the ground electrode 60, and between the second capacitor 72 and the ground electrode 60. One end of the third capacitor 73 is electrically connected to the other end of the first capacitor 71 and the other end of the second capacitor 72. The other end of the third capacitor 73 is electrically connected to the ground electrode 60. The other ends of the first capacitor 71 and the second capacitor 72 are, in other words, electrically connected to the ground electrode 60 via the third capacitor 73.

[0065] In this way, by providing the third capacitor 73, for example, when at least one of the first capacitor 71 and the second capacitor 72 has a short-circuit failure, it is possible to suppress the output side of the rectifier circuit 30 from being directly connected to the ground electrode 60 and the current of the DC component after being rectified by the rectifier circuit 30 from flowing into the ground path. For example, it is possible to improve the reliability of the power supply device 10 while suppressing the generation of electrical noise. However, the third capacitor 73 is provided as needed and can be omitted.

[0066] As described above, in the power supply device 10 according to the present embodiment, the grounding circuit 62 is provided on the path after rectification by the rectification circuit 30. Thereby, in the power supply device 10 according to the present embodiment, for example, the grounding circuit 62 can be brought closer to the conversion circuit 32 (switching element 51), which is a noise source, as compared with a configuration in which the grounding circuit 62 is provided on the path before rectification between the input unit 24 and the rectification circuit 30. In this way, by bringing the grounding circuit 62 closer to the noise source, for example, electrical noise radiated from the portion between the noise source and the grounding circuit 62 can be suppressed, and the electrical noise can be reduced more appropriately.

[0067] Further, when the grounding electrode 60 is provided on the substrate 20 at a position closer to the output unit 26 than the rectification circuit 30, by providing the grounding circuit 62 on the path after rectification by the rectification circuit 30, the wiring path of the grounding circuit 62 can be made shorter than when the grounding circuit 62 is provided on the path before rectification by the rectification circuit 30. Thereby, the area occupied by the wiring path of the grounding circuit 62 on the substrate 20 can be reduced. For example, it is possible to suppress the substrate 20 from becoming larger due to the lengthening of the wiring path of the grounding circuit 62. Also, it is possible to suppress the wiring path of the grounding circuit 62 itself from being affected by electrical noise and the suppression effect of electrical noise from decreasing.

[0068] In this way, by providing the grounding circuit 62 on the path after rectification by the rectification circuit 30 and providing the grounding electrode 60 at a position closer to the output unit 26 than the rectification circuit 30, the wiring path of the grounding circuit 62 can be made shorter. And thereby, it is possible to suppress the enlargement of the substrate 20 and the like, and it is possible to more appropriately reduce electrical noise.

[0069] Also, a ground electrode 60 is provided in proximity to the switching element 51 of the first converter 41 and thermally coupled to the switching element 51. Thereby, the ground electrode 60 can function as a heat sink for the switching element 51, suppressing an increase in the number of components, etc. Also, by disposing the ground electrode 60 near the switching element 51 which is a noise source, for example, electrical noise generated by the switching element 51 can be made to more easily flow through the ground path. Therefore, electrical noise can be more appropriately reduced.

[0070] Also, a ground electrode 60 is provided in proximity to the switching element 51 of the first converter 41, and a ground circuit 62 is provided on the path between the rectifier circuit 30 and the first converter 41. Thereby, for example, radiation of electrical noise to the input unit 24 side can be suppressed, the wiring path of the ground circuit 62 can be made shorter, and the effects of suppressing the increase in size of the substrate 20 and reducing electrical noise can be enhanced.

[0071] In this example, the ground circuit 62 is provided on the path between the rectifier circuit 30 and the first converter 41. The ground circuit 62 is not limited to this, and may be provided, for example, on the path between the first converter 41 and the second converter 42. One end of the first capacitor 71 and one end of the second capacitor 72 may be electrically connected to the path between the first converter 41 and the second converter 42. One end of the first capacitor 71 may be connected, for example, to the input terminal 42a of the second converter 42. One end of the second capacitor 72 may be connected, for example, to the input terminal 42b of the second converter 42. For example, when the ground electrode 60 is provided in proximity to the switching element 51 of the first converter 41, the ground circuit 62 is provided on the path immediately after the first converter 41. Thereby, for example, radiation of electrical noise to the output unit 26 side can be suppressed, the wiring path of the ground circuit 62 can be made shorter, and the effects of suppressing the increase in size of the substrate 20 and reducing electrical noise can be enhanced.

[0072] The ground circuit 62 may be provided, for example, on the path between the second converter 42 and the output section 26. One end of the first capacitor 71 may be connected to, for example, the output terminal 42c of the second converter 42. One end of the second capacitor 72 may be connected to, for example, the output terminal 42d of the second converter 42. For example, the switching element 55 of the second converter 42 may be a source of noise. In this case, the ground circuit 62 is preferably provided, for example, on the path between the first converter 41 and the second converter 42 or on the path between the second converter 42 and the output section 26. Further, when the switching element 55 is a source of noise, the ground electrode 60 may be provided in proximity to the switching element 55 and function as a heat sink for the switching element 55.

[0073] As described above, the configuration of the conversion circuit 32 may have at least one switching element and may be any configuration capable of converting rectified power into DC power by switching the switching element. The ground electrode 60 is provided in proximity to the switching element and thermally coupled to the switching element. Thereby, the ground electrode 60 can also be used as a heat sink for the switching element, and heat dissipation of the switching element can be achieved while suppressing an increase in the number of components of the power supply device 10.

[0074] FIG. 3 is a block diagram schematically showing a modified example of the power supply device according to the embodiment. As shown in FIG. 3, in the power supply device 10a, the ground circuit 62a further includes a first inductor 81 and a second inductor 82. Note that components that are substantially the same in function and configuration as those in the above embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

[0075] The first inductor 81 is connected in series with the first capacitor 71. The second inductor 82 is connected in series with the second capacitor 72. The first inductor 81 is provided between the first path and the first capacitor 71. The second inductor 82 is provided between the second path and the second capacitor 72. The first inductor 81 may be provided between the first capacitor 71 and the third capacitor 73 (ground electrode 60). The second inductor 82 may be provided between the second capacitor 72 and the third capacitor 73 (ground electrode 60).

[0076] Thus, by further providing the first inductor 81 and the second inductor 82 in the ground circuit 62a, the magnitude of the impedance between the first path and the ground electrode 60 and the magnitude of the impedance between the second path and the ground electrode 60 can be adjusted. For example, by adjusting the magnitude of the impedance of the ground path according to the frequency characteristics of the electrical noise generated in the conversion circuit 32, the electrical noise can be more appropriately reduced.

[0077] The magnitude of the inductance of the second inductor 82 is, for example, substantially the same as the magnitude of the inductance of the first inductor 81. The magnitude of the inductance of the second inductor 82 is, for example, 90% or more and 110% or less of the magnitude of the inductance of the first inductor 81.

[0078] Thereby, even when the first inductor 81 and the second inductor 82 are provided, the impedance between the first path and the ground electrode 60 is made equal to the impedance between the second path and the ground electrode 60, and the generation of electrical noise can be more appropriately suppressed. However, the magnitude of the inductance of the second inductor 82 does not necessarily have to be the same as the magnitude of the inductance of the first inductor 81. For example, when the magnitudes of the parasitic inductance components of each path are different, the magnitude of the inductance of the second inductor 82 may be made different from the magnitude of the inductance of the first inductor 81 in order to adjust the impedances of each path to be equal.

[0079] FIG. 4 is a block diagram schematically showing a modification of the power supply device according to the embodiment. As shown in FIG. 4, in the power supply device 10b, the grounding circuit 62b further includes an inductor 83. The inductor 83 is provided between the connection point between the other end of the first capacitor 71 and the other end of the second capacitor 72, and the grounding electrode 60. In this example, the inductor 83 is provided between the connection point between the other end of the first capacitor 71 and the other end of the second capacitor 72, and the third capacitor 73. The inductor 83 may be provided between the third capacitor 73 and the grounding electrode 60.

[0080] Thus, even when the inductor 83 is provided instead of the first inductor 81 and the second inductor 82, similarly to the above, the magnitude of the impedance of the grounding path can be adjusted according to the frequency characteristics of the electrical noise, and the electrical noise can be more appropriately reduced. Note that the grounding circuit 62b may have, for example, the first inductor 81 and the second inductor 82, and further have the inductor 83 (third inductor).

[0081] FIG. 5 is a block diagram schematically showing a modification of the power supply device according to the embodiment. As shown in FIG. 5, in the power supply device 10c, the grounding circuit 62c further includes a first resistor element 91 and a second resistor element 92. Note that components that are substantially the same in function and configuration as those in the above embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

[0082] The first resistor element 91 is connected in series with the first capacitor 71. The second resistor element 92 is connected in series with the second capacitor 72. The first resistor element 91 is provided between the first path and the first capacitor 71. The second resistor element 92 is provided between the second path and the second capacitor 72. The first resistor element 91 may be provided between the first capacitor 71 and the third capacitor 73 (grounding electrode 60). The second resistor element 92 may be provided between the second capacitor 72 and the third capacitor 73 (grounding electrode 60).

[0083] Thus, by further providing the first resistor element 91 and the second resistor element 92 in the grounding circuit 62c, the magnitude of the impedance between the first path and the grounding electrode 60 and the magnitude of the impedance between the second path and the grounding electrode 60 can be adjusted. For example, by adjusting the magnitude of the impedance of the grounding path according to the frequency characteristics of the electrical noise generated in the conversion circuit 32, the electrical noise can be more appropriately reduced.

[0084] The magnitude of the resistance value of the second resistor element 92 is, for example, substantially the same as the magnitude of the resistance value of the first resistor element 91. The magnitude of the resistance value of the second resistor element 92 is, for example, 90% or more and 110% or less of the magnitude of the resistance value of the first resistor element 91.

[0085] Thereby, even when the first resistor element 91 and the second resistor element 92 are provided, the impedance between the first path and the grounding electrode 60 is made equal to the impedance between the second path and the grounding electrode 60, and the generation of electrical noise can be more appropriately suppressed. However, the magnitude of the resistance value of the second resistor element 92 does not necessarily have to be the same as the magnitude of the resistance value of the first resistor element 91. For example, in the case where the magnitudes of the resistance values of the respective paths are different, the magnitude of the resistance value of the second resistor element 92 may be made different from the magnitude of the resistance value of the first resistor element 91 in order to adjust the impedances of the respective paths to be equal.

[0086] FIG. 6 is a block diagram schematically showing a modified example of the power supply device according to the embodiment. As shown in FIG. 6, in the power supply device 10d, the grounding circuit 62d further has a resistor element 93. The resistor element 93 is provided between the connection point of the other end of the first capacitor 71 and the other end of the second capacitor 72 and the grounding electrode 60. In this example, the resistor element 93 is provided between the connection point of the other end of the first capacitor 71 and the other end of the second capacitor 72 and the third capacitor 73. The resistor element 93 may be provided between the third capacitor 73 and the grounding electrode 60.

[0087] Thus, even when the resistor element 93 is provided instead of the first resistor element 91 and the second resistor element 92, similarly to the above, the magnitude of the impedance of the grounding path can be adjusted according to the frequency characteristics of the electrical noise, and the electrical noise can be more appropriately reduced. Note that the grounding circuit 62d may have, for example, a configuration that includes the first resistor element 91 and the second resistor element 92 and further includes the resistor element 93 (third resistor element). Further, the grounding circuit 62d may further include, for example, the first inductor 81, the second inductor 82, or the inductor 83. In other words, the configurations of the grounding circuits 62a to 62d shown in FIGS. 3 to 6 can be arbitrarily combined.

[0088] FIGS. 7(a) to 7(c) are graphs schematically showing an example of the characteristics of the power supply device according to the embodiment. FIGS. 7(a) to 7(c) schematically show an example of the frequency characteristics of the electrical noise radiated from the power supply device to the outside. The horizontal axis in FIGS. 7(a) to 7(c) represents the frequency of the electrical noise radiated from the power supply device to the outside. The vertical axis in FIGS. 7(a) to 7(c) represents the magnitude of the electrical noise radiated from the power supply device to the outside in decibel notation.

[0089] FIG. 7(a) schematically shows an example of the frequency characteristics of the electrical noise when the grounding circuit 62 shown in FIG. 2 is provided. In other words, FIG. 7(a) schematically shows an example of the characteristics of the grounding circuit 62 provided with only a capacitor.

[0090] FIG. 7(b) schematically shows an example of the frequency characteristics of the electrical noise when the grounding circuit 62a shown in FIG. 3 is provided. In other words, FIG. 7(b) schematically shows an example of the characteristics of the grounding circuit 62a provided with a capacitor and an inductor.

[0091] FIG. 7(c) schematically shows an example of the frequency characteristics of the electrical noise when the grounding circuit 62c shown in FIG. 5 is provided. In other words, FIG. 7(c) schematically shows an example of the characteristics of the grounding circuit 62c provided with a capacitor and a resistor element.

[0092] In each of the characteristics of FIGS. 7(a) to 7(c), the configurations other than the grounding circuit are substantially the same. In other words, the characteristic of FIG. 7(b) represents an example of the characteristic of the grounding circuit 62a in which an inductor is further provided in the grounding circuit of the characteristic of FIG. 7(a). In other words, the characteristic of FIG. 7(c) represents an example of the characteristic of the grounding circuit 62c in which a resistance element is further provided in the grounding circuit of the characteristic of FIG. 7(a).

[0093] As shown in FIG. 7(a), in the grounding circuit 62 provided with only a capacitor, the electrical noise near 80 MHz is higher than that in other frequency portions.

[0094] As shown in FIG. 7(b), in the grounding circuit 62a provided with a capacitor and an inductor, while the electrical noise near 80 MHz can be reduced with respect to the characteristic of FIG. 7(a), the electrical noise near 30 MHz has become higher.

[0095] As shown in FIG. 7(c), in the grounding circuit 62c provided with a capacitor and a resistance element, the electrical noise near 80 MHz can be reduced as compared with the characteristic of FIG. 7(a), and the electrical noise near 30 MHz can also be reduced as compared with the characteristic of FIG. 7(b).

[0096] Thus, the frequency characteristics of the electrical noise radiated from the power supply device 10 to the outside change according to the impedance characteristics of the grounding circuit 62. As a result of intensive studies, the inventor of the present application has found that in a relatively high frequency band such as 80 MHz or higher, the electrical noise is reduced by increasing the impedance of the grounding path of the grounding circuit 62, and in a relatively low frequency band such as 30 MHz or lower, the electrical noise is reduced by decreasing the impedance of the grounding path of the grounding circuit 62. In the examples shown in FIGS. 7(b) and 7(c), in order to suppress the electrical noise near 80 MHz, the impedance of the grounding circuit 62 was increased, and it is considered that the electrical noise near 30 MHz has increased as compared with the example shown in FIG. 7(a).

[0097] The impedance characteristics of the resistive element are substantially constant with respect to changes in frequency. On the other hand, the impedance characteristics of the inductor change according to the frequency. The impedance of the inductor increases as the frequency rises. Therefore, it is preferable to adjust the impedance of the grounding path of the grounding circuit 62 by arbitrarily combining a capacitor, an inductor, and a resistive element so that electrical noise can be appropriately suppressed in a desired frequency range.

[0098] This embodiment includes the following aspects. (Appendix 1) A substrate, A power supply circuit provided on the substrate, which converts the input AC power into DC power corresponding to the light source module and supplies the converted DC power to the light source module to turn on the light source module. An output unit provided on the substrate and having a pair of output terminals, namely a first output terminal on the high potential side and a second output terminal on the low potential side, for outputting the DC power converted by the power supply circuit to the light source module. A grounding electrode provided on the substrate and electrically connected to an external ground potential portion to be set to the ground potential. A grounding circuit provided on the substrate for suppressing electrical noise radiated from the substrate to the outside. Comprising The power supply circuit Has a pair of input terminals, a high potential output terminal, and a low potential output terminal, and converts the AC power input through the pair of input terminals into rectified power, and outputs the converted rectified power from the high potential output terminal and the low potential output terminal. A rectifier circuit. A conversion circuit that converts the rectified power converted by the rectifier circuit into DC power corresponding to the light source module and outputs the converted DC power to the output unit. Having The grounding circuit A first capacitor provided between a first path between the high potential output terminal and the first output terminal and the grounding electrode. A second capacitor provided between a second path between the low potential output terminal and the second output terminal and the ground electrode; A power supply device characterized by having the same.

[0099] (Appendix 2) The ground circuit connects the first path and the ground electrode via the first capacitor and connects the second path and the ground electrode via the second capacitor such that the impedance between the first path and the ground electrode is equal to the impedance between the second path and the ground electrode. The power supply device according to Appendix 1, characterized by this.

[0100] (Appendix 3) The ground circuit further includes a third capacitor provided between the first capacitor and the ground electrode and between the second capacitor and the ground electrode. The power supply device according to Appendix 1 or 2, characterized by this.

[0101] (Appendix 4) The ground circuit is A first inductor connected in series with the first capacitor; A second inductor connected in series with the second capacitor; The power supply device according to any one of Appendices 1 to 3, further characterized by having the same.

[0102] (Appendix 5) The ground circuit further includes an inductor provided between the connection point of the first capacitor and the second capacitor and the ground electrode. The power supply device according to any one of Appendices 1 to 4, further characterized by having the same.

[0103] (Appendix 6) The ground circuit is A first resistor element connected in series with the first capacitor; A second resistor element connected in series with the second capacitor; The power supply device according to any one of Appendices 1 to 5, further characterized by having the same.

[0104] (Appendix 7) The grounding circuit further includes a resistance element provided between a connection point of the first capacitor and the second capacitor and the grounding electrode, and the power supply device according to any one of Appendices 1 to 6 is characterized in that.

[0105] (Appendix 8) The conversion circuit A first converter that suppresses the generation of harmonics in the input current of the rectifier circuit by converting the rectified power converted by the rectifier circuit into another power, A second converter that converts the power after conversion by the first converter into DC power corresponding to the light source module, and has One end of the first capacitor is electrically connected to a path between the high potential output terminal and the first converter, One end of the second capacitor is electrically connected to a path between the low potential output terminal and the first converter, and the power supply device according to any one of Appendices 1 to 7 is characterized in that.

[0106] (Appendix 9) The conversion circuit has at least one switching element, and converts the rectified power into the DC power by switching the switching element, The grounding electrode is thermally coupled to the switching element, and the power supply device according to any one of Appendices 1 to 8 is characterized in that.

[0107] (Appendix 10) A light source module having a light source, The power supply device according to any one of Appendices 1 to 9, and a lighting fixture characterized by comprising.

[0108] Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalent scope thereof.

Explanation of Reference Numerals

[0109] 2... Lighting fixture, 10, 10a to 10d... Power supply device, 12... Light source module, 12a... Light source, 14... Support plate, 16... Terminal block, 20... Substrate, 22... Power supply circuit, 23... Case, 24... Input section, 26... Output section, 28... Control circuit, 30... Rectifier circuit, 32... Conversion circuit, 41... First converter, 42... Second converter, 43... High-frequency removal capacitor, 44... Smoothing capacitor, 51... Switching element, 52... Inductor, 53... Diode, 55... Switching element, 56... Diode, 57... Inductor, 58... Output capacitor, 60... Ground electrode, 62, 62a to 62d... Ground circuit, 71... First capacitor, 72... Second capacitor, 73... Third capacitor, 81... First inductor, 82... Second inductor, 83... Inductor, 91... First resistance element, 92... Second resistance element, 93... Resistance element

Claims

1. A substrate, a power supply circuit provided on the substrate, which converts the input AC power into DC power corresponding to the light source module and supplies the converted DC power to the light source module to turn on the light source module, an output unit provided on the substrate, having a pair of output terminals including a first output terminal on the high potential side and a second output terminal on the low potential side for outputting the DC power converted by the power supply circuit to the light source module, a ground electrode provided on the substrate and electrically connected to a portion of an external ground potential to be set to the ground potential, a ground circuit provided on the substrate for suppressing electrical noise radiated from the substrate to the outside, comprising: the power supply circuit includes: a rectification circuit having a pair of input terminals, a high potential output terminal, and a low potential output terminal, which converts the AC power input through the pair of input terminals into rectified power and outputs the converted rectified power from the high potential output terminal and the low potential output terminal, a conversion circuit that converts the rectified power converted by the rectification circuit into DC power corresponding to the light source module and outputs the converted DC power to the output unit, and having: the ground circuit includes: a first capacitor provided between a first path between the high potential output terminal and the first output terminal and the ground electrode, a second capacitor provided between a second path between the low potential output terminal and the second output terminal and the ground electrode, and a power supply device characterized by having the above.

2. The ground circuit connects the first path and the ground electrode via the first capacitor and connects the second path and the ground electrode via the second capacitor such that the impedance between the first path and the ground electrode is equal to the impedance between the second path and the ground electrode. The power supply device according to Claim 1 is characterized by this.

3. The ground circuit further includes a third capacitor provided between the first capacitor and the ground electrode and between the second capacitor and the ground electrode. The power supply device according to Claim 1 is characterized by this.

4. The ground circuit includes: a first inductor connected in series with the first capacitor, a second inductor connected in series with the second capacitor, and a power supply device according to Claim 1 is characterized by further having the above.

5. The power supply device according to claim 1, wherein the grounding circuit further includes an inductor provided between a connection point of the first capacitor and the second capacitor and the grounding electrode.

6. The grounding circuit further includes a first resistor element connected in series with the first capacitor, and a second resistor element connected in series with the second capacitor. The power supply device according to claim 1, characterized in that it further has the above.

7. The power supply device according to claim 1, wherein the grounding circuit further includes a resistor element provided between a connection point of the first capacitor and the second capacitor and the grounding electrode.

8. The conversion circuit includes a first converter that suppresses the generation of harmonics in the input current of the rectifier circuit by converting the rectified power converted by the rectifier circuit into another power, and a second converter that converts the power after conversion by the first converter into DC power corresponding to the light source module. It has One end of the first capacitor is electrically connected to a path between the high potential output terminal and the first converter, The power supply device according to claim 1, wherein one end of the second capacitor is electrically connected to a path between the low potential output terminal and the first converter.

9. The conversion circuit has at least one switching element, and converts the rectified power into the DC power by switching the switching element. The power supply device according to claim 1, wherein the grounding electrode is thermally coupled to the switching element.

10. A lighting fixture comprising a light source module having a light source, and the power supply device according to any one of claims 1 to 9. characterized in that it is provided with the above.

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