Lighting devices and lighting fixtures

Abstract

To suppress an increase in size and cost of a device and furthermore to reduce interfering wave voltage in a specific frequency band.SOLUTION: A lighting device 100 comprises a filter circuit 1, a converter circuit 3, and a constant current circuit 4. The filter circuit 1 suppresses noise to be propagated from the lighting device 100 to an external power source 7. The converter circuit 3 converts an input voltage input from the external power source 7 via the filter circuit 1 into a DC voltage, and outputs the DC voltage. The constant current circuit 4 keeps current supplied from the converter circuit 3 to a light source 8 including one or more light-emitting elements 81 constant. An operation frequency of the converter circuit 3 is less than 50 kHz when the phase of an input current of the converter circuit 3 is at least in ranges from 45 to 135 degrees and from 225 to 315 degrees.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a lighting device for turning on a light source, and a lighting fixture. [Background technology]

[0002] Patent Document 1 discloses a lighting device having a filter device. The filter device has a composite choke coil, an across-the-line capacitor, and two normal mode choke coils. The composite choke coil has an inductance as a common mode choke coil and an inductance as a normal mode choke coil. The across-the-line capacitor is electrically connected between two output terminals of the composite choke coil. The two normal mode choke coils are electrically connected to two output terminals of the composite choke coil, respectively.

[0003] The lighting device described in Patent Document 1 attenuates interference voltage in the frequency range of 9 kHz to 526.5 kHz so as to meet the standards of "Limits and methods of measurement of radio disturbance characteristics of electric lighting and similar equipment" (CISPR15 (2000), Amd. No. 1 (2001), Amd. No.2 (2002)) established by the International Special Committee on Radio Interference (CISPR). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2013-258631 A Summary of the Invention [Problem to be solved by the invention]

[0005] The lighting device described in Patent Document 1 uses two normal mode choke coils, which tends to increase the number of parts. Therefore, even if the lighting device described in Patent Document 1 can reduce interference voltage in a specific frequency band, there are problems such as an increase in the size of the device and an increase in manufacturing costs.

[0006] The present invention provides a lighting device and the like that can reduce interference voltage in a specific frequency band while suppressing increases in size and cost of the device. [Means for solving the problem]

[0007] A lighting device according to one aspect of the present invention includes a filter circuit that suppresses noise transmitted from the lighting device to an external power source, a converter circuit that converts an input voltage input from the external power source through the filter circuit into a DC voltage and outputs the DC voltage, and a constant current circuit that maintains constant a current supplied from the converter circuit to a light source including one or more light-emitting elements, wherein the operating frequency of the converter circuit is less than 50 kHz when the phase of the input current to the converter circuit is at least 45 degrees or more and 135 degrees or less, and 225 degrees or more and 315 degrees or less. the filter circuit includes a choke coil having a first inductance in normal mode and a second inductance in common mode, a first capacitor connected between a pair of electric wires connecting the external power supply and the converter circuit, and a second capacitor connected between at least one of the pair of electric wires and a circuit ground, and does not include a choke coil for normal mode. .

[0008] A lighting fixture according to one aspect of the present invention includes the lighting device, the light source that is turned on by the current supplied from the lighting device, and a fixture body that holds the lighting device and the light source. Effect of the Invention

[0009] A lighting device or the like according to one aspect of the present invention has the advantage that it is possible to reduce interference voltage in a specific frequency band while suppressing an increase in size and cost of the device. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a circuit diagram showing a configuration of a lighting device according to an embodiment. [Diagram 2] FIG. 2 is a perspective view showing an external appearance of the lighting fixture according to the embodiment. [Diagram 3] FIG. 3 is a waveform diagram of an input current of a converter circuit in a lighting device according to an embodiment. [Figure 4] FIG. 4 is an explanatory diagram of a first result of comparing a lighting device according to the embodiment with a lighting device of a comparative example. [Diagram 5] FIG. 5 is an explanatory diagram of a second result of comparing the lighting device according to the embodiment with the lighting device of the comparative example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, the embodiments will be described in detail with reference to the drawings. Note that the embodiments described below are all comprehensive or specific examples. The numerical values, shapes, materials, components, component arrangement and connection forms, steps, and order of steps shown in the following embodiments are merely examples and are not intended to limit the present invention. In addition, among the components in the following embodiments, components that are not described in the independent claims will be described as optional components.

[0012] In addition, each drawing is a schematic diagram and is not necessarily a precise illustration. In addition, in each drawing, the same reference numerals are used for substantially the same configuration, and duplicated explanations may be omitted or simplified.

[0013] (Embodiment) [composition] First, the configuration of a lighting device according to an embodiment will be described with reference to Fig. 1 and Fig. 2. Fig. 1 is a circuit diagram showing the configuration of a lighting device 100 according to an embodiment. Fig. 2 is a perspective view showing the appearance of a lighting fixture 200 according to an embodiment. The lighting device 100 is a device that lights up a light source 8 by supplying a current to the light source 8. Power is supplied to the lighting device 100 from an external power source 7. The external power source 7 is, for example, a system power source such as a commercial power source, and is an AC power source.

[0014] The light source 8 has one or more light-emitting elements 81. In the embodiment, the light source 8 is configured by connecting a plurality of light-emitting elements 81 in series, the light-emitting elements 81 being solid-state light-emitting elements such as light-emitting diodes (LEDs). In the embodiment, the light source 8 is an elongated line light source called a light bar.

[0015] The lighting device 100 is held in the fixture body 20 together with the light source 8 to form the lighting fixture 200. In other words, the lighting fixture 200 includes the lighting device 100, the light source 8 that is turned on by the current supplied from the lighting device 100, and the fixture body 20 that holds the lighting device 100 and the light source 8.

[0016] The fixture body 20 is installed, for example, at a predetermined location in a building. In the embodiment, the luminaire 200 is a ceiling-mounted luminaire. Therefore, the fixture body 20 is attached to a ceiling in a room using bolts or the like. Of course, the luminaire 200 may be installed at a location other than the ceiling, such as a wall or floor in a room.

[0017] In the embodiment, the fixture body 20 is made of sheet metal, and is formed into a box shape that is long and flat in one direction by performing bending processing on the metal plate. The fixture body 20 is provided with a recess having a rectangular opening surface, and the lighting device 100 and the light source 8 are arranged in this recess. This recess is covered with a long diffusion cover 10. The diffusion cover 10 may be configured integrally with the light source 8.

[0018] 1, the lighting device 100 includes a filter circuit 1, a rectifier circuit 2, a converter circuit 3, and a constant current circuit 4. The lighting device 100 further includes a control circuit 5 and a remote controller 6.

[0019] The filter circuit 1 is a circuit that suppresses noise transmitted from the lighting device 100 to the external power supply 7. In the embodiment, the filter circuit 1 suppresses common mode noise and normal mode noise as noise. That is, the filter circuit 1 has a normal mode filter F1.

[0020] The filter circuit 1 includes a choke coil 11, a first capacitor 12, and a second capacitor 13. In the embodiment, the rectifier capacitor 22 of the rectifier circuit 2 is also a component of the filter circuit 1.

[0021] The choke coil 11 is connected between the external power supply 7 and the rectifier circuit 2. Specifically, the choke coil 11 is configured such that one of two inductors is inserted into the electric wire L1 on the high potential side of the pair of electric wires L1, and the other inductor is inserted into the electric wire L1 on the low potential side of the pair of electric wires L1.

[0022] The choke coil 11 is a common mode choke coil, and is configured to generate a differential mode (normal mode) inductance by a portion of the magnetic flux leaking. That is, the choke coil 11 has a first inductance in the normal mode and a second inductance in the common mode. The first inductance functions as a part of the normal mode filter F1. The second inductance functions as a part of the common mode filter.

[0023] The first capacitor 12 is connected between a pair of electric wires L1 that connect the external power supply 7 and the converter circuit 3. In the embodiment, the first capacitor 12 is connected between the pair of electric wires L1 in the upstream stage of the choke coil 11, that is, between the external power supply 7 and the choke coil 11. The first capacitor 12 functions as a part of the normal mode filter F1.

[0024] The second capacitor 13 is connected between at least one of the pair of electric wires L1 and the circuit ground. In the embodiment, the second capacitor 13 is connected between the electric wire L1 on the lower potential side of the pair of electric wires L1 and the circuit ground at the rear stage of the choke coil 11, that is, between the choke coil 11 and the rectifier circuit 2. The second capacitor 13 functions as a part of the common mode filter.

[0025] The rectifier circuit 2 has a diode bridge 21 and a rectifier capacitor 22. The diode bridge 21 is connected to the choke coil 11, and full-wave rectifies the voltage input to the rectifier circuit 2 via the choke coil 11 (i.e., the AC voltage output from the external power supply 7). The rectifier capacitor 22 is connected between a pair of electric wires L1 between the diode bridge 21 and the converter circuit 3, and smoothes the full-wave rectified voltage output from the diode bridge 21. Therefore, the rectifier circuit 2 rectifies the AC voltage output from the external power supply 7 and outputs a rectified voltage. This rectified voltage corresponds to the input voltage of the converter circuit 3.

[0026] As already described, in the embodiment, the rectifying capacitor 22 functions as a part of the normal mode filter F1. That is, the normal mode filter F1 includes the first inductance of the choke coil 11, the rectifying capacitor 22, and the first capacitor 12.

[0027] The cutoff frequency of the normal mode filter F1 is smaller than the operating frequency of the converter circuit 3. In particular, in the embodiment, the cutoff frequency of the normal mode filter F1 is less than 20 kHz. Here, the cutoff frequency of the normal mode filter F1 is determined based on the first inductance of the choke coil 11, the capacitance of the first capacitor 12, and the capacitance of the rectifier capacitor 22. Therefore, in the embodiment, the first inductance of the choke coil 11, the capacitance of the first capacitor 12, and the capacitance of the rectifier capacitor 22 are adjusted so that the cutoff frequency of the normal mode filter F1 is less than 20 kHz.

[0028] The converter circuit 3 is a non-insulated boost chopper circuit, which converts an input voltage input from an external power supply 7 via a filter circuit 1 into a DC voltage and outputs the DC voltage. Here, "non-insulated" means that there is no electrical insulation between the input terminal and the output terminal. In this embodiment, the converter circuit 3 is connected in a subsequent stage to the rectifier circuit 2. The converter circuit 3 is a DC-DC conversion circuit that receives the rectified voltage output by the rectifier circuit 2 as an input voltage, converts the rectified voltage into a DC voltage, and outputs the DC voltage.

[0029] Specifically, the converter circuit 3 has an inductor 31, a switch element 32, a diode 33, and a capacitor 34. One end of the inductor 31 is connected to the high potential output end of the rectifier circuit 2. The other end of the inductor 31 is connected to the drain of the switch element 32 and the anode of the diode 33.

[0030] The switch element 32 is an element that is switched to an on state or an off state based on a first drive signal from the control circuit 5. In the embodiment, the switch element 32 is an n-channel type MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor). The drain of the switch element 32 is connected to the other end of the inductor 31 and the anode of the diode 33. The source of the switch element 32 is connected to the low potential side output end of the rectifier circuit 2. The first drive signal from the control circuit 5 is input to the gate of the switch element 32.

[0031] The cathode of the diode 33 is connected to one end of the capacitor 34 and to the high potential input end of the constant current circuit 4. The capacitor 34 is connected between the pair of electric wires L1, and the other end is connected to the low potential input end of the constant current circuit 4.

[0032] FIG. 3 is a waveform diagram of the input current of the converter circuit 3 in the lighting device 100 according to the embodiment. FIG. 3(a) is a waveform diagram of the input current of the converter circuit 3, and FIG. 3(b) is a diagram in which the input current waveform is partially enlarged. Specifically, FIG. 3(b) is a diagram in which the waveform near the peak of the input current (the waveform of the area surrounded by a circle A1 in FIG. 3(a)) is partially enlarged. The peak of the input current appears when the phase of the input current is 90 degrees or 270 degrees. In FIG. 3(a), the waveform of the input current of the converter circuit 3 is shown as being filled in black, but in reality, the waveform of the input current of the converter circuit 3 is a waveform in which a triangular current waveform as shown in FIG. 3(b) is repeated in a very short period.

[0033] In the embodiment, the period T1 of the input current is 20 μs or more near the peak of the input current. That is, near the peak of the input current, the control circuit 5 controls the switch element 32 of the converter circuit 3 so that the switching frequency of the switch element 32, in other words, the operating frequency of the converter circuit 3, is less than 50 kHz. In particular, in the embodiment, the control circuit 5 controls the switch element 32 so that the operating frequency of the converter circuit 3 is less than 50 kHz when the phase of the input current of the converter circuit 3 is at least 45 degrees or more and 135 degrees or less, and at least 225 degrees or more and 315 degrees or less.

[0034] If the operating frequency of the converter circuit 3 is less than 20 kHz, it will be in the frequency band of human audible sounds, and the operating sound of the converter circuit 3 may be perceived by the user as noise. For this reason, it is preferable that the operating frequency of the converter circuit 3 is 20 kHz or higher. In this case, the operating sound of the converter circuit 3 will be less likely to be perceived by the user as noise.

[0035] Furthermore, when the input current of the converter circuit 3 is not near the peak, there is no particular restriction on the operating frequency of the converter circuit 3, but near the lower limit of the input current, it is preferable that the operating frequency of the converter circuit 3 is lower than when the input current is near the peak. The lower limit of the input current appears when the phase of the input current is 0 degrees or 180 degrees. In this way, by making the operating frequency of the converter circuit 3 relatively low near the lower limit of the input current, distortion of the input current waveform is less likely to occur.

[0036] The constant current circuit 4 is a non-isolated step-down chopper circuit, and is a circuit that maintains a constant current supplied from the converter circuit 3 to the light source 8. Specifically, the constant current circuit 4 has a switch element 41, a diode 42, an inductor 43, and a capacitor 44.

[0037] The switch element 41 is an element that is switched to an on state or an off state based on a second drive signal from the control circuit 5. In the embodiment, the switch element 41 is an n-channel MOSFET. The drain of the switch element 41 is connected to the high potential side output terminal of the converter circuit 3. The source of the switch element 41 is connected to the cathode of the diode 42 and one of the two ends of the inductor 43. The second drive signal from the control circuit 5 is input to the gate of the switch element 41.

[0038] The control circuit 5 can be realized by, for example, a microcomputer. The microcomputer is a one-chip semiconductor integrated circuit having a memory such as a ROM (Read Only Memory) or a RAM (Random Access Memory) in which a program is stored, a processor (CPU; Central Processing Unit) that executes the program, a timer, and an input / output circuit including an A / D converter or a D / A converter. The control circuit 5 may be realized by using an electric circuit other than a microcomputer.

[0039] The control circuit 5 is a circuit that controls the lighting device 100 by controlling the converter circuit 3 and the constant current circuit 4. The control circuit 5 generates a first drive signal that drives the converter circuit 3, and outputs the generated first drive signal to the gate of the switch element 32 of the converter circuit 3. The control circuit 5 also generates a second drive signal that drives the constant current circuit 4, and outputs the generated second drive signal to the gate of the switch element 41 of the constant current circuit 4. The first drive signal and the second drive signal are both binary signals that periodically alternate between a HIGH level and a LOW level.

[0040] The control circuit 5 controls the lighting device 100 based on a signal from, for example, the remote controller 6. For example, when the control circuit 5 receives a dimming signal indicating the luminance of the light source 8 from the remote controller 6, the control circuit 5 controls the converter circuit 3 and the constant current circuit 4 so that a current corresponding to the luminance is supplied to the light source 8. In addition, when the control circuit 5 receives a light-off signal from the remote controller 6 to turn off the light source 8, the control circuit 5 controls the converter circuit 3 and the constant current circuit 4 so that no current is supplied to the light source 8.

[0041] The remote controller 6 is an operating device for transmitting a signal for controlling the lighting device 100 to the control circuit 5. The remote controller 6 transmits a signal corresponding to a user's operation to the control circuit 5. The remote controller 6 transmits, for example, an infrared signal or a wireless signal other than an infrared signal to the control circuit 5.

[0042] [advantage] The advantages of the lighting device 100 according to the embodiment will be described below. FIG. 4 is an explanatory diagram of a first result of comparing the lighting device 100 according to the embodiment with a lighting device of a comparative example. FIG. 4(a) shows the frequency characteristic of the interference voltage in the lighting device of the comparative example. The lighting device of the comparative example here differs from the lighting device 100 according to the embodiment in that the operating frequency of the converter circuit 3 exceeds 50 kHz near the peak of the input current of the converter circuit 3. FIG. 4(b) shows the frequency characteristic of the interference voltage in the lighting device 100 according to the embodiment. In both FIG. 4(a) and FIG. 4(b), the vertical axis represents the interference voltage (unit: dB (μV / m)) and the horizontal axis represents the logarithm of the frequency (unit: MHz).

[0043] The solid lines in Figures 4(a) and 4(b) show the waveforms of the peak value of the disturbance voltage at the power terminals when the output voltage of the external power source 7 (i.e., the input voltage of the lighting device) is 100V and the lighting device is in operation. The dashed lines B1 in Figures 4(a) and 4(b) show the permissible value of the quasi-peak disturbance voltage in the CISPRJ 15 standard, which complies with the "Limits and methods of measurement of radio disturbance characteristics of electric lighting and similar equipment" of the International Special Committee on Radio Interference (CISPR). The dashed and dotted lines B2 in Figures 4(a) and 4(b) show the permissible value of the average value of the disturbance voltage in the CISPRJ 15 standard.

[0044] Specifically, in the CISPRJ 15 standard, the permissible values ​​for the quasi-peak value of the disturbance voltage are 110 dB (μV) for 9 kHz to 50 kHz, 92 to 102 dB (μV) for 50 kHz to 150 kHz, 68 to 78 dB (μV) for 150 kHz to 0.5 MHz, 56 dB (μV) for 0.5 MHz to 5 MHz, and 60 dB (μV) for 5 MHz to 30 MHz. Also, in the CISPRJ 15 standard, the permissible values ​​for the average value of the disturbance voltage are 58 to 68 dB (μV) for 150 kHz to 0.5 MHz, 46 dB (μV) for 0.5 MHz to 5 MHz, and 50 dB (μV) for 5 MHz to 30 MHz.

[0045] As shown in Fig. 4(a), in the lighting device of the comparative example, the peak value of the interference voltage shows a maximum value at a frequency of 50 kHz, and the peak value exceeds the allowable value of the quasi-peak value of the interference voltage in the CISPRJ 15 standard. In other words, in the lighting device of the comparative example, the interference voltage does not meet the CISPRJ 15 standard.

[0046] On the other hand, as shown in Fig. 4(b), in the lighting device 100 according to the embodiment, the peak value of the disturbance voltage shows a maximum value at frequencies below 50 kHz, and at a frequency of 50 kHz, the peak value is below the allowable value of the quasi-peak disturbance voltage in the CISPRJ 15 standard. In other words, in the lighting device 100 according to the embodiment, the disturbance voltage meets the CISPRJ 15 standard.

[0047] In the first result, as shown in Figure 4, the peak value of the interference voltage is compared with the allowable value of the quasi-peak value of the interference voltage in the CISPRJ 15 standard, but the quasi-peak value is lower than the peak value. Therefore, if the peak value of the interference voltage is lower than the allowable value of the quasi-peak value of the interference voltage in the CISPRJ 15 standard, the peak value of the interference voltage will naturally be lower than the allowable value of the peak value of the interference voltage in the CISPRJ 15 standard. The same is true for the second result shown in Figure 5, which will be described later.

[0048] As described above, in the lighting device 100 according to the embodiment, the operating frequency of the converter circuit 3 is set to less than 50 kHz near the peak of the input current of the converter circuit 3, thereby shifting the frequency at which the peak value of the interference voltage shows a maximum value to a frequency band less than 50 kHz. Therefore, in the lighting device 100 according to the embodiment, it is possible to reduce the interference voltage at a frequency of 50 kHz (i.e., a specific frequency band) without providing a choke coil for normal mode in the filter circuit 1. In other words, the lighting device 100 according to the embodiment has the advantage of being able to reduce the interference voltage in a specific frequency band while suppressing an increase in the size and cost of the device.

[0049] FIG. 5 is an explanatory diagram of a second result comparing the lighting device 100 according to the embodiment with a lighting device of a comparative example. (a) of FIG. 5 shows the frequency characteristics of the interference wave voltage in the lighting device of the comparative example. The lighting device of the comparative example here differs from the lighting device 100 according to the embodiment in that the cutoff frequency of the normal mode filter F1 exceeds the operating frequency of the converter circuit 3. (b) of FIG. 5 shows the frequency characteristics of the interference wave voltage in the lighting device 100 according to the embodiment. Note that the lighting device 100 here differs from the lighting device 100 in the first result in that the operating frequency of the converter circuit 3 exceeds 50 kHz near the peak of the input current of the converter circuit 3.

[0050] The solid lines in Figures 5(a) and 5(b) represent the waveforms of the peak value of the interference voltage at the power supply terminals during operation of the lighting device when the output voltage of the external power supply 7 (i.e., the input voltage of the lighting device) is 100V. The dashed lines B3 in Figures 5(a) and 5(b) represent the permissible value of the quasi-peak value of the interference voltage in the CISPRJ 15 standard. The dashed lines B4 in Figures 5(a) and 5(b) represent the permissible value of the average value of the interference voltage in the CISPRJ 15 standard.

[0051] As shown in Fig. 5(a), in the lighting device of the comparative example, the peak value of the interference voltage shows a maximum value at a frequency of 50 kHz, and the peak value exceeds the allowable value of the quasi-peak value of the interference voltage in the CISPRJ 15 standard. In other words, in the lighting device of the comparative example, the interference voltage does not meet the CISPRJ 15 standard.

[0052] 5(b), in the lighting device 100 according to the embodiment, the peak value of the disturbance voltage shows a maximum value at a frequency of 50 kHz, but the peak value is below the allowable value of the quasi-peak value of the disturbance voltage in the CISPRJ 15 standard. In other words, in the lighting device 100 according to the embodiment, the disturbance voltage meets the CISPRJ 15 standard.

[0053] As described above, in the lighting device 100 according to the embodiment, the cutoff frequency of the normal mode filter F1 is set lower than the operating frequency of the converter circuit 3, particularly the cutoff frequency is set to less than 20 kHz, thereby reducing the maximum peak value of the interference voltage. Therefore, in the lighting device 100 according to the embodiment, it is possible to reduce the interference voltage at a frequency of 50 kHz (i.e., a specific frequency band) without providing a choke coil for normal mode in the filter circuit 1. That is, the lighting device 100 according to the embodiment has the advantage of being able to reduce the interference voltage in a specific frequency band while suppressing an increase in size and cost of the device.

[0054] Here, it is possible to satisfy the CISPRJ 15 standard simply by setting the operating frequency of the converter circuit 3 to less than 50 kHz near the peak of the input current of the converter circuit 3. However, it is preferable to further set the cutoff frequency of the normal mode filter F1 to less than 20 kHz, since this makes it possible to more reliably satisfy the CISPRJ 15 standard.

[0055] (Modification) Although the embodiment has been described above, the present invention is not limited to the above embodiment. Modifications of the embodiment will be listed below. The modifications described below may be combined as appropriate.

[0056] In the embodiment, the output voltage of the external power source 7 (i.e., the input voltage of the lighting device) is 100V, but is not limited to this. For example, the output voltage of the external power source 7 may exceed 100V. That is, when the input voltage is 100V, the peak value of the interference voltage is the largest, so if the CISPRJ 15 standard is satisfied when the input voltage is 100V, the CISPRJ 15 standard will also be satisfied when the input voltage exceeds 100V.

[0057] In the embodiment, the first capacitor 12 is provided in the upstream of the choke coil 11, but this is not limited thereto. For example, the first capacitor 12 may be connected between the pair of electric wires L1 in the downstream of the choke coil 11, that is, between the choke coil 11 and the rectifier circuit 2.

[0058] In the embodiment, the lighting device 100 includes the rectifier circuit 2, but is not limited to this. For example, the lighting device 100 does not need to include the rectifier circuit 2. In this case, the converter circuit 3 may be configured as an AC-DC converter circuit that converts an AC voltage input from an external power source 7 via a filter circuit 1 into a DC voltage and outputs the DC voltage.

[0059] In the embodiment, the lighting device 100 includes the control circuit 5 and the remote controller 6, but is not limited to this. For example, the control circuit 5 and the remote controller 6 do not have to be included as components of the lighting device 100.

[0060] In the embodiment, the light emitting element 81 is a light emitting diode element, but is not limited thereto. For example, the light emitting element 81 may be an organic EL (Electro Luminescence) element or the like. Also, in the embodiment, the light source 8 is configured by connecting a plurality of light emitting elements 81 in series, but is not limited thereto. For example, the light source 8 may be configured by connecting a plurality of light emitting elements 81 in parallel, or may be configured by connecting a plurality of sets of two or more light emitting elements 81 connected in series in parallel. Of course, the light source 8 may be configured by only one light emitting element 81.

[0061] (summary) As described above, the lighting device 100 includes the filter circuit 1, the converter circuit 3, and the constant current circuit 4. The filter circuit 1 suppresses noise transmitted from the lighting device 100 to the external power supply 7. The converter circuit 3 converts the input voltage input from the external power supply 7 via the filter circuit 1 into a DC voltage and outputs it. The constant current circuit 4 maintains a constant current supplied from the converter circuit 3 to the light source 8 including one or more light emitting elements 81. The operating frequency of the converter circuit 3 is less than 50 kHz when the phase of the input current to the converter circuit 3 is at least 45 degrees or more and 135 degrees or less, and 225 degrees or more and 315 degrees or less.

[0062] According to such lighting device 100, by shifting the frequency at which the peak value of the interference voltage shows a maximum value to outside the specific frequency band, it is possible to reduce the interference voltage in the specific frequency band without providing a normal mode choke coil in the filter circuit 1. In other words, such lighting device 100 has the advantage of being able to reduce the interference voltage in the specific frequency band while suppressing the increase in size and cost of the device.

[0063] In addition, for example, in the lighting device 100, the filter circuit 1 includes a normal mode filter F1. The cutoff frequency of the normal mode filter F1 is lower than the operating frequency of the converter circuit 3.

[0064] According to such lighting device 100, by reducing the maximum peak value of the interference voltage, it is possible to reduce the interference voltage in a specific frequency band without providing a normal mode choke coil in the filter circuit 1. That is, such lighting device 100 has the advantage that it is possible to reduce the interference voltage in a specific frequency band while suppressing an increase in the size and cost of the device.

[0065] Also, for example, in the lighting device 100, the filter circuit 1 has a choke coil 11, a first capacitor 12, and a second capacitor 13. The filter circuit 1 has a first inductance in a normal mode and a second inductance in a common mode. The first capacitor 12 is connected between a pair of electric wires L1 that connect the external power supply 7 and the converter circuit 3. The second capacitor 13 is connected between at least one of the pair of electric wires L1 and the circuit ground.

[0066] Such a lighting device 100 has the advantage that it is possible to reduce interference voltage in a specific frequency band while suppressing increases in size and cost of the device.

[0067] For example, the lighting device 100 further includes a rectifier circuit 2. The rectifier circuit 2 has a diode bridge 21 and a rectifier capacitor 22, and rectifies an AC voltage output from an external power supply 7, and outputs the rectified voltage as an input voltage. The converter circuit 3 is a DC-DC conversion circuit that converts the rectified voltage into a DC voltage and outputs it.

[0068] Such a lighting device 100 has the advantage that it is possible to reduce interference voltage in a specific frequency band while suppressing increases in size and cost of the device.

[0069] For example, the lighting device 100 further includes a rectifier circuit 2. The rectifier circuit 2 has a diode bridge 21 and a rectifier capacitor 22, and rectifies an AC voltage output from an external power supply 7, and outputs the rectified voltage as an input voltage. The converter circuit 3 is a DC-DC conversion circuit that converts the rectified voltage into a DC voltage and outputs the DC voltage. The normal mode filter F1 includes a first inductance and the rectifier capacitor 22. The cutoff frequency of the normal mode filter F1 is less than 20 kHz.

[0070] Such a lighting device 100 has the advantage that it is possible to reduce interference voltage in a specific frequency band while suppressing increases in size and cost of the device.

[0071] Also, for example, in the lighting device 100, the operating frequency of the converter circuit 3 is 20 kHz or higher.

[0072] Such a lighting device 100 has the advantage that the operating sound of the converter circuit 3 is less likely to be perceived as noise by the user.

[0073] For example, a lighting fixture 200 includes the above-mentioned lighting device 100, a light source 8, and a fixture body 20. The light source 8 is turned on by a current supplied from the lighting device 100. The fixture body 20 holds the lighting device 100 and the light source 8.

[0074] Such lighting fixture 200 has the advantage of being able to reduce interference voltage in a specific frequency band while preventing an increase in size and cost of the device. [Explanation of symbols]

[0075] 1. Filter circuit 11 Choke coil 12 First Capacitor 13 Second Capacitor 2 Rectifier circuit 20. Equipment body 21 Diode Bridge 22 Rectifier capacitor 3 Converter circuit 4 Constant current circuit 7 External power supply 8 light source 81 Light emitting element 100 Lighting Device 200 Lighting fixtures F1 Normal Mode Filter L1 wire

Claims

1. a filter circuit for suppressing noise transmitted from the lighting device to an external power supply; a converter circuit that converts an input voltage input from the external power supply through the filter circuit into a DC voltage and outputs the DC voltage; a constant current circuit that maintains a constant current supplied from the converter circuit to a light source including one or more light emitting elements; The operating frequency of the converter circuit is less than 50 kHz when the phase of the input current of the converter circuit is at least 45 degrees or more and 135 degrees or less, and at least 225 degrees or more and 315 degrees or less; the filter circuit includes a choke coil having a first inductance in normal mode and a second inductance in common mode, a first capacitor connected between a pair of electric wires connecting the external power supply and the converter circuit, and a second capacitor connected between at least one of the pair of electric wires and a circuit ground, and does not include a choke coil for normal mode; Lighting device.

2. the filter circuit includes a normal mode filter, a cutoff frequency of the normal mode filter is less than the operating frequency of the converter circuit; The lighting device according to claim 1 .

3. a rectifier circuit having a diode bridge and a rectifier capacitor, rectifying the AC voltage output from the external power supply and outputting the rectified voltage as the input voltage; The converter circuit is a DC-DC conversion circuit that converts the rectified voltage into the DC voltage and outputs the DC voltage. The lighting device according to claim 1 or 2.

4. a rectifier circuit having a diode bridge and a rectifier capacitor, rectifying the AC voltage output from the external power supply and outputting the rectified voltage as the input voltage; the converter circuit is a DC-DC conversion circuit that converts the rectified voltage into the DC voltage and outputs the DC voltage, the normal mode filter includes the first inductor and the rectifier capacitor, The cutoff frequency of the normal mode filter is less than 20 kHz. The lighting device according to claim 2.

5. The operating frequency of the converter circuit is 20 kHz or more. The lighting device according to any one of claims 1 to 4.

6. A lighting device according to any one of claims 1 to 5, the light source that is lit by the current supplied from the lighting device; and a fixture body for holding the lighting device and the light source. Lighting fixtures.

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