JP2009195033A - Power supply device and lighting fitting - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power supply device and a lighting fitting, which realize a countermeasure against a harmonic current component and a countermeasure against an excess voltage. <P>SOLUTION: In the power supply device, energy discharged through secondary winding 23b of a switching transformer 23 by turning on/off of a switching transistor 24 is converted into a DC output by a rectifier smoothing circuit 27, and light emitting diodes 28 to 31 are lighted by the DC output. A smoothing capacitor 13 with a small capacity and an excess voltage absorbing means 17 having a capacitor 15 with a large capacity are arranged in an output terminal of a full-wave rectifying circuit 12 rectifying AC power of an AC power supply 11. The smoothing capacitor 13 with a small capacity satisfies a harmonic current specification on a harmonic current component included in the output of the full-wave rectifying circuit 12, and the capacitor 15 with a large capacity absorbs an excess voltage of lightning surge invading from the AC power supply 11. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a power supply device and a lighting fixture that are optimal for driving a semiconductor light emitting element such as a light emitting diode.

  Recently, as a power source for a semiconductor light emitting element such as a light emitting diode, a DC power source device using a switching means is often used.

As this type of power supply device, as disclosed in Patent Document 1, a low-frequency alternating current such as a commercial power supply is full-wave rectified by a full-wave rectifier circuit and smoothed by a smoothing capacitor to be converted to direct current. Some output is supplied to a switching element or a load. In this case, the smoothing capacitor is set to a capacity that satisfies the harmonic current standard for the higher-order current component included in the DC output, that is, the harmonic current component.
JP 2001-313423 A

  By the way, in such a power supply device, when a lightning surge occurs on the AC power supply side, the overvoltage (surge voltage) of this lightning surge enters the device through the full-wave rectifier circuit and damages circuit elements such as switching elements. May end up. For this reason, conventionally, it has been considered that a smoothing capacitor has a function of absorbing overvoltage surge energy to protect circuit elements from lightning surges.

  However, it is necessary to use a smoothing capacitor having a relatively small capacity in order to satisfy the harmonic current standard. However, a capacitor having a small capacity cannot absorb a large amount of surge energy and cannot protect circuit elements. Therefore, if the capacity of the smoothing capacitor is increased to ensure absorption of overvoltage, the harmonic current standard cannot be satisfied for the harmonic current component.

  In this way, if the smoothing capacitor has the function of absorbing surge energy, the circuit element cannot be protected against overvoltage by taking measures to satisfy the harmonic current standard, and conversely, When protective measures are taken, the problem of not satisfying the harmonic current standard arises.

  On the other hand, there is a lighting fixture using a semiconductor light emitting element as a light source, in which an LED module is configured by a plurality of light emitting diodes (LEDs) which are semiconductor light emitting elements, and the LED module can be connected to a power supply device. However, in such a power supply device, for example, when the LED module is disconnected from the power supply device in order to replace the LED module, the power supply device is in an unloaded state while being energized, and outputs a voltage higher than the rated voltage of the light emitting diode. For this reason, when the LED module is connected to the power supply device from this state, an overcurrent (transient current) flows into the LED module, and the overcurrent may damage the light emitting diode or the like.

  This invention is made | formed in view of the said situation, and it aims at providing the power supply device and lighting fixture which can also implement | achieve the protection countermeasure with respect to an overvoltage with the countermeasure with respect to a harmonic current component.

  The invention according to claim 1 is set to a rectifying means for rectifying alternating current power and converting it into direct current; smoothing the output of the rectifying means connected to the rectifying means and setting a capacity corresponding to a predetermined harmonic current component. A smoothing capacitor; an overvoltage absorbing means connected to the output side of the rectifying means and absorbing an overvoltage entering through the rectifying means; and driven by a switching means to generate a DC output from the output of the smoothing capacitor; DC output generating means for lighting the semiconductor light emitting element.

  According to a second aspect of the present invention, in the first aspect of the invention, the overvoltage absorbing means is a current passing circuit that passes a one-way current on the output side of the rectifying means; and is charged via the current passing circuit. A charging circuit for absorbing the overvoltage; and a discharging circuit connected to the charging circuit and constantly discharging the charging charge of the charging circuit.

  According to a third aspect of the present invention, there is provided a lighting fixture comprising the power source device according to the first or second aspect and a fixture main body having the power source device.

  According to the first aspect of the present invention, it is possible to provide a power supply apparatus that can realize a countermeasure against overvoltage as well as a countermeasure against harmonic current components.

  According to the second aspect of the present invention, since a charging circuit composed of a capacitor having a large capacity for absorbing overvoltage is connected to the output side of the rectifying means regardless of whether or not overvoltage is generated, it is immediately possible when lightning surge overvoltage occurs. Therefore, reliable overvoltage protection becomes possible.

  According to the third aspect of the present invention, it is possible to provide a luminaire that can satisfy the harmonic current standard and can realize a protective measure against overvoltage.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
First, the lighting fixture to which the power supply device of the present invention is applied will be briefly described. 1 and 2, reference numeral 1 denotes an instrument body, and the instrument body 1 is made of aluminum die-casting and has a cylindrical shape with both ends opened. The appliance body 1 is internally divided into three in the vertical direction by partition members 1 a and 1 b, and a space between the lower opening and the partition member 1 a is formed in the light source unit 2. The light source unit 2 is provided with a plurality of LEDs 2a and reflectors 2b as semiconductor light emitting elements. The plurality of LEDs 2a are arranged and mounted at equal intervals along the circumferential direction of a disk-shaped wiring board 2c provided on the lower surface of the partition member 1a.

  A space between the partition members 1 a and 1 b of the instrument body 1 is formed in the power supply chamber 3. In the power supply chamber 3, a wiring board 3a is disposed on the partition member 1a. The wiring board 3a is provided with each electronic component constituting the power supply device of the present invention for driving the plurality of LEDs 2a. The DC power supply device and the plurality of LEDs 2 a are connected by lead wires 4.

  A space between the partition plate 1 b of the instrument body 1 and the upper opening is formed in the power supply terminal chamber 5. In the power terminal room 5, a power terminal block 6 is provided on the partition plate 1b. This power supply terminal block 6 is a terminal block for supplying AC power of commercial power to the power supply device in the power supply chamber 3, and serves as a power cable terminal portion on both sides of the box 6a made of electrically insulating synthetic resin. It has an insertion port 6b, an insertion port 6c serving as a feed cable terminal, a release button 6d for separating the power line and the feed line, and the like.

  FIG. 3 shows a schematic configuration of the power supply device of the present invention incorporated in the power supply chamber 3 of the lighting fixture configured as described above.

  In FIG. 3, 11 is an AC power source, and this AC power source 11 is a commercial power source (not shown). The AC power supply 11 is connected to an input terminal of a full-wave rectifier circuit 12 as a rectifier. The full wave rectification circuit 12 generates a direct current obtained by full wave rectification of the AC power from the AC power supply 11.

  A smoothing capacitor 13 and overvoltage absorbing means 17 are connected in parallel between the positive and negative output terminals of the full-wave rectifier circuit 12. The smoothing capacitor 13 smoothes the output of the full-wave rectifier circuit 12. Here, the smoothing capacitor 13 has a capacity corresponding to a higher-order current component included in the DC output, that is, a harmonic current component, and a harmonic current standard ( The one having a small capacity that satisfies IEC61000-2-3 (effective power 25 W or less) is used. The overvoltage absorbing means 17 includes a diode 14 having the polarity shown in the figure, which forms a current passing circuit that passes current in one direction on the output side of the full-wave rectifier circuit 12, a series circuit of a capacitor 15 that forms a charging circuit, and a capacitor 15 It consists of an impedance element, here a resistor 16, constituting a discharge circuit connected in parallel. Capacitor 15 is charged via diode 14 and absorbs overvoltage of lightning surge that enters from AC power supply 11 via full-wave rectifier circuit 12. Here, a capacitor having a large capacity capable of absorbing overvoltage surge energy is used. The resistor 16 always discharges the charge charged in the capacitor 15.

  A series circuit of a primary winding 23a of a switching transformer 23, which is a flyback transformer, and a switching transistor 24 as a switching means is connected to both ends of the smoothing capacitor 13. The switching transformer 23 has a secondary winding 13b that is magnetically coupled to the primary winding 23a.

  A snubber circuit 22 including a parallel circuit of a capacitor 19 and a resistor 20 and a series-parallel circuit of a diode 21 having the polarity shown in the figure is connected to both ends of the primary winding 23a of the switching transformer 23. This snubber circuit 22 absorbs the flyback voltage generated in the primary winding 23 a of the switching transformer 23 by charging by the capacitor 19 and discharging of the resistor 20, and absorbs the ringing voltage generated by the leakage inductance of the switching transformer 23 by the capacitor 19. To do.

  The secondary winding 23b of the switching transformer 23 is connected to a rectifying / smoothing circuit 27 including a diode 25 and a smoothing capacitor 26 having polarities as shown in FIG. The rectifying / smoothing circuit 27 constitutes a DC output generating means together with the switching transistor 24 and the switching transformer 23, rectifies the AC output generated from the secondary winding 23b of the switching transformer 23 by the diode 25, and converts the rectified output into a smoothing capacitor. 26 is smoothed and generated as a DC output.

  The light-emitting diodes 28 to 31 (four in the illustrated example) that are semiconductor light-emitting elements connected in series as loads are equivalent to the LEDs 2 a described in FIG. 2 at both ends of the smoothing capacitor 26 of the rectifying and smoothing circuit 27. ) Is connected.

  The current detector 32 is connected in series to the series circuit of the light emitting diodes 21 to 31. The current detector 32 detects the current flowing through the light emitting diodes 21 to 31 and outputs a detection signal corresponding to the detected current.

  A control circuit 33 is connected to the current detection unit 32 as control means. The control circuit 33 is driven by a power supply unit (not shown), and the switching transistor 24 is switched on and off by its operation to drive the switching transformer 23. In this case, the control circuit 33 compares the detection signal of the current detection unit 32 with a reference value (not shown), controls the on / off operation of the switching transistor 24 based on the comparison result, and the current flowing through the light emitting diodes 28 to 31. Is controlled to be constant.

  A dimming operation unit 34 is connected to the control circuit 33 as dimming means. The dimming operation unit 34 inputs a dimming signal for adjusting the light amount of the light emitting diodes 28 to 31 to the control circuit 33. The control circuit 33 changes the reference value in accordance with the dimming signal from the dimming operation unit 34, and turns on / off the switching transistor 24 based on the changed reference value, whereby the light amounts of the light emitting diodes 28 to 31 are changed. Can be adjusted within a range of 0 to 100% of the rating, for example.

  Next, the operation of the embodiment configured as described above will be described.

  Now, when AC power from the AC power supply 11 is applied to the full-wave rectifier circuit 12, the full-wave rectifier circuit 12 performs full-wave rectification, and the switching transformer 23 and the switching transistor 24 via the smoothing capacitor 13 and the overvoltage absorbing means 17. To be supplied.

  In this case, the smoothing capacitor 13 has a small capacity and smoothes the output including the high-order current component of the full-wave rectifier circuit 12 to convert the DC output satisfying the harmonic current standard to the switching transformer 23 and the switching transistor. 24. In this case, in the overvoltage absorbing means 17, the capacitor 15 is charged via the diode 14 by the output of the smoothing capacitor 13. The electric charge charged in the capacitor 15 is always discharged through the resistor 16.

  In this state, the switching transformer 23 is driven to be switched by turning on and off the switching transistor 24 by the control circuit 33. In this case, when the switching transistor 24 is turned on, current is passed through the primary winding 23a of the switching transformer 23 to store energy, and when the switching transistor 24 is turned off, energy stored in the primary winding 23a is discharged through the secondary winding 23b. To do. As a result, a direct current output is generated via the rectifying and smoothing circuit 27, and the light emitting diodes 28 to 31 are turned on by the direct current output.

  The current flowing through the light emitting diodes 28 to 31 is detected by the current detector 32, and a detection signal corresponding to the detected current is output to the control circuit 33. The control circuit 33 controls the on / off operation of the switching transistor 24 based on the comparison result between the detection signal from the current detection unit 32 and a reference value (not shown), and controls the current flowing through the light emitting diodes 28 to 31 to be constant.

  From this state, when a lightning surge enters the AC power supply 11, an overvoltage is applied to the capacitor 15 via the diode 14 of the overvoltage absorbing means 17. In this case, since the capacitor 15 having a large capacity is used, the overvoltage surge energy is absorbed by the capacitor 15. Thereby, it is possible to suppress the overvoltage of the lightning surge from affecting the circuit elements such as the switching transistor 24, and it is possible to reliably protect these circuit elements from the lightning surge.

  Therefore, if this is done, the energy released through the secondary winding 23b of the switching transformer 23 when the switching transistor 24 is turned on / off is converted into a DC output by the rectifying / smoothing circuit 27, and the light emitting diodes 28 to 31 are converted by this DC output. A power supply device that is lit, and has a smoothing capacitor 13 having a small capacity at an output terminal of a full-wave rectifier circuit 12 that rectifies the AC power of the AC power supply 11, and a capacitor 15 having a large capacity that can absorb surge energy of overvoltage. Overvoltage absorbing means 17 having a large capacity are provided, the harmonic current component included in the output of the full-wave rectifier circuit 12 is satisfied by the smoothing capacitor 13 having a small capacity, and the AC power supply 11 is formed by the capacitor 15 having a large capacity. More intrusion overvoltage was absorbed. As a result, the output including the higher-order current component of the full-wave rectifier circuit 12 is smoothed by the smoothing capacitor 13 having a small capacity, and an output satisfying the harmonic current standard can be supplied to the switching transistor 24 side. . Further, by absorbing the overvoltage of the lightning surge in the capacitor 15, it is possible to suppress the influence of the overvoltage on circuit elements such as the switching transistor 24, and it is possible to reliably protect these circuit elements from the lightning surge.

  Further, the overvoltage absorbing means 17 is connected to the output side of the full-wave rectifier circuit 12 regardless of whether or not an overvoltage is generated, and is always charged with the capacitor 15 for absorbing the overvoltage. An immediate response can be made and reliable overvoltage protection becomes possible. In other words, compared to the configuration that operates only when an overvoltage occurs, the operation timing may differ from the setting for the device that operates only when this overvoltage occurs, due to variations in the constituent elements. If it is a structure, the consideration with respect to the dispersion | variation in an element can also be reduced and reliable overvoltage protection is realizable. Furthermore, the overvoltage absorbing means 17 is composed of a diode 14, a capacitor 15, and a resistor 16, and has a small number of parts. Therefore, even if it is incorporated in a power supply device, the circuit configuration of the entire device is not complicated, and the power supply device It can be kept inexpensive.

(Second Embodiment)
FIG. 4 shows a schematic configuration of a power supply device according to the second embodiment of the present invention. The same parts as those in FIG.

  In this case, the overvoltage absorbing means 36 connected in parallel to the smoothing capacitor 13 has a series circuit of a Zener diode 37 and a capacitor 39 connected to both ends of the smoothing capacitor 13 and a resistor 38 connected in parallel to the capacitor 39. Yes. The Zener diode 37 has a Zener voltage set so as to respond to an overvoltage of a lightning surge. A base of a transistor 40 that is a switching element is connected to a connection point between the Zener diode 37 and the capacitor 39. The transistor 40 has a collector connected to a connection point of the Zener diode 37 and the smoothing capacitor 13 via a parallel circuit of a capacitor 41 constituting a charging circuit and a resistor 42 constituting a discharging circuit, and an emitter being a capacitor 39 and a smoothing capacitor. It is connected to 13 connection points. When the Zener diode 37 is turned on due to overvoltage, the transistor 40 is turned on by a current flowing through the Zener diode 37. The capacitor 41 absorbs an overvoltage applied when the transistor 40 is turned on, and a capacitor having a large capacity capable of absorbing overvoltage surge energy is used here.

  Others are the same as FIG.

  In such an overvoltage absorbing means 36, when a lightning surge enters the AC power supply 11, the Zener diode 37 responds to the overvoltage of the lightning surge. When the Zener diode 37 is turned on, the transistor 40 is turned on by a current flowing from the Zener diode 37 to the capacitor 39, and an overvoltage is applied to the capacitor 41. In this case, since the capacitor 41 having a large capacity is used, the overvoltage is absorbed by the capacitor 41.

  Therefore, even if it does in this way, it can suppress that the overvoltage of a lightning surge influences circuit elements, such as the switching transistor 24, and can protect these circuit elements from a lightning surge reliably.

(Modification)
FIG. 5 shows a modification of the overvoltage absorbing means applied to the second embodiment.

  In this case, in the overvoltage absorbing means 43, a series circuit of a Zener diode 44 and a capacitor 46 is connected to both ends of the smoothing capacitor 13, and a resistor 49 constituting a discharging circuit is connected in parallel to the capacitor 46 constituting the charging circuit. ing. The Zener diode 44 has a Zener voltage set so as to respond to an overvoltage of a lightning surge. A gate of a thyristor 47 serving as a switching element is connected to a connection point between the Zener diode 44 and the capacitor 46. In the thyristor 47, the connection point of the Zener diode 44 and the smoothing capacitor 13 is connected to the anode through a parallel circuit of the capacitor 48 and the resistor 49, and the connection point of the capacitor 46 and the smoothing capacitor 13 is connected to the cathode. When the Zener diode 44 is turned on due to an overvoltage, the thyristor 47 is turned on with a gate pulse. The capacitor 48 absorbs overvoltage applied when the thyristor 47 is turned on, and a capacitor having a large capacity capable of absorbing overvoltage surge energy is used here.

  Even when such an overvoltage absorbing means 43 is used, when a lightning surge enters the AC power supply 11, the Zener diode 44 responds to the lightning surge overvoltage. When the zener diode 44 is turned on, a gate pulse is applied to the thyristor 47 by the current flowing from the zener diode 44 to the capacitor 46, and the overvoltage is applied to the capacitor 48. In this case, since the capacitor 48 having a large capacity is used, the overvoltage is absorbed by the capacitor 48.

  Therefore, even if it does in this way, it can suppress that the overvoltage of a lightning surge influences circuit elements, such as the switching transistor 24, and can protect these circuit elements from a lightning surge reliably.

(Third embodiment)
FIG. 6 shows a schematic configuration of a power supply apparatus according to the third embodiment of the present invention. The same parts as those in FIG.

  In this case, the overvoltage absorbing means 51 has a MOSFET 52 connected as a semiconductor element at both ends of the smoothing capacitor 13. The MOSFET 52 has an avalanche resistance (surge resistance) with a built-in Zener diode (not shown). When an overvoltage is applied, the Zener diode operates and absorbs surge energy of the overvoltage by the avalanche resistance.

  Others are the same as FIG.

  In such an overvoltage absorbing unit 51, when a lightning surge enters the AC power supply 11, the overvoltage is applied to the MOSFET 52 of the overvoltage absorbing unit 51. In this case, the MOSFET 52 absorbs the overvoltage due to the avalanche resistance due to the Zener diode.

  Therefore, since the surge energy of the lightning surge overvoltage can be absorbed by the MOSFET 52, the surge energy reaching the circuit elements such as the switching transistor 24 can be significantly suppressed, and these circuit elements are reliably protected from the lightning surge. be able to.

(Fourth embodiment)
In the fourth embodiment, overcurrent to the LED module can be suppressed.

  FIG. 7 shows a schematic configuration of the fourth embodiment of the present invention. The same parts as those in FIG.

  In this case, an output terminal 54 is connected to one end of the smoothing capacitor 26 of the rectifying and smoothing circuit 27, and an output terminal 55 is connected to the other end via the current detection unit 32. An LED module 56 can be connected to the output terminals 54 and 55 via input terminals 57 and 58. In the LED module 56, an overcurrent suppressing unit 59 and a plurality (four in the illustrated example) of light emitting diodes 64 to 67 connected in series are connected in series between input terminals 57 and 58. ing. In the overcurrent suppressing means 59, a series circuit of a resistor 62 and a capacitor 63 is connected between the input terminal 57 and the light emitting diodes 64 to 67, and the base of the transistor 60 as a switching element is connected to the connection point of the resistor 62 and the capacitor 63. Is connected. The transistor 60 has a collector connected to the input terminal 57 and an emitter connected to a connection point between the capacitor 63 and the light emitting diode 64 via a resistor 61. The capacitor 63 charges the overcurrent flowing from the power supply side via the resistor 62. The transistor 60 turns on when the potential at the connection point between the resistor 62 and the capacitor 63 reaches a predetermined value, and supplies the output of the rectifying and smoothing circuit 27 to the light emitting diodes 64 to 67 via the resistor 61.

  Others are the same as FIG.

  In such a configuration, for example, in order to replace the LED module 56, the LED module 56 is disconnected from the output terminals 54 and 55 on the power supply side, and then another LED module 56 is connected to the output terminals 54 and 55. .

  In this case, when the LED module 56 is disconnected from the output terminals 54 and 55, the power supply device remains in an energized state and is in a no-load state, so that a voltage higher than the rated voltage of the light emitting diodes 64 to 67 is output to the output terminals 54 and 55. Is done.

  If a new LED module 56 is connected to the output terminals 54 and 55 in this state, an overcurrent flows into the LED module 56. This overcurrent is input to the capacitor 63 via the resistor 62 of the overcurrent suppressing means 59 and is charged by the capacitor 63. Thereafter, when the potential at the connection point between the resistor 62 and the capacitor 63 reaches a predetermined value due to this charging, the transistor 60 is turned on. Thereafter, the output of the rectifying and smoothing circuit 27 is supplied to the light emitting diodes 64 to 67 through the resistor 61. The light emitting diodes 64 to 67 are turned on.

  As a result, even if an overcurrent flows into the LED module 56, the overcurrent is absorbed by the charging of the capacitor 63, so that the overcurrent to the light emitting diodes 64 to 67 is suppressed. 64-67 can be reliably protected from overcurrent.

(Modification)
FIG. 8 shows a schematic configuration of a modification of the fourth embodiment.

  In this case, an output terminal 73 is connected to one end of the smoothing capacitor 26 of the rectifying and smoothing circuit 27 via an overcurrent suppressing means 68, and an output terminal 74 is connected to the other end via the current detection unit 32. Light emitting diodes 78 to 81 are connected to the output terminals 73 and 74 via input terminals 76 and 77 of the LED module 75. In the overcurrent suppressing means 68, a series circuit of a resistor 71 and a capacitor 72 is connected between one end of the smoothing capacitor 26 and the output terminal 73, and a connection point of the resistor 71 and the capacitor 72 is connected to a transistor 69 that is a switching element. The base is connected. The transistor 69 has a collector connected to one end of the smoothing capacitor 26 and an emitter connected to the output terminal 73 via a resistor 70.

  Even in this case, when an overcurrent is generated and flows into the overcurrent suppressing means 68, the overcurrent is input to the capacitor 72 through the resistor 71 and charged by the capacitor 72. Thereafter, when the potential at the connection point of the resistor 71 and the capacitor 72 reaches a predetermined value due to this charging, the transistor 69 is turned on. Thereafter, the output of the rectifying and smoothing circuit 27 is supplied to the light emitting diodes 78 to 81 via the resistor 70. Then, the light emitting diodes 78 to 81 are turned on.

  Therefore, even if an overcurrent flows through the LED module 75 in this way, the overcurrent is absorbed by the charging of the capacitor 72. Therefore, the overcurrent to the light emitting diodes 64 to 67 is suppressed, and the light emission. The diodes 64 to 67 can be reliably protected from overcurrent.

  In addition, this invention is not limited to the said embodiment, In the implementation stage, it can change variously in the range which does not change the summary. For example, in the above-described embodiment, the capacitance corresponding to the harmonic current component of the smoothing capacitor 13 is a capacitance that satisfies the harmonic current standard. However, the capacitance is not limited to this and is not limited to this. Any point may be set as long as it can cope with the wave current component. In the above-described embodiment, the constant current control for controlling the current flowing through the light emitting diodes 24 to 27 to be always constant has been described. However, the present invention is not limited to this, and the voltage applied to the light emitting diode is always constant. The constant voltage control to be controlled may be applied. Further, in the above-described embodiment, the example of the light emitting diode is described as the semiconductor light emitting element, but the present invention can be applied to the case where another semiconductor light emitting element such as a laser diode is used. Furthermore, in the above-described embodiment, the cause of the overvoltage has been described in the case of the lightning surge. However, the case where the overvoltage occurs due to another cause can also be applied. Further, the overcurrent is not limited to the case where it is connected to the power supply device of the LED module, but can be applied to the case where the overcurrent occurs due to other causes.

  Furthermore, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. For example, even if some constituent requirements are deleted from all the constituent requirements shown in the embodiment, the problem described in the column of the problem to be solved by the invention can be solved, and is described in the column of the effect of the invention. If the above effect is obtained, a configuration from which this configuration requirement is deleted can be extracted as an invention.

The perspective view which shows the lighting fixture with which the power supply device concerning the 1st Embodiment of this invention is applied. Sectional drawing of the lighting fixture to which the power supply device concerning 1st Embodiment is applied. The figure which shows schematic structure of the power supply device concerning 1st Embodiment. The figure which shows schematic structure of the power supply device concerning the 2nd Embodiment of this invention. The figure which shows schematic structure of the modification of 2nd Embodiment. The figure which shows schematic structure of the power supply device concerning the 3rd Embodiment of this invention. The figure which shows schematic structure of the 4th Embodiment of this invention. The figure which shows schematic structure of the modification of the 4th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Instrument body, 2 ... Light source part, 2a ... LED
3 ... Power supply room, 5 ... Power supply terminal room 11 ... AC power supply, 12 ... Full wave rectification circuit
13: capacitor, 17, 36, 43 ... overvoltage absorbing means,
23 ... Switching transformer, 24 ... Switching transistor,
27. Rectification smoothing circuit,
28-31, 64-67, 78-81 ... light emitting diode,
32 ... Current detection unit, 33 ... Control circuit,
59, 68 ... Overcurrent suppressing means

Claims (3)

Rectifying means for rectifying AC power and converting it to DC;
A smoothing capacitor connected to the rectifying means and smoothing the output of the rectifying means and set to a capacity corresponding to a predetermined harmonic current component;
An overvoltage absorbing means connected to the output side of the rectifying means and absorbing an overvoltage entering through the rectifying means;
DC output generating means driven by switching means, generating DC output from the output of the smoothing capacitor, and lighting the semiconductor light emitting element;
A power supply device comprising: The overvoltage absorbing means includes a current passing circuit for passing a unidirectional current on the output side of the rectifying means; a charging circuit for absorbing the overvoltage charged through the current passing circuit; The power supply apparatus according to claim 1, further comprising a discharge circuit that is connected and discharges the charge of the charging circuit at all times. 3. A lighting fixture comprising: the power supply device according to claim 1; and an appliance main body having the power supply device.

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