JP2005310755A - Discharge lamp lighting device and luminaire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a discharge lamp lighting device and a luminaire with the discharge lamp lighting device applied for discharge lamps of a plurality of different kinds of rated power whereby output voltage of a DC power supply circuit and capacitance of a capacitor of a resonance circuit are not restricted in circuit design, a problem such as excess preheating or lack of preheating does not occur even when the discharge lamps of the plurality of different kinds of rated power are used, and a number of parts used for preheating is not increased. <P>SOLUTION: An inverter circuit 10 is connected to the DC power supply circuit 4, a series circuit of a second inductor 15 for ballast and a capacitor 16 for resonance is connected to MOS type FET 12 of the inverter circuit in parallel, and the discharge lamp 17 is connected to the capacitor for resonance in parallel and a resonance circuit is formed. A pair of preheating coils 18a and 18b are additionally provided on a secondary side of the second inductor 15, the one preheating coil 18a is connected to one filament 17a of the discharge lamp, the other preheating coil 18b is connected to the other filament 17b of the discharge lamp, and a preheating circuit is formed. An oscillation frequency of the inverter circuit is set to be near a resonance frequency of the resonance circuit under no load. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a discharge lamp lighting device capable of lighting a plurality of types of discharge lamps having different rated lamp powers, and an illumination device including the discharge lamp lighting device.

Conventionally, this type of discharge lamp lighting device includes an inverter circuit provided with a pair of switching elements that are connected in series between output terminals of a DC power supply circuit and alternately turned on and off at a high frequency, and each of the switching elements. A resonance circuit including at least one inductor, a capacitor, and a discharge lamp is connected in parallel to one side, and the capacitor of the resonance circuit is connected in parallel with the discharge lamp via the filament of the discharge lamp, and the discharge lamp is started and lit. For a discharge lamp comprising a plurality of types of fluorescent lamps having different rated powers, in which a preheating current is supplied from the inverter circuit to the filament of the discharge lamp during a predetermined preheating time until a predetermined total luminous flux is obtained. During steady lighting, regardless of the type of discharge lamp, the inverter circuit is operated at the first frequency set near the resonance frequency when no load is applied to the resonance circuit. Is, those with any value in the range of 320V~440V regardless of the type of discharge lamp output voltage is used for the DC power supply circuit is known (e.g., Patent Document 1, etc.).
Further, a series circuit of a preheating transformer and a capacitor is connected in parallel to a midpoint of the modified half-bridge type inverter circuit, that is, one switching element of a pair of switching elements connected in series via a DC cut capacitor, It is known that a preheating transformer includes two preheating windings as secondary windings, and each preheating winding preheats a filament of a discharge lamp (for example, Patent Document 2).
JP 2002-117996 A JP 2003-168484 A

However, since the preheating current flows through the capacitor of the resonance circuit in the device described in Patent Document 1, the amount of preheating current is determined by the lamp voltage, the operating frequency of the inverter circuit, and the capacity of the resonance capacitor. Therefore, in order not to deteriorate the life of the discharge lamp, there is a restriction that the preheating current must be made appropriate.
In addition, when a lamp with a lamp voltage more than doubled is installed, the current flowing through the filament doubles in proportion to the lamp voltage, and when the preheat amount is designed for the lamp with the lowest lamp voltage, the lamp voltage For lamps with a high lamp voltage, the preheating current is approximately doubled, resulting in a short lamp life and unnecessary power loss due to excessive preheating, and when the preheating amount is designed for a lamp with a high lamp voltage, There was a problem of low preheating with low lamps.

As described above, in the capacitor preheating method, when applied to a plurality of types of discharge lamps having different rated powers, there are certain restrictions on the output voltage VDC of the DC power supply circuit and the capacitor capacity of the resonance circuit, and the discharge lamp is lit. Since the amount of preheating current flowing through the lamp directly depends on the lamp voltage, there has been a problem of excessive preheating and insufficient preheating.
Moreover, the thing of patent document 2 will use a special preheating transformer and a capacitor | condenser in order to form a preheating circuit, and there existed a problem which the number of parts to use increases and a structure becomes complicated.

  The present invention is applied to a plurality of types of discharge lamps having different rated powers, and there is no restriction on the output voltage of the DC power supply circuit and the capacity of the capacitor of the resonant circuit in designing the circuit. There are no problems such as excessive preheating or insufficient preheating even if different types of discharge lamps are used, and there is no increase in the number of parts used for preheating, and the discharge lamp lighting Provided is a lighting device including the device.

  The invention according to claim 1 flows in a DC power supply circuit, an inverter circuit having one or more switching elements connected to the DC power supply circuit, and an inductor, a discharge lamp, and a filament of the discharge lamp connected to the switching elements. A preheat winding is magnetically coupled to the secondary side of the inductor and a resonance circuit including a capacitor provided without current passing through the inductor, and the preheat current is supplied to the filament by connecting the preheat winding to the filament of the discharge lamp. When a discharge lamp with a different rated power is lit, the inverter circuit is operated at the same lighting frequency as the resonance frequency when the resonance circuit is under no load so that the lamp current flowing through the discharge lamp is substantially constant. And a discharge lamp lighting device comprising a control means.

  In this apparatus, since the current flowing through the capacitor of the resonance circuit does not flow through the filament of the discharge lamp, there is no restriction on the output voltage of the DC power supply circuit or the capacitance of the capacitor of the resonance circuit in designing the circuit. In addition, the voltage generated in the inductor of the resonant circuit is small compared to the change in lamp voltage even when a discharge lamp with a different rated power is used, so the lamp voltage changes when a discharge lamp with a different rated power is used. However, the effect on the preheating current can be reduced as compared with the capacitor preheating method, and there is no possibility that problems such as excessive preheating and insufficient preheating will occur.

  The invention according to claim 2 further preheats when comparing the ratio of the highest lamp voltage to the lowest lamp voltage among the discharge lamp groups having different rated powers and the ratio of the respective preheating current amounts. The discharge lamp lighting device is configured such that the ratio of the current amount is small.

  The invention described in claim 3 further includes detection means for directly or indirectly detecting the lamp current flowing through the discharge lamp, and the lamp current flowing through the discharge lamp when the discharge lamp having a different rated power is lit. The discharge lamp lighting device includes control means for operating the inverter circuit according to the detection output of the detection means so as to be constant.

According to a fourth aspect of the present invention, the discharge lamp lighting device according to any one of the first to third aspects further includes a current control means for reducing or cutting off a current flowing through the preheating circuit after the discharge lamp is turned on. Stuff.
A fifth aspect of the present invention is an illuminating apparatus comprising the discharge lamp lighting device according to any one of the first to fourth aspects and a lighting fixture incorporating the discharge lamp lighting device.

  According to the first to fourth aspects of the present invention, when applied to a plurality of types of discharge lamps having different rated powers, restrictions are imposed on the output voltage of the DC power supply circuit and the capacitance of the capacitor of the resonance circuit in designing the circuit. In addition, using multiple types of discharge lamps with different rated powers does not cause problems such as excessive preheating or insufficient preheating. It is possible to provide a discharge lamp lighting device in which no loss occurs and the number of parts used for preheating does not increase.

  According to the fourth aspect of the present invention, the influence of the change in the lamp voltage on the preheating current can be almost eliminated, and the discharge lamp lighting that can reliably prevent the wasteful preheating current from flowing through the filament when the discharge lamp is turned on. Equipment can be provided.

  According to the invention described in claim 5, when applied to a plurality of types of discharge lamps having different rated powers, there is no restriction on the output voltage of the DC power supply circuit and the capacity of the capacitor of the resonance circuit in designing the circuit. In addition, even if multiple types of discharge lamps with different rated power are used, there will be no problems such as preheating or insufficient preheating, and the number of parts used for preheating will not increase. A lighting device using the device can be provided.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
First, an embodiment in which the oscillation frequency of the inverter circuit is fixed in the vicinity of the resonance frequency at the time of no load of the resonance circuit will be described.

(First embodiment)
As shown in FIG. 1, an input terminal of a full-wave rectifier 2 composed of a diode bridge is connected to an AC power source 1, and a capacitor 3 is connected in parallel to the output terminal of the full-wave rectifier 2.

  Further, a DC power supply circuit 4 composed of a boost chopper circuit is connected to the output terminal of the full-wave rectifier 2. The DC power supply circuit 4 connects a first MOS FET (field effect transistor) 6 as a switching element in parallel to the output terminal of the full-wave rectifier 2 via a first inductor 5 for chopper. A smoothing capacitor 8 is connected in parallel to one MOS type FET 6 through a diode 7 in forward polarity, and the pulsating voltage output from the full-wave rectifier 2 is converted to a desired DC voltage. The first MOS type FET 6 is subjected to switching control by a chopper control unit 9.

  An inverter circuit 10 is connected to the output terminal of the DC power supply circuit 4, that is, the smoothing capacitor 8. The inverter circuit 10 includes second and third MOS type FETs 11 and 12 as a pair of switching elements, and a series circuit of the MOS type FETs 11 and 12 is connected in parallel to the smoothing capacitor 8. The MOS type FETs 11 and 12 are alternately controlled to be turned on / off by a high frequency of a constant frequency by an inverter control unit 13 constituting a control means.

  A series circuit of a DC cut capacitor 14, a ballast second inductor 15 and a resonance capacitor 16 is connected in parallel to the third MOS type FET 12 of the inverter circuit 10 and is released to the resonance capacitor 16. One end of the filaments 17a and 17b of the lamp 17 is connected in parallel to form a resonance circuit.

A pair of preheating windings 18a and 18b are provided on the secondary side of the second inductor 15, one preheating winding 18a is connected to one filament 17a of the discharge lamp 17, and the other preheating winding 18 is connected. 18b is connected to the other filament 17b of the discharge lamp 17 to form a preheating circuit.
The frequency at which the inverter control unit 13 performs on / off control of each of the MOSFETs 11 and 12 is set in the vicinity of the resonance frequency of the resonance circuit when there is no load.

  In such a configuration, when the AC power supply 1 is turned on, a pulsating voltage is output from the full-wave rectifier 2 and supplied to the DC power supply circuit 4. In the DC power supply circuit 4, the first MOS type FET 6 is switching-controlled by the chopper controller 9, energy is stored in the first inductor 5 when the FET 6 is on, and when the stored energy is off of the FET 6. The smoothing capacitor 8 is discharged through the diode 7. In this way, a desired DC voltage is output from the smoothing capacitor 8 and supplied to the inverter circuit 10.

  In the inverter circuit 10, the MOS control FETs 13 and 12 are on / off controlled by the inverter control unit 13 at a frequency in the vicinity of the resonance frequency when there is no load in the resonance circuit. Then, a rectangular high-frequency voltage is generated between both ends of the third MOS type FET 12 and applied to the resonance circuit. As a result, the voltage applied to the second inductor 15 changes and a predetermined voltage is generated in the preheating windings 18a and 18b, whereby a preheating current flows through the filaments 17a and 17b of the discharge lamp 17.

  Before the discharge lamp 17 is lit, a high voltage is applied between the filaments 17a and 17b of the discharge lamp 17 to preheat the filaments 17a and 17b. The discharge lamp 17 is lit by the starting voltage after preheating. And when the discharge lamp 17 starts lighting, the voltage applied between each filament 17a, 17b of the discharge lamp 17 will fall. In this way, a constant rated lamp current flows through the discharge lamp 17, thereby maintaining the lighting. Further, the voltage generated in each preheating winding 18a, 18b is also reduced, and the current flowing through the preheating circuit is kept low.

  In this apparatus, it is possible to use H-type lamps FHT24, FHT32, FHT42, etc., which have the same lamp current but different rated lamp power, as the discharge lamp 17. Even when such discharge lamps with different rated lamp power are used, if the oscillation frequency of the inverter circuit 10 is set to be substantially the same as the resonance frequency vicinity of the resonance circuit when there is no load, the inverter output voltage when there is no load is Since it becomes high, the load curve of the inverter has a substantially constant current characteristic, so that the lamp current can be controlled to be constant.

  When discharge lamps with different rated lamp power are used, the lamp voltage at the time of lighting is different. In the case of the capacitor preheating method, a change in lamp voltage appears as a change in preheating current. However, even if the lamp voltage at the time of lighting changes, the voltage generated in the second inductor 15 does not change in proportion to the change, and the change is small. For this reason, even when a discharge lamp having a different rated lamp power is used, the current flowing through the preheating circuit during lighting is not significantly changed compared to the capacitor preheating method.

For example, when the output voltage Vdc from the DC power supply circuit 4 is 410 V, the inductance of the second inductor 15 is 1.35 mH, the capacitor of the resonance capacitor 16 is 3300 pF, and the lighting frequency is 77 kHz, the lamp current of the FHT24W fluorescent lamp is Is about 285 mA and the lamp voltage is about 70V. In the fluorescent lamp of FHT42W, the lamp current is substantially equal to FHT24W, and the lamp voltage is about 140V. At this time, the voltage generated in the second inductor 15 is about 200V for FHT24W and about 240V for FHT42W. That is, even if the lamp voltage is doubled, the voltage generated in the second inductor 15 increases only about 1/6. In this way, the ratio of the preheating current amount of both can be reduced with respect to the ratio of the lowest voltage and the highest voltage of the rated power at which the lamp current can be controlled substantially constant.
On the other hand, in the capacitor preheating method, since the preheating amount is 2πf × lamp voltage, when the lamp voltage is doubled, the preheating current is also doubled.

  As described above, by generating the preheating current by the voltage generated in the second inductor 15, a large preheating current flows through the filaments 17a and 17b even when the discharge lamp having a small rated lamp power is switched to the discharge lamp having a large rated power. There is nothing. Thereby, the power loss due to the preheating current can be reduced, and the lamp life can be prevented from being shortened due to the excessive lamp current.

Further, since the resonance current of the resonance circuit is not used as the preheating current, the preheating current does not flow into the resonance capacitor 16. Therefore, in designing the circuit, the output voltage from the DC power supply circuit 4 and the capacitance of the resonance capacitor 16 are not restricted, and the circuit design becomes easy.
The second inductor 15 forms a resonance circuit necessary for the device, and is not used exclusively for preheating. Therefore, even if a pair of preheating windings 18a and 18b are added to the secondary side of the second inductor 15, a preheating circuit is constructed using originally necessary parts, and is used for preheating. The number of parts to be increased will not increase. Therefore, the number of parts used does not increase and the configuration is not complicated.

(Second Embodiment)
In addition, the same code | symbol is attached | subjected to the part same as embodiment mentioned above, and detailed description is abbreviate | omitted.
As shown in FIG. 2, a current transformer 21 for detecting a lamp current and a current cutoff circuit 22 are newly provided, and open / close switches 23 and 24 are inserted in the preheating circuit. About others, it is the same as embodiment mentioned above.

  That is, the primary winding of the current transformer 21 is inserted in series in the resonance circuit, and the voltage generated in the secondary winding is supplied to the current cutoff circuit 22. The opening / closing switch 23 is inserted in series in a preheating circuit comprising a preheating winding 18a and one filament 17a of the discharge lamp 17, and a preheating circuit comprising the preheating winding 18b and the other filament 17b of the discharge lamp 17. The opening / closing switch 24 is inserted in series.

  The current interrupt circuit 22 controls opening / closing of the open / close switches 23 and 24. That is, the current flowing through the current transformer 21 is different between preheating and lighting, and the current cutoff circuit 22 controls the open / close switches 23 and 24 based on the amount of change.

  In this configuration, since the open / close switches 23 and 24 are closed until the discharge lamp 17 is turned on after the power is turned on, a preheating current flows through the preheating circuit. When the discharge lamp 17 is turned on and a lamp current flows through the discharge lamp 17, the current transformer 21 detects it, and the current cut-off circuit 22 opens the open / close switches 23 and 24. Thus, the current flowing through the preheating circuit is interrupted while the discharge lamp 17 is lit.

  Therefore, the preheating current can be reliably interrupted during lighting for any of the discharge lamps having different rated lamp powers. In this embodiment as well, there are no restrictions on the output voltage of the DC power supply circuit and the capacity of the capacitor of the resonant circuit in the circuit design, which is applied to a plurality of types of discharge lamps having different rated powers. Even if multiple types of discharge lamps with different electric power are used, there will be no problems such as overheating or underheating, so that overheating will not shorten the lamp life or cause unnecessary power loss. As for the fact that the number of parts used for preheating does not increase, the same effects as those of the first embodiment described above are achieved.

Next, an embodiment in which the oscillation frequency of the inverter circuit is controlled so that the lamp current flowing through the discharge lamp is detected directly or indirectly and the lamp current becomes constant will be described.
(Third embodiment)
In addition, the same code | symbol is attached | subjected to the part same as embodiment mentioned above, and detailed description is abbreviate | omitted.
As shown in FIG. 3, the configuration of the preheating circuit is the same as that of the first embodiment. The primary winding of the current transformer 21 is inserted in series between the other filament 17b of the discharge lamp 17 and the other end of the resonance capacitor 16, and the secondary winding is an input terminal of a full-wave rectifier 25 comprising a diode bridge. Connected to. A resistor 26 and a capacitor 27 are connected in parallel to the output terminal of the full-wave rectifier 25, and a lamp IC detected by the current transformer 21 from the parallel circuit of the resistor 26 and the capacitor 27 is used as a DC voltage value to control IC. The circuit 28 is supplied.

  The control IC circuit 28 alternately controls the high frequency switching of the second and third MOS type FETs 11 and 12 in the inverter circuit 10 and changes the switching frequency according to the voltage value from the parallel circuit of the resistor 26 and the capacitor 27. Thus, the lamp current is controlled to be constant.

  On the other hand, the connection point of the second and third MOS type FETs 11 and 12 in the inverter circuit 10 is connected to the cathode of the diode 32 via the capacitor 31 and to the cathode of the constant voltage diode 34 via the diode 33 in the forward polarity. Connected. The source terminal of the third MOS type FET 12 is connected to the anode of the diode 32 and the anode of the constant voltage diode 34. A smoothing capacitor 35 is connected in parallel to the constant voltage diode 34, and a voltage output across the smoothing capacitor 35 is supplied to the control IC circuit 28 as a power supply voltage.

  In such a configuration, when the discharge lamp 17 is lit, a large lamp current flows through the discharge lamp 17. This lamp current is detected by the current transformer 21 and a voltage is generated in the secondary winding. This voltage is full-wave rectified by the full-wave rectifier 25, and a DC voltage is generated in the parallel circuit of the resistor 26 and the capacitor 27.

  The control IC circuit 28 receives this DC voltage, and controls the switching frequency of the MOS type FETs 11 and 12 of the inverter circuit 10 so that a constant lamp current flows according to the voltage value. Thus, the lamp current can be controlled to be constant by controlling the oscillation frequency of the inverter circuit 10. Accordingly, in this case as well, it is possible to use H-type lamps FHT24, FHT32, FHT42, etc. having the same lamp current and different rated lamp power as the discharge lamp 17.

Note that this device also applies to multiple types of discharge lamps with different rated powers, so that there are no restrictions on the output voltage of the DC power supply circuit and the capacitor capacity of the resonant circuit when designing the circuit. Using different types of discharge lamps will not cause problems such as overheating or underheating, so overheating will not shorten the lamp life, cause unnecessary power loss, and preheating. As a result, the number of parts used for the purpose does not increase, and the same effects as those of the first embodiment described above are achieved.
In this embodiment as well, a current interrupt circuit is provided as shown in FIG. 2, and the current interrupt circuit opens the open / close switch inserted in the preheating circuit to interrupt the current while the discharge lamp is lit. I can.

(Fourth embodiment)
In this embodiment, an illumination device incorporating a discharge lamp lighting device will be described.
As shown in FIG. 4, the discharge lamp lighting device 100 is incorporated in the central back surface portion of the lighting fixture 101, and the discharge lamp 17 is loaded between the sockets 101 a and 101 b provided on the discharge lamp mounting surface of the lighting fixture 101. . The configuration of the discharge lamp lighting device 100 is the configuration of any of the first to third embodiments described above.

  As described above, by incorporating any of the discharge lamp lighting devices described in the above-described embodiments, various discharge lamps having the same lamp current and different rated lamp power can be used. In addition, in designing the circuit, it is possible to realize a lighting device that is not restricted by the output voltage of the DC power supply circuit or the capacitance of the capacitor of the resonance circuit. In addition, using multiple types of discharge lamps with different rated powers does not cause problems such as overheating or insufficient preheating. Therefore, overheating can cause the lamp to have a short life or unnecessary power loss. No lighting device can be realized. Moreover, since the existing inductor is used in the preheating circuit, the number of parts does not increase for preheating.

The circuit block diagram which shows the 1st Embodiment of this invention. The circuit block diagram which shows the 2nd Embodiment of this invention. The circuit block diagram which shows the 3rd Embodiment of this invention. The perspective view which shows the illuminating device incorporating the discharge lamp lighting device which concerns on the 4th Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 2 ... Full wave rectifier, 4 ... DC power supply circuit, 10 ... Inverter circuit, 11, 12 ... MOS type FET, 13 ... Inverter control part, 15 ... 2nd inductor, 16 ... Resonance capacitor, 17 ... Discharge lamp, 17a , 17b ... Filament, 18a, 18b ... Preheating winding.

Claims (5)

DC power supply circuit;
An inverter circuit having one or more switching elements connected to a DC power supply circuit;
A resonant circuit including an inductor, a discharge lamp, and a capacitor provided without passing through a current flowing through the filament of the discharge lamp, connected to the switching element;
A preheating circuit in which a preheating winding is magnetically coupled to the secondary side of the inductor, and the preheating winding is connected to the filament of the discharge lamp, thereby supplying a preheating current to the filament;
Control for operating the inverter circuit at substantially the same lighting frequency as the resonance frequency when no load is applied to the resonance circuit so that the lamp current flowing through the discharge lamp is substantially constant when the discharge lamps having different rated powers are lit. With means;
A discharge lamp lighting device comprising: DC power supply circuit;
An inverter circuit having one or more switching elements connected to a DC power supply circuit;
A resonant circuit including an inductor, a discharge lamp, and a capacitor provided without passing through a current flowing through the filament of the discharge lamp, connected to the switching element;
A preheating circuit in which a preheating winding is magnetically coupled to the secondary side of the inductor, and the preheating winding is connected to the filament of the discharge lamp, thereby supplying a preheating current to the filament;
Control for operating the inverter circuit at substantially the same lighting frequency as the resonance frequency when no load is applied to the resonance circuit so that the lamp current flowing through the discharge lamp is substantially constant when the discharge lamps having different rated powers are lit. With means;
Comprising
When the ratio of the highest lamp voltage to the lowest lamp voltage among the discharge lamp groups having different rated powers is compared with the ratio of the respective preheating current amounts, the ratio of the preheating current amounts is reduced. A discharge lamp lighting device characterized by comprising. DC power supply circuit;
An inverter circuit having one or more switching elements connected to a DC power supply circuit;
A resonant circuit including an inductor, a discharge lamp, and a capacitor provided without passing through a current flowing through the filament of the discharge lamp, connected to the switching element;
A preheating circuit in which a preheating winding is magnetically coupled to the secondary side of the inductor, and the preheating winding is connected to the filament of the discharge lamp, thereby supplying a preheating current to the filament;
Detecting means for directly or indirectly detecting a lamp current flowing through the discharge lamp;
Control means for operating the inverter circuit in accordance with the detection output of the detection means so as to make the lamp current flowing through the discharge lamp substantially constant when the discharge lamps having different rated powers are lit;
A discharge lamp lighting device comprising:   The discharge lamp lighting device according to any one of claims 1 to 3, further comprising a current control means for reducing or cutting off a current flowing through the preheating circuit after the discharge lamp is turned on. apparatus. A discharge lamp lighting device according to any one of claims 1 to 4;
A lighting fixture incorporating the discharge lamp lighting device;
An illumination device comprising:

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