JPH05182778A - Discharge lamp lighting device and luminaire employing same device - Google Patents

Abstract

PURPOSE:To provide a discharge lamp lighting device and a luminaire employing the lighting device which prevents the occurrence of disorders where elements constituting an inverter are damaged owing to the unstable operation of a self exciting type inverter affected by a halfwave discharge phenomenon which takes place at the life end of the discharge lamp. CONSTITUTION:Connection with the primary coil 8a of a current transformer 8, a ballast inductor 9, a direct current disconnecting capacitor 10 and the series circuit of a discharge lamp 11, is made between the output terminals of a self exciting type inverter 3 which converts direct current voltage into high frequencies, a starting capacitor 14 is concurrently connected to the discharge lamp 11 in series, and the secondary coil 8b of the current transformer 8 is connected to the base of the output transistor 7 of the self exciting type inverter 3, so that the discharge lamp 11 is lighted by the high frequency output out of the self exciting type inverter 3. In this case, a bypass capacitor 17 for discharging high voltage which is charged to a direct current disconnecting capacitor 10 by a halfwave discharge phenomenon taking place at the life end of the discharge lamp 11, is connected to both the primary coil 8a of the current transformer 8 and the series circuit of the ballast inductor 9 in parallel.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge lamp lighting device for lighting a discharge lamp by a self-excited inverter using a current transformer and a lighting fixture using the discharge lamp lighting device. The present invention relates to an inverter that is prevented from malfunctioning due to a half-wave discharge phenomenon.

[0002]

2. Description of the Related Art As a discharge lamp lighting device using a self-excited inverter, for example, one shown in FIG. 6 is known. In this figure, the output of the rectifier circuit 2 that converts the commercial AC power supply 1 into a DC power supply and extracts it is input to a self-excited inverter 3 and converted into a high frequency by the self-excited inverter 3. The self-excited inverter 3 is configured by connecting a parallel resonance circuit 6 of a capacitor 4 and an inductor 5 to a switching output transistor 7 in series. A diode 16 is connected in parallel with the transistor 7. The connection point between the parallel resonance circuit 6 which is the output terminal on one side of the self-excited inverter 3 and the output transistor 7 is connected through a series circuit of the primary winding 8a of the current transformer 8, the ballast inductor 9 and the DC cut capacitor 10. The discharge lamp 11 is connected to one end, and the other end of the discharge lamp 11 is connected to the inverter 3
Is connected to the output terminal on the other side. Also, filament capacitors 12 and 13 are connected between both ends of the filaments 11a and 11b of the discharge lamp 11, respectively, and a starting capacitor 14 is connected between the non-power source side terminals of both filaments 11a and 11b. One end of the secondary winding 8b of the current transformer 8 is connected to the base of the output transistor 7 via the capacitor 15, and the other end of the secondary winding 8b is connected to the emitter side. In this discharge lamp lighting device, the output from the secondary side of the current transformer 8 is input to the base of the output transistor 7 as a control signal for switching, so that the output transistor 7 is self-excited to repeatedly turn on and off to cause parallel resonance. The DC voltage is converted into a high frequency by the inverter 3 including the circuit 6. This high-frequency output is supplied to the discharge lamp 11 via the ballast inductor 9 and the DC cut capacitor 10, so that the load of the discharge lamp 11 is lit at high frequency.

[0003]

By the way, in such a discharge lamp lighting device, when the discharge lamp 11 reaches the end of its life, it is in a half-wave discharge state, and is rectified in the direction from the filament 11a to the filament 11b. The cutting capacitor 10 is charged with electric charges with a polarity as shown in FIG. When the voltage across the capacitor increases due to this charging, the discharge lamp 11 to which this high voltage is applied is dielectrically destroyed,
The charge charged in the capacitor 10 is discharged in the direction opposite to the half-wave discharge through the ballast inductor 9, the primary winding 8a of the current transformer 8 and the discharge lamp 11. If such a discharge current flows through the primary winding 8a of the current transformer 8, the ON time of the output transistor 7 to which the output of the secondary winding is input becomes long, and excessive energy is accumulated in the parallel resonant circuit 6. Then, a high voltage is applied from the resonance circuit 6 to the next oscillation cycle of the output transistor 7,
Can be destroyed. Further, conventionally, when the lamp voltage applied to both ends of the discharge lamp 11 is detected, it is necessary to separately provide a lamp voltage detection circuit, which causes a problem that the configuration of the lighting device is complicated.

The present invention has been proposed to solve the problems of the prior art, and the operation of the self-excited inverter becomes unstable due to the half-wave discharge phenomenon occurring at the end of the life of the discharge lamp. It is an object of the present invention to provide a discharge lamp lighting device capable of preventing a failure such as destruction of an element forming an inverter and detecting a lamp voltage with a simple structure, and a lighting fixture using the discharge lamp lighting device. ..

[0005]

In order to achieve this object, the present invention provides a primary winding of a current transformer, a ballast inductor, a DC cutting capacitor between output terminals of a self-excited inverter for converting a DC voltage into a high frequency. And a series circuit of a discharge lamp, a starting capacitor is connected in parallel to this discharge lamp, and the secondary winding of the current transformer is connected to the control terminal of the switching element of the self-excited inverter. In a discharge lamp lighting device that lights a discharge lamp by high frequency output from an inverter,
A bypass capacitor for discharging the high voltage charged in the DC cut capacitor due to the half-wave discharge phenomenon at the end of the life of the discharge lamp is connected in parallel with the series circuit of the primary winding of the current transformer and the ballast inductor. It is configured to be connected.

Further, in the discharge lamp lighting device of the present invention, the bypass capacitor for discharging the high voltage charged in the DC cut capacitor due to the half-wave discharge phenomenon at the end of the life of the discharge lamp is used for the DC cut. It is connected in parallel to the series circuit of the condenser and the discharge lamp.

Further, the discharge lamp lighting device of the present invention includes the first bypass capacitor and the second bypass capacitor for discharging the high voltage charged in the DC cut capacitor due to the half-wave discharge phenomenon at the end of the life of the discharge lamp. Connecting the series circuit of the bypass capacitor of the above in parallel with the series circuit of the DC cutting capacitor and the discharge lamp, and
The lamp voltage of the discharge lamp is detected from the connection point of the bypass capacitor.

Further, in the lighting equipment according to the present invention, the discharge lamp lighting device having these configurations is built in the equipment main body, and the load of the discharge lamp mounted on the equipment main body is turned on by the output of the discharge lamp lighting device. ing.

[0009]

According to the structure corresponding to claim 1 described above, since the bypass capacitor is connected in parallel to the primary winding of the current transformer and the ballast inductor, the DC cut capacitor is charged at the end of the life of the discharge lamp. The generated high voltage can be discharged through the bypass capacitor without passing through the primary winding of the current transformer.

According to the structure according to claim 2, since the bypass capacitor is connected in parallel to the direct current cut capacitor and the discharge lamp, the high voltage charged in the direct current cut capacitor at the end of the life of the discharge lamp. The voltage can be discharged through this bypass capacitor without passing through the primary winding of the current transformer.

According to the third aspect of the invention, the series circuit of the direct current cut capacitor and the first and second bypass capacitors connected in parallel to the discharge lamp allows the discharge lamp to reach the end of its life. The high voltage charged in the DC cut capacitor can be discharged without passing through the primary winding of the current transformer, and the lamp voltage of the discharge lamp can be taken out from the connection point of the first and second bypass capacitors. You can

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of a discharge lamp lighting device according to the present invention and a lighting fixture using the lighting device will be described in detail below with reference to the drawings. An embodiment of this discharge lamp lighting device is shown in the block diagram of FIG. The same parts as those in the conventional example are designated by the same reference numerals, and the description of the overlapping parts will be partially omitted. In this figure, the output of the rectifier circuit 2 that rectifies and smoothes the commercial AC power supply 1 is supplied to the self-excited inverter 3,
The DC voltage is converted into a high frequency by the self-excited inverter 3. A series circuit of a primary winding 8a of a current transformer 8, a ballast inductor 9, a DC cut capacitor 10 and a discharge lamp 11 is connected to both ends of the output terminal of the self-excited inverter 3, and the discharge lamp 11 is started in parallel. Capacitor 14 is connected. The secondary winding 8b of the current transformer 8 is connected to the base of the output transistor 7, which is a switching element of the self-excited inverter 3. A bypass capacitor 17 is connected in parallel to the series circuit of the primary winding 8 a of the current transformer 8 and the ballast inductor 9.

In the discharge lamp lighting device having such a configuration, the bypass capacitor 17 is provided in parallel with the primary winding 8a of the current transformer 8 and the ballast inductor 9, so that the life of the discharge lamp 11 is at the end of its life. The DC high voltage charged in the DC cut capacitor 10 due to the half-wave discharge phenomenon is discharged through the bypass capacitor 17. Therefore, the discharge current that sometimes flows in the opposite direction due to the charging voltage of the capacitor 10 during half-wave discharge does not flow through the primary winding 8a of the current transformer 8, and the operation of the inverter 3 can be stabilized.

Next, a discharge lamp lighting device of another embodiment shown in FIG. 2 will be described. In this embodiment, a bypass capacitor 18 is connected in parallel to a discharge lamp 11 and a DC cut capacitor 10 connected in series to the discharge lamp 11, and the DC cut capacitor 10, the bypass capacitor 18 and the discharge capacitor 18 are connected. The primary winding 8a of the current transformer 8 is prevented from entering the loop of the electric lamp 11. The bypass capacitor 18 is the starting capacitor 14
An extremely small capacity can be used as compared with the above.

In this configuration, the reverse discharge current due to the high voltage charged in the DC cut capacitor 10 due to the half-wave discharge phenomenon at the end of the life of the discharge lamp 11 is discharged through the bypass capacitor 18. Since the current does not flow in the primary winding 8a of the current transformer 8, the inverter 3
It is possible to solve the problem that the inverter operation becomes unstable due to changes in the drive conditions of.

Next, a discharge lamp lighting device of another embodiment shown in FIG. 3 will be described. In this embodiment, the series circuit of the first and second bypass capacitors 19 and 20 is connected in parallel to the series circuit of the DC cut capacitor 10 and the discharge lamp 11. In order to detect the lamp voltage from the connection point of the bypass capacitors 19 and 20, the rectifying diode 2 having the connection point side as the cathode is used.
1 is connected in parallel to the second bypass capacitor 20, and this connection point is connected to the output terminal 24 by the rectifying diode 22. Also, this output terminal 24
A smoothing capacitor 23 is connected between the ground and the ground.

In this structure, the high voltage charged in the DC cut capacitor 10 during the half-wave discharge is the first and second high voltage.
Since it is discharged through the series circuit of the bypass capacitors 19 and 20 and does not flow to the primary winding 8a of the current transformer 8, the operation of the inverter 3 can be stabilized. Further, from the connection point of the capacitors 19 and 20, a divided voltage for the AC component of the series circuit of the DC cutting capacitor 10 and the discharge lamp 11 connected to the load side can be taken out. The output terminal 2 is rectified by 22 and smoothed by the capacitor 23.
From 4, a detection voltage proportional to the lamp voltage is obtained.

Next, a discharge lamp lighting device of another embodiment shown in FIG. 4 will be described. In this embodiment, the present invention is applied to a self-excited half-bridge inverter.
In this figure, in a self-excited half-bridge inverter 25 to which DC power is supplied from the rectifier circuit 2, output transistors 26 and 27 of switching elements are connected in series, and diodes 28 and 29 are connected in parallel to the respective transistors 27 and 28. It is connected. A primary winding 30a of the current transformer 30, a ballast inductor 9, a starting capacitor 10 and a series circuit of a discharge lamp 11 are connected between the output terminals of the self-exciting half-bridge inverter 25, and a secondary winding 30b of the current transformer 30 is connected. , 30c are connected to the bases of the output transistors 26, 27, respectively. Further, a bypass capacitor 31 for bypassing and discharging the high voltage charged in the DC cut capacitor 10 at the time of half-wave discharge is provided at the connection point between the ballast inductor 9 and the DC cut capacitor 10 and the collector side of the output transistor 26. It is connected.

According to this configuration, even when the capacitor 10 is charged with a high voltage at the end of the life of the discharge lamp 11 and a discharge current flows in the direction opposite to the half-wave discharge direction, the discharge current is the current transformer 30. Since it does not flow through the primary winding 30a but flows through the bypass capacitor 31, the operation of the inverter 25 can be stabilized.

Although only one example applied to the self-excited half-bridge inverter is shown in FIG. 4, each of the present invention can be applied to the self-excited half-bridge inverter.

Next, a lighting fixture using the above-described discharge lamp lighting device of each embodiment will be described with reference to FIG. In this figure, a discharge lamp lighting device U composed of the above-mentioned self-excited inverter is provided in the fixture body 33 attached to the ceiling 32.
A discharge lamp 1 in which a connection cable extending from the discharge lamp lighting device U is a fluorescent lamp via a socket.
Connected to 1. In the figure, 34 is a reflector, and 35 is a louver.

[0022]

As described above, according to the present invention, the DC cut capacitor is charged with a high voltage by the half-wave discharge phenomenon that occurs at the end of the life of the discharge lamp, and the discharge current in the opposite direction to the half-wave discharge is generated. Even if the current flows, this discharge current can flow through the bypass capacitor, so that the discharge current at this time does not flow in the primary winding of the current transformer. As a result, it is possible to prevent a problem in which a discharge current flows in the primary winding of the current transformer, drive conditions change, the operation of the inverter becomes unstable, and the switching element is destroyed. The reliability of the lighting fixture using this discharge lamp lighting device can be improved. Also, since the lamp voltage at both ends of the discharge lamp can be taken out from the connection point of the DC cut capacitor and the bypass capacitor connected in parallel to the discharge lamp, there is no need to provide a separate lamp voltage detection circuit as in the conventional case, The structure of the lighting device can be simplified, and the size of the lighting fixture can be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a discharge lamp lighting device according to the present invention.

FIG. 2 is a block diagram showing a discharge lamp lighting device according to another embodiment.

FIG. 3 is a block diagram showing a discharge lamp lighting device of still another embodiment.

FIG. 4 is a block diagram showing a discharge lamp lighting device of still another embodiment.

FIG. 5 is a schematic configuration diagram of a lighting fixture using the discharge lamp lighting device according to the present invention.

FIG. 6 is a block diagram showing a conventional discharge lamp lighting device.

[Explanation of symbols]

 U Discharge lamp lighting device 1 Commercial AC power supply 2 Rectifier circuit 3,25 Self-excited inverter 6 Parallel resonance circuit 7, 26, 27 Output transistor 8, 30 Current transformer 8a, 30a Current transformer primary winding 9 Ballast inductor 10 For DC cut Capacitor 11 Discharge lamp 14 Starting capacitor 12,13 Filament capacitor 17,18,19,20 Bypass capacitor 21,22 Rectifying diode 23 Smoothing capacitor 33 Instrument body 35 Louver

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[Procedure amendment]

[Submission date] November 26, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Title of invention

[Correction method] Change

[Correction content]

Discharge lamp lighting device and lighting fixture using this lighting device

Claims (4)

[Claims] 1. A primary winding of a current transformer between output terminals of a self-excited inverter for converting a DC voltage into a high frequency,
Connect a series circuit of a ballast inductor, a DC cut capacitor and a discharge lamp, and connect a starting capacitor in parallel to this discharge lamp, and connect the secondary winding of the current transformer to the control terminal of the switching element of the self-excited inverter. In the discharge lamp lighting device, which is connected to the inverter to light the discharge lamp by the high-frequency output from the self-excited inverter, the high voltage charged in the DC cut capacitor is discharged by the half-wave discharge phenomenon at the end of the life of the discharge lamp. A discharge lamp lighting device characterized in that a bypass capacitor for performing the above operation is connected in parallel to a series circuit of the primary winding of the current transformer and a ballast inductor. 2. A primary winding of a current transformer between output terminals of a self-excited inverter for converting a DC voltage into a high frequency,
Connect a series circuit of a ballast inductor, a DC cut capacitor and a discharge lamp, and connect a starting capacitor in parallel with this discharge lamp, and connect the secondary winding of the current transformer to the control terminal of the switching element of the self-excited inverter. In the discharge lamp lighting device that is connected to the above, and lights the discharge lamp by the high frequency output from this self-excited inverter, the high voltage charged in the DC cut capacitor is discharged by the half-wave discharge phenomenon at the end of the life of the discharge lamp. A discharge lamp lighting device characterized in that a bypass capacitor for performing the above operation is connected in parallel to a series circuit of the DC cut capacitor and the discharge lamp. 3. A primary winding of a current transformer between output terminals of a self-excited inverter for converting a DC voltage into a high frequency,
Connect a series circuit of a ballast inductor, a DC cut capacitor and a discharge lamp, and connect a starting capacitor in parallel to this discharge lamp, and connect the secondary winding of the current transformer to the control terminal of the switching element of the self-excited inverter. In the discharge lamp lighting device, which is connected to the inverter to light the discharge lamp by the high-frequency output from the self-excited inverter, the high voltage charged in the DC cut capacitor is discharged by the half-wave discharge phenomenon at the end of the life of the discharge lamp. For connecting a series circuit of a first bypass capacitor and a second bypass capacitor for parallel connection to the series circuit of the DC cut capacitor and a discharge lamp, and A discharge lamp lighting device characterized by detecting a lamp voltage of a discharge lamp from a connection point. 4. A discharge lamp lighting device according to claim 1, 2 or 3 is built in a fixture body, and a load of a discharge lamp mounted on the fixture body is lit by the output of the discharge lamp lighting device. A lighting fixture using a discharge lamp lighting device.