JP2003323993A - Discharge lamp lighting system and lighting fixture - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the size of a current detecting part for driving a main switch and conveniently and quickly detect the breakage of a filament electrode of a discharge lamp. <P>SOLUTION: One end of the discharge lamp is connected to a gland line and an automatic transformer To is connected between the gland line and one end of an output winding T2 of an inverter transformer T to form a load circuit. A load current in the discharge lamp 5 is detected by the automatic transformer To and a current is supplied to a control circuit 4 for driving the main switch Tr. The control circuit 4 controls an off-period for the main switch Tr to be fixed and an on-period to be changed so that high frequency voltage is generated between both ends of the output winding T2 of the inverter transformer T to light the discharge lamp 5 on. <P>COPYRIGHT: (C)2004,JPO

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 and a lighting fixture in which a discharge lamp is lit at a high frequency by a high frequency lighting circuit having a single main switch.

[0002]

2. Description of the Related Art Generally, a discharge lamp lighting device having a high-frequency lighting circuit having a single-stone main switch forms a load circuit in which a discharge lamp is connected to its output side through an insulating inverter transformer. The load current of the load circuit is used to drive the main switch on the input side of the inverter transformer.

FIG. 6 is a circuit diagram of a conventional discharge lamp lighting device 1 of this type. The DC voltage generation circuit 2 is a DC voltage power supply that generates a DC voltage from the commercial AC power supply Vs, and the DC voltage from the DC voltage generation circuit 2 is input to the high frequency lighting circuit 3. The high-frequency lighting circuit 3 is controlled by the control circuit 4 so that the main switch Tr is turned on / off to supply high-frequency power from the primary winding T1 of the inverter transformer T to the secondary winding T2 to light the discharge lamp 5. That is, the load circuit of the discharge lamp is insulated by the inverter transformer T.

A partial smoothing circuit 6 is provided between the DC voltage generating circuit 2 and the high frequency lighting circuit 3, and when the switching element Tr is turned on, a current flows from the positive side of the DC voltage generating circuit 2 to the switching element Tr. Shed. This allows
The input current can be made to flow from the commercial AC power supply Vs even in the valley period when the voltage value of the commercial AC power supply Vs is small, and the input current is approximated to a sine wave.

Then, as a constant voltage source of the control circuit 4, a current flowing through the inverter transformer T is detected by the tertiary winding T3 of the inverter transformer T, and the current is rectified and smoothed to form a control voltage and a detection voltage. The Tr is on / off controlled. Further, the load current of the discharge lamp 5 is detected by the current transformer CT, and the main switch Tr is driven based on the current flowing through the secondary winding CT2.

In order to detect the disconnection of the filament electrode of the discharge lamp 5, power is applied to the filament electrode from the high potential side through a resistor or the like, and a voltage is generated in the disconnection detection unit to detect the disconnection of the filament electrode. I was trying to do it.

[0007]

However, in the conventional discharge lamp lighting device, since the load current on the secondary side of the inverter transformer T is detected by the current transformer CT, the main switch Tr is driven. The current transformer CT for detecting the current for driving the main switch Tr needs to be of an insulating type, and therefore the winding is composed of a primary winding and a secondary winding.
Winding is required, and the size is large to secure the insulation distance.

Further, since the disconnection of the discharge lamp 5 is detected by connecting a resistor from the high potential side, a resistor having high withstand voltage and high power is required. In some cases, a plurality of resistors are required. Was needed. Further, since high resistance is required, it sometimes takes time to rise to a detectable potential.

It is an object of the present invention to provide a discharge lamp lighting device and a lighting device which can miniaturize a current detecting portion for driving a main switch and can easily and quickly detect disconnection of a filament electrode of a discharge lamp. is there.

[0010]

A discharge lamp lighting device according to the invention of claim 1; a direct current voltage power supply; an inverter transformer and a single-stone main switch connected in series between the outputs of the direct current voltage power supply; A high frequency lighting circuit having a resonance capacitor connected in parallel to the inverter transformer and configured to output a high frequency voltage across the output winding of the inverter transformer when the main switch is turned on and off. A load circuit in which the discharge lamp is lit by the high frequency voltage of the high frequency lighting circuit generated across the output winding of the inverter transformer and one end of the discharge lamp is connected to the ground line;
An autotransformer connected between the ground line of the load circuit and one end of an output winding of the inverter transformer to supply a current for driving the main switch by a load current of the discharge lamp; A detection winding provided to detect a resonance current due to the resonance of the inverter transformer and the resonance capacitor; and a control winding for fixing the OFF period of the main switch to change the ON time and generating the detection winding in the OFF period. And a control circuit configured to input a direct-current voltage as a control voltage.

In the present invention and the following inventions, the definitions and technical meanings of terms are as follows unless otherwise specified.

The DC voltage power supply is a DC voltage generation circuit for generating a DC voltage, and includes both a DC voltage generation circuit for directly generating a DC voltage and an AC power supply converted to DC.

The high-frequency lighting circuit converts a DC voltage into a high-frequency voltage, and a resonance capacitor is connected in parallel with the primary winding of the inverter transformer and the primary winding of the inverter transformer forms a resonant circuit. To generate high frequency voltage. In addition, a one-stone main switch is connected in series with the primary winding of the inverter transformer, and the high-frequency voltage generated in the secondary winding that is the output winding of the inverter transformer is controlled by turning the main switch on and off.

A discharge lamp is connected to the secondary winding that is the output winding of the inverter transformer, and one end of the discharge lamp is connected to the ground line, and a load circuit that lights the discharge lamp by the high frequency voltage of the high frequency lighting circuit is connected. I am configuring. An autotransformer is connected between the ground line of the load circuit and one end of the output winding of the inverter transformer, and the autotransformer supplies a current for driving the main switch by the load current of the discharge lamp.

The control circuit controls ON / OFF of the main switch, and controls so that the OFF period of the main switch is fixed and the ON time is changed. A detection winding is provided as a tertiary winding in the inverter transformer, and this detection winding detects the resonance current due to the resonance of the inverter transformer and the resonance capacitor, and controls the DC voltage generated in the detection winding during the off period. It is used as the control voltage and detection voltage of the circuit.

According to the present invention, since the current for driving the main switch is obtained by the single-turn autotransformer,
Winding can be simplified and miniaturized. In addition, the DC voltage generated in the detection winding of the inverter transformer during the OFF period of the main switch is input as the control voltage and the detection voltage of the control circuit, and this DC voltage is almost constant without fluctuation of the lamp voltage of the discharge lamp. Therefore, it is possible to prevent the control circuit from detecting the lamp defect or stopping the operation.

In the discharge lamp lighting device according to a second aspect of the present invention, in the first aspect of the invention, the filament electrode of the discharge lamp connected to the ground line side of the load circuit is broken during ON / OFF control of the main switch. A circuit is sometimes formed, and a filament electrode breakage detection circuit for generating a voltage by a current from the output winding of the inverter transformer is provided.

According to the present invention, in addition to the first aspect of the present invention, a filament electrode breakage detection circuit for detecting the breakage of the filament electrode of the discharge lamp connected to the ground line side of the load circuit is additionally provided.

The filament electrode of the discharge lamp connected to the ground line side has a first resistor and a diode.
If the filament electrode on the ground line side of the discharge lamp is cut or not attached, the second series connection circuit of the second series connection circuit is connected in parallel with the second series connection circuit of the resistor and the detection capacitor. The detection capacitor is charged with the DC component of the current from the output winding of the inverter transformer, and the detection capacitor is charged to detect the potential rise at one end opposite to the ground line side.

According to the present invention, the electric current on the output side which is the secondary winding of the inverter transformer is used to generate a potential in the detection capacitor, and the generated potential is based on the ground line. The electrode breakage detection circuit can be realized with a simple configuration. Further, since a resistor having a relatively small resistance value can be used, it is possible to shorten the time until the potential rises to the detectable potential.

A discharge lamp lighting device according to a third aspect of the present invention is the discharge lamp lighting device according to the first or second aspect, in which the filament electrode of the discharge lamp connected to the high potential side of the load circuit during on / off control of the main switch is A circuit is formed when the wire is broken, and a filament electrode breakage detection circuit that generates a voltage by the current from the output winding of the inverter transformer is provided.

According to the invention of claim 1 or 2, a filament electrode disconnection detection circuit for detecting disconnection of the filament electrode of the discharge lamp connected to the high voltage side of the load circuit is additionally provided.

The filament electrode of the discharge lamp connected to the high-voltage side of the load circuit has a first resistor and a diode.
If the filament electrode on the high-voltage side of the discharge lamp is cut or not attached, the second series connection circuit is connected in parallel with the second series connection circuit of the resistor and the detection capacitor. The detection capacitor is charged with the DC component of the current from the output winding of the inverter transformer, and the potential rise is detected. In this case, since the detection capacitor is not connected to the ground line, the generated potential is different from the reference voltage of the circuit, so the voltage is detected by, for example, a photocoupler.

According to the present invention, the current on the output side, which is the secondary winding of the inverter transformer, is used to generate the potential in the detection capacitor, so that the filament electrode breakage detection for detecting the breakage of the filament electrode on the high voltage side is detected. The circuit can be realized with a simple configuration. Further, since a resistor having a relatively small resistance value can be used, it is possible to shorten the time until the potential rises to the detectable potential.

According to a fourth aspect of the present invention, in the discharge lamp lighting device according to the second or third aspect of the invention, the filament electrode disconnection detection circuit operates during ON / OFF control of the main switch, and then the main switch is turned ON / OFF. When the control is stopped, an external power source for holding the operation of the filament electrode breakage detection circuit is supplied to the filament electrode breakage detection circuit.

According to the invention of claim 2 or 3, the operation of the filament electrode breakage detection circuit is maintained even after the on / off control of the main switch of the high frequency lighting circuit is stopped.

After the high frequency lighting circuit is stopped, the filament electrode breakage detection circuit is supplied with an external power source to keep the operation of the filament electrode breakage detection circuit. The external power supply may be either a DC voltage power supply or an AC voltage power supply.

According to the present invention, the filament breakage can be confirmed even after the high frequency lighting circuit is stopped, so that the maintainability is improved.

A lighting fixture according to a fifth aspect of the present invention comprises: the discharge lamp lighting device according to any one of the first to fourth aspects; and a lighting fixture main body in which the discharge lamp lighting device is provided. It is characterized by doing.

According to the present invention, there is provided a lighting fixture equipped with the discharge lamp lighting device having the operation of any one of the first to fourth aspects of the invention.

[0031]

Embodiments of the present invention will be described below. FIG. 1 is a circuit configuration diagram of a discharge lamp lighting device according to a first embodiment of the present invention. The first embodiment differs from the conventional example shown in FIG. 6 in that instead of the current transformer CT, one end of the discharge lamp 5 in the load circuit is connected to the ground line, and the ground line of the load circuit and the inverter transformer are connected. An auto transformer To is provided between the output winding of T and one end of the output winding, and the auto transformer To detects a load current of the discharge lamp 5 and supplies a current for driving the main switch Tr.

In FIG. 1, the discharge lamp lighting device 1 is
It has a DC voltage generating circuit 2 as a DC voltage source, a high frequency lighting circuit 3, a control circuit 4 and a partial rectification circuit 6, and is configured to light the discharge lamp 5 at a high frequency.

In the DC voltage generating circuit 2, the commercial AC power supply Vs is connected to the input side of the rectifier 7 via the noise filter 8 consisting of the capacitor C1 and the inductor L1, and the power factor improving capacitor C2 is connected to the output side. ing. The negative side of the rectifier 7 is connected to the earth E. The noise filter 8 mainly removes high-frequency components propagating from the output side of the rectifier 7 to the commercial AC power supply Vs side. The rectifier 7 rectifies the AC voltage of the commercial AC power supply Vs. The capacitor C2 acts to reduce the harmonics of the input current and improves the input power factor. Thus, the DC voltage generation circuit 2 generates a DC voltage.

A high frequency lighting circuit 3 and a partial smoothing circuit 6 are connected between the outputs of the DC voltage generating circuit 2. First, the high frequency lighting circuit 3 will be described. A series circuit of a primary winding T1 of an inverter transformer T and a main switch Tr of one stone is connected to both ends of a capacitor C2 of the DC voltage generating circuit 2, and a resonance capacitor C3 is provided in parallel with the primary winding T1 of the inverter transformer T. It is connected. The primary winding T1 of the inverter transformer T and the resonance capacitor C3 form a resonance circuit.

The inverter transformer T has a tertiary winding T3 as a detection winding wound around the primary winding T1. Both ends of the tertiary winding (detection winding) T3 are connected to the control circuit 4 via the diode D1. An electrolytic capacitor C4 is connected to both ends of the tertiary winding T3.

In the tertiary winding T3, the main switch Tr is turned off, and the resonance current due to the resonance between the primary winding T1 of the inverter transformer T and the resonance capacitor C3 is applied to the primary winding T1 from the negative side of the DC voltage generating circuit 2. The polarity is preset so that a current flows in the forward direction of the diode D1 when flowing to the positive electrode side. The current flowing through the tertiary winding T3 is converted into a DC voltage (detection voltage) by the electrolytic capacitor C4 and input to the control circuit 4. A constant voltage is supplied to the control circuit 4 by the DC voltage, and an overvoltage or an undervoltage generated in the primary winding T1 of the inverter transformer T is detected.

A field effect transistor FET is connected between the base (control terminal) and the emitter of the main switch Tr, and the winding (series winding and shunt winding) of the autotransformer To, the capacitor C5 and the diode D2 are connected. The series circuit of is connected. And the auto transformer To
The diode D3 is connected in parallel with the series circuit of the winding and the capacitor C5 with the cathode on the capacitor C5 side. The diode D2 is connected in the forward direction with respect to the base of the main switch Tr so that the base current can be supplied to the base. The gate (control terminal) of the field effect transistor FET is connected to the control circuit 4, and the base of the main switch Tr is connected to the control circuit 4 via the starting resistor R1.

When the discharge lamp lighting device 1 is started up, the control circuit 4 supplies a starting current to the base of the main switch Tr via the resistor R1. As a result, the main switch Tr is turned on. Then, when a current flows through the winding of the autotransformer To so as to be in the forward direction of the diode D2, the main switch T
The base current is supplied to the base of r, and the main switch Tr is turned on. When a current flows in the winding of the autotransformer To in the direction opposite to the diode D2, this current flows in the closed circuit of the winding of the autotransformer To, the diode D3 and the capacitor C5. The capacitor C5 is
This is to match the phase of the current flowing through the winding of the auto transformer To with the phase of the current supplied to the base of the main switch Tr.

The field effect transistor FET is
The main switch T is turned on and off by the control of the control circuit 4.
Short (on) or non-short (off) between the base and emitter of r. Then, the field effect transistor FE
When T is turned on, even if the base current is supplied to the base of the main switch Tr by the winding of the auto transformer To,
The main switch Tr is turned off and the field effect transistor FET
When is turned off, the main switch Tr can be turned on. Here, the control circuit 4 is configured to turn off the field effect transistor FET during a period in which a current is flowing in the winding of the autotransformer To in the direction opposite to the diode D2.

As described above, the control circuit 4 turns on the field effect transistor FET and turns off the main switch Tr when the main switch Tr is turned on by the current flowing through the winding of the autotransformer To. That is, the ON period of the main switch Tr can be changed by the ON / OFF operation of the field effect transistor FET by the control circuit 4.

That is, the control circuit 4 is the high frequency lighting circuit 3
The ON / OFF operation of the main switch Tr is fixed during the OFF period, and is changed by controlling the ON / OFF operation of the field effect transistor FET during the ON period, and the ON period and the OFF period are independently controlled. Then, by changing the ON period, the high frequency lighting circuit 3 can obtain a predetermined output voltage (high frequency voltage).

Further, the control circuit 4 controls the main switch Tr when the input DC voltage is not within a preset predetermined voltage range, that is, when an undervoltage or an overvoltage is generated in the primary winding T1 of the inverter transformer T. It is configured to stop the on / off operation of.

Next, the output of the high frequency lighting circuit 3 is formed between both ends of a secondary winding T2 as an output winding of the inverter transformer T. As shown in FIG. 1, the discharge lamp 5 is connected to both ends of the secondary winding T2 of the inverter transformer T via a series circuit of a DC cutting capacitor C6 and a shunt winding of the autotransformer To. That is,
The pair of filament electrodes 9a and 9b of the discharge lamp 5 are
The power supply side is connected to the secondary winding T2 of the inverter transformer T through a series circuit of the DC cut capacitor C6 and the shunt winding of the auto transformer To, and the non-power supply side is connected to both ends of the preheat starting capacitor C7. .

The preheat starting capacitor C7 causes the filament electrodes 9a and 9b of the discharge lamp 5 to form a closed circuit with the secondary winding T2 of the inverter transformer T. Transformer T
The filament electrodes 9a and 9b are preheated by the output current (high-frequency current) induced in the secondary winding T2. The DC cut capacitor C6 cuts off the DC component of the lamp current flowing through the discharge lamp 5.

The autotransformer To induces a high-frequency current flowing in the shunt winding in the series winding to generate the autotransformer To.
Main switch Tr using the current flowing in the winding
To be supplied to. In this first embodiment,
In FIG. 1, when the high frequency current flows from the ground line side of the autotransformer To to the DC cut capacitor C6 side, the polarity of the winding of the autotransformer To is preset so that the base current is supplied to the main switch Tr. Has been done.

Next, a partial smoothing circuit 6 is provided between the DC voltage generating circuit 2 and the high frequency lighting circuit 3.
That is, the series circuit including the electrolytic capacitor C8, the inductor L2, and the diode D4 is the resonance capacitor C.
3 is connected in parallel. By supplying a current to this series circuit when the main switch Tr is turned on, the input current can be supplied from the commercial AC power supply Vs even in a valley period when the voltage value of the commercial AC power supply Vs is small, so that the input current is sinusoidal. It approaches the waves.

A diode D5 connected in parallel with the series circuit of the electrolytic capacitor C8 and the inductor L2.
Is to recirculate the regenerative current due to the electromagnetic energy of the inductor L2 in the closed circuit of the electrolytic capacitor C8, the inductor L2 and the diode D5. Further, the diode D6 connected between the connection point A of the inductor L2 and the diode D4 and the negative side of the DC voltage generating circuit 2
Represents the discharge current of the electrolytic capacitor C8, the primary winding T1 of the inverter transformer T, the main switch Tr, and the diode D.
6, the inductor L2 and the electrolytic capacitor C8 are circulated in a closed circuit.

Next, the operation of the first embodiment of the present invention will be described. When an AC voltage is applied from the commercial AC power supply Vs, the capacitor C2 which is the output end of the DC voltage generation circuit 2
A DC voltage is generated at both ends of the DC voltage, and this DC voltage is applied to the series circuit of the primary winding T1 of the inverter transformer T and the main switch Tr.

On the other hand, the control circuit 4 supplies a starting current to the base of the main switch Tr via the starting resistor R1 to turn on the main switch Tr. When the main switch Tr is turned on, current flows from the positive side of the DC voltage generating circuit 2 to the primary winding T1 of the inverter transformer T, the main switch Tr and the negative side of the DC voltage generating circuit 2. At this time, electromagnetic energy is stored in the primary winding T1 of the inverter transformer T.

The secondary winding T of the inverter transformer T
A current is induced in 2 and the induced current is generated by the filament electrode 9a of the discharge lamp 5, the preheating starting capacitor C7, the filament electrode 9b of the discharge lamp 5, and the auto transformer T.
It flows in the path of the shunt winding of o, the DC cut capacitor C6 and the secondary winding T2 of the inverter transformer T. At this time, the filament electrodes 9a and 9b of the discharge lamp 5 are preheated.

The auto transformer To induces a high frequency current flowing in the shunt winding in the series winding. The current flowing through the winding (series winding and shunt winding) of the auto transformer To is supplied to the base of the main switch Tr via the diode D2 and flows from the base to the emitter side. As a result, the main switch Tr is supplied with the current flowing through the winding of the auto transformer To to the base and maintains the ON state.

Then, the control circuit 4 uses the automatic transformer T
When the main switch Tr is kept in the ON state by the current flowing through the winding o, the supply of the starting current to the main switch Tr via the resistor R1 is stopped. After that, the main switch Tr
Is turned on by supplying the base with the current flowing through the winding of the autotransformer To.

Further, the control circuit 4 turns on the field effect transistor FET when the ON period of the main switch Tr reaches a predetermined period. As a result, the auto transformer T
The current flowing in the o winding is a field effect transistor FET
Flow to the base side of the main switch Tr,
Also, since the base charge is discharged by the field effect transistor FET, the main switch Tr is turned off.

When the main switch Tr is turned off, the regenerative current due to the electromagnetic energy accumulated in the primary winding T1 of the inverter transformer T causes the connection point B, the resonance capacitor C3,
It flows in the closed circuit (resonant circuit) of the connection point C and the primary winding T1. The induced current induced in the secondary winding T2 of the inverter transformer T maintains the flow from the filament electrode 9a of the discharge lamp 5 toward the filament electrode 9b. The connection point B is an inverter transformer T
Is a connection point of the primary winding T1, the collector of the main switch Tr and the resonance capacitor C3, and is a connection point of the connection point C, the primary winding T1 of the inverter transformer T, the capacitor C2 and the resonance capacitor C3.

Next, the primary winding T of the inverter transformer T
When the electromagnetic energy stored in 1 is consumed, a discharge current due to the electric charge stored in the resonance capacitor C3 causes a closing of the connection point B, the primary winding T1 of the inverter transformer T, the connection point C and the resonance capacitor C3. It flows in the circuit (resonance circuit). At this time, the induced current induced in the secondary winding T2 of the inverter transformer T is the direct current cut capacitor C6, the shunt winding of the auto transformer To, the filament electrode 9b of the discharge lamp 5, the preheat starting capacitor C7, and the discharge. It flows in the path of the filament electrode 9a of the lamp 5 and the secondary winding T2 of the inverter transformer T, and the discharge lamp 5
The filament electrodes 9a and 9b are preheated.

The current induced in the winding of the autotransformer To flows in the closed circuit of the winding of the diode D3, the capacitor C5 and the autotransformer To and is not supplied to the base of the main switch Tr. At this time, the control circuit 4
Turns off the field effect transistor FET. Even if the field effect transistor FET is turned off, the auto transformer T
Since the current induced in the o winding is not supplied to the base of the main switch Tr, the main switch Tr maintains the off state.

When the charge accumulated in the resonance capacitor C3 is consumed from the connection point B side, a discharge current due to the charge accumulated in the resonance capacitor C3 from the connection point C side is generated at the connection point C and the inverter transformer T. Flows through the primary winding T1, the connection point B, and the resonance capacitor C3. At this time, the induced current induced in the secondary winding T2 of the inverter transformer T is caused by the filament electrode 9a of the discharge lamp 5.
Side to the filament electrode 9b side, the current induced in the winding of the autotransformer To is the diode D2.
Is supplied to the base of the main switch Tr via, and the main switch Tr is turned on.

When the main switch Tr is turned on, current flows from the positive side of the DC voltage generating circuit 2 through the primary winding T1 of the inverter transformer T, the main switch Tr and the negative side of the DC voltage generating circuit 2, and thereafter, repeat.

Here, in the operation of the discharge lamp lighting device 1, the control circuit 4 fixes the off period of the on / off period of the main switch Tr, and changes the on period by controlling the on / off operation of the field effect transistor FET. Then, the control circuit 4 controls the tertiary winding T of the inverter transformer T.
The DC voltage generated in the electrolytic capacitor C4 by the current flowing in 3 is input as the control voltage and the detection voltage.
As a result, a constant voltage is input to the control circuit 4 to operate, the main switch Tr is turned on / off, and the discharge lamp 5
Is lit with a predetermined lamp power. And the control circuit 4
When the DC voltage is out of the predetermined voltage range, that is, when an undervoltage or an overvoltage occurs in the primary winding T1 of the inverter transformer T, the on / off operation of the main switch Tr is stopped and the discharge lamp 5 is turned off. Let

The DC voltage generated in the electrolytic capacitor C4 by the current flowing in the tertiary winding T3 of the inverter transformer T is generated in the fixed off period of the on / off period of the main switch Tr. That is, when the main switch Tr is turned off, the regenerative current due to the electromagnetic energy accumulated in the primary winding T1 of the inverter transformer T flows in the resonance circuit of the primary winding T1 and the resonance capacitor C3, and the primary winding T1.
On the other hand, when the DC voltage generating circuit 2 flows from the negative electrode side to the positive electrode side, a current flows through the tertiary winding T3 to generate a DC voltage (detection voltage).

The electromagnetic energy accumulated in the primary winding T1 is accumulated by the current flowing from the DC voltage generating circuit 2 or the partial smoothing circuit 8 to the primary winding T1 and the main switch Tr during the ON period of the main switch Tr. The amount of accumulation increases according to the length of the ON period of the main switch Tr, but since the OFF period of the main switch Tr is fixed, the change in the resonance current flowing through the primary winding T1 is small, and the tertiary winding T3 is small.
The change in the current flowing through the line is unlikely to occur. That is, when the ON period of the main switch Tr changes, the output voltage of the high-frequency lighting circuit 3 changes, so the lamp voltage of the discharge lamp 5 also changes. ) Is almost constant.

As described above, the resonance current of the primary winding T1 of the inverter transformer T and the resonance capacitor C3 is induced in the tertiary winding T3 during the off period of the main switch Tr.
By inputting the DC voltage generated by the current flowing through the tertiary winding T3 to the control circuit 4 as the control voltage and the detection voltage, the control circuit 4 turns on the main switch Tr without directly receiving the fluctuation of the lamp voltage of the discharge lamp 5. Turn on / off control. Therefore, even if the ambient temperature of the discharge lamp 5 changes,
Since the DC voltage input to the control circuit 4 does not change in accordance with the fluctuation, the control circuit 4 is erroneously detected that the discharge lamp 5 that is normally lit is a defect, or erroneous control that stops the operation of the control circuit 4. To be prevented.

By connecting one end of the discharge lamp 5 on the secondary side of the inverter transformer T to the ground line,
The same potential as the primary side of the inverter transformer T (driving circuit for the main switch) is created. Therefore, the current (voltage) of the load circuit can be supplied as the drive source of the main switch Tr by the auto transformer To. Since the current for driving the main switch is changed to the two-winding current transformer and obtained by the single-turn autotransformer To, the winding can be simplified and downsized.

Next, a second embodiment of the present invention will be described. FIG. 2 is a circuit configuration diagram of a discharge lamp lighting device according to a second embodiment of the present invention. The second embodiment differs from the first embodiment shown in FIG. 1 in that the filament electrode 9b of the discharge lamp 5 connected to the ground line side of the load circuit during on / off control of the main switch Tr.
The filament electrode breakage detection circuit 10b for detecting the breakage is additionally provided. The same elements as those of the first embodiment shown in FIG. 1 are designated by the same reference numerals, and duplicate description will be omitted.

In FIG. 2, the filament electrode disconnection detection circuit 10b is provided between the filament electrode 9b of the discharge lamp 5 connected to the ground line side of the load circuit and the ground line, and includes the resistor R2 and the diode D7. First series connection circuit, resistor R3 and detection capacitor C
9 is connected in parallel with a second series connection circuit.

When the filament electrode 9b on the ground line side of the discharge lamp 5 is cut or not attached during the on / off control of the main switch Tr, the secondary winding T2, which is the output winding of the inverter transformer T, and the discharge lamp. 5
Filament electrode 9a, preheat starting capacitor C7,
Filament electrode breakage detection circuit 10b, auto transformer T
o, a DC cut capacitor C6, a circuit of the secondary winding T2 of the inverter transformer T (hereinafter referred to as a forward circuit), or a circuit of the reverse winding T2 of the inverter transformer T, a DC cut capacitor C6, Auto transformer T
o, filament electrode breakage detection circuit 10b, preheat starting capacitor C7, filament electrode 9a of discharge lamp 5,
A circuit of the secondary winding T2 of the inverter transformer T (hereinafter referred to as a reverse circuit) is formed.

When the forward circuit is formed, in the filament electrode disconnection detection circuit 10b, current flows through the second series connection circuit of the resistor R3 and the detection capacitor C9, while the reverse circuit is formed. When the filament electrode disconnection detection circuit 10b is operating, a current flows through the first series connection circuit of the resistor R2 and the diode D7. Therefore, the detection transformer C9 has an inverter transformer T
The direct current component contained in the current of the secondary side circuit is charged. As a result, the potential of the detection capacitor rises, and this potential is detected to detect the filament electrode 9b of the discharge lamp 5.
Detects disconnection and unattached.

According to the second embodiment, the power is not obtained from the high potential side (DC line) which is the primary side of the inverter transformer T, and the potential is generated by using the current on the secondary side. The filament electrode breakage detection circuit can be realized with a simple configuration. Further, since the generated potential is based on the ground line, it is easy to detect a rise in potential, and a resistor having a relatively small resistance value for generating a potential can be used. Therefore, it is possible to shorten the time required to reach the detectable potential.

Next, a third embodiment of the present invention will be described. FIG. 3 is a circuit configuration diagram of a discharge lamp lighting device according to a third embodiment of the present invention. The third embodiment differs from the first embodiment shown in FIG. 1 in that the filament electrode 9a of the discharge lamp 5 connected to the high voltage side of the load circuit is disconnected during the on / off control of the main switch Tr. A filament electrode breakage detection circuit 10a for detection is additionally provided. The same elements as those of the first embodiment shown in FIG. 1 are designated by the same reference numerals, and duplicate description will be omitted.

In FIG. 3, the filament electrode breakage detection circuit 10a is provided between the filament electrode 9a of the discharge lamp 5 connected to the high voltage side of the load circuit and the high voltage line, and includes the resistor R2 and the diode D7. The serial connection circuit 1 and the second serial connection circuit of the resistor R3 and the detection capacitor C9 are connected in parallel. The voltage detected by the detecting capacitor C9 is displayed and output by the photocoupler 11.

When the high voltage side filament electrode 9a of the discharge lamp 5 is cut or not attached during the on / off control of the main switch Tr, the secondary winding T2 which is the output winding of the inverter transformer T and the filament electrode are disconnected. Detection circuit 10a, preheat starting capacitor C7, discharge lamp 5
Filament electrode 9b, auto transformer To, DC cutting capacitor C6, circuit of the secondary winding T2 of the inverter transformer T (forward circuit), or the circuit of the secondary winding T2 of the reverse inverter transformer T, DC Cutting capacitor C6, auto transformer To, filament electrode 9b of discharge lamp 5, preheating starter capacitor C7, filament electrode breakage detection circuit 10a, inverter transformer T
The secondary winding T2 circuit (reverse circuit) is formed.

When the forward circuit is formed, in the filament electrode disconnection detection circuit 10a, current flows through the second series connection circuit of the resistor R3 and the detection capacitor C9, while the reverse circuit is formed. When the filament electrode disconnection detection circuit 10b is operating, a current flows through the first series connection circuit of the resistor R2 and the diode D7. Therefore, the detection transformer C9 has an inverter transformer T
The direct current component contained in the current of the secondary side circuit is charged. As a result, the potential of the detection capacitor rises, and this potential is detected to detect the filament electrode 9b of the discharge lamp 5.
Detects disconnection and unattached. In this case, the reference of the potential generated in the detection capacitor C9 is different from the reference potential of the circuit, so the potential is detected by the photocoupler 11.

In the above description, the filament electrode disconnection detection circuit 10a is provided in the first embodiment shown in FIG. 1, but the filament electrode disconnection detection circuit 10a is provided in the second embodiment shown in FIG. The electrode breakage detection circuit 10a may be provided.

According to the third embodiment, the power is not obtained from the high potential side (DC line), which is the primary side of the inverter transformer T, and the secondary side current is used to generate the potential. The filament electrode breakage detection circuit can be realized with a simple configuration. Further, since a resistor having a relatively small resistance value for generating the potential can be used, the time required to reach the detectable potential can be shortened.

Next, a fourth embodiment of the present invention will be described. FIG. 4 is a circuit configuration diagram of a discharge lamp lighting device according to a fourth embodiment of the present invention. The fourth embodiment differs from the second embodiment shown in FIG. 2 in that the filament electrode disconnection detection circuit 10b operates during the on / off control of the main switch Tr, and then the on / off control of the main switch stops. If the filament electrode breakage detection circuit 10
An external power supply for holding the operation of b is supplied to the filament electrode breakage detection circuit 10b. The same elements as those of the second embodiment shown in FIG. 2 are designated by the same reference numerals, and duplicate description will be omitted.

In FIG. 4, when the filament electrode breakage detection circuit 10b is in operation, the detection capacitor C9 is charged with a direct current component, but the main switch Tr of the high frequency lighting circuit 3 is stopped, and the inverter transformer T is turned off. When the secondary current stops flowing, the electric charge of the detecting capacitor C9 starts discharging. When the electric charge of the detection capacitor C9 is discharged, the potential drops, and it becomes impossible to detect disconnection or non-attachment of the filament electrode.

Therefore, when the ON / OFF control of the main switch is stopped, the output of the DC voltage generating circuit 2 is supplied to the filament electrode disconnection detection circuit 10b, and after the ON / OFF control of the main switch Tr of the high frequency lighting circuit 3 is stopped. Also,
The operating state of the filament electrode breakage detection circuit 10b is maintained.

In the above description, the output of the DC voltage generating circuit 2 is used as the external power source to detect the filament electrode breakage detecting circuit 10b.
However, the commercial AC power supply Vs may be supplied. In this case, commercial AC power supply V
s, filament electrode disconnection detection circuit 10b, ground line, rectifier 7, circuit of commercial AC power supply Vs, or vice versa commercial AC power supply Vs, rectifier 7, ground line, filament electrode disconnection detection circuit 10b, commercial AC power supply A Vs circuit is formed.

Further, the case of supplying the external power source has been described in the first embodiment shown in FIG.
An external power supply may be supplied to the second embodiment shown in FIG.

According to the fourth embodiment, the filament disconnection can be confirmed even after the high frequency lighting circuit is stopped, so that the maintainability is improved.

Next explained is the fifth embodiment of the invention. FIG. 5: is an external view of the lighting fixture which shows the 5th Embodiment of this invention. The same elements as those in FIG. 1 are designated by the same reference numerals and duplicate description will be omitted.

The luminaire 12 shown in FIG. 5 is a direct luminaire that is directly attached to the ceiling or the like. The luminaire 12 includes lamp sockets 14 a, 14 at both ends of the lower surface of the luminaire main body 13.
b is provided, and the discharge lamp 5 which is a fluorescent lamp is sandwiched and connected between the lamp sockets 14a and 14b.

Further, a reflector 15 which is optically opposed to the discharge lamp 5 and has a reflecting surface 15a for reflecting the light emitted from the discharge lamp 5 is attached to the lighting fixture body 13. Further, the lighting fixture body 13 is provided with the discharge lamp lighting device 1 on the back side of the reflecting surface 15a.

[0084]

According to the invention of claim 1, since the current for driving the main switch is obtained by the single-turn autotransformer, the winding can be simplified and downsized. In addition, the DC voltage generated in the detection winding of the inverter transformer during the OFF period of the main switch is input as the control voltage and the detection voltage of the control circuit, and this DC voltage is almost constant without fluctuation of the lamp voltage of the discharge lamp. Therefore, it is possible to prevent the control circuit from detecting the lamp defect or stopping the operation.

According to the invention of claim 2, a potential is generated in the detection capacitor by utilizing the current on the output side which is the secondary winding of the inverter transformer, and the generated potential is based on the ground line. Therefore, the filament electrode breakage detection circuit can be realized with a simple configuration. Further, since a resistor having a relatively small resistance value can be used, it is possible to shorten the time until the potential rises to the detectable potential.

According to the third aspect of the present invention, since a potential is generated in the detection capacitor by utilizing the current on the output side which is the secondary winding of the inverter transformer, the filament for detecting the disconnection of the filament electrode on the high voltage side. The electrode breakage detection circuit can be realized with a simple configuration. Further, since a resistor having a relatively small resistance value can be used, it is possible to shorten the time until the potential rises to the detectable potential.

According to the invention of claim 4, the filament break can be confirmed even after the high frequency lighting circuit is stopped, so that the maintainability is improved.

According to the invention of claim 5, claims 1 to 4
A lighting fixture equipped with a discharge lamp lighting device having the effect of any one of the inventions can be obtained.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram of a discharge lamp lighting device according to a first embodiment of the present invention.

FIG. 2 is a circuit configuration diagram of a discharge lamp lighting device according to a second embodiment of the present invention.

FIG. 3 is a circuit configuration diagram of a discharge lamp lighting device according to a second embodiment of the present invention.

FIG. 4 is a circuit configuration diagram of a discharge lamp lighting device according to a second embodiment of the present invention.

FIG. 5 is an external view of a lighting fixture showing a fifth embodiment of the present invention.

FIG. 6 is a circuit configuration diagram of a conventional discharge lamp lighting device.

[Explanation of symbols]

1 ... Discharge lamp lighting device, 2 ... DC voltage generating circuit, 3 ...
High frequency lighting circuit, 4 ... Control circuit, 5 ... Discharge lamp, 6 ...
Partial smoothing circuit, 7 ... Rectifier, 8 ... Noise filter, 9
... filament electrode, 10 ... filament electrode disconnection detection circuit, 11 ... photocoupler, 12 ... illumination equipment, 13 ... illumination equipment body, 14 ... lamp socket, 15a ... reflection surface, 1
5 ... Reflector

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 3K072 AA02 AC02 AC11 BA03 BB01                       CA16 DB03 DD04 DE02 EB03                       EB07 GB04 GC02                 3K073 AA93 BA09 CF02 CF10 CG55                       CJ16 CJ18 CL10

Claims (5)

[Claims] 1. A direct current voltage power source; an inverter transformer and a single main switch connected in series between the outputs of the direct current voltage power source, and a resonance capacitor connected in parallel to the inverter transformer. A high-frequency lighting circuit configured to output a high-frequency voltage across the output winding of the inverter transformer by turning on and off the main switch; and the high-frequency generated across the output winding of the inverter transformer. A load circuit that lights a discharge lamp with a high frequency voltage of a lighting circuit and has one end of the discharge lamp connected to a ground line; and a load circuit connected between the ground line of the load circuit and one end of an output winding of the inverter transformer An autotransformer that supplies a current for driving the main switch by the load current of the discharge lamp A detection winding provided in the inverter transformer for detecting a resonance current due to the resonance of the inverter transformer and a resonance capacitor; and a control winding for fixing the OFF period of the main switch and changing the ON time, and the OFF period. And a control circuit configured to input a DC voltage generated in the detection winding as a control voltage, the discharge lamp lighting device. 2. A circuit is formed when the filament electrode of the discharge lamp connected to the ground line side of the load circuit is broken during the on / off control of the main switch, and the circuit is formed by the current from the output winding of the inverter transformer. The discharge lamp lighting device according to claim 1, further comprising a filament electrode breakage detection circuit that generates a voltage. 3. A circuit is formed when the filament electrode of the discharge lamp connected to the high potential side of the load circuit is broken during ON / OFF control of the main switch, and a circuit is formed by the current from the output winding of the inverter transformer. 3. The discharge lamp lighting device according to claim 1, further comprising a filament electrode disconnection detection circuit that generates a voltage. 4. The filament electrode disconnection detection circuit is maintained for operation when the filament electrode disconnection detection circuit operates during the on / off control of the main switch and the on / off control of the main switch is stopped thereafter. The discharge lamp lighting device according to claim 2 or 3, wherein an external power source is supplied to the filament electrode breakage detection circuit. 5. A lighting device comprising: the discharge lamp lighting device according to any one of claims 1 to 4; and a lighting fixture body in which the discharge lamp lamp lighting device is provided. Equipment.