JP2837854B2 - Discharge lamp lighting device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge lamp lighting device that controls high-frequency lighting of a discharge lamp.

[Prior Art] In an electronic ballast having an inverter circuit, a discharge lamp such as a fluorescent lamp is turned on at a high frequency. When the fluorescent lamp reaches the end of its life, a discharge activating substance of a filament is consumed and the discharge becomes unstable. As a result, the lamp current increases, and as a result, the current flowing through the inverter circuit increases, so that an undesirable load is applied to the oscillation switching transistor and the like.

For this reason, conventionally, as seen in Japanese Patent Application Laid-Open No. Sho 56-42996, when the lamp current increases at the end of life and the filament of the fluorescent lamp runs out, it is detected and the oscillation operation of the inverter circuit is detected. What stops it is known.

[Problems to be Solved by the Invention] However, in such a method in which the disconnection of the filament of the fluorescent lamp is detected and the oscillation operation of the inverter is stopped, a large current continues to flow in the inverter circuit for a relatively long time. Overcurrent flows through the switching transistor and the like for a longer time, shortening the life of the circuit component, and possibly damaging the circuit component.

Therefore, the present invention is to provide a discharge lamp lighting device that can stop the oscillation operation of the inverter circuit immediately after the end of the life of the discharge lamp and can reliably prevent the life and damage of circuit components such as the switching transistor for oscillation from being reduced. It is assumed that.

When a plurality of discharge lamps are turned on by the inverter circuit, for example, even if one of them reaches the end of life, if the remaining discharge lamps are normal, the remaining discharge lamps may be used for one end of life. It would be irrational if all lights could not be turned on.

Therefore, the invention described in claim (2) is for controlling the lighting of a plurality of discharge lamps. Even if the oscillation operation of the inverter circuit is stopped for the discharge lamp at the end of life, the discharge lamp at the end of life is stopped. An object of the present invention is to provide a discharge lamp lighting device capable of operating an inverter circuit by removing the discharge lamp and reliably controlling lighting of the remaining discharge lamps.

[Means for Solving the Problems] The invention according to claim (1) is a discharge lamp having a switching transistor for oscillation and a current feedback transformer, and having a filament through an choke coil for a high frequency from an inverter circuit that oscillates a high frequency. In a discharge lamp lighting device for supplying high-frequency lighting of the discharge lamp to a discharge lamp, current detection means for detecting a current of a preheating circuit for supplying a preheating current to the filament of the discharge lamp, and discharge current by the current amount detected by the current detection means. Life determining means for determining the end of life of the lamp and holding the determination result of the end of life, and determining means for determining whether or not the discharge lamp is mounted, based on the amount of current detected by the current detecting means,
Stop control means for stopping the oscillation operation of the inverter circuit for a certain period when the life judgment result by the life judgment means is at the end of life, and start means for starting and controlling the inverter circuit when the stop control for a certain period by the stop control means is completed. After starting control of the inverter circuit by the starting means,
The judgment result held by the life judgment means is the end of life, and
If the determination means has determined that the discharge lamp is mounted, stop control of the inverter circuit oscillating operation by the stop control means is performed again, and after starting control of the inverter circuit by the start means,
The judgment result held by the life judgment means is the end of life, and
If the determination means determines that the discharge lamp is not mounted, the end of life judgment result held by the life judgment means is erased.

According to a second aspect of the present invention, an oscillation switching transistor and a current feedback transistor are provided, and a high frequency from an inverter circuit that oscillates a high frequency is supplied to a plurality of discharge lamps each having a filament via a choke coil. In a discharge lamp lighting device for lighting a discharge lamp at a high frequency, a current detection means for detecting a current of a preheating circuit for supplying a preheating current to a filament of each discharge lamp, and a life of each discharge lamp is determined by an amount of current detected by the current detection means. The end of life is determined, and the life determination unit that holds the determination result of the end of life, and the amount of current detected by the current detection unit,
Determining means for determining whether or not each discharge lamp is mounted,
A stop control means for stopping the oscillation operation of the inverter circuit for a certain period when at least one of the life judgment results of each discharge lamp by the life judgment means is at the end of the life. Starting means for controlling the start-up of the circuit, wherein after the start-up control of the inverter circuit by the starting means, at least one end-of-life judgment result is held in the life judgment means, and the life judgment means judges the end of life. If the determination means has determined that there is mounting, the stop control means again controls the oscillation operation of the inverter circuit, and the start means controls the start of the inverter circuit. Is held, and the life determining means determines that the discharge lamp whose life is at the end of life has not been mounted, that the discharge lamp is not mounted. It is to erase the determination result of the end of life for the discharge lamp is held.

[Operation] In the invention described in claim (1), when the discharge lamp is exhausted at the end of its life and the discharge active material of the filament is consumed and the discharge hardly occurs, the current flowing in the preheating circuit increases.
This current increase is detected by the current detecting means, the end of life is determined by the life determining means, the result is held, and the oscillation operation of the inverter circuit is stopped for a certain period.
Also, it is determined whether or not the discharge lamp that has been determined to be at the end of life by the determining means is mounted. Then, after a lapse of a certain period, the inverter circuit is activated by the activation means. At this time, if the end-of-life discharge lamp is still mounted, the oscillation operation of the inverter circuit is stopped again. If the end-of-life discharge lamp is removed, the end-of-life determination result held by the life determining means is deleted.

In the invention described in claim (2), when at least one of the plurality of discharge lamps reaches the end of life, an increase in current at that time is detected by the current detecting means, and the life of the discharge lamp at the end of life is detected by the life determining means. The end period is determined, the result is held, and the oscillation operation of the inverter circuit is stopped for a certain period. Also, it is determined whether or not the discharge lamp that has been determined to be at the end of life by the determining means is mounted. Then, after a lapse of a predetermined period, the inverter circuit is activated by the activation means. At this time, if the end-of-life discharge lamp is still mounted, the oscillation operation of the inverter circuit is stopped again. If the end-of-life discharge lamp is removed, the end-of-life determination result of the discharge lamp held by the life determining means is deleted. As a result, the oscillating operation of the inverter circuit is continued, and the remaining discharge lamps can maintain lighting.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings.

As shown in FIG. 1, a DC power supply E is connected to an inverter circuit CC1.
Are connected.

The inverter circuit CC1 includes a pair of NPN type oscillation switching transistors Q ₁ and Q ₂ and a current feedback base transformer T 1.
It consists of B. The base transformer TB has a primary winding L
₁ and two secondary windings L ₂ and L _3. One end of one secondary winding L ₂ is connected to the base of the transistor Q ₁ via a resistor R ₃ , and the other end is connected to a transistor Q ₁ Emitter and transistor
It is connected to the connection point between the collector of Q _2. And the other 2
One end of winding L ₃ via a resistor R ₄ is connected to the base of the transistor Q _2, and the other end thereof is connected to the emitter of the transistor Q _2. Note that diodes D ₁ and D ₂ are connected in parallel to the transistors Q ₁ and Q ₂ , respectively, with the polarity shown. The base transformer primary winding L ₁ of TB is connected at one end to the connection point between the collector of the transistor to Q ₁ emitter and the transistor Q _2, the choke and the other end respectively coil CH
It is connected to one end of the _1, CH _2.

The choke coil CH ₁ the other end is connected to one end of the filament F ₁ of the fluorescent lamp H ₁ as a discharge lamp, the other end of the choke coil CH ₂ is the filament F ₃ of the fluorescent lamp of H ₂ as a discharge lamp Connected to one end.

Between the other ends of the two filaments F ₁ and F ₂ of the fluorescent lamp H ₁ , a preheating current detecting transformer TF _{1 serving} as current detecting means is connected.
Winding L ₄ and the preheating circuit Y ₁ series circuit is connected between the capacitor C ₁ is formed. The series circuit connection between the fluorescent lamp two filaments F _3, 1 winding preheating current detecting transformer TF ₂ is between the other end of F ₄ is a current detector L ₆ and the capacitor C ₂ of H ₂ by preheating circuit Y ₂ are formed.

_One ends of the filaments F ₂ and F ₄ of the fluorescent lamps H ₁ and H ₂ are connected to each other, and one end of a capacitor C ₃ and a capacitor.
It is connected to a connection point between one end of the C _4.

The other end of the capacitor C ₃ is the oscillation transistor Q ₁
Is connected to the collector to a connection point between the positive terminal of the DC power source E, the other end of the capacitor C ₄ is connected to a connection point between the load terminal of the DC power source E and the emitter of the oscillation transistor Q ₂ I have.

Secondary winding L ₅ represents terminal K of the preheating current detecting transformer TF ₁
Are connected to _1, K ₂ via the diode _{D 3, D 4, D 5} , the input terminal of the full-wave rectifying circuit DB ₁ consisting of D _6. Secondary winding L ₇ of the preheating current detecting transformer TF ₂ is connected to an input terminal of the full-wave rectifying circuit DB ₂ consisting of a diode _{D 7, D 8, D 9} , D 10 through the terminals K _3, K ₄ doing.

The negative electrode side of the output terminals of the full-wave rectifier circuit DB ₁ is grounded, the positive side input terminal of the protection circuit CC2 through a resistor R ₇ is grounded through a parallel circuit of a capacitor C ₅ and the resistor R ₅ It is connected to I _1. The full-wave rectifier circuit DB ₂
The negative side of the output terminal of the ground, the positive electrode side capacitor C ₆
Resistor is grounded through a parallel circuit of a resistor R ₆ and
Through R ₈ are connected to the protection circuit CC2 another input terminal I _2.

Based of the oscillation transistor to Q ₁ the inverter circuit CC1 is grounded via the NPN type control transistor Q _3. And through the base resistor R ₂ of the transistor Q ₃ is connected to the output terminal O ₁ of the protection circuit CC2, and a collector connected to said protection circuit CC2 Another output terminal O _2. The base of the control transistor Q _3, the resistor R ₁ is connected between the emitters.

The protection circuit CC2, as shown in FIG. 2, the level comparator circuit CC3 to the input unit; CC4 and fluorescent lamp 1 lighting confirmation circuit CC5, provided a fluorescent lamp 2 lights up confirming circuit CC 6, wherein the input from the input terminal I ₁ Level comparison circuit CC3 and fluorescent lamp 1 lighting confirmation circuit C
And supplies the input from the input terminal I ₂ to the level comparison circuit CC4 and fluorescent lamp 2 lights up check circuit CC6 supplies to C5.

The level comparison circuits CC3 and CC4 are each a preheating circuit
It detects the rise in the level of the voltage input from the input terminals I ₁ and I ₂ when the current of Y ₁ and Y ₂ increases.
S1 and S2 are supplied to end-of-life determination circuits CC7 and CC8, respectively.

The lighting confirmation circuits CC5 and CC6 have input terminals I ₁ and I, respectively.
Fluorescent H ₁ and H ₂ confirms whether lit by a signal from the _2, confirm lighting and confirms the lighting signals S5 and S6
Is output.

The end-of-life determination circuit CC7 measures the time that the signal S1 is continuously input when the detection signal S1 is input from the level comparison circuit CC3, and determines the life when the time becomes equal to or longer than a predetermined time. An output S7 is sent out, and the end-of-life judgment result is stored in a judgment result circuit CC9 which is a judgment means. In addition, the end-of-life judgment circuit CC
8, when the detection signal S2 is input from the level comparison circuit CC4, measures the time during which the signal S2 is continuously input, and sends out the life determination output S8 when the time becomes equal to or longer than a predetermined time. And a judgment result circuit CC as a judgment means.
The end-of-life judgment result is stored in 10.

Life judgment output from the end of life judgment circuits CC7 and CC8
Are respectively input S7 and S8 of 4 input type OR gate G _1, wherein each judgment result circuits CC9, CC10 is arranged to output a respective determination signals S9, S10 Storing determination results of the end of life. And the signal S from the judgment result circuit CC9
9 and a lighting confirmation signal S5 from the fluorescent lamp 1 lighting confirmation circuit CC5.
A is input to the second input type AND gate G _2. Also it has entered the determination result lighting confirmation signal S6 from the signal S10 in the circuit CC10 fluorescent lamp 2 lights up check circuit CC6 two input type AND gate G _3. And each of the AND gates G ₂ , G
₃ of the output are input to the OR gate G _1.

And are respectively supplied to the OR gate G ₁ control output circuit of the output constitutes the stop control means CC11 and control output timer CC 12.

The control output circuit CC11 is one which outputs a high level signal to the output terminal O ₁ in response to a signal from the OR gate G _1, the output time of the signal is controlled to a predetermined time by the control output timer CC12 It has become so.

The control output timer CC12 same time also the time for controlling the output time of the high level signal from the control output circuit CC11 by a signal input from the OR gate G _1, and so as to stop controlling the operation of the startup output circuit CC13 .

The two lighting confirmation circuits CC5 and CC6 are also provided with a lighting confirmation signal S5.
And is input and S6 to the 2 input type NOR gate G _4. Then it supplies a signal from the NOR gate G ₄ on the activation output circuit CC 13.

The activation output circuit CC13 is the control output timer CC12 operating with stop control is released the NOR gate G ₄ for the cause of the inverter circuit CC1 oscillation starts output terminal O ₂ to the high-level signal is inputted from by the outputs repeated until the fluorescent lamp to light the starting pulse, and supplies a signal to the high level while outputting repeatedly starting pulse to the second input type OR gate G _5, G _6.

Each of the OR gates G ₅ and G ₆ is also provided with each of the lighting confirmation circuits C.
Inverted signals ▲ ▼, ▲ ▼ of S5, S6 from C5, CC6 are input, respectively. The output of the OR gate G5 is supplied to the determination result circuit CC9, and the output of the OR gate G6 is supplied to the determination result circuit CC10.

Each of the determination result circuits CC9 and CC10 is the OR gate G ₅ ,
A high level signal from the G ₆ is so as to erase the determination result of the end of life that contains the input predetermined reference time.

In the present embodiment having such a configuration, when the power is turned on, both the fluorescent lamps H ₁ and H ₂ are turned off, so that the start output circuit CC13 operates to supply a start pulse to the inverter circuit CC1, and the inverter The circuit CC1 starts oscillating.
Thus the filament F ₁ of the preheating circuit Y ₁ and Y ₂ are respectively a preheating current flows through the fluorescent lamp _{H 1, H 2, F 2} , F 3, F 4 is preheated, respectively. The high voltage is applied between the filament of each fluorescent lamp H _1, H _2, eventually Fluorescent H _1, H ₂ is to be high frequency lighting.

Also, when a current flows through the preheating circuits Y ₁ and Y ₂ , voltages are generated in the secondary windings L ₅ and L ₇ of the preheating current detection transformers TF ₁ and TF ₂ , respectively, so that each input terminal I ₁ of the protection circuit CC 2 each voltage signal I ₂ is turned is confirmed by the lighting confirmation circuits CC5 and CC6 entered. That is, it is determined that the fluorescent lamps H ₁ and H ₂ are mounted.

When the fluorescent lamp H ₁ and H ₂ is the end of life discharge activators of one or both of the filament F _1, F ₂ of during the lighting operation, such as a fluorescent lamp H ₁ is exhausted, discharge occurs less likely become by preheating circuit the current flowing through the Y ₁ is increased. Thus the level of voltage generated in the secondary winding L ₅ of the preheating current detecting transformer TF ₁ is increased.

Thus the high pressure level is increased to be input to the input terminal I ₂ of the protection circuit CC2, the detection signal S from the level comparator circuit CC3
1 is generated and supplied to the end-of-life determination circuit CC7.

End of life determination circuit CC7 determines that the fluorescent lamp H ₁ by measuring the detection signal S1 from the level comparator circuit CC3 is input continuously over a predetermined time or more has become the end of life,
It outputs the life judgment output S7 and stores the judgment result in the judgment result circuit CC9.

Although the current flowing through the preheating circuit Y ₁ is also at startup lighting in case a fluorescent lamp H ₁ is normal is increased until the fluorescent lamp H ₁ starts lighting, the end of life determination circuit CC7 in this time life The time is set so as not to make a terminal determination. The same applies to the end of life determination circuit CC8 for fluorescent lamps H _2.

When life determination output to S7 life terminal determining circuit CC7 is sent, the control output circuit CC11 outputs a high level signal for a predetermined time the output terminal O ₁ by the control output timer CC 12.
Thus, the control transistor Q ₃ is turned on to stop the oscillation of the inverter circuit CC1.

Thus it is possible to the current flowing through the preheating circuit Y ₁ becomes end of life increases filaments stops inverter circuit CC1 oscillation operation before disconnection. Therefore, there is no fear that the oscillation switching transistors Q ₁ , Q _2, etc. are adversely affected. That is, it is possible to reliably prevent the life of the circuit components such as the switching transistor for oscillation and the like from being shortened.

Oscillation of the inverter circuit CC1 is turned off both of the discharge lamp H ₁ and H ₂ are both Stopping, and since both no current flows through the preheating circuit Y ₁ and Y _2, the input terminals I _1, I ₂ to the input As a result, the fluorescent lamp 1 lighting confirmation circuit CC5 and the fluorescent lamp 2 lighting confirmation circuit CC6 stop the lighting confirmation operation. That is, a non-lighting confirmation state is set.

The fluorescent lamp 1 lighting confirmation circuit CC5 determination result circuit CC9 be stopped the lighting confirmation operation of the fluorescent lamp H ₁ holds the storage state of the determination result of the end of life.

When a predetermined time has elapsed in this state, the output of the high-level signal from the control output circuit CC11 is stopped, and the operation stop control of the start output circuit CC13 by the control output timer circuit CC12 is released, and the start pulse is output from the start output circuit CC13. The output is repeated until the fluorescent lamp is turned on.

Thus it will flow again current preheating circuit Y ₁ and Y _2, since the fluorescent lamp H ₁ of the end of life is intact, current flows in the preheating circuit Y _1, which is a fluorescent lamp 1 lighting confirmation circuit CC
Appears as ₅ S5 output. The output of the S ₅ AND gate G
Is input to _2, the output of S9 in the determination result circuits CC9 this time the AND gate G ₂ for holding the high level outputs a high level, to operate the control output circuit CC11 via OR gate G _1. Thus the control transistor Q ₃ is turned on again so that the oscillation of the inverter circuit CC1 is stopped.

With such is left fluorescent lamp H ₁ end-of-life is mounted, oscillation of the inverter circuit CC1 is to be stopped immediately be resumed at predetermined time intervals.

When removing the fluorescent lamp H ₁ in this state, the output of the lighting confirmation signal S5 since the fluorescent lamp 1 lighting check circuit CC5 is not confirmed lighting is stopped. Also eliminated Thus the AND gate G ₂ output.

Thus control output circuit CC11 signal gone from the OR gate G ₁ does not operate. And inverter circuit
CC1 when starting the oscillation operation by the activation pulse from the start output circuit CC13 then the operation comes to lighting control only Fluorescent H ₂ not stopped.

Thus Fluorescent H ₂ Another by removing the fluorescent lamp H ₁ of the end of life will be lit successfully.

This operation is also performed when the filament F ₁ or F ₂ in a state where the fluorescent lamp H ₁ is mounted becomes impossible lighting disconnected.

The fluorescent lamp 1 lighting confirmation circuit CC5 this time to erase the determination result of the end of life stored in the determination result circuit CC8 via OR gate G _5.

When a new fluorescent lamp H ₁ ′ is installed in this state,
Since the inverter circuit CC1 is oscillating, the fluorescent lamp H
₁ 'will be lit immediately. And the fluorescent light H ₁ ′
Turns on, the fluorescent lamp 1 lighting confirmation circuit CC5 turns on the lighting confirmation signal S
5 will be output. Further, since the output of the determination signal S9 from the determination result circuit CC9 is stopped, the AND gate G ₂
, And the control output circuit CC11 is not operated.

Thus, the new fluorescent lamp H ₁ ′ can be kept lit without being mistaken for the end of life.

Furthermore, when both of the fluorescent lamps are removed while the protection circuit CC2 is operating, both the lighting confirmation signal S5 from the fluorescent lamp 1 lighting confirmation circuit CC5 and the lighting confirmation signal S6 from the fluorescent lamp 2 lighting confirmation circuit CC6 are generated. does not start output circuit CC13 by a signal from the NOR gate G ₄ are determined through the oR gate G _5, G ₆ the time or trigger pulse defines exits results circuit CC9
And the judgment result of CC10 is deleted.

In this way, when both of the fluorescent lamps are removed, the judgment result indicating that the lamp is at the end of life is unconditionally canceled regardless of the fluorescent lamps H ₁ and H ₂ .

In the above-described embodiment, two fluorescent lamps are lit. However, the present invention is not limited to this.
One or three or more lamps may be lit.

[Effects of the Invention] As described in detail above, according to the invention of claim (1), the oscillating operation of the inverter circuit can be stopped immediately after the end of the life of the discharge lamp, and the oscillating switching transistor of the inverter circuit It is possible to prevent an overcurrent from flowing to the circuit components such as the end of life due to the lighting of the discharge lamp at the end of life, and to reliably prevent the life reduction and breakage of the circuit components. Further, even if the oscillation operation of the inverter circuit is stopped due to the discharge lamp at the end of its life, the discharge lamp at the end of its life can be removed and replaced with a new discharge lamp to immediately turn on the lamp.

According to the invention described in claim (2), the oscillating operation of the inverter circuit can be stopped as soon as at least one of the discharge lamps reaches the end of its life, and the life of the circuit components such as the switching transistor for oscillation of the inverter circuit is reduced. It is possible to prevent an overcurrent from flowing due to lighting of the terminal discharge lamp, and to reliably prevent the life and damage of circuit components from being shortened. In addition, even if the oscillation operation of the inverter circuit is stopped due to the discharge lamp at the end of its life, the inverter circuit can be operated to oscillate by removing the discharge lamp at the end of its life. It can be lit reliably.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention, and FIG. 2 is a block diagram showing a configuration of a protection circuit in FIG. CC1 ...... inverter circuit, Q _1, Q ₂ ...... oscillating transistor, TB ...... current feedback based transformer, Q ₃ ...... control transistor, CH _1, CH ₂ ...... choke coil, H _1, H ₂ ...... fluorescent lamp, TF _1, TF ₂ ...... preheating current detecting transformer, CC2 ...... protection circuit, CC3, CC4 ...... level comparison circuit, CC7, CC8 ...... end of life determination circuit, CC9, CC10 ...... determination result circuit, CC11: Control output circuit, CC12: Control output timer, CC13: Start-up output circuit.

Continuation of the front page (56) References JP-A-61-153997 (JP, A) JP-A-61-153998 (JP, A) JP-A-62-157696 (JP, A) JP-A-61-10898 (JP, A) JP-A-61-10899 (JP, A) JP-A-1-251593 (JP, A) JP-A-1-186595 (JP, A) JP-B-61-31600 (JP, B2) (58) Field surveyed (Int.Cl. ⁶ , DB name) H05B 41/24

Claims (2)

(57) [Claims] 1. An oscillation switching transistor and a current feedback transformer, wherein a high frequency from an inverter circuit which oscillates a high frequency is supplied to a discharge lamp having a filament through a choke coil, and the discharge lamp is lit at a high frequency. In the device, current detection means for detecting a current of a preheating circuit for flowing a preheating current to the filament of the discharge lamp, and the amount of current detected by the current detection means, to determine the end of life of the discharge lamp, and to determine the end of life. A life determining means for holding the discharge lamp based on the amount of current detected by the current detecting means, and when the life determining result by the life determining means is at the end of life, the inverter circuit Stop control means for stopping the oscillation operation for a certain period of time, and when the stop control by the stop control means for a certain period of time ends, Starting control for starting and controlling the inverter circuit, and after starting control of the inverter circuit by the starting means,
When the judgment result held by the life judgment means is at the end of life, and when the judgment means judges that the discharge lamp is mounted, stop control is again performed to stop the oscillation operation of the inverter circuit by the stop control means, After starting control of the inverter circuit by the starting means,
If the judgment result held by the life judgment means is the end of life and the judgment means judges that the discharge lamp is not mounted, the judgment result of the end of life held by the life judgment means is deleted. Discharge lamp lighting device characterized by the above-mentioned. 2. An oscillation switching transistor and a current feedback transformer are provided, and a high frequency from an inverter circuit that oscillates a high frequency is supplied to a plurality of discharge lamps having filaments via choke coils, and each of the discharge lamps is turned on at a high frequency. A discharge lamp lighting device, wherein a current detection means for detecting a current of a preheating circuit for supplying a preheating current to the filament of each of the discharge lamps, and an end of life of each of the discharge lamps is determined by a current amount detected by the current detection means. And a life determining means for holding the end-of-life determination result, and a current amount detected by the current detecting means,
Determining means for determining whether or not each discharge lamp is mounted,
When at least one of the life judgment results of each discharge lamp by the life judgment means is at the end of life, a stop control means for stopping the oscillation operation of the inverter circuit for a certain period, and a stop control for a certain period by the stop control means is terminated. Starting means for starting and controlling the inverter circuit, after starting control of the inverter circuit by the starting means,
If at least one of the end-of-life judgment results is held in the life judgment means and the judgment means judges that the discharge lamp whose end of life has been judged by the life judgment means is mounted, the stop control is performed. Means for stopping the oscillation operation of the inverter circuit again by means, and after the start-up control of the inverter circuit by the start-up means,
If at least one of the end-of-life judgment results is held in the life judgment means and the judgment means judges that the discharge lamp whose end of life has been judged by the life judgment means is not mounted, the life judgment is made. A discharge lamp lighting device for erasing the end-of-life judgment result for the discharge lamp held by the means.