JPH06196279A - Discharge lamp lighting device - Google Patents

Abstract

PURPOSE:To light another discharge lamp for a light compensation with a simple structure at the time of the flame failure of a discharge lamp by connecting the other discharge lamp in parallel with this discharge lamp, and keeping it charged at the low voltage after one of multiple discharge lamps is lighted. CONSTITUTION:DL1 of multiple discharge lamps DL1, DL2 is connected to a power source Vs via a current limiting element L1, and a switch Sa is turned on to light it. After the discharge lamp DL1 is started, a switch Sb is turned on to charge the discharge lamp DL2, the voltage across both ends of the discharge lamp DL1 is lowered, and the discharge lamp DL2 is not lighted. When the flame failure of the discharge lamp DL1 occurs due to the momentary voltage drop of the power source Vs, the restart of the discharge lamp DL1 takes time, however the discharge lamp DL2 is lighted in its place. A light compensation can be attained with a simple circuit structure.

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 having a plurality of discharge lamps and having a light compensation function for lighting another discharge lamp in place of the extinguished discharge lamp.

[0002]

2. Description of the Related Art FIG. 12 is a circuit diagram of a conventional discharge lamp lighting device. In the figure, Vs is an AC power supply, L1 and L2 are inductors, DL1 and DL2 are discharge lamps, and Sa is a switch element. The discharge lamps DL1 and DL2 are different lamps or lamps of different wattage. When the switch element Sa is connected to the terminal T1 side, the switch element Sa, the discharge lamp DL1, the inductor L1, and the AC power source Vs are switched from the AC power source Vs.
A current flows through the path of, and the discharge lamp DL1 is turned on. Further, when the switch element Sa is connected to the terminal T2 side, the switch element Sa, the inductor L2, the discharge lamp DL2, the inductor L1, the AC power source Vs from the AC power source Vs.
A current flows through the path of, and the discharge lamp DL2 is turned on. The inductor L2 is inserted as necessary to compensate for the difference in lamp current between the discharge lamps DL1 and DL2.

Now, it is assumed that when the switch element Sa is connected to the terminal T1 side and the discharge lamp DL1 is lit, the AC power supply Vs undergoes a momentary power failure or voltage drop and the discharge lamp DL1 goes out. When the discharge lamp DL1 is a high pressure discharge lamp, the vapor pressure in the arc tube during lighting is high,
Once it disappears, it takes a few minutes to a dozen minutes to restart. This means that the darkness continues for several minutes to several tens of minutes until the discharge lamp DL1 is restarted, which is very unfavorable for safety.

A conventional example for solving such a problem is shown in FIG. The same elements as those of the circuit of FIG. 12 are designated by the same reference numerals, and duplicate description will be omitted. In the circuit of FIG. 13, 10 is a light compensation device, and the lamp voltage detection circuit 1
1, rectifying / smoothing circuit 12, voltage level detection circuit 13, switch circuit 14, incandescent lamp 15, and noise filter 16
It consists of When the discharge lamp DL1 goes out, the lamp voltage detecting circuit 11 detects the lamp voltage, the rectifying / smoothing circuit 12 rectifies and smoothes it to convert it into a DC voltage, and then the voltage level detecting circuit 13 performs voltage comparison to switch the switch circuit. 14 ON / OFF, incandescent lamp 1
5 is turned on. Such a light compensation device 10
By combining the above, it becomes possible to perform light compensation when the discharge lamp DL1 goes out, but there is a problem that a complicated circuit configuration is required, the circuit device becomes large, and the cost becomes high.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and it is an object of the present invention to perform light compensation when a discharge lamp goes out with a simple structure. It is to provide a discharge lamp lighting device.

[0006]

In the discharge lamp lighting device of the present invention, in order to solve the above-mentioned problems, as shown in FIG. 1, at least one of a plurality of discharge lamps DL1 and DL2 is used. The first switch element Sa for selectively connecting the discharge lamp DL1 of No. 1 to the power source Vs via the current limiting element such as the inductor L1 and the discharge lamp DL1 after the at least one discharge lamp DL1 is started. A second switch element Sb for connecting at least one other discharge lamp DL2 in parallel is provided.

Here, a plurality of discharge lamps DL1, DL2
Can be a different or different wattage discharge lamp, and the switch element S
The a is connected so that at least one lamp is turned on with priority when the power is turned on. In order to determine that the discharge lamp DL1 has started, the timer circuit may time the elapse of a predetermined time required for the start, or it may be determined by detecting the lamp current, the lamp voltage, or the like. . In the circuit of FIG. 1, after the AC power source Vs is turned on, the discharge lamp DL is
The control circuit K controls the switch element Sb so that the switch element Sb is in the OFF state for the time required for the start of No. 1 (for example, 10 seconds), and the switch element Sb is in the ON state after the elapse of this time. In addition, the time required to restart the discharged discharge lamp DL1 (for example, 15
Time), the control circuit K causes the switch element S
b may be turned off, or the switch element Sb may be kept on until the power is cut off.

[0008]

According to the configuration of FIG. 1, the first switch element Sa is
The discharge lamp DL1 is connected to the power supply Vs via the switch, and the second switch element Sb is turned on after the time required for starting the discharge lamp DL1 elapses. Therefore, when the power is turned on, the discharge lamp DL1 has priority. Lights up. After the discharge lamp DL1 is started, the second switch element Sb is turned on. At that time, since the voltage across the discharge lamp DL1 has dropped,
The discharge lamp DL2 does not light up. After that, when the discharge lamp DL1 is extinguished due to an instantaneous voltage drop of the power supply Vs, etc., the second switch element Sb is turned on, and therefore the discharge lamp DL2.
Lights up instead. As a result, the light compensation function can be realized with a simple circuit configuration, and it is possible to prevent the light output at the time of disappearance from being lost.

[0009]

FIG. 2 is a circuit diagram of the first embodiment of the present invention.
This embodiment embodies the basic configuration of the present invention shown in FIG. The same elements as those of the circuit of FIG. 1 are designated by the same reference numerals and the description thereof will be omitted. Reference numeral 5 denotes a power supply circuit, which lowers the AC power supply Vs, rectifies and smoothes it, and supplies the DC power supply voltage Vc
Create c. ICa is a timer circuit, which starts the timer operation when the timer input Ai rises to the high level, and the timer output Ao becomes the high level when the time required for starting the discharge lamp DL1 or DL2 (for example, 10 seconds) elapses. The timer time of the timer circuit ICa is determined by the capacitor Ca and the resistor Ra.
ICb is another timer circuit, which starts the timer operation when the timer input Bi rises to the high level,
The timer output Bo is maintained at the High level for at least the time (for example, 15 minutes) required to restart the discharge lamp DL1 or DL2. As a result, the relay Ry is excited and its contact Sb is held ON. This timer time is determined by the capacitor Cb and the resistor Rb. After that, when the timer time elapses, the timer output Bo becomes Low level. As a result, the excitation of the relay Ry is released, and the contact Sb of the relay Ry becomes O.
Become FF.

FIG. 3 is a diagram for explaining the operation of this embodiment. Figure 3
3A is the voltage of the AC power supply Vs, FIG. 3B is the timer output Ao of the timer circuit ICa, FIG. 3C is the timer output Bo of the timer circuit ICb, and FIG. 3D is ON / OFF of the switch element Sb. OFF, FIG. 3 (e) shows turning on / off of the discharge lamp DL1, and FIG. 3 (f) shows turning on / off of the discharge lamp DL1. Hereinafter, the operation when the discharge lamp DL1 is started and normally lit and then extinguished due to the instantaneous voltage drop of the AC power supply Vs will be described. In the figure, after turning on the AC power supply Vs at time t1 and starting the discharge lamp DL1 at time t2, after the time required for starting the discharge lamp DL1 (about 10 seconds) has elapsed, at time t3, the timer of the timer circuit ICa The output Ao becomes High level. As a result, the timer circuit ICb starts the timer operation, and the timer output B
o becomes High level, and the switch element Sb is turned on. After that, after the time required for restarting the discharge lamp DL1 (about 15 minutes) has elapsed, the timer output Bo of the timer circuit ICb becomes Low level, and the switch element Sb is turned off. After that, the discharge lamp DL1 is normally turned on until time t4.

Now, at time t4, when the power supply voltage of the AC power supply Vs drops momentarily, the discharge lamp DL1 goes out. Time t
5, even if the power supply voltage of the AC power supply Vs is restored, the discharge lamp DL
1 cannot restart immediately. Therefore, the discharge lamp DL
The discharge lamp DL1 does not start even after the time (about 10 seconds) required for the normal start of No. 1 has elapsed. In this case, the switch element Sb is turned on at time t6, so that the discharge lamp DL2
Lights up. Then, after the time required for restarting the discharge lamp DL1 (about 15 minutes) has elapsed, the switch element Sb is turned off at time t7. As a result, the discharge lamp DL2 is turned off and the discharge lamp DL1 is turned on. With the above operation, light compensation can be performed with a simple structure, and the device can be downsized.

FIG. 4 is a circuit diagram of the second embodiment of the present invention. In this embodiment, the timer circuit ICb is omitted from the first embodiment shown in FIG. In this circuit, when the discharge lamp DL1 is extinguished due to the instantaneous voltage drop of the AC power supply Vs, the other discharge lamps DL2 are kept lit until the AC power supply Vs is reset. And the cost can be reduced. Further, in the case of the first embodiment shown in FIG. 2, when the discharge lamp DL1 is extinguished due to the end of life or the like, the discharge lamps DL1 and DL2 alternately blink, but there is a drawback. In the case of the second embodiment shown, there is an advantage that the blinking is not repeated because the other discharge lamp DL2 remains lit.

FIG. 5 is a diagram for explaining the operation of this embodiment. Figure 5
5A shows the voltage of the AC power supply Vs, FIG. 5B shows the timer output Ao of the timer circuit ICa, FIG. 5C shows ON / OFF of the switch element Sb, and FIG. 5D shows lighting of the discharge lamp DL1. Turning off, FIG. 5 (e) shows turning on / off of the discharge lamp DL2. Hereinafter, the operation when the discharge lamp DL1 is started and normally lit and then extinguished due to the instantaneous voltage drop of the AC power supply Vs will be described. In the figure, after turning on the AC power supply Vs at time t1 and starting the discharge lamp DL1 at time t2, after the time required for starting the discharge lamp DL1 (about 10 seconds) has elapsed, at time t3, the timer of the timer circuit ICa The output Ao becomes High level. As a result, the switch element Sb is turned on. After that, the discharge lamp DL1 is normally turned on until time t4.

Now, at time t4, when the power supply voltage of the AC power supply Vs instantaneously drops, the discharge lamp DL1 goes out. Time t
5, even if the power supply voltage of the AC power supply Vs is restored, the discharge lamp DL
1 cannot restart immediately. Therefore, the discharge lamp DL
The discharge lamp DL1 does not start even after the time (about 10 seconds) required for the normal start of No. 1 has elapsed. In this embodiment, since the switch element Sb is already turned on at the time t3,
The discharge lamp DL2 is turned on. With the above operation, light compensation can be performed with a simple structure, and the device can be downsized.

FIG. 6 is a circuit diagram of the third embodiment of the present invention. The same elements as those of the first embodiment shown in FIG. 2 are designated by the same reference numerals and the description thereof will be omitted. In the figure, CT is a current transformer, G1 is a counter circuit, Sc is a switch element, and 6 is an OR circuit. The basic operation is the same as that of the first embodiment shown in FIG. 2, except that a circuit for preventing repeated blinking at the end of the life of the discharge lamp DL1 is added. The lamp current is detected by the current transformer CT, the number of times the discharge lamp is not lit is counted by the counter circuit G1, and when the predetermined number is reached, the switch element Sc is turned on by the output of the counter circuit G1. As a result, the driving transistor Q1 is supplied with the high-level output of the timer circuit ICa via the OR circuit 6, and the other discharge lamp DL2 is kept lit.

FIG. 7 is a circuit diagram of the fourth embodiment of the present invention. The same elements as those of the second embodiment shown in FIG. 4 are designated by the same reference numerals and the description thereof will be omitted. In FIG. 7, 7 is a current detection circuit, 8 is an abnormality determination circuit, and 9 is a drive circuit. When the discharge lamp DL1 is in an abnormal state, the detection signal from the current detection circuit 7 is determined to be abnormal by the abnormality determination circuit 8, and the discharge lamp DL1 is detected.
It outputs a single signal for the time when 1 disappears. By this signal, the switch element Sd is momentarily turned off via the drive circuit 9. That is, for example, if the discharge lamp DL1 becomes abnormal during lighting, the switch element Sd momentarily becomes OF.
After that, the discharge lamp DL1 goes out, and then the switch element Sd is turned on to start the discharge lamp DL2. By using such a circuit configuration, not only the light compensation when the discharge lamp is not lit, but also the abnormal discharge lamp can be turned off and the lighting can be switched to another discharge lamp with a simple configuration.
Here, the abnormality of the discharge lamp is a mode in which a state in which the lamp current abnormally increases due to slow leak, half-wave discharge, etc. continues, and the heat generation of the inductor L1 increases, and if the inductor L1 continues for a long time, Winding may cause smoke or fire.

FIG. 8 shows a specific configuration of the circuit shown in FIG. First, the current detection circuit 7 includes a current transformer 71 for detecting a lamp current and a current transformer 71.
And a rectifier circuit 72 for rectifying the secondary winding output of the. Next, the abnormality determination circuit 8 includes timer circuits IC8 and IC9 which are general-purpose integrated circuits. The operating time of the timer circuit IC8 is the resistance R ₈ and the capacitor C ₈
It is set by the time constant of. Also, the timer circuit I
The operating time of C9 is set by the time constant of the resistor R ₉ and the capacitor C ₉ . The detection signal of the current detection circuit 7 is
The values are averaged by the time constants of the resistor R ₇ and the capacitor C ₇ and applied to the inverting input terminal of the comparator 81 composed of a general-purpose operational amplifier. The reference voltage Vk is applied to the non-inverting input terminal of the comparator 81. The output terminal of the comparator 81 is connected to the input terminal of the timer circuit IC8. The output terminal of the timer circuit IC8 is input to the logical sum circuit 82 together with the output terminal of the comparator 81. The output terminal of the OR circuit 82 is connected to the input terminal of the timer circuit IC9. Next, the drive circuit 9 is composed of a pulse transformer 91 whose primary side is connected to the output terminal of the timer circuit IC9, and a relay 92 which is connected to the secondary side of the pulse transformer 91. The contact of the relay 92 is the switch element Sd.

FIG. 9 is a circuit diagram of the main circuit portion of the fifth embodiment of the present invention, and FIG. 10 is a circuit diagram of the control circuit portion of the present embodiment. The circuit configuration will be described below. First, the main circuit section will be described. The positive electrode of the DC power supply V1 is N
The cathode of the diode D1 and one end of the inductor L1 are connected via a switching element S1 formed of a PN type power transistor or the like. The other ends of the discharge lamps DL1 and DL2 are connected to the diode D via the lamp current detection circuit 1.
It is connected to the anode of No. 1 and the negative electrode of the DC power supply V1, and is grounded. The lamp current detection circuit 1 includes a resistor for current-voltage conversion. Discharge lamp DL1 or DL2
When the current flowing through the resistor flows through the resistor, a voltage drop occurs across the resistor, and this voltage is output as a lamp current detection signal. It should be noted that the output of the lamp current detection circuit 1 is averaged by a capacitor or the like connected in parallel to the resistor and does not include a high frequency component.

Next, the control circuit 2 includes an integrated circuit IC1 for a switching regulator. The output voltage of the lamp current detection circuit 1 is input to the input terminal IN of the integrated circuit IC1 as a lamp current detection signal. Then, depending on the magnitude of the detection signal, the output terminal O of the integrated circuit IC1
The duty of the control signal output from the UT (the ratio between the high level period and the low level period) changes. The output terminal OUT of the integrated circuit IC1 has an open collector output and is pulled up to the level of the control power supply voltage Vcc by the resistor R ₁ . The fundamental oscillation frequency of the control signal is determined by the time constant of the capacitor C ₂ and the resistor R ₂ .

The drive circuit 3 comprises a pulse transformer PT ₃ , one end of the primary winding of which has an output terminal O of the control circuit 2.
It is connected to the UT. The other end of the primary winding of the pulse transformer PT ₃ is grounded via the capacitor C ₃ . A series circuit of resistors R ₃ and R ₀ is connected to the secondary winding of the pulse transformer PT ₃ , and a signal obtained at both ends of the resistor R ₀ is given to the control electrode of the switching element S1.

The overcurrent detection circuit 4 includes timer circuits IC2 and IC3 which are general-purpose integrated circuits. The operating time of the timer circuit IC2 is the resistance R ₄ and the capacitor C ₄
It is set by the time constant of. Also, the timer circuit I
The operating time of C3 is set by the time constant of the resistor R ₅ and the capacitor C ₅ . The detection signal of the lamp current detection circuit 1 is applied to the inverting input terminal of the comparator 41 which is a general-purpose operational amplifier. The reference voltage Vk is applied to the non-inverting input terminal of the comparator 41. The output terminal of the comparator 41 is connected to the input terminal of the timer circuit IC2. The output terminal of the timer circuit IC2 is
It is input to the logical sum circuit 42 together with the output terminal of the comparator 41. The output terminal of the OR circuit 42 is connected to the input terminal of the timer circuit IC3. The output terminal of the timer circuit IC3 is connected to the base of the transistor Q ₀ . The emitter of the transistor Q ₀ is grounded, and the collector is connected to the output terminal of the control circuit 2.

FIG. 11 is a diagram for explaining the operation of this embodiment. 11A shows a current flowing through the discharge lamp DL1 (or DL2), and FIG. 11B shows an output voltage V of the lamp current detection circuit 1.
b, FIG. 11C is a voltage Vc at the output terminal of the comparator 41, FIG. 11D is a voltage Vd at the output terminal of the timer circuit IC2, and FIG. 11E is a voltage Ve at the input terminal of the timer circuit IC3. 11 (f) is the voltage Vf of the output terminal of the timer circuit IC3, and FIG. 11 (g) is the switching element S.
1 drive signal.

The operation of this embodiment will be described below.
When the DC power supply V1 is turned on at the timing of t1 in FIG. 11, the discharge lamp DL1 is started at the timing of t2. The voltage Vb detected by the lamp current detection circuit 1 is shown in FIG.
As shown in (b), it is compared with the reference voltage Vk by the comparator 41. The reference voltage Vk is set between the normal voltage and the abnormal voltage. Comparator 4
The output voltage Vc of 1 is as shown in FIG.
The timer circuit IC2 starts the timer operation after the voltage Vc at the input terminal changes from the high level to the low level, and as shown in FIG. 11 (d), for the time T4 determined by the time constant of the resistor R ₄ and the capacitor C _4. The voltage Vd at the output terminal becomes High level. This timer circuit IC2
By inputting the input voltage Vc and the output voltage Vd of the above into the logical sum circuit 42, the output voltage Ve of the logical sum circuit 42 becomes as shown in FIG. When the output voltage Ve of the logical sum circuit 42 changes from the high level to the low level, the timer circuit IC3 starts the timer operation and is determined by the time constant of the resistor R ₅ and the capacitor C ₅ as shown in FIG. 11 (f). During the period T5, the output terminal voltage Vf is H
It becomes the high level. As a result, the transistor Q ₀ is turned on, the output signal of the control circuit 2 is clamped, and Lo
The w level is maintained, and the switching element S1 stops operating at the timing of t6 to t7 in FIG. Then t7
When the switching element S1 restarts oscillation at the timing of, the discharge lamp DL2 is started.

Here, the timer circuit IC2 is used by the lamp current detection circuit 1 to determine whether the discharge lamp starts when the detection voltage Vb exceeds the reference voltage Vk or when there is an abnormality, and the detection voltage Vb uses the reference voltage Vk. It is determined whether or not the detected voltage Vb still exceeds the reference voltage Vk when at least the discharge lamp starting process time has elapsed since the voltage exceeded. Even if the detection voltage Vb detected by the lamp current detection circuit 1 transiently rises at the time of starting the discharge lamp, the detection voltage Vb becomes the reference voltage Vk when the starting process time of the discharge lamp elapses.
Since it is smaller than the above, it is not determined to be an abnormal state. On the contrary, when the discharge lamp is abnormal, the detection voltage Vb is always higher than the reference voltage Vk. Therefore, if the detection voltage Vb of the lamp current detection circuit 1 exceeds the reference voltage Vk for the set time T4 of the timer circuit IC2 or more. , Judge as an abnormal condition. The other timer circuit IC3 sets at least the time required for the discharge lamp to go out.

[0025]

According to the discharge lamp lighting device of the first aspect, another discharge lamp is turned on instead of the discharge lamp whose lamp is extinguished and the starting voltage is increased. Therefore, the discharge lamp is turned on by an instantaneous voltage drop of the power supply voltage. Even if the inside discharge lamp goes out, there is an effect that it is possible to solve the inconvenience that the light output is not obtained before the restart.

According to the discharge lamp lighting device of the second aspect,
When the extinguished discharge lamp becomes restartable, the discharge lamp that was lit as an alternative means goes out and the discharge lamp that was lit at the beginning lights up, so the color temperature of multiple discharge lamps and rated output Even when the values are different, the desired discharge lamp can be operated so as to be preferentially turned on.

According to the discharge lamp lighting device of the third aspect,
The discharged discharge lamp remains extinguished, and another discharge lamp that has been turned on continues to be turned on as an alternative means, which has the advantage of simplifying the configuration of the control means.

According to the discharge lamp lighting device of the fourth aspect,
If the discharge lamp repeatedly goes out even if the power is on, the alternative discharge lamp can be lit up until the power is shut off without restarting the extinguished discharge lamp. Therefore, it is possible to prevent the blinking of the optical output from continuing.

According to the discharge lamp lighting device of the fifth aspect,
By momentarily cutting off the switch element connected in series to the power supply, it is possible to extinguish a discharge lamp that is in an abnormal state at the end of its life, etc., and turn on another discharge lamp connected in parallel with it. There is an effect that switching from an abnormal discharge lamp to a normal discharge lamp can be realized with a simple circuit configuration by skillfully utilizing the property that the starting voltage of the discharge lamp increases.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a basic configuration of the present invention.

FIG. 2 is a circuit diagram of the first embodiment of the present invention.

FIG. 3 is an operation explanatory diagram of the first embodiment of the present invention.

FIG. 4 is a circuit diagram of a second embodiment of the present invention.

FIG. 5 is an operation explanatory diagram of the second embodiment of the present invention.

FIG. 6 is a circuit diagram of a third embodiment of the present invention.

FIG. 7 is a circuit diagram showing a basic circuit configuration of a fourth embodiment of the present invention.

FIG. 8 is a circuit diagram showing a specific circuit configuration of a fourth embodiment of the present invention.

FIG. 9 is a circuit diagram showing a basic circuit configuration of a fifth embodiment of the present invention.

FIG. 10 is a circuit diagram showing a specific circuit configuration of a fifth embodiment of the present invention.

FIG. 11 is an operation explanatory diagram of the fifth embodiment of the present invention.

FIG. 12 is a circuit diagram of a conventional example.

FIG. 13 is a circuit diagram of another conventional example.

[Explanation of symbols]

 Vs AC power supply Sa switch element Sb switch element L1 inductor K control circuit DL1 discharge lamp DL2 discharge lamp

Claims (5)

[Claims] 1. A first switch element for selectively connecting at least one of a plurality of discharge lamps to a power source via a current limiting element, and the discharge switch after the at least one discharge lamp is started. A discharge lamp lighting device comprising a second switch element for connecting at least one other discharge lamp in parallel to the electric lamp. 2. After a lapse of a predetermined time required for restarting the discharge lamp connected to the power source through the first switch element,
The discharge lamp lighting device according to claim 1, further comprising control means for turning off the second switch element. 3. The discharge lamp lighting device according to claim 1, wherein once the second switch element is turned on, the second switch element is kept on until the power is cut off. 4. A counter circuit for detecting the number of extinguishing times of a discharge lamp connected to a power source via a first switch element, wherein the extinguishing number of times is detected while the power source is continuously energized. The discharge lamp lighting device according to claim 2, wherein the control means is sometimes configured to keep the second switch element in an ON state until the power is cut off. 5. A discharge lamp lighting device in which a plurality of discharge lamps are connected in parallel to a power source via a current limiting element, and an abnormality detection unit for detecting an abnormality of the discharging discharge lamp is provided, and the abnormality is detected. Control means for holding the switch element connected in series to the power source in the OFF state for at least the time necessary for the discharge lamp to extinguish, and for returning the switch element to the ON state again after the discharge lamp extinguishes. Discharge lamp lighting device characterized by.