JPH0223044A - Emergency discharge lamp lighting device - Google Patents

Abstract

PURPOSE:To reduce the size and weight of circuit by recharging the battery, in a circuit for lighting a discharge lamp through an output transformer with AC current produced by driving an oscillation circuit with the battery upon occurrence of power interruption, through the output transformer when the power is not interrupted. CONSTITUTION:Upon interruption of an AC power source 27, a first oscillation circuit 7 is driven with the output from a first DC power source equipment 1 comprising a battery 2 to produce high frequency output which is then fed through an output transformer 4 to a secondary winding 17 in order to produce high frequency output lighting a discharge lamp 14. Current fed from the AC power source 27 is normally rectified 28 and smoothed through a second DC power source equipment 30 and fed to a second oscillation circuit 32 which transmits high frequency wave to the secondary winding 17 of the output transformer 4 lighting the discharge lamp 14. At the same time, the high frequency wave transferred from the secondary 17 to the primary 5 of the output transformer 4 is rectified 39 through a recharge circuit 37 in order to recharge the battery 2. By such arrangement, the size and weight of the device are reduced, resulting in cost reduction.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a discharge lamp emergency light lighting device, and is a device for lighting a discharge lamp using a battery power source in an emergency such as a power outage. The present invention relates to a device for charging a battery of the emergency power source while lighting a discharge lamp.

(Prior Art) In a conventional discharge lamp lighting device, in order to charge a battery as an emergency power source, for example, Japanese Patent Laid-Open No. 53-1142
As described in Japanese Patent No. 73, a charging transformer is used in addition to the output transformer of the oscillation circuit, and the battery is charged when the discharge lamp is lit by the AC power source.

(Problems to be Solved by the Invention) The conventional discharge lamp emergency light lighting device described above requires the use of a charging-only transformer that is used only for charging the battery, resulting in high cost and the need to incorporate a charging transformer. Therefore, there were problems such as being heavy and requiring space to incorporate a charging transformer, making the device larger.

The present invention has been made in view of the above-mentioned problems, and while a discharge lamp is lit by a normal AC power source, the primary winding of the output transformer of the first oscillation circuit operated by the output of the battery power source is To provide a TIl electric lamp emergency light lighting device which rectifies the induced voltage to charge a battery, eliminates a transformer exclusively for charging, is inexpensive, lightweight, and can be incorporated into a small size.

[Structure of the invention]

(Means for Solving the Problems) The discharge lamp emergency light lighting device of the present invention includes a first DC power supply device composed of a battery power source, and a secondary winding side of an output transformer using an input of the first DC power supply device. a first oscillator circuit that generates a high-frequency output, a second DC power supply that smoothes and rectifies an AC power source and outputs a DC power source, and a secondary winding of an output transformer by the input of the second DC power supply. a second oscillation circuit that generates a high frequency output on the side; a discharge lamp that is connected to the secondary winding side of the output transformer and is lit by the high frequency output of either the first or second oscillation circuit;
switching means for causing the first DC power supply to oscillate the first oscillation circuit instead of the second oscillation circuit when the second DC 2N power supply is cut off, the first oscillation circuit A charging circuit having a charging diode is provided in parallel with the oscillation transistor.

(Function) The discharge lamp emergency light lighting device of the present invention normally smoothes and rectifies the output of the AC power supply in the second DC power supply device.
The high frequency output is supplied to the secondary winding of the output transformer of the first oscillation circuit, and the discharge lamp is lit by the oscillation action of the second oscillation circuit. Then, the voltage induced on the primary winding side of the output transformer of the first oscillation circuit is rectified by a rectifier diode of a charging circuit connected in parallel with the oscillation transistor to charge the battery with a pulsating current. When AC power is not supplied, the first oscillation circuit is operated with the output from the DC N source device of the battery N source Ml, and the discharge lamp is lit with the high frequency output induced in the secondary winding side of the output transformer. let

(Embodiment) The configuration of an embodiment of the present invention will be described with reference to FIG. 1 of the drawings.

Reference numeral 1 designates a first DC power supply device, which has a battery power supply 2. The 1-pole side of the battery power supply 2 is connected to an input inductor, e.g. 85 intermediate taps 6 are connected. Both ends of the primary winding 5 of the output transformer 4 are connected to a self-excitation oscillation circuit 7 which is a first oscillation circuit, and this self-excitation oscillation circuit 7 is connected to one side of the battery power supply 2. ing.

The self-excited oscillation circuit 7 is a primary winding m of the output transformer 4.
Each oscillation transistor 8.9 has a collector connected to both ends of the oscillation transistor 8.
, 9 are connected in common to one pole side of the battery power source 2. Each base of each oscillation transistor 8.9 is connected to the slave side of the battery power source 2 via a starting resistor 10.11, and each base of each oscillation transistor 8.9 is connected to the feedback winding of the output transformer 4. Connected to both ends of line 12. In addition, a resonant capacitor 13 is connected in parallel with the second winding 5 of the output transformer 4.
is connected.

Further, 14 is a discharge lamp, and filaments 15 and 16 of this discharge lamp 14 are connected to the secondary winding 17 of the output transformer 4.
A ballast inductor, for example, a ballast transformer 18
A preheating circuit is connected via the primary winding, and the secondary preheating windings 19.20 of the output transformer 4 are respectively connected to the filament 15.16 of the discharge lamp 14 via a preheating control transformer 21.22. Connected to 23.24. This preheating control transformer 21 -・Next answer aI2
2. The winding directions of 22 are opposite to each other, and the preheating &11 ti11 circuit 25 formed by the leap path connected to this preheating control transformer 21 and this secondary winding includes a switch serving as a preheating I11 control switch means. When the preheating control switch element 26 is opened, the elements 26 and the heat control transformers 21 and 22 generate electromotive forces in opposite directions for the same current direction, and are in a relationship that cancels each other out. When the preheating control switch element 26 is short-circuited, the inductance of the primary winding 1i; i22°22 of the preheating control transformer 21 is reduced. The preheating control switch element 26 is opened when the discharge lamp 14 is turned on, and uses, for example, a relay or an inductor operated by a switch drive signal, and sets a low excavation frequency during preheating. When lighting, a high oscillation frequency is set and a switching effect is performed. Also, this preheating I
The ll till switch element 26 uses the signal as a trigger by energizing a circuit that detects the lamp current when the discharge lamp 14 is lit, or by energizing a circuit that detects the voltage when the discharge lamp 14 is lit. Relays and semiconductors that perform switching can be used.

Further, 27 is a commercial AC power source, and this AC power source 27 is connected to a rectifier circuit 28 that full-wave rectifies the power from this AC power source 27 and converts it into DC, and is connected to both ends of this rectifier circuit 28.
Smoothing capacitor 29 smoothing the output of this rectifier circuit 28
A second DC power supply device 30 is configured.

A separately excited oscillation circuit 32 serving as a second oscillation circuit is connected between the two poles of the second DC power supply device 30. The separately excited oscillation circuit 32 has a power supply resistor 33 and a power stabilizing capacitor 34 connected in series between the two poles of the second DC power supply device 30. connection point and the second DC power supply device 30
A switching control t[lIc35 is connected between one pole side of the t[lIc35. This control 1C35 has an excavation transistor 3.
6 is connected, and the collector of this oscillation transistor 36 is connected to one filament 15 of the discharge lamp 14.
and one end of the secondary winding of the output transformer 4, and its emitter is connected to one pole side of the second DC power supply device 30. Further, the slave side of the second DC type Ill device 30 is connected to a connection point between the other filament 16 of the discharge lamp 14 and the other end of the secondary winding of the output transformer 4.

Further, 37 is a charging circuit, and rectifier diodes 38 and 39 and current limiting resistors 40 and 41 connected in series between the emitters and collectors of the oscillation transistors 8 and 9 of the self-help oscillation circuit 7 are connected, respectively.

Further, 79 detects the output of the second DC power supply device 30, and while this second DC power supply vA device 30 is outputting, the excavation of the first excavation circuit 7 is stopped and the second DC power supply device 79 detects the output of the second DC power supply device 30. Power supply device 3
This is a switching means that operates the first oscillation circuit 7 when the output of 0 is cut off.

Next, the operation of this embodiment will be explained.

In normal times, when the Tt source switch (not shown) is opened, the AC input from the commercial power supply 27 is full-wave rectified by the DC power supply 30, and the DC output is supplied to the external excitation circuit 32. III [C circuit 35 is activated and excavation transistor 36 is turned on. Further, the DC power outputted from the second DC power supply device 30 is transmitted from the 1-pole side through the discharge lamp 14, through the oscillation transistor 36 of the separately excitation line circuit 32, which is turned on, and then to the second DC power source 30. The discharge lamp 14 is lit by the high-frequency output generated by the separate excitation line circuit 32, which flows to one pole side of the 12-source device 3G.

When the discharge lamp 14 is turned on, the voltage induced in the primary winding l115 of the output transformer 4 is controlled by a current limiting resistor 40°41.
, the pulsating current flowing through the charging diodes 38 and 39 charges the disjoint power source. Further, when the second DC power supply device 30 is cut off, the switching means 79 supplies the drain power output from the battery voltage [2 of the DC power supply device ff1 to the self-excited oscillation circuit 7, and the starting resistor 10.11 is Then, a current flows from the base of the oscillating transistor 8.9 to the emitter, the oscillating transistor 8.9 is operated in oscillation, and the high frequency voltage induced in the secondary winding 17 of the output transformer 5 is applied to the discharge lamp 14. , the discharge lamp 14 is turned on. When starting the discharge lamp 14, a voltage is applied to the filaments 15, 16 of the discharge lamp 14 in the preheating circuits 23, 24, respectively.

At this time, the preheating control switch element 26 of the preheating control circuit 25
is closed, the inductance of the primary winding IJ22.22 of the preheating control transformer 21 of the preheating circuit 23.24 is reduced, and the filament 15 of the discharge lamp 14 is
．． A preheating current flows through 16. This filament 15,1
6 is preheated, Group 1 lamp 14 outputs! -Both filaments 15 and 16 of the discharge lamp 14 connected to both ends of the secondary winding 17 of the lance 5 via the ballast transformer 18
During this time, discharge is started and the discharge lamp 14 is lit.

When the discharge lamp 14 is turned on, the preheating control circuit 2
The preheating-control switch element 2G of No. 5 is connected to the discharge lamp 14.
(7) Pre-off
1ilIllal” Lance 21(7)-Next tN122.
22N, electromotive forces in opposite directions are generated, cancel each other out, increase the inductance of the primary winding, and prevent the flow of preheating current.

Next, the configuration of a specific embodiment of the present invention will be explained with reference to FIG. 2 of the drawings.

Similar to the configuration shown in FIG.
Output transformer 4, self-help oscillation circuit 7 which becomes the first oscillation circuit
, a discharge lamp lighting circuit having a discharge lamp 14, a preheating circuit 23, 24, a preheating control circuit 25, a second DC power supply circuit 30, a separately excited oscillation circuit 32 serving as a second oscillation circuit, and a charging circuit 37; The bases of the oscillation transistors 8 and 9 of the self-help oscillation circuit 7 serving as the first oscillation circuit are connected to the output side of the oscillation stop circuit 45 of the illustrated switching means 79 via a starting resistor 10.11.

Further, the commercial AC power supply 27 is connected to a rectifier circuit 28 that rectifies the power from the AC power supply 21 and converts it into DC via a fuse 46, and is connected to both ends of the rectifier circuit 28, and the output of the rectifier circuit 28 is A second DC power supply device 30 includes a smoothing capacitor 29 for smoothing the current. A discharge resistor 47 is connected in parallel to this smoothing capacitor 29.

A separately excited oscillation circuit 32 is connected between both types of this second DC power supply device 30. The separately excited oscillation circuit 32 has a power supply resistor 33 and a power stabilizing capacitor 34 connected in series between both types of the second DC ill device 30,
A switching Ib'1lll IC 35 is connected between the connection point between the power supply resistor 33 and the power supply stabilizing capacitor 34 and one pole side of the second DC power supply device 30. The control 1035 is connected to a pulse width adjusting variable resistor 48 and a time constant capacitor 49 for determining the oscillation frequency, which are connected to the -pole side of the DC power supply 30. Further, a bias resistor 50 is connected to this control 111C35, and a collector of an NPN type main transistor 51 is connected to this bias resistor 50 and a connection point between the power supply resistor 33 and the power supply stabilizing capacitor 34. A PNP drive transistor 52 is connected to the emitter of the drive transistor 52, and the collector of the drive transistor 52 is connected to one pole side of the second DC power supply 30, and the bases of both transistors 51 and 52 are connected to a common terminal. It is connected to the surface writing control IC 35. A bias resistor 53 is connected between the base connection point and the emitter connection point of both transistors 51 and 52, and the oscillation transistor 36 is connected to the emitter connection point of both transistors 51 and 52 via a drive base resistor 54. A handling diode 55 is connected in parallel with this drive base resistor 54. Further, a bias resistor 57 connected to one pole side of the second DC power supply device 30 is connected to a connection point between the base of the oscillation transistor 36 and the drive base resistor 54. Further, the emitter of this oscillation transistor 36 is connected to the one pole side of the DC power supply device 3Q, and a snubber resistor 58 and a spanner capacitor 59 are connected in series in parallel between the collector and emitter of this oscillation transistor 36. . The collector of the oscillation transistor 36 is connected to the connection point between the backflow blocking diode 60 and the clamp circuit diode 61, and the clamp circuit diode 61 is connected to the clamp circuit capacitor 62. A clamp circuit resistor 63 is connected in parallel, and this clamp circuit capacitor 62 is connected to one pole side of the second DC power supply device 30.

Further, an IC oscillation frequency determining time constant resistor 64,65 is connected to the control IC 35, and an oscillation frequency switching transistor 66 is connected to the IC oscillating frequency determining time constant resistor 65.
The emitter of this oscillation frequency switching transistor 66 is connected to the connection point of the IC oscillation frequency determining time constant resistor 64, 65, and the base of this oscillation frequency switching transistor 6G is connected to a bias resistor 67. Furthermore, a bias resistor 68 is connected between the base and emitter of this oscillation frequency switching transistor 66.
fiVll is connected.

Further, the secondary winding of the ballast transformer 18 is connected to a bias resistor 67 connected to the base of the oscillation frequency switching transistor 66 via a rectifier diode 69,
The other end of the secondary winding of this ballast transformer 18 is connected to the emitter of the oscillation frequency switching transistor 66. Further, a discharge resistor 10 and a smoothing capacitor 71 are connected in parallel with the secondary winding of this ballast transformer 18, respectively.

Further, the charging circuit 37 is connected to the intermediate tap 6 of the primary winding 5 of the output transformer 4 from the battery power source 2, and to both ends of the secondary winding 5, and is connected to each emergency oscillation transistor of the self-help oscillation circuit 7. Charging diodes 38.8.9 are connected in parallel between the collectors and emitters of 38.
39, a current reducing resistor 40.degree. 41, and a circuit extending to one pole of the battery power source 2.

Furthermore, 72 is an AC power input detection circuit of the switching means 79;
connected in series between the connection point between the power supply resistor 33 and the power stabilizing capacitor 34 connected to the child side of the second DC power supply 30 and the single pole side of the second DC power supply 113G. It is formed by a switching Zener diode 73, a Zener diode bias resistor 74, and a photocoupler light emitting element 15.

Furthermore, the oscillation stop circuit 45 includes a connection point between the input choke coil 3 connected to the secondary side of the battery power source 2 and the starting resistor 10.11 connected to the base of the oscillation transistor 8.9 of the self-excited oscillation circuit 7. The emitter and collector of a PNPN switching transistor 76 are connected between the base and the collector of the switching transistor 76, and a bias resistor 77 is connected between the base and collector of the switching transistor 76. Also, this switching 1
The collector and emitter of the photocoupler photoreceptor 18 are connected between the emitter and base of the Ranjistaf 6.

In this way, the switching means 79 is in contact with the oscillation stop circuit 45.
' R source input detection circuit 72.

Next, the operation of this embodiment will be explained.

Normally, when a power switch (not shown) is opened, the AC input from the commercial AC power supply 27 is full-wave rectified by the second DC power supply 30 and outputted to the passive oscillation circuit 3.
2, the υJIIt IC circuit 35 operates,
Main transistor 51 and drive transistor 52 are rendered conductive, and oscillation transistor 36 is rendered conductive. Also the second
The DC power output from the DC power supply F3G is applied to the secondary winding 11 of the output transformer 4, and the voltage induced in the preheating winding 19, 20 of the output transformer 4 is applied to the filament 15, 16 of the discharge lamp 14. are added to each.

At this time, the preheating control switch/element 2 of the preheating control circuit 25
6 is open, the inductance of the primary winding 22.22 of the preheating control transformer 21 of the preheating circuit 23.24 is reduced, and the filament 15 of the discharge lamp 14 is
．． A preheating current flows through 16. This filament 1-15.
16 is preheated, the discharge lamp 14 is discharged, and the DC power supplied from the →-one pole side of the second DC power supply device 30 is passed through the ballast transformer 18 and from one filament 15 of the discharge lamp 14 to the other. The electric current flows to one pole side of the second DC power supply device 30 through the filament 16 and the oscillation transistor 36 of the separately excited oscillation circuit 32, which is turned on, and the discharge lamp 14 is lit. When the discharge lamp 14 is turned on, the voltage induced in the secondary winding of the ballast transformer 18 turns on the oscillation frequency switching transistor 6G, and the separately excited oscillation circuit 32 operates the IC oscillation oscillation frequency determining time constant capacitor 4.
9 and the IC oscillation frequency determination time constant.The discharge lamp 1 is oscillated at a frequency determined by the time constant of the resistors 64 and 65.
4, it is turned on by the high frequency output output from the separately excited oscillation circuit 32. When the discharge lamp 14 is turned on, the preheating control switch element 26 of the preheating control circuit 25 is driven by the lighting signal of the discharge lamp 14 and opened, and the primary windings 22 and 22 of the preheating control transformer 21 are Electromotive forces in opposite directions are generated and cancel each other out, increasing the inductance of the primary winding and blocking the flow of preheating current.

Further, when the discharge lamp 14 is turned on, the voltage induced in the primary winding 5 of the output transformer 4 by the switching action of the oscillation transistor 36 is transferred to the charging diode 38, 39.
Full-wave rectification is carried out at the input choke coil 3, battery power supply 2,
Current reducing resistor 40, charging diode 38 or current reducing resistor 4
1. A charging circuit 31 that connects both ends of the primary winding 5 of the output 1-lance 4 via a charging diode 39 supplies a pulsating current to the battery power source 2 to charge it. At this time, the oscillation frequency of the self-help oscillation circuit 7 determined by the resonance capacitor 13 and the output transformer 4, the oscillation wave number determining time constant capacitor 49 for IC oscillation, and the time constant resistor 64 for determining the frequency for IC oscillation.
There is a difference in the frequency of the separately excited circuit 32 determined by the time constant of 65, and the discharge lamp 1 is caused by the oscillation of the separately excited circuit 32 by adjusting the impedance of the ballast transformer 18.
4 continues lighting. In addition, when DC is normally being supplied from the DC power supply device 30, the photocoupler photodetector 78 of the oscillation stop circuit 45 is non-conductive due to the light emission from the photocoupler photodiode 75 of the AC power input detection circuit 72, and switching is performed. Due to the non-conduction of the transistor 76, battery power is applied to the self-help oscillation circuit 7! The DC power source 2 is not supplied, the oscillation transistor 8.9 is not oscillated, and the self-excited oscillation circuit 7 is not activated.

In addition, in an emergency such as a power outage, when the voltage of the AC power supply 21 disappears, the output from the second DC power supply 30 disappears.
The photocoupler light emitter 75 of the AC power supply input detection circuit 72 conducts the photocoupler photodetector 78 of the lift stop circuit 45,
When the switching transistor 16 becomes conductive, DC power from the battery power source 2 is supplied to the self-excited oscillation circuit 7, one of the oscillation transistors 8 and 9 becomes conductive, and the automatic oscillation circuit 7 oscillates.
The pair of transistors 8 and 9 are feedback-controlled by the output generated in the feedback winding 12 and become conductive and non-conductive alternately. A high-frequency output having a frequency of 1 is generated via the ballast transformer 18, and the discharge lamp 14 is lit.

Note that during this emergency lighting, the charging diodes 66, 67 and charging resistors 68, 69 of the charging circuit 37 have the function of absorbing surges generated by the operation of the automatic oscillation circuit 7.

In addition, when starting with the battery power supply 2, by opening a power switch (not shown), the DC power of the battery power supply 2 is supplied to the self-help oscillation circuit 7, and one of the oscillation transistors 8 and 9 becomes conductive, and self-excited oscillation is started. Circuit 7 oscillates and feedback winding 1
A pair of transistors 8.9 are feedback-controlled by the output generated at the output transformer 2, and are alternately made conductive and non-conductive. High frequency power is supplied to the discharge lamp 14 via a ballast transformer 18. At this time, when applied to the secondary winding 17 of the output transformer 4, the voltage induced in the preheating winding $919.20 of the output transformer 4 is applied to the filaments h15 and 16 of the discharge lamp 14, respectively. At this time, the preheating control circuit 25 preheating W 1+1
Since the 1fl switch element 26 is closed, the inductance of the primary winding 22, 22 of the preheating control transformer 21 of the preheating circuit 23, 24 is reduced, and a preheating current is applied to the filament 15, 16 of the discharge lamp 14. flows.

Then, by preheating the filament 15.16, the discharge lamp 1
4 lights up, the preheating control switch element 26 of the preheating control circuit 25 is opened due to the lighting of the discharge lamp 14,
The primary winding I of this preheating control transformer 21! Electromotive forces in opposite directions are generated in J22゜22, cancel each other out, and create a primary WI
The inductance of 22.22 increases and the flow of preheating current is blocked.

Further, in the embodiment, the charging circuit 37 is connected to the intermediate tap 6 of the primary winding 5 of the output transformer 4, and both ends of the primary winding 5 of the battery power source 2, and the self-excited oscillation circuit 7. A charging diode 38, 39 and a current reducing resistor 40, 41 are connected in parallel between the collector and emitter of each emergency oscillation transistor 8, 9, and a circuit leading to one pole of the battery power source 2 is formed. , as shown in FIG.
- Each emergency oscillation transistor 8 of the self-help oscillation circuit 7
A charging diode 38.39 and a current reducing resistor 40.41 are connected in parallel between the collector and emitter of , 9, respectively.
It can also be formed by a circuit extending from both ends of the primary winding 115 of the output transformer 4, to the intermediate tap 6 of the secondary winding 5, and to one end of the battery power source 2.

In the above embodiment, the self-help oscillation circuit 7 was used as the first oscillation circuit in the emergency lighting circuit, and the separately excited oscillation circuit 32 was used as the second oscillation circuit in the constant lighting circuit. An excitation oscillation circuit may be used, and an automatic oscillation circuit may be used as the constant lighting circuit, and the oscillation circuit may have -. or two oscillation transistors.

〔Effect of the invention〕

According to the present invention, under normal conditions, a discharge lamp is lit by the output of a DC power supply device that smoothes and rectifies the output of an AC power source, and in an emergency such as a power outage, the discharge lamp can be lit by the battery power that is charged during normal lighting. An emergency lamp lighting device that uses an output transformer to charge a battery that serves as a DC power supply in an emergency without using a dedicated transformer for charging, and can be assembled at low cost, lightweight, and compact. be.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of a discharge lamp lighting device showing one embodiment of the present invention, Fig. 2 is a circuit diagram of a discharge lamp lighting device showing a specific embodiment, and Fig. 3 is a charging circuit showing another embodiment. FIG. 1. First DC power supply device, 2. Battery power supply, 4.
- Output transformer, 5...-secondary winding, 7... first oscillation circuit, 8.9... oscillation transistor, 14... discharge lamp, 17... secondary winding, 27... alternating current power supply, 30・Second
DC power supply device, 32... second oscillation circuit, 37... charging circuit, 38. 39... rectifying diode.

Claims (1)

[Claims] (1) A first DC power supply device consisting of a battery power source, a first oscillation circuit that generates a high frequency output on the secondary winding side of the output transformer based on the input of the first DC power supply device, and a first DC power supply device that smooths the AC power supply. a second DC power supply device that rectifies and outputs DC power; a second oscillation circuit that generates a high frequency output on the secondary winding side of the output transformer based on the input of the second DC power supply; and the output transformer. a discharge lamp connected to the secondary winding side of the oscillation circuit and lit by the high frequency output of either the first or second oscillation circuit; and a first DC power supply when the second DC power supply is cut off. and switching means for causing the first oscillation circuit to oscillate instead of the second oscillation circuit, and a charging circuit having a charging diode is provided in parallel with the oscillation transistor of the first oscillation circuit. Discharge lamp emergency light lighting device.