JP2506966B2 - Discharge lamp lighting device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a discharge lamp lighting device for starting and lighting a discharge lamp at a high frequency.

2. Description of the Related Art A conventional discharge lamp lighting device is disclosed in, for example, Japanese Patent Application No. 62-3285.
The circuit was as shown in Fig. 4 like No. 96.

That is, in FIG. 4, reference numeral 4 is a power supply including a commercial power supply 1, a rectifying bridge 2, and a smoothing capacitor 3 with a constant output voltage polarity, 5 is a capacitor connected in series to its output, and 6 is a capacitor 5. Is a transistor which is a switch with a control terminal connected between the power source 4 and the power source 4, and a series circuit of the fluorescent lamp 7 and the inductance 8 is connected in parallel to the capacitor 5 and in parallel with the end of the fluorescent lamp 7 opposite to the power source. A series circuit of a starting circuit including a capacitor 9 and an inductance 10 and a positive temperature coefficient thermistor is connected. The positive temperature coefficient thermistor 21 is connected to the side opposite to the transistor. 22 is a Zener diode whose one end is connected to the connection point A between the positive temperature coefficient thermistor 21 and the capacitor 9, and 23 is a Zener diode.
A diode 21 connected to the other end of 22 and a transistor connected to the other end of the diode 21 and having a collector connected to the capacitor 13. Reference numeral 11 is a self-excited switching circuit including a capacitor 5, a transistor 6, and an inductance 8. Reference numeral 12 is a driving inductance in which one end is connected to the base of the transistor 6, and the secondary winding 8b of the inductance 8 and the driving capacitor are provided between the other end and the emitter.
Thirteen series circuits are connected. 17 is a timer circuit composed of voltage dividing resistors 14 and 15 connected to the output end of the power supply circuit 4 and a capacitor 16 having one end connected to the midpoint thereof, and 18 is a capacitor 16
, Which is a control switch with the other end connected to the base and the collector connected in parallel to the inductance 12, 19 is the cathode connected to the base of the transistor 6 and the other end is a resistor
It is a diode connected to the emitter of the transistor 6 via 20.

The operation of the conventional circuit configured as above will be described. When the power is turned on, a voltage is generated in the power supply circuit 4, a starting current flows through the resistor 14 of the timer circuit 17, the capacitor 16 and the base of the transistor 18, and the transistor 18 becomes conductive. At the same time, the base current makes the transistor 6 conductive. To do. Initially, the fluorescent lamp 7 is not turned on, and the current flows from the power supply circuit 4 through the inductance 8, the filament electrode of the fluorescent lamp 7, the capacitor 9 and the inductance 10.
It flows through the transistor 6. At this time, a positive voltage is generated in the secondary winding 8b of the inductance 8 and the base current of the transistor 7 is supplied via the capacitor 13 and the inductance 12 to keep the transistor 6 on. At this time, the current flowing through the primary winding 8a of the inductance 8 is the resonance current of the capacitor 9 and the inductance 8. Here, the current flowing by the positive voltage generated in the secondary winding 8b of the inductance 8 is the inductance 12 and the capacitor 13
Although it is a series resonance current at the natural oscillation frequency of, since the transistor 18 is actually conducting, it flows from the emitter of the transistor 18 to the collector in the reverse direction to some extent, so that the resonance state is weak and the inductance 12 hardly functions. The vibration cycle becomes short as it approaches the charge / discharge time of the capacitor 13. Therefore, the capacitor 13 has the secondary winding 8b.
When the base current of the transistor 6 stops flowing due to the influence of the inductance 12 and the base current of the transistor 6 is slightly drawn in the opposite direction due to the influence of the inductance 12, the transistor 6 is about to turn off, and therefore the voltage generated in the inductance 8b. When becomes smaller, the electric charge accumulated in the capacitor 13 is applied in the opposite direction between the base and emitter of the transistor 6, and feedback is applied, so that the transistor 6 is rapidly turned off. When the transistor 6 is turned off, the energy stored in the series resonance circuit of the capacitor 9 and the inductance 8 and the inductance 10 is released to the capacitor 5, the fluorescent lamp 7, the capacitor 9, the inductance 8 and the inductance 10 and vibrates to preheat the fluorescent lamp 7. It becomes an electric current. At this time, the fluorescent lamp 7 is replaced by the condenser 9
Set the oscillation state so that it will not start with the voltage generated at. Inductance 8 1 when transistor 6 is off
The oscillating current flowing through the secondary winding 8a causes a negative voltage to be generated in the secondary winding 8b of the inductance 8. At this time, the transistor 18 conducts in the forward direction and the inductance 12 does not function at all.
A reverse voltage is applied between the base and emitter of the transistor 6 via the transistor 6 to keep the transistor 6 off. When the oscillating current passes the negative peak, a positive voltage is gradually generated in the secondary winding 8b of the inductance 8, and the voltage charged in the reverse direction in the capacitor 13 during the off period of the transistor 6 is forwarded to the base of the transistor 6. Applied in the direction, the transistor 6 is turned on. At this time, since the current of the inductance 8 is still flowing in the opposite direction immediately after turn-on, the current flows from the base to the collector via the diode 19 and the resistor 20. The reverse current of the inductance 8 gradually decreases and a forward current flows through the transistor 6, and the above operation is repeated thereafter. With the above oscillation operation, the temperature of the preheating electrode of the fluorescent lamp 7 rises with the passage of time.

The timer circuit 17 supplies the base current of the transistor 18 while accumulating the charge in the capacitor 16 via the resistor 14 after the power is turned on, and when it is charged to the voltage by the resistors 14 and 15 after a predetermined time, the timer circuit 17 is further charged. After this time, the current is cut off and the capacitor 16
No current will flow through the base of transistor 18 until the charge on is discharged. Therefore, after a predetermined time, the transistor
When 18 is turned off, when the transistor 6 is turned on, a positive voltage is generated in the secondary winding 8b of the inductance 8 and the capacitor 13
A base current is supplied to the transistor 6 through the inductor 12 and the inductance 12. This base current is a resonance current of the capacitor 13 and the inductance 12, and the base current of the transistor 6 changes from positive to negative in the vicinity of its half cycle, and when the accumulated charge of the transistor 6 is released, the transistor 6 is turned off. Before starting the fluorescent lamp 7, the inductance 8
And the capacitor 9 are in series resonance, and the capacitor 9
In the above, each inductance and capacitor are set so as to generate a voltage which is much larger than that at the time of lighting and at the time of preheating before the operation of the timer circuit, and which is sufficient to start the fluorescent lamp 7. Therefore, the fluorescent lamp 7 is started. After starting, the circuit operation is almost the same as after the timer circuit 17 operates, but since the impedance of the fluorescent lamp 7 is connected in parallel with the impedance of the capacitor 9 and the inductance 10, the current of the capacitor 9 decreases and the fluorescent lamp 7 is turned on. An electric current flows. Therefore, resonance between the inductance 8 and the capacitor 9 almost disappears, and the secondary winding of the inductance 8
Positive and negative voltages corresponding to the difference between the output voltage of the power supply circuit 4 and the lamp voltage are generated in 8b, and the inductance 8 and the capacitor 5
The transistor 6 is turned on / off according to the natural vibration frequency of the fluorescent lamp 7, the inductance 12 and the capacitor 13 to keep the fluorescent lamp 7 lit. The inductance 10 is for removing the DC component of the current of the fluorescent lamp 7.
In addition, the transistor 23 stops the current for driving the transistor 6 from the drive circuit of the switching circuit 11 by the current flowing into the base. In the conventional circuit configured as described above, when the electrodes 7a and 7b of the fluorescent lamp 7 are in an abnormal emitterless state, there is almost no electrode that directly flows from the power supply circuit 4 through the lamp. Flow through the positive temperature coefficient thermistor 21 to rapidly increase the resistance value of the positive temperature coefficient thermistor, and
By turning on 23, the oscillating operation of the switching circuit 11 is stopped, and the current flowing from the power supply circuit 4 through the fluorescent lamp 7 and the capacitor 9 almost disappears, so that the base current of the transistor 6 flowing by the inductance 8 disappears. The oscillation operation of 11 stops.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, in the configuration as described above, when the lamp voltage becomes high, the current flowing through the PTC thermistor 21 becomes large, and the PTC thermistor 21 raises the temperature and lights the normal lamp. Nevertheless, there is a problem in that it may not be possible to maintain the lighting of the lamp. Further, when the discharge lamp is difficult to start, there is a problem that the positive temperature coefficient thermistor 21 may malfunction and may not start depending on the surrounding environment. Moreover, since a large current always flows through the PTC thermistor 21 when the power is turned on, the temperature of the PTC thermistor 21 rises somewhat. Therefore, if the power supply is repeatedly turned on and off, the temperature of the positive temperature coefficient thermistor 21 may rise, which may make it impossible to turn on the lamp.

Means for Solving the Problems In order to solve the above problems, the present invention solves the above-mentioned problems by providing a power source having a constant output voltage polarity, at least one switch with a control terminal connected to an output terminal of the power source, an inductance and a capacitor. A switching circuit for starting and lighting a discharge lamp connected to the output end by turning on and off the power source and a forward current by the switch, a drive circuit connected to the switch, and the discharge lamp or An abnormality detection circuit that detects a circuit abnormality and outputs a signal, a stop circuit that inputs the output signal of the abnormality detection circuit, outputs a signal to the drive circuit, and turns off the switch, and is connected to the drive circuit A dimmer circuit that controls a driving circuit to dimm the discharge lamp, a timer circuit a that outputs a signal for a predetermined time, and a timer circuit a that responds to a signal from the timer circuit a. Then, the light control circuit and the reset circuit a for invalidating the abnormality detection circuit are provided.

The present invention has the above-described configuration, and when the discharge lamp is started in the dimming mode, the timer circuit a operates the reset circuit a to invalidate the abnormality detection circuit, thereby starting the discharge lamp and lighting all outputs. After a predetermined time after the operation of the reset circuit a is finished by the timer circuit a, the dimming circuit is operated to perform dimming, and when the discharge lamp is abnormal, the operation of the reset circuit a is finished by the timer circuit a. The signal of the abnormality detection circuit is transmitted to the stop circuit to stop the oscillation operation of the switching circuit 11 via the drive circuit.

Embodiment An embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is an operation block diagram of a circuit showing an embodiment of a discharge lamp lighting device of the present invention. FIG. 2 is a signal diagram of each block of the embodiment of the discharge lamp lighting device of the present invention, and FIG. 3 is a circuit diagram of the embodiment of the discharge lamp lighting device of the present invention. 1 and 3, a power supply 4, a fluorescent lamp 7 as a discharge lamp, a capacitor 9, a switching circuit 1
1, a timer circuit 36 which is a timer circuit b composed of resistors 44 and 45 and a capacitor 46, and an inductance 41 and a capacitor
The drive circuit 30 including the diode 40, the diode 42, the resistor 43, and the secondary winding 8b has the same configuration and operation as the conventional example.
The resistors 44 and 45, the capacitor 46, the inductance 41, the capacitor 40, the diode 42, and the resistor 43 in FIG.
Resistance 14, 15, capacitor 16, inductance 12,
It is the same as the capacitor 13, the diode 19 and the resistor 20.

The difference from the conventional example is that the resistors 52 and 53 and the inductor 54 that are connected in parallel to the fluorescent lamp 7 and on the side opposite to the transistor 6 and the inductance 54, and the diodes 55 and 56 that are connected to the cathodes at both ends of the series circuit of the resistors 52 and 53. A transistor 57 and a transistor 57 in which the emitter is connected to the midpoint of the series circuit of resistors 52 and 53, and the anodes of diodes 55 and 56 are connected to the base.
Anomaly detection circuit 34 consisting of resistor 58 connected to the collector of diode 58 and diode 59 connected to the other end of resistor 58 at the anode
And the cathode of diode 59 and transistor 6 of power supply 4
A reset circuit including a transistor 50 having a collector / emitter connected to the side end, a diode 49 connected in the reverse direction between the base / emitter of the transistor 50, and a diode 51 having an anode connected to the collector of the transistor 50.
a33, a stop circuit 35 composed of a thyristor 65 in which the base and emitter of the transistor 6 are connected in a short-circuit manner and the cathode of the diode 51 is connected to the gate, and a switch with another control terminal connected in parallel to the driving inductance 12. Is a transistor 60 and a constant voltage diode 64 and a constant voltage diode whose anode is connected to the base of the transistor 60
Resistor 63 connected to the cathode of 64, the other end of resistor 63 and power supply 4
A dimming circuit including a series circuit of a switch 62 and a diode 61 connected between the other end of the resistor 63 and one end of the AC power supply 1 and a capacitor 62 connected between the other end of the transistor 6 and the end of the transistor 6.
A timer circuit, which is a timer circuit a for a predetermined time t3, including a series circuit of a resistor 47 and a capacitor 48 connected between the lamp-side output end of the power source 4 and the base of the transistor 50.
A diode 66 in which the cathode is connected to the midpoint of the series circuit of 32 and the timer circuit 32, and the cathode is connected to the run side end of the power supply 4.
Is a reset circuit 37 which is a reset circuit b.

The operation of the circuit of the embodiment configured as above will be described below with reference to FIG. The switch 38 is initially turned off. When the fluorescent lamp 7 is normal, when the power is turned on, a voltage is generated in the power supply circuit 4, the timer circuit 36 starts to operate, and it is started via the resistor 44 and the capacitor 46 and the base of the transistor 60 of the dimming circuit 31. A current flows and the transistor 60 and the transistor 6 become conductive. Initially fluorescent lamp 7
Does not light up and the current operates in the same manner as in the conventional example, and the transistor 6 is kept on.

At this time, as shown in FIG. 2, the timer circuit 32 starts to operate similarly to the timer circuit 36, and the signal current is supplied to the base of the transistor 50 of the reset circuit 33 via the resistor 47 and the capacitor 48. Therefore, the transistor 50 is on and the reset circuit 33 maintains the reset state. Therefore, the abnormality detection circuit 34 is disabled. In addition, the dimming circuit 31 does not depend on the switch 38 and the reset circuit 33
Has been disabled by. Therefore, in the state of the drive circuit 30, only the transistor 60 is turned on in parallel with the inductance 41 as in the conventional example, and the subsequent oscillation operation is also the same. Therefore, the fluorescent lamp 7 is preheated and the temperature of the preheating electrode of the fluorescent lamp 7 rises with the lapse of time due to the above oscillation operation.

The timer circuit 32 continues to supply the base current of the transistor 50 while accumulating electric charge in the capacitor 48 via the resistor 57 after the power is turned on. Also, the timer circuit 36 supplies the base current of the transistor 60 while accumulating electric charge in the capacitor 46 via the resistor 44 after the power is turned on, and charges up to the voltage by the resistors 44 and 45 after a predetermined time t1 in FIG. Then, the transistor 60 is turned off because it is not charged any more. When the transistor 60 is turned off, the oscillation operation is performed in the same manner as in the conventional example, the voltage is larger than that at the time of preheating before the operation of the timer circuit 36 is stopped, and a sufficient voltage for starting the fluorescent lamp 7 is generated, and the fluorescent lamp 7 is started. To do. Since the lamp voltage is high when the starting voltage is applied, when the transistor 6 is turned on, a current flows from the positive terminal of the power supply through the resistors 52 and 53 and the inductance 54 to the inductance 8 to the transistor 6. Therefore, a voltage drop occurs in the resistors 52 and 53. The voltage drop generated at this time is low on the inductance 54 side and high on the electrode 7a side. At this time, the resistance 53
The diode 56 and the transistor 57 are turned on by the voltage drop generated at, and an output signal is output from the collector terminal of the transistor 57 via the resistor 58. But,
At this time as well, since the reset circuit 33 is operating, no signal is output from the reset circuit 33 to the stop circuit 37.

After the start, the operation of the circuit is almost the same as after the operation of the timer circuit 36 is stopped, and the transistor 6 is controlled to be turned on / off in the same manner as in the conventional example to keep the fluorescent lamp 7 lit. The inductance 54 is also for removing the DC component of the current of the fluorescent lamp 7. Further, at this time, the lamp voltage becomes small, so that the transistor 57 of the abnormality detection circuit 34 is off and no signal is output. Further, the timer circuit 32 is still outputting during the above period, and the capacitor 48 is charged. Capacitor 48
When a predetermined time t3 in FIG. 2 in which the voltage is charged to near the output voltage of the power supply 4 is reached, the output of the timer circuit 32 is stopped and the transistor 50 of the reset circuit 33 is turned off.

The capacitor 62 of the dimming circuit 31 when the switch 38 is off.
Is a resistor that is not charged from the AC power supply 1 via the diode 61.
63, no current flows from the constant voltage diode 64 to the transistor 60. Therefore, after that, the fluorescent lamp 7 maintains the full output lighting.

Next, when the switch 38 is on, after the power is turned on, the AC voltage of the AC power source 1 is half-wave rectified by the diode 61 and the capacitor 62 via the switch 38, and the rectified voltage is passed through the resistor 63 and the constant voltage diode 64. Applied to the base of transistor 60. Since the reset circuit 33 is operating before the predetermined time t3, the current flowing through the resistor 63 flows to the transistor 50 and does not flow to the transistor 60. for that reason,
The fluorescent lamp 7 is in a full output lighting state. Next, a predetermined time
When t3 elapses, the transistor 50 of the reset circuit 33 is turned off and the voltage is applied from the capacitor 62 to the base of the transistor 60 via the resistor 63 and the constant voltage diode 64. for that reason,
The transistor 60 becomes conductive. When the transistor 60 becomes conductive, the current flowing through the inductance 41 of the drive circuit 30 is shunted and the resonance state is attenuated. Therefore, the resonance frequency is increased practically, and the on-time of the transistor 6 is shortened, so that the lamp current of the fluorescent lamp 7 is reduced and the fluorescent lamp 7 is dimmed.

Next, when the fluorescent lamp 7 is in the emitterless state of the electrodes, which is in an abnormal state at the end of its life or the like, when the power supply 4 is turned on, the switching circuit 11 starts the oscillation operation as in the conventional example. However, since the electrodes of the fluorescent lamp 7 are emitterless, the lamp voltage becomes large, and when the transistor 6 is on, the resistors 52 and 53 and the inductance 54 to the inductance 8 are connected from the positive terminal of the power supply as when the starting voltage is applied. As a result, the electrode flows to the transistor 6. Because of this, the resistance
A voltage drop occurs at 52,53. The voltage drop generated at this time is low on the inductance 54 side and high on the electrode 7a side. At this time, the transistor 57 of the diode 56 is turned on by the voltage drop generated in the resistor 53, and an output signal is output from the collector terminal of the transistor 57 via the resistor 58 at time t1. At this time, the reset circuit 33
Since is on, no signal is output to the stop circuit 37. When the reset circuit 33 reaches the time when the predetermined time t3 of the timer circuit 32 has elapsed, the reset circuit 33 stops operating, and therefore, the abnormality detection circuit 34 outputs a current to the gate of the thyristor 65 of the stop circuit 35. Therefore, the thyristor 65 is turned on and the base and emitter of the transistor 6 are short-circuited. At the same time, the output current of the abnormality detection circuit 34 flows through the reset circuit 33, the constant voltage diode 64, and the base of the transistor 60. Therefore, the oscillation state of the switching circuit 11 becomes close to that at the time of dimming and is attenuated. Therefore, the transistor 6 is easily turned off, and the switching circuit 11 that is surely turned off at time t4 can be stopped.

In the above case, once the operation of the switching circuit 11 is stopped, unless the timer circuit 36 is reset, the starting current does not flow from the timer circuit 36, and therefore the restart is not performed.

When the AC power supply 1 is turned off, the capacitor 48 of the timer circuit 32 is immediately discharged via the diodes 66 and 49 of the reset circuit 37. At the same time, the capacitor 46 of the timer circuit 36 is immediately discharged via the resistors 44 and 45 and the transistor 60. Therefore, the next time the AC power supply 1 is turned on,
The timer circuits 32 and 36 can operate, and the reset circuit 33 can be operated whenever the starting current flows through the capacitor 46. Therefore, it is possible to prevent the fluorescent lamp 7 from failing to start, and to extend the life of the fluorescent lamp. Can be stretched. Therefore, it can fully cope with the momentary power failure of the AC power supply.

With the above-mentioned configuration, by setting the resistance values of the resistors 52 and 53 appropriately, by using the abnormality detection circuit 35 of the electronic circuit in which the detection level can be freely set, the lamp voltage at lighting Irrespective of the size, and since a temperature element such as a positive temperature coefficient thermistor is not used, it is not affected by the ambient temperature and can be repeatedly turned on / off even in a place with a high ambient temperature. Further, in the case of a normal lamp, since the reset circuit 33 is operated for the predetermined time t3, it can be reliably started and lit, and stable dimming can be maintained. Further, when the discharge lamp 7 is abnormal, it can be repeatedly and reliably detected regardless of the surrounding conditions, and the oscillation of the switching circuit 11 can be reliably stopped, so that reliability, ease of use, and safety can be realized with a simple and inexpensive structure.

Further, in this embodiment, the transistor 60 of the dimming circuit 31 is connected in parallel to the inductance 41 of the drive circuit 30 and the emitter is connected to the capacitor 40. At the time of dimming lighting and preheating, when the charge of the capacitor 40 flows into the base of the transistor 6 through the transistor 60 without passing through the inductance 41 when the transistor 6 is turned on, the transistor 6 causes the capacitor 5 and the inductance 8 of the switching circuit 11 to operate. There is a case where the collector-emitter voltage of the transistor 6 is forcibly turned on at the time when the collector-emitter voltage of the transistor 6 is still present due to the vibration of, and therefore the turn-on loss of the transistor 6 may increase. With the configuration of this embodiment, when the transistor 6 is turned on, the charge of the capacitor 40 is
Transistor 6 without passing through inductance 41 through 60
It is possible to reduce the flow into the base of the transistor, to allow it to flow through the inductance 41, to delay the turn-on timing, and to turn on after the collector-emitter voltage of the transistor 6 drops, greatly reducing the turn-on loss of the transistor 6. Can be reduced to

Furthermore, by connecting a diode in the forward direction in series to the collector of the transistor 60, the electrode flowing in the forward direction from the base of the transistor 60 to the collector can be cut off, and the electrode flowing from the base to the collector can also be cut off. The turn-on timing can be adjusted appropriately and the loss can be reduced.

As described above, according to the present invention, the oscillation of the switching circuit can be reliably stopped by the abnormality detection circuit 34 having a simple configuration when the discharge lamp 7 is abnormal or at the end of its life. In addition, it can be repeatedly restarted and can be used in high temperature environments. Also,
Since the detection level can be set regardless of the lamp voltage during lighting, it can be applied to any lamp. Further, the normal lamp is surely turned on and turned on, and the dimming can be promptly changed, so that it can be immediately started even in the case of an immediate restart or a sequential power failure.

Further, by inputting the output current of the abnormality detection circuit 34 also to the dimming circuit, it is possible to more surely stop the oscillation at the time of abnormality.

Further, since the input of the dimming circuit 31 is obtained by half-wave rectification directly from the AC power supply 1 without depending on the output of the power supply circuit 4, the dimming level can be set independently of other circuits. The power supply voltage fluctuation characteristics during dimming can also be set independently. That is, the secondary winding voltage of the inductance 8 is proportional to the value obtained by subtracting the lamp voltage from the output voltage of the power supply 4, and is proportional to the power supply voltage, and this voltage is proportional to the lamp output. On the other hand, the dimming input is proportional to the voltage of the AC power supply 1, and therefore, is inversely proportional to the oscillation state of the drive circuit and inversely proportional to the lamp output. Therefore, the dimming input and the secondary winding voltage of the inductance 8 have an opposite relationship with the lamp output, and the two compensate each other for fluctuations in the power supply voltage. Therefore, since the dimming input voltage can be set independently, the power supply voltage variation characteristic can be easily set freely. Further, the AC power source 1 can be provided with the dimming / all-optical switch 38, and the dimming can be switched by the power switch portion, and the operation can be simplified.

Further, in the embodiment of the present invention, dimming can be performed with a simple structure in which the transistor 60 is connected in parallel with the inductance 41. Furthermore, the transistor 60 of the dimming circuit 31 can be used for preheating, and the configuration can be simplified. Further, by connecting the transistor 60 so that the emitter is on the side of the capacitor 40, the loss of the transistor 6 can be greatly reduced. In addition, the transistor
The loss can be further reduced by connecting a diode in series with the collector of 60.

Although the discharge lamp 7 is a fluorescent lamp in the embodiment of the present invention, it may be a high pressure discharge lamp. Further, the abnormality detection circuit 34, the timer circuits 32 and 36, the stop circuit 35, the dimming circuit 3
1, drive circuit 30, switching circuit 11, reset circuit 33,
The configuration of 37, may be other as long as it has each required function. That is, in the present embodiment, the switching circuit 11 is a self-excited one-stone resonance type inverter, but may be separately excited, and the same effect can be obtained by using a multi-stone type. Further, although the thyristor 63 is used as the stop circuit 37, another circuit may be used as long as it can stop the oscillation of the transistor 6. The same effect can be obtained even if the abnormality detection circuit 34 detects an abnormality in the circuit instead of the abnormality in the lamp. Also, transistors 6,5
0,57,60 may be other things such as FET.

As described above, according to the present invention, when the discharge lamp is abnormal or at the end of its life, the dimming circuit having a simple structure can reliably start, turn on, and adjust the discharge lamp regardless of the surrounding environment. In addition to being able to emit light, it is possible to realize a discharge lamp lighting device that can detect the state when an abnormality occurs and reliably stop the oscillation of the switching circuit, and can be used repeatedly.

[Brief description of drawings]

1 is a circuit block diagram of an embodiment of the present invention, FIG. 2 is a circuit waveform diagram of an embodiment of the present invention, FIG. 3 is a circuit diagram of an embodiment of the present invention, and FIG. 4 is a conventional discharge lamp lighting. It is a circuit diagram of an apparatus. 1 ... Commercial power supply, 4 ... Power supply circuit, 7 ... Fluorescent lamp,
6 ... Transistor, 30 ... Drive circuit, 31 ... Dimming circuit, 33 ... Reset circuit, 34 ... Abnormality detection circuit, 35 ...
Stop circuit.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Shigeru Horii 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Masataka Ozawa 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. Within

Claims (9)

(57) [Claims] 1. A power source having a constant polarity of output voltage, at least one switch with a control terminal connected to an output terminal of the power source, an inductance and a capacitor, and the power source and the forward current switch. A switching circuit that turns on and off the discharge lamp connected to the output terminal to start and light it, a drive circuit connected to the switch, and an abnormality detection that detects an abnormality in the discharge lamp or circuit and outputs a signal A circuit, a stop circuit that inputs the output signal of the abnormality detection circuit and outputs a signal to the drive circuit to turn off the switch, and a drive circuit that is connected to the drive circuit and controls the drive circuit to dimm the discharge lamp. Dimming circuit, a timer circuit a that outputs a signal for a predetermined time, and the dimming circuit and the abnormality detection circuit are disabled according to the signal from the timer circuit a. Discharge lamp lighting device that includes a set circuit a. 2. The discharge lamp lighting device according to claim 1, further comprising a reset circuit b for resetting the timer circuit a in response to turning on / off of a power source. 3. An output signal of the abnormality detection circuit is reset circuit a.
The discharge lamp lighting device according to claim 1 or 2, wherein the discharge lamp lighting device inputs the light to the dimming circuit via the. 4. A power supply having a constant polarity of output voltage is a power supply for rectifying an AC power supply, and a series circuit of a rectifying element and a capacitor is connected from one end of the AC power supply to one end of a switch with a control terminal. Claims 1 and 2 in which the voltage of the capacitor is connected to the dimming circuit via a resistor.
Item 3. A discharge lamp lighting device according to item 3 or item 3. 5. A power source having a constant output voltage polarity, at least one switch with a control terminal connected to the output terminal of the power source, an inductance and a capacitor, and the switch for supplying a forward current to the power source. A switching circuit for turning on / off the discharge lamp connected to the output end to start / light by the switch, and a driving inductance and a driving capacitor connected to the switch and provided with a driving capacitor and a driving inductance. A discharge lamp lighting device comprising: a drive circuit using resonance; and a dimming circuit including at least another switch with a control terminal connected in parallel to the drive inductance to control the drive circuit to control the discharge lamp. 6. A drive circuit which is connected to a switch with a control terminal and which includes a drive inductance and a drive capacitor and uses resonance of the drive capacitor and the drive inductance, and at least connected in parallel to the drive inductance. The discharge lamp lighting according to any one of claims 1 to 5, further comprising: a switch with another control terminal that controls the drive circuit to control the discharge lamp. apparatus. 7. The discharge lamp is a preheat-starting type discharge lamp, and a timer circuit b for outputting a signal to the dimming circuit for a predetermined time shorter than the predetermined time of the timer circuit a is provided. Discharge lamp lighting device according to the item. 8. The switch according to claim 1, wherein the other switch with a control terminal is a transistor and is connected so that a current flows to a midpoint of the driving inductance and the driving capacitor. Discharge lamp lighting device. 9. The diode according to claim 8, further comprising a diode connected between the switch with the control terminal and the other switch with the control terminal so that a current flows to a midpoint of the drive inductance and the drive capacitor. Discharge lamp lighting device.