JPH01309297A - Discharge lamp lighting device - Google Patents

Abstract

PURPOSE:To enable starting-up and lighting of a discharge lamp surely and enable stoppage of oscillations in a switching circuit surely at an abnormal time by providing an abnormal detection circuit and a dimming circuit. CONSTITUTION:Upon start-up of dimming mode of a discharge lamp 7, total output lighting is executed by operating a reset circuit a33 by a timer circuit b34 to invalidate an abnormal detection circuit 35 so as to start a discharge lamp 7, and then, after operation of the circuit a33 is completed by the circuit b34, a timer circuit a32 is operated and after a specified time, a dimming circuit 31 is operated, then dimming is carried out. Further, upon abnormal time of the lamp 7, after the operation of reset circuit a33 is competed, a signal of the abnormal detection circuit 35 is set to a stopping circuit 37, then through a drive circuit 30, the oscillation operation of a switching circuit 11 is stopped. It is thus possible to surely perform start-up lighting and dimming and to stop oscillations of the circuit 11 surely upon abnormal time.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a discharge lamp lighting device for starting and lighting a discharge lamp at high frequency.

Prior Art A conventional discharge lamp lighting device is disclosed in Patent Application No. 62, for example.
-328596, the circuit was as shown in Figure 4.

That is, in FIG. 4, 4 is a power supply whose output voltage has a constant polarity, which is composed of a commercial power supply 1, a rectifier bridge 2, and a smoothing capacitor 3, 5 is a capacitor connected in series to its output, and 6 is a capacitor 5. A transistor is a switch with a control terminal connected between the capacitor 5 and the power supply 4, and a series circuit of a fluorescent lamp 7 and an inductance 8 is connected in parallel to the capacitor 5, and a series circuit of a fluorescent lamp 7 and an inductance 8 is connected in parallel to the opposite end of the fluorescent lamp 7 on the source side. A series circuit consisting of a starting circuit consisting of a capacitor 9 and an inductance 10 and a positive characteristic thermistor is connected to. The positive characteristic thermistor 21 is connected to the anti-transistor side. 22
23 is a Zener diode whose one end is connected to the connection point A between the positive characteristic thermistor 21 and the capacitor 9; 23 is the diode 21 connected to the other end of the Zener diode 22; the collector is connected to the other end of the diode 21 and the collector is connected to the capacitor 13. It is a transistor. In addition, 11 is a capacitor 5
This is a self-excited switching circuit consisting of a transistor 6 and an inductance 8. A driving inductance 12 has one end connected to the base of the transistor 6, and a series circuit of a secondary winding 8b of the inductance 8 and a driving capacitor 13 is connected between the other end and the emitter.

17 is a voltage dividing resistor 14 connected to the output terminal of the power supply circuit 4.
15, a timer circuit consisting of a capacitor 16 with one end connected to its midpoint, 18 a transistor which is a control switch with the other end of the capacitor 16 connected to the base and the collector connected in parallel to the inductance 12, and 19 a transistor with the cathode connected. This is a diode connected to the base of transistor 6 and the other end connected to the emitter of transistor 6 via resistor 20.

The operation of the conventional circuit configured as above will be explained.

When the power is turned on, a voltage is generated in the power supply circuit 4 and the timer times W! 17 resistor 14, capacitor 16 and transistor 1
The starting current flows through the base of transistor 18.
conducts, and at the same time, its base current causes transistor 6 to conduct.

Initially, the fluorescent lamp 7 is not lit, and current flows from the power supply circuit 4 through the transistor 6 via the inductance 8, the filament electrode of the fluorescent lamp 7, the capacitor 9, and the inductance 10. At this time, the inductance is 8
A positive voltage is generated in the secondary winding 8b of the transistor 6, and the base current of the transistor 6 is supplied through the capacitor 13 and the inductance 12, thereby keeping the transistor 6 on. At this time, the current flowing through the primary winding 1!8a of the inductance 8 is a resonant current between the capacitor 9 and the inductance 8.

Here, the current flowing due to the positive voltage generated in the secondary winding 8b of the inductance 8 is a series resonant current at the natural oscillation frequency of the inductance 12 and the capacitor 13, but since the transistor 18 is actually conductive, the transistor 18 flows in the reverse direction from the emitter to the collector to some extent, so the resonance state is weak and the inductance 12 hardly functions, so its oscillation period becomes close to the charging/discharging time of the capacitor 13 and becomes short. Therefore, when the capacitor 13 is charged to near the voltage generated in the secondary winding 8b and the base current of the transistor 6 stops flowing, the base current of the transistor 6 is slightly pulled in the opposite direction due to the influence of the inductance 12, and the transistor 6 is turned off. Therefore, when the voltage generated in the inductance 8b becomes smaller, the charge accumulated in the capacitor 13 is fed back in the opposite direction between the base and emitter of the transistor 6, and the transistor 6 is rapidly turned off.

When the transistor 6 is turned off, the energy stored in the series resonant circuit of the capacitor 9 and 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, causing vibration, and preheating the fluorescent lamp 7. It becomes an electric current. At this time, the oscillation state is set so that the fluorescent lamp 7 is not started by the voltage generated in the capacitor 9.

The oscillating current flowing through the primary winding 8a of the inductance 8 when the transistor 6 is off is the oscillating current flowing through the primary winding 8a of the inductance 8
Generate a negative voltage at JI8b. At this time, the transistor 18 conducts in the forward direction and the inductance 12 does not function at all, so this voltage causes the diode 19 to
A reverse voltage is applied between the base and emitter of the transistor 6 through the resistor 20 to keep the transistor 6 off.

When the oscillating current passes a negative peak, a positive voltage gradually occurs in the secondary winding 8b of the inductance 8, and the transistor 6
During the off period, the voltage charged in the capacitor 13 in the reverse direction is applied to the base of the transistor 6 in the forward direction, and the transistor 6 is turned on.

At this time, immediately after turn-on, the current in inductance 8 is still flowing in the opposite direction, so diode 19 and resistor 2
Current flows from the base to the collector through 0. The reverse current in the inductance 8 gradually decreases, and a forward current begins to flow through the transistor 6, and the above operation is repeated thereafter. Due to the above oscillation operation, the temperature of the preheated north pole of the fluorescent lamp 7 increases as time passes.

What about the timer circuit 17? After the power is turned on, charge is accumulated in the capacitor 16 via the resistor 14, and the transistor 1
Supply a base current of 8, and after a certain time the resistance 14.15
Once the capacitor 16 is charged to the voltage , it will not be charged any more, and from this point on, no current will flow to the base of the transistor 18 until the current is cut off and the charge in the capacitor 16 is discharged via the resistor 14.15. Therefore, when the transistor 18 is turned off after a predetermined time, a positive voltage is generated in the secondary winding 8b of the inductance 8 when the transistor 6 is turned on, and a base current is supplied to the transistor 6 via the capacitor 13 and the inductance 12. This base current is a resonant current of the capacitor 13 and the inductance 12, and around the half cycle, the base current of the transistor 6 changes from positive to negative, 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 a series resonant state, and the capacitor 9 has a much larger value than when the lamp is lit and larger than when preheating before the timer circuit operates, which causes the fluorescent lamp 7 to start. Each inductance and capacitor are set to generate enough voltage for Therefore, the fluorescent lamp 7 is started. After starting, the operation of the circuit is almost the same as after the operation of the timer circuit 17, but the impedance of the fluorescent lamp 7 is changed to the capacitor 9 and the inductance 1.
Since the capacitor 9 is connected in parallel with zero impedance, the current in the capacitor 9 decreases and current flows through the fluorescent lamp 7. Therefore, the resonance between the inductance 8 and the capacitor 9 is almost eliminated, and a positive and negative voltage is generated in the secondary winding 8b of the inductance 8 according to the difference between the output voltage of the power supply circuit 4 and the lamp voltage, and the inductance 8 and the capacitor 5 are connected to each other. The transistor 6''?: controls on/off according to the natural vibration frequency of the fluorescent lamp 7, inductance 12, and capacitor 13 to keep the fluorescent lamp 7 lit.The inductance 10 is used to remove the DC component of the current of the fluorescent lamp 7. It is.

Further, the transistor 23 is used to stop the current that drives the transistor 6 from the drive circuit of the switching circuit 11 due to the current flowing into the pace.

In the conventional circuit configured as described above, when the electrodes 7a and b of the fluorescent lamp 7 are emitterless when there is an abnormality, almost no current flows directly from the power supply circuit 4 through the lamp. flows through the PTC thermistor 21, rapidly increases the resistance value of the PTC thermistor, turns on the transistor 23, and stops the oscillation operation of the switching circuit 11.
Since almost no current flows from the power supply circuit 4 through the fluorescent lamp 7 and the capacitor 9, the inductance 8
Since the base current of the transistor 6 that flows due to the current is eliminated, the oscillation operation of the switching circuit 11 is stopped.

In addition, when controlling the light in this discharge lamp lighting device,
By connecting a transistor, which is a control switch, in parallel to the capacitor 13, and by making this transistor and the transistor 18 conductive by the output current of another timer circuit, the lamp current is reduced by reducing the oscillation state of the drive circuit. Let's do it.

Problem to be Solved by the Invention However, in the above configuration, when the lamp voltage increases, the current flowing through the PTC thermistor 21 increases, and the PTC thermistor 21 increases in temperature, causing a normal lamp to light. However, there is a problem in that it may not be possible to keep the lamp lit.

Further, if the discharge lamp is difficult to start, there is a problem that depending on the surrounding environment, the positive temperature coefficient thermistor 21 may malfunction and the lamp cannot be started. Also, since a large current always flows through the positive temperature coefficient thermistor 21 when the power is turned on,
The temperature of the positive temperature coefficient thermistor 21 increases somewhat. Therefore,
There is a problem in that when the power is repeatedly turned on and off, the temperature of the positive temperature coefficient thermistor 21 rises, making it impossible to light the lamp.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides a power supply whose output voltage has a constant polarity, a switch connected to the output end of the power supply and having at least one control terminal, an inductance, and a capacitor. a switching circuit that starts and lights a discharge lamp connected to an output end by turning on and off a forward current to the power supply by the switch; a driving circuit connected to the switch; and a driving circuit connected to the switch; an abnormality detection circuit that detects an abnormality in a circuit and outputs a signal; a stop circuit that inputs an output signal of the abnormality detection circuit and outputs a signal to the drive circuit to turn off the switch; and a stop circuit that is connected to the drive circuit. a dimmer circuit that controls a drive circuit to dim the discharge lamp; a timer circuit a that outputs a signal to the dimmer circuit after a predetermined time; and a timer circuit that outputs a signal for a predetermined time. , a reset circuit a for resetting the timer circuit a and disabling the abnormality detection circuit in response to a signal from the timer circuit a.

According to the above-described configuration, the present invention operates the reset circuit a using the timer circuit to disable the abnormality detection circuit at the time of starting the dimming mode of the discharge lamp, thereby starting the discharge lamp and lighting it at full output. After finishing the operation of the reset circuit a by the timer circuit, the timer circuit a is operated and after a predetermined time, the dimming circuit is operated to dim the light, and when there is an abnormality in the discharge lamp, the reset circuit a is activated by the timer circuit mb.
After completing the operation, the signal from the abnormality detection circuit is transmitted to the stop circuit to stop the oscillation operation of the switching circuit 11 via the drive circuit.

Example Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is an operational block diagram of a circuit showing an embodiment of the discharge lamp lighting device of the present invention. FIG. 2 is a signal diagram of each block of an 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 timer circuit d consisting of a power source 4, a fluorescent lamp 7 which is a discharge lamp, a capacitor 9, a switching circuit 11, a resistor 14, 15 and a capacitor 16
A timer circuit 38, an inductance 12, a capacitor 13, a diode 1p, a resistor 20, and 2 large windings! 8b
The configuration and operation of the drive circuit 30 consisting of the following are the same as those of the conventional example.

What is different from the conventional example is a resistor 52.53 connected in parallel to the fluorescent lamp 7 and a resistor on the side opposite to the transistor 6, an inductance 54, and a diode 55.56 whose cathode is connected to both ends of the series circuit of the resistor 52.53. and resistance 52+
An abnormality detection circuit 35 includes a transistor 57 whose emitter is connected to the midpoint of the series circuit of diodes 53 and 53, anodes of diodes 55 and 56 are connected to the base, and a resistor 58 which is connected to the collector of the transistor 57; A resistor 59 connected between the terminal and the transistor 6 side end of the power supply 4
and a resistor 60 and a capacitor 61 connected in parallel to the resistor 59
A timer circuit 36, which is a timer circuit C, consists of a series circuit with a resistor 62 connected to the midpoint of the series circuit, and a thyristor 63 connected to short-circuit the base and emitter 1 of the transistor 6. A stop circuit 37, a transistor 18 which is a control switch connected in parallel to the drive inductance 12, and a drive capacitor 13.
Transistor 2, which is a control switch connected in parallel to
3, a resistor 41 connected to the base of the transistor 23, a resistor 40 connected to the base of the transistor 18, and a diode 42 having an anode connected to the other end of the resistor 41 and a cathode connected to the other end of the resistor 40. 31, a timer circuit 32 for a predetermined time ta, and a timer circuit 38, which is composed of an integrating circuit including a resistor 43 and a capacitor 44 connected to the output end of the power supply 4, and a Zener diode 45 whose cathode is connected to the midpoint of the integrating circuit. A resistor 50 is connected to the middle point of the resistors 14 and 15, a capacitor 51 is connected to the other end of the resistor 50, and the other end of the capacitor 51 is used as an output terminal for a predetermined time tb. A series circuit of a resistor 46 and a transistor 47 connected in parallel to 44, a resistor 48 connected between the base and emitter of the transistor 47, and a diode whose cathode is connected to the collector of the transistor 47 and whose anode is connected to the resistor 59 of the timer circuit 36. a reset circuit 33 consisting of a transistor 47 whose base is connected to the output end of the timer circuit 34;
A reset circuit consists of a diode 64 connected from the middle point of the resistor 50 and capacitor 51 of the timer circuit 34 to the positive voltage terminal of the power supply 4.A series circuit of a Zener diode 69 connected in parallel to the capacitor 44 and a dimmer switch 7o is constructed. A Zener diode 65 whose anode was connected to the output terminal of the capacitor 16 and whose cathode was connected to the base of the transistor 6 was connected in the forward direction from the midpoint of the capacitor 13 and the inductance 12 of the drive circuit 30 to the negative terminal of the power supply 4. These are a series circuit of a diode 67 and a power switch 68, and a resistor 66 connected between the cathode of the diode 67 and the resistor 15.

The operation of the circuit of the embodiment configured as described above will be explained below with reference to FIG. Note that the power switch 68 is initially turned off. If the fluorescent lamp 7 is normal, when the power is turned on, voltage is generated in the power supply circuit 4 and the timer starts! 38 starts to operate, a starting current flows through the resistor 14 and capacitor 16, through the resistor 40 of the dimming circuit 31, and through the base of the transistor 18, and the transistor 18 and transistor 6 become conductive. Initially, the fluorescent lamp 7 is not lit and the current operates in the same manner as in the conventional example, keeping the transistor 6 on.

At this time, as shown in FIG. 2, the timer circuit 34
begins to operate in the same manner as the timer circuit 38, and a signal current is supplied to the base of the transistor 47 of the reset circuit 38 via the resistor 50 and capacitor 51t-. Therefore, the transistor 47 is turned on to short-circuit the integrating capacitor 44 of the timer circuit 32 via the resistor 46, and the timer circuit 32 maintains the reset state. Also, diode 4
The input terminal of the timer circuit wI36 is short-circuited through 9.
The abnormality detection circuit 35 is disabled. Furthermore, since the timer circuit 32 is not operating, the transistor 23 of the dimming circuit 31 is off. Therefore, since the state of the drive circuit 30 is the same as in the conventional example, only the transistor 18 in parallel with the inductance 12 is turned on, 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 increases over time due to the above oscillation operation.

Note that the timer circuit 34 accumulates charge in the capacitor 51 via the resistor 50 after the power is turned on, and the transistor 47
continues to supply base current.

Further, the timer circuit 38 also accumulates charge in the capacitor 16 via the resistor 14 after the power is turned on, and the transistor 18
for a predetermined time t1 in FIG.
Later, when it is charged to the voltage across resistors 14 and 15, it is no longer charged, so transistor 18 is turned off.

When the transistor 18 turns off, it performs an oscillation operation similar to the conventional example, and generates a voltage that is greater than that during preheating before the timer circuit 38 stops operating, and is sufficient to start the fluorescent lamp 7, and the fluorescent lamp 7 starts. do. Note that when this starting voltage is applied, the lamp voltage is large, so when the transistor 6 is on, a current flows from the positive terminal of the power supply through the resistor 52, 53, the inductance 54, and the inductance 8 to the transistor 6.

Therefore, a voltage drop occurs across the resistors 52 and 53.

Note that the voltage drop that occurs at this time is lower on the inductance 54 side and higher on the tffiTa side. At this time, resistance 53
Due to the voltage drop that occurs, the diode 56 and the transistor 57 are turned on, and an output signal is output from the collector terminal of the transistor 57 via the resistor 58.

However, at this time as well, since the reset circuit 33 is operating, no signal is output from the timer circuit 36 to the stop circuit 37.

After starting, the operation of the circuit is almost the same as after the timer circuit 38 stops operating, but the transistor 6 is turned on and off as in the conventional example.
The fluorescent lamp 7 is kept lit by off control. Note that the inductance 54 is also used to remove the DC component of the current of the fluorescent lamp 7. Further, at this time, since the lamp voltage becomes small, the transistor 57 of the abnormality detection circuit 35 is turned off and no signal is output. Furthermore, the timer circuit 34 continues to output during the above period, and the capacitor 33 is charged.

When the predetermined time t3 in FIG. 2, in which the capacitor 33 is charged to the voltage divided by the resistor 14.15, comes, the output of the timer circuit 34 disappears and the transistor 47 of the reset circuit 33 is turned off. When the reset circuit 33 stops operating, the capacitor 44 of the timer circuit 32 begins to be charged.

When the dimmer switch 70 is on, the capacitor 44 of the timer circuit 32 is charged from the power supply 4 via the resistor 43, but the Zener voltage of the Zener diode 69 is made smaller than the Zener voltage of the Zener diode 45.
The Zener diode 45 is not conductive and no signal is output from the timer circuit 32 to the dimming circuit 31.Therefore, the fluorescent lamp 7 maintains full output lighting from now on.

Next, when the dimmer switch 70 is off, after a predetermined time ta, when the voltage of the capacitor 44 reaches the Zener voltage of the Zener diode 69, the Zener diode 69 begins to conduct, and a signal is sent from the timer circuit 32 to the dimmer circuit 1131. Current is output. This signal current causes the transistor 23
conducts through the resistor 41, and the transistor 18 also conducts through the diode 42 and the resistor 40. transistor 23
When 18 becomes conductive, the current flowing through the capacitor 13 and inductance 12 of the drive circuit 30 is shunted, and the resonance state is attenuated. Therefore, the resonant frequency actually increases and the on-time of the transistor 6 becomes shorter, so that the lamp current of the fluorescent lamp 7 decreases, and the fluorescent lamp 7 is dimmed.

Next, when the fluorescent lamp 7 is in an abnormal electrode emitterless state at the end of its life, etc., when the power source 4 is turned on, the switching circuit +1811 starts oscillating operation as in the conventional example. However, since the electrodes of the fluorescent lamp 7 are emitterless, the lamp voltage increases, and when the transistor 6 is on, just like when the starting voltage is applied, the inductance 8 is connected from the positive terminal of the power supply to the resistor 52, 53 and the inductance 54. As a result, current flows to transistor 6. Therefore, a voltage drop occurs across the resistors 52 and 53.

Note that the voltage drop that occurs at this time is lower on the inductance 54 side and higher on the electric iTa side. At this time, the voltage drop generated across the resistor 53 turns on the diode 56 and the transistor 57, and an output signal is output from the collector terminal of the transistor 57 via the resistor 58 at time t1.

At this time, since the reset circuit 33 is on, no signal is output from the timer circuit 36 to the stop circuit 37.
When the reset circuit 33 reaches time t3 after the predetermined time tb of the timer circuit 834 has elapsed, the reset circuit 33 stops operating, so that a voltage is generated in the resistor 59 of the timer circuit 36, and the capacitor 61 is charged via the resistor 60. be done. At time t5 when the voltage of the capacitor 61 reaches the gate turn-on voltage of the thyristor 63 of the stop circuit 837, a signal current is outputted to the gate of the thyristor 63 of the stop circuit 37 via the resistor 62. Therefore, the thyristor 63 is turned on, the pace and emitter of the transistor 6 are short-circuited, and the transistor 6 is turned off. Note that if energy remains in the drive circuit etc. even after the transistor 6 is turned off, the transistor 6 may try to turn on again, but the charge accumulated in the capacitor 61 from the timer circuit 36 is discharged via the resistor 62. Since the output signal continues to be output for a predetermined period of time, the thyristor 63 is always on until time t7, and by time t7, the transistor 6 can be reliably turned off (time t6) and the switching circuit 11 can be stopped.

In the above case, once the operation of the switching circuit stops, unless the timer circuit 38 is reset, no starting current will flow from the timer circuit 3-3, and the switching circuit will not restart. Further, even after the reset circuit 33 stops operating, the timer circuit 32 continues to operate, but there is no problem.

With the above configuration, the abnormality detection circuit 35 of the electronic circuit, in which the detection level can be freely set by appropriately setting the resistance values of the resistors 52 and 53, is used to control the lamp voltage during lighting. Regardless of the size of
Because it does not use a temperature element like a positive temperature coefficient thermistor,
It is not affected by ambient temperature and can be turned on and off repeatedly even in high ambient temperatures. In addition, in the case of a normal lamp, the reset circuit 33 is operated for a predetermined time tb, so that the lamp can be reliably started and lit.
Since it switches to dimming after , it can stably switch to dimming and maintain it. In addition, in the event of an abnormality in the discharge lamp 7, it can be detected repeatedly and reliably regardless of the surrounding conditions, and the oscillation of the switching circuit 11 can be reliably stopped, improving reliability, ease of use, and safety.
This can be achieved with an inexpensive configuration. Furthermore, in this example,
The current of the timer circuit 34 is equal to the timer times! Since it is connected to the power supply 4 through the 838 resistor 14, when the power supply 4 is turned off, the capacitor 5 is discharged at the same timing as the capacitor 16 is discharged.
1 is also discharged, so even if the power source 4 is turned on immediately next time, the reset circuit 33 is always activated when the starting current flows through the capacitor 16, so the fluorescent lamp 7
This can prevent the engine from failing to start.

Next, the reset circuit 39 will be explained. Each timer circuit 32
, 34, 36. The charge on the capacitor of 38 cannot be removed immediately. Therefore, even if an attempt is made to start, each timer does not operate, so the switching circuit 11 does not oscillate.However, it usually takes some time for the fluorescent lamp 7 to stop discharging while the voltage of the power source 4 decreases. ,
During this time, some amount of electricity is discharged.

At this time, when the timer circuit 34 hardly operates even if the starting current flows through the capacitor 16, the reset circuit 33 immediately stops operating, the output signal of the timer circuit 82 is generated, and the dimming circuit is activated from the beginning. If the lamp voltage is activated and cannot generate the lamp voltage necessary for starting, or even if it can be generated, the output from the abnormality detection circuit 35 is transmitted to the stop circuit 37 via the timer circuit 36, and the stop circuit 37
operates to stop transistor 6. Therefore, there was a problem in that the engine could not be started in some cases. To solve this problem, a simple configuration is adopted in which a diode is connected from the middle point of the timer circuit 34 to the power supply. . For this reason,
If the voltage of the power source 4 decreases even a little, the charge in the capacitor 51 is discharged to the positive voltage output terminal of the power source 4 through the diode 64, thereby preparing for the next start. That is,
Even if the power supply 4 is turned on immediately after this, the timer circuit 34
Since the reset circuit 33t can be operated, the abnormality detection circuit 35 is disabled by operating the reset circuit 33t, and the timer circuit 32 is reset, so that the fluorescent lamp 7 can be started.

Next, the operation of the power switch 68 will be explained. The power switch 68 is initially off and is not operating at all at this time. When the power switch 68 is turned on when the fluorescent lamp 7 is lit, the charge in the capacitor 16 is discharged from the resistor 66, the power switch 68, the emitter of the transistor 6, the base, and the Zener diode 65. at the same time,
Drive circuit 3 via diode 67 and power switch 68
0 resonance voltage can be kept low. Therefore, the transistor 6 is turned off and the switching circuit 11 stops oscillating. - Once stopped, as long as the power switch 68 is on, the partial voltage across the resistor 14.15 remains constant and the voltage across the capacitor 16 also remains constant, so no starting current flows and the switching circuit 11 stops oscillating. remain as it is. Next, when the power switch 68 is turned off, the resistance 14.1
Since the partial pressure of the fluorescent lamp 5 is increased and the timer circuit 38 and the timer circuit 34 can be operated, the fluorescent lamp 7 can always be started and lit after being preheated once, so that blackening of the fluorescent lamp 7 can be reduced. Further, since the fluorescent lamp 7 can be turned on and off using a simple small signal switch circuit called the power switch 68, a high-performance switch such as a touch switch can be used. .

As described above, according to the present invention, when an abnormality occurs in the discharge lamp 7 or at the end of its life, the oscillation of the switching circuit can be reliably stopped using an abnormality detection circuit having a simple configuration. It can also be restarted repeatedly and can be used in high-temperature environments. In addition, the detection level can be set regardless of the lamp voltage when lit, so it can be applied to any lamp. In addition, a normal lamp can be reliably started and lit, and can be quickly switched to a dimmer.
Immediate restart and instant start even in the event of a momentary power outage.

In the embodiment of the present invention, the discharge lamp 7 is a fluorescent lamp, but a high-pressure discharge lamp may be used. In this case, the timer circuit 38 can slow down the starting state of the switching circuit 11 to reduce stress on the circuit. Also,
The basic effect can be obtained even if the timer circuit 38 is turned off. In addition, an abnormality detection circuit 35, timer circuits 32, 34, 36, 3
8, stop circuit '1837, dimming circuit 31, drive circuit 30,
The configuration of the switching circuit 11 may be any other configuration as long as each required function is provided. That is, in this embodiment, the switching circuit 11 is a self-excited single-stone resonant inverter, but it may be separately excited, and the same effect can be obtained with other types of inverters. Further, although the thyristor 63 is used as the stop circuit 37, other types may be used as long as they can stop the oscillation of the transistor 6.

Furthermore, the effect of stopping the circuit can be obtained even without the timer circuit 36.

Moreover, the same effect can be obtained even if the abnormality detection circuit 35 detects an abnormality in the circuit rather than an abnormality in the lamp. Further, the power switch 68 only needs the timer circuit 38, and can be used in the same way even if it is not a dimming circuit.

As described in detail, according to the present invention, the discharge lamp can be reliably started, turned on, and regulated using a dimming circuit with a simple configuration when the discharge lamp is abnormal or at the end of its life, regardless of the surrounding environment. It is possible to realize a discharge lamp lighting device that not only can emit light, but also can detect termination in the event of an abnormality and reliably stop the oscillation of the switching circuit, and can be used repeatedly.

[Brief explanation of the drawing]

Fig. 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 method. FIG. 3 is a circuit diagram of the device. DESCRIPTION OF SYMBOLS 1... Commercial power supply, 4... Power supply circuit, 7... Fluorescent lamp, 6... Transistor, 30... Drive circuit, 3
1...Dimmer circuit, 33...Reset circuit, 35...
- Abnormality detection circuit, 37...stop circuit. Figure 2 (CL) Sei Hayabusa Lasop

Claims (6)

[Claims] (1) A power source whose output voltage has a constant polarity, at least one switch with a control terminal connected to the output end of the power source, an inductance, and a capacitor, and a forward current connected to the power source is turned on by the switch. - A switching circuit that turns off and starts and lights up the discharge lamp connected to the output terminal, a drive circuit connected to the switch, and an abnormality detection circuit that detects an abnormality in the discharge lamp or circuit and outputs a signal. 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 control circuit that is connected to the drive circuit and controls the drive circuit to dim the discharge lamp. an optical circuit; a timer circuit a that outputs a signal to the dimming circuit after a predetermined time;
A timer circuit b that outputs a signal for a predetermined time period of the timer circuit a, and a reset circuit a that resets the timer circuit a and disables the abnormality detection circuit in response to a signal from the timer circuit b. Discharge lamp lighting device. (2) Claim 1, comprising a reset circuit b that resets the timer circuit b in response to power on/off.
Discharge lamp lighting device as described in . (3) Connected between the abnormality detection circuit, the stop circuit, and the reset circuit a, and outputs a signal to the stop circuit for a predetermined time according to the signal of the abnormality detection circuit, and outputs a signal to the stop circuit for a predetermined period of time according to the signal from the abnormality detection circuit, and 3. The discharge lamp lighting device according to claim 1, further comprising a timer circuit c that invalidates the signal from the abnormality detection circuit in accordance with the above. (4) Claim 1 comprising a timer circuit d which outputs a signal to a dimming circuit for a predetermined time shorter than the predetermined time of the timer circuit b to reduce the output to the lamp for the predetermined time. The discharge lamp lighting device according to item 1, 2 or 3. (5) A power source whose output voltage has a constant polarity, at least one switch with a control terminal connected to the output end of the power source, an inductance, and a capacitor, and a forward current connected to the power source is turned on by the switch. - A switching circuit that turns off and starts and lights up the discharge lamp connected to the output terminal, and a driving inductance and a driving capacitor that are connected to the switch and are connected to the switch to prevent resonance between the driving capacitor and the driving inductance. It consists of a series circuit consisting of a drive circuit to be used, a control switch element connected in parallel to the drive inductance, another capacitor, and a resistor a whose one end is connected to a power supply, and the signal from the other end of the other capacitor is connected to the drive circuit. A timer circuit that outputs to the control terminal of the control switch element, a constant voltage diode whose anode is connected to the output side end of the other capacitor, and a cathode is connected to the control terminal of the switch with a control terminal, and the midpoint of the series circuit. A resistor b connected to one end, a diode connected between the midpoint of the driving inductance and the driving capacitor to the other end of the resistor b, and a side opposite to the resistor a of the power source, the resistor b and the diode A discharge lamp lighting device consisting of a power switch connected between the (6) The drive circuit is connected to the switch with a control terminal and includes a drive inductance and a drive capacitor, and uses resonance between the drive capacitor and the drive inductance, and the dimming circuit is connected to at least the drive circuit. A timer circuit d includes a control switch element connected in parallel to an inductance, and a timer circuit d is composed of a series circuit of another capacitor and a resistor a whose one end is connected to a power supply, and a signal from the other end of the other capacitor is transmitted to the control switch element. A constant voltage diode with an anode connected to the output side end of the other capacitor and a cathode connected to the control terminal of the switch with a control terminal, and one end connected to the midpoint of the series circuit. a resistor b, a diode connected between the midpoint between the driving inductance and the driving capacitor and the other end of the resistor b, and a midpoint between the opposite resistor a side of the power supply and the resistor b and the diode. A discharge lamp lighting device according to any one of claims 1 to 5, comprising a power switch connected between the discharge lamp lighting device and the power switch connected between the discharge lamp lighting device and the power switch.