JPH0636881A - Discharge lamp lighting device - Google Patents

Abstract

PURPOSE:To provide a discharge lamp lighting device capable of saving power and extending the life of a discharge lamp. CONSTITUTION:At starting a discharge lamp FL1, the charged voltage of a capacitor C12 is increased according to the time constant between a resistor R11 and a resistor R12. Until the voltage of the capacitor 12 reaches a regulated voltage, a relay contact Ry1S connects a filament preheating power source winding Tr1c to an input winding Tr3a. The voltage induced in the filament preheating power source winding Tr1c is supplied to the input winding Tr3a, and a voltage is induced in filament preheating windings Tr3b, Tr3c to preheat filaments FL1a, FL1b. When the charged voltage of the capacitor C12 reaches the regulated voltage, a transistor Q11 is ON, and the relay contact Ry1S connects a capacitor C3 to a filament FL1b. By connecting the capacitor C3 to the filament FL1b by the relay contact Ry1S, the discharge lamp FL1 starts lighting.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge lamp lighting device for performing soft start by an inverter circuit.

[0002]

2. Description of the Related Art As a conventional discharge lamp lighting device of this type, for example, a structure shown in FIG. 7 is known.

The conventional discharge lamp lighting device shown in FIG.
A full-wave rectifier circuit 2 such as a diode bridge is connected to a commercial AC power source E via a filter circuit 1 for removing noise. A smoothing capacitor C1 is connected between the output terminals of the full-wave rectifier circuit 2, and an inverter circuit 3 is connected between both terminals of the capacitor C1.

Further, the inverter circuit 3 includes the primary winding of the inverter transformer Tr1 between both terminals of the capacitor C1.
Tr1a and the collector and emitter of a transistor Q1 which is a switching element are connected in series, and a resonance capacitor C2 is connected in parallel to the primary winding Tr1a of the transistor Q1.
A freewheeling diode D1 is connected between the collector and emitter of the transistor Q1.

Further, the secondary winding Tr1b of the inverter transformer Tr1 is connected to the filaments FL1a and FL1b of the discharge lamp FL1 via a DC cutting capacitor C3.
A starting capacitor C4 is connected between the filaments FL1a and FL1b.

Then, the AC of the commercial AC power supply E is subjected to noise removal by the filter circuit 1 and full-wave rectification by the full-wave rectification circuit 2.
After being smoothed to a direct current by the capacitor C1, the primary winding Tr1a and the capacitor C2 resonate, and the transistor Q1 oscillates at a high frequency to output a high frequency. When the discharge lamp FL1 is started, the output of the inverter circuit 3 is the secondary winding Tr1b and the filament FL1 of the discharge lamp FL1.
The filaments FL1a and FL1b are preheated by flowing through the path of a, the capacitor C4, the capacitor C3 and the secondary winding Tr1b. At the same time, the resonance voltage generated in the capacitor C4 is
When the filaments FL1a and FL1b of 1 are applied and the filaments FL1a and FL1b are preheated, the discharge lamp FL1 starts lighting.

When the discharge lamp FL1 is lit, the terminal voltage generated in the capacitor C4 is reduced to the voltage when the discharge lamp FL1 is lit, and the current flowing through the capacitor C4 is also approximately the resonance voltage and when the discharge lamp FL1 is lit. Reduced to the ratio with the voltage.

However, in the case of the conventional circuit shown in FIG. 7, even when the discharge lamp FL1 is turned on, the filament
Due to the current flowing through the capacitor C4, a resistance loss occurs in the FL1a and FL1b due to the resistance of the filaments FL1a and FL1b. This resistance loss is about 9 to 10% of the optical output power ratio of the discharge lamp FL1. become.

On the other hand, when the discharge lamp FL1 is turned on, a current to the filaments FL1a, FL1b is necessary in order to prolong the life of the discharge lamp FL1 without unnecessarily exhausting the discharge active substance from the filaments FL1a, FL1b. Was said. However, according to the experiment, when the discharge lamp FL1 is turned on, the discharge of the filaments FL1a, FL1b is always performed from one point if the discharge current for maintaining the specified brightness is supplied even if there is no heating current. , Filament FL1a,
It was found that the temperature of FL1b could reach the specified value.

Therefore, when the discharge lamp FL1 is turned on,
Heating the filaments FL1a, FL1b rather reduces the efficiency of the device.

Further, in the case of the conventional example shown in FIG. 7, since the preheating of the filaments FL1a and FL1b of the discharge lamp FL1 and the high voltage for starting the discharge lamp FL1 are simultaneously applied,
The filament lamps FL1a and FL1b are not preheated, and the discharge lamp FL1 lights up, which shortens the life of the discharge lamp FL1.

Further, the filament FL1 of the discharge lamp FL1
For example, a configuration shown in FIG. 8 is known as a circuit in which a and FL1b are preheated in advance and the life of the discharge lamp FL1 is taken into consideration.

The circuit shown in FIG. 8 is obtained by providing the circuit shown in FIG. 7 with a soft start circuit 4. This soft start circuit 4 has a resistor in parallel with the capacitor C1.
Connect a series circuit of R1 and capacitor C5
A series circuit of a resistor R2 and a resistor R3 is connected in parallel with C5. Also, at the connection point of the resistors R2 and R3,
A resistor R4 is connected, the other end of the resistor R4 is connected to the gate of the field effect transistor Q2, and a freewheeling diode D2 is connected between the source and drain of the field effect transistor Q2.
Is connected, and the drain is connected to the capacitor C6, and the field effect transistor Q2 via the capacitor C6 is connected to the capacitor C7.

Further, the transformer Tr2 is connected to the capacitor C3.
Is connected to the detection winding Tr2a, and the output winding Tr2b of the transformer Tr2 is connected between the capacitor C6 and the base of the transistor Q1. Further, a series circuit of a resistor R5 and a diode D3 is connected between the base and the emitter of the transistor Q1.

Then, when the discharge lamp FL1 is started, the full-wave rectifier circuit 2 outputs to charge the capacitor C5. According to the voltage of the capacitor C5, the voltage divided by the resistors R2 and R3 is supplied to the gate of the field effect transistor Q2 via the resistor R4, and the resistance value between the drain and source of the field effect transistor Q2 is gradually increased. The frequency of the resonance current supplied to the base of the transistor Q1 is lowered, and the voltage supplied to the discharge lamp FL1 is gradually increased.

[0016]

However, in the conventional example shown in FIG. 8, the soft start circuit 4 gradually increases the voltage supplied to the discharge lamp FL1 to preheat the filaments FL1a and FL1b. Is less and the time to preheat filaments FL1a and FL1b becomes longer, and
There is a problem that it is difficult to greatly improve the life of the discharge lamp FL1.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a discharge lamp lighting device which can save power and can prolong the life of the discharge lamp.

[0018]

The discharge lamp lighting device according to claim 1, wherein the filament of the discharge lamp is preheated with a preheating voltage, and then a voltage higher than the preheating voltage is applied to the discharge lamp. And a filament preheating inductor that is magnetically coupled to the inductor and preheats the filament, in a discharge lamp lighting device including an inverter circuit having an inductor.

A discharge lamp lighting device according to a second aspect is the discharge lamp lighting device according to the first aspect, further comprising a timer circuit for heating the filament for a predetermined time after the output of the inverter circuit.

[0020]

In the discharge lamp lighting device according to the first aspect of the present invention, the filament preheating inductor magnetically coupled to the inductor of the inverter circuit is provided, and the filament preheating inductor preheats the filament. Can be preheated and the discharge lamp has a long life.

The discharge lamp lighting device according to a second aspect is the discharge lamp lighting device according to the first aspect, further comprising a timer circuit for heating the filament for a predetermined time after the output of the inverter circuit. Since the filament is not preheated later, power saving is further achieved.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the discharge lamp lighting device of the present invention will be described below with reference to the drawings. The parts corresponding to those of the conventional example shown in FIG.

In the discharge lamp lighting device shown in FIG. 1, a full-wave rectifying circuit 2 such as a diode bridge is connected to a commercial AC power source E via a filter circuit 1 for removing noise. A smoothing capacitor C1 is connected between the output terminals of the full-wave rectifier circuit 2, and an inverter circuit 3 is connected between both terminals of the capacitor C1.

Further, the inverter circuit 3 includes the primary winding of the inverter transformer Tr1 between both terminals of the capacitor C1.
Tr1a and the collector and emitter of a transistor Q1 which is a switching element are connected in series, and a resonance capacitor C2 is connected in parallel to the primary winding Tr1a of the transistor Q1.
A freewheeling diode D1 is connected between the collector and emitter of the transistor Q1.

Further, the secondary winding Tr1b as an inductor of the inverter transformer Tr1 is connected to the filaments FL1a and FL1b of the discharge lamp FL1 via a DC cut capacitor C3 and a relay contact Ry1S. A starting capacitor C11 is connected between the filaments FL1a and FL1b via a relay contact Ry1S.

The inverter transformer Tr1 is provided with a filament preheating power winding Tr1c as a filament preheating inductor, and the filament preheating power winding Tr1c has an input winding Tr3a of the filament preheating transformer Tr3. The filament preheating windings Tr3b and Tr3c of the transformer Tr3 for filament preheating are connected to the filaments FL1a and FL1b of the discharge lamp FL1.

A timer circuit 5 is connected in parallel to the capacitor C1, and a series circuit of a resistor R11, a resistor R12 and a capacitor C12 is connected to the timer circuit 5, and the timer circuit 5 is connected in parallel to the resistor R12 and the capacitor C12. Zener diode ZD1 is connected, and resistor R13 and resistor R14 are connected in parallel to capacitor C12.
Resistor R15 and Zener diode ZD in parallel with ZD1
2 series circuits are connected. The non-inverting input terminal of the operational amplifier OP1 forming the comparator is connected to the connection point of the resistors R13 and R14, and the inverting input terminal is connected to the connection point of the resistor R15 and the Zener diode ZD2. Further, the output terminal of the operational amplifier OP1 is connected to the base of the transistor Q11 via the resistor R16, and the resistor R17 is connected between the base and the emitter of the transistor Q11. Also, resistors R11 and R1
Between the connection point of 2 and the base of transistor Q11 is a relay coil that drives resistor R18 and relay contact Ry1S.
Ry1L is connected in series, and a freewheeling diode D11 is connected in parallel to the relay coil Ry1L.

Next, the operation of the embodiment shown in FIG. 1 will be described with reference to FIG.

First, the AC of the commercial AC power source E is subjected to noise removal by the filter circuit 1, full-wave rectified by the full-wave rectifier circuit 2, smoothed by the capacitor C1, and then resonated by the primary winding Tr1a and the capacitor C2, and the transistor Q1 oscillates at high frequency and outputs at high frequency. In addition, when starting the discharge lamp FL1, the charging voltage of the capacitor C12 is as shown in FIG.
As shown in (d), it gradually increases according to the time constants of the resistors R11 and R12. And this capacitor C12
In the period TA until the charging voltage of reaches the specified voltage set by the Zener diode ZD2, the operational amplifier OP2 outputs the inverted output, the current is not supplied to the base of the transistor Q11, and the transistor Q11 keeps the off state. No current flows through the coil Ry1L, and the relay contact Ry1S connects the filament preheating power supply winding Tr1c and the input winding Tr3a.

The power supply winding Tr1c for filament preheating
Is supplied to the input winding Tr3a to induce a voltage in the filament preheating windings Tr3b and Tr3c to discharge the discharge lamp FL1.
Preheat filaments FL1a and FL1b. In this case, since no voltage is applied between the filament FL1a and the filament FL1b, the filament FL1a and the filament FL1b are only preheated and the discharge lamp FL1 is not turned on. Therefore, the discharge lamp FL1 does not light before the filament FL1a and the filament FL1b are preheated,
The discharge-active substance, that is, the emitter of the filaments FL1a and FL1b is not emitted unnecessarily. The voltage of the capacitor C11 at this time is
The state becomes high as shown in (a).

Then, the charging voltage of the capacitor C12 gradually increases as shown in FIG.
When the charging voltage of reaches the specified voltage set by Zener diode ZD2, operational amplifier OP2 performs non-inverting output, current is supplied to the base of transistor Q11, transistor Q11 turns on, and the current flows to relay coil Ry1L. Supplied, the relay contact Ry1S is a capacitor C3 and filament
Connect to FL1b.

The period T during which the relay contact Ry1S is switched
Since B is about 2 ms, filaments FL1a, FL
Even if 1b is opened, it does not adversely affect the lighting operation and life of the discharge lamp FL1.

When the relay contact Ry1S connects between the capacitor C3 and the filament FL1b, a high voltage is applied between the filament FL1a and the filament FL1b, and the discharge lamp FL1 starts lighting. Since the filaments FL1a and FL1b are preheated sufficiently in advance at the time of starting, it is possible to prevent the emitters from being emitted more than necessary at the time of lighting, and it is possible to prevent the life of the discharge lamp FL1 from being shortened.

Further, since the relay contact Ry1S connects between the capacitor C3 and the filament FL1b, the filament preheating power supply winding Tr1c and the input winding Tr3a are separated from each other, so that when the discharge lamp FL1 is lit, the filament is heated. Since the filament preheating current is not supplied to the FL1a and the filament FL1b, the efficiency is increased by 4 to 5% as compared with the conventional one, and the lighting time until the discharge lamp FL1 becomes defective is increased about 7 times.

Next, a two-lamp type configuration in which the discharge lamps FL1 and FL2 are connected in series will be described with reference to FIG.

The circuit shown in FIG. 3 is different from the circuit shown in FIG. 1 in that the filament preheating transformer Tr3 has three filament preheating windings Tr3b, Tr3c, Tr3d, and the filament FL1b and discharge of the discharge lamp FL1. Lamp FL2
The filament FL2a of is connected. The filament preheating windings Tr3b, Tr3c, Tr3d are connected to the filament FL1a of the discharge lamp FL1, the connection point of the filament FL1b of the discharge lamp FL1 and the filament FL2a of the discharge lamp FL2, and the filament FL2b of the discharge lamp FL2. There is.

Then, as in the case shown in FIG. 1, each filament FL1a, FL1b, FL2a, FL2b is turned on for a predetermined time after the power is turned on.
After preheating, the discharge lamps FL1 and FL2 are turned on.

A two-lamp configuration in which the discharge lamps FL1 and FL2 are connected in parallel will be described with reference to FIG.

The circuit shown in FIG. 4 is different from the circuit shown in FIG. 1 in that the filament preheating transformer Tr3 has three filament preheating windings Tr3b, Tr3c, Tr3d, and the filament FL1b and the discharge of the discharge lamp FL1. Lamp FL2
The filament FL2b of is connected. The filament preheating windings Tr3b, Tr3c, Tr3d are the filament FL1a of the discharge lamp FL1, the filament FL2a of the discharge lamp FL2,
Also, they are connected to the connection points of the filament FL1b of the discharge lamp FL1 and the filament FL2b of the discharge lamp FL2, respectively. Also, capacitors C11 and C15 for starting are connected between both ends of the discharge lamps FL1 and FL2, and a choke coil L11 is connected in series to the discharge lamp FL1 and also to the discharge lamp FL2. Choke coil L12 is connected in series.

Then, similarly to the case shown in FIG. 1, after the filaments FL1a, FL1b, FL2a, FL2b are preheated for a predetermined time after the power is turned on, the discharge lamps FL1, FL2 are turned on.

Next, another embodiment will be described with reference to FIG.

The embodiment shown in FIG. 5 differs from the embodiment shown in FIG. 1 in that the relay contact Ry1S connects and disconnects the capacitor C3 and the filament FL1b. Also, connect the resistor R21 and capacitor C1 to the output terminal of the operational amplifier OP1.
6 and the resistor R22 in parallel with the capacitor C16, and the transistor Q1 via the Zener diode ZD3.
Connected to the base of 2. In addition, transistor Q12
A resistor R23 is connected between the collector and the emitter of the transistor Q12, a transistor Q13 is connected to the collector of the transistor Q12, and a resistor R24 is connected between the collector and the base of the transistor Q13. Furthermore, this transistor Q1
Rectifier circuit 6 is connected between the emitter and collector of 3,
The rectifier circuit 6 is connected between the filament preheating power source winding Tr1c and the input winding Tr3a and has a switching function.

Next, the operation of the embodiment shown in FIG. 5 will be described.

First, the AC of the commercial AC power supply E is output at a high frequency by the inverter circuit 3 via the filter circuit 1, the full-wave rectification circuit 2 and the capacitor C1. Also, the discharge lamp FL
At the start of 1, the charging voltage of the capacitor C12 gradually increases according to the time constants of the resistors R11 and R12. Then, until the charging voltage of the capacitor C12 reaches the specified voltage set by the Zener diode ZD2, the operational amplifier OP1 performs inverting output, current is not supplied to the base of the transistor Q11, and the transistor Q11 remains off. No current flows through the relay coil Ry1L, and the relay contact Ry1S connects between the filament preheating power supply winding Tr1c and the filament FL3b.

On the other hand, while the operational amplifier OP1 is performing inverting output, the capacitor C16 is not charged and the Zener diode ZD3 is not turned on.
Since the transistor Q13 and the transistor Q13 remain off, the load of the rectifier circuit 6 between the filament preheating power supply winding Tr1c and the input winding Tr3a becomes the lowest, so the voltage induced in the filament preheating power supply winding Tr1c is reduced. Input winding Tr
It is supplied to 3a, and a voltage is induced in the filament preheating windings Tr3b, Tr3c to preheat the filaments FL1a, FL1b of the discharge lamp FL1. In this case, since no voltage is applied between the filament FL1a and the filament FL1b, the filament FL1a and the filament FL1b are only preheated,
The discharge lamp FL1 does not light. Therefore, the filament FL
Discharge lamp before 1a and filament FL1b are preheated
FL1 does not light, filament FL1a and filament
The discharge active substance of FL1b, that is, the so-called emitter is not emitted unnecessarily. At this time, the voltage of the capacitor C11 becomes high.

After that, when the charging voltage of the capacitor C12 gradually increases and the charging voltage of the capacitor C12 reaches the specified voltage set by the Zener diode ZD2, the operational amplifier
OP1 outputs a non-inverted output, current is supplied to the base of the transistor Q11, the transistor Q11 is turned on, current is supplied to the relay coil Ry1L, and the relay contact Ry1S connects between the capacitor C3 and the filament FL1b.

When the relay contact Ry1S connects between the capacitor C3 and the filament FL1b, a high voltage is applied between the filament FL1a and the filament FL1b, and the discharge lamp FL1 starts lighting.

On the other hand, when the operational amplifier OP1 outputs a non-inverted output, the capacitor C16 is gradually charged, and when the Zener voltage of the Zener diode ZD3 is exceeded, the transistor Q12 and the transistor Q13 are sequentially turned on and the load of the rectifier circuit 6 is increased. Becomes larger, the voltage of the input winding Tr3a is lowered, and the preheating of the filaments FL1a and FL1b is completed. At the time of starting, since the filaments FL1a and FL1b are preheated sufficiently in advance,
It is possible to prevent the emitter from being emitted more than necessary at the time of lighting, and to prevent the life of the discharge lamp FL1 from being shortened. Also, after preheating the filaments FL1a, FL1b of the discharge lamp FL1, the discharge is started without stopping the current supply to the filaments FL1a, FL1b, so that the discharge can be performed more reliably and the discharge lamp FL1 Can have a long life.

Another embodiment will be described with reference to FIG.

In the embodiment shown in FIG. 6, a half bridge type is used for the inverter circuit 3. Then, in the circuit shown in FIG. 1, an inverter circuit 3 is connected to both ends of a capacitor C1, and the inverter circuit 3 has a collector and an emitter of a transistor Q21 and a transistor Q22.
The collector and emitter of are connected in series, and the collector and emitter of these transistors Q21 and transistor Q22
Diode for free return between collector and emitter of
D21 and diode D22 are connected.

A series circuit of a voltage dividing capacitor C21 and a capacitor C22 is connected between both ends of the capacitor C1. The primary winding Tr4a and the capacitor C23 of the transformer Tr4 serving as a choke coil are connected between the connection point of the emitter of the transistor Q21 and the collector of the transistor Q22 and the connection point of the capacitors C21 and C22. Secondary winding of Tr4
Tr4b is connected to the input winding of the filament preheating transformer Tr3, and the filament preheating windings Tr3b and Tr3c of the filament preheating transformer Tr3 are connected to the filaments FL1a and FL1b of the discharge lamp FL1.

Next, the operation of the embodiment shown in FIG. 6 will be described.

First, the AC of the commercial AC power supply E is passed through the filter circuit 1, the full-wave rectification circuit 2 and the capacitor C1 to form the transistor Q21 and the transistor
The Q22 is alternately turned on and off to oscillate a high frequency and output a high frequency. When the discharge lamp FL1 is started, the relay contact Ry1S is connected by the timer circuit 5 between the filament preheating power source winding Tr1c and the input winding Tr3a.

The power supply winding Tr1c for filament preheating
Is supplied to the input winding Tr3a to induce a voltage in the filament preheating windings Tr3b and Tr3c to discharge the discharge lamp FL1.
Preheat filaments FL1a and FL1b. In this case, since no voltage is applied between the filament FL1a and the filament FL1b, the filament FL1a and the filament FL1b are only preheated and the discharge lamp FL1 is not turned on. Therefore, the discharge lamp FL1 does not light before the filament FL1a and the filament FL1b are preheated,
The discharge-active substance, that is, the emitter of the filaments FL1a and FL1b is not emitted unnecessarily.

Then, when a predetermined time has elapsed, the timer circuit 5 supplies a current to the relay coil Ry1L, and the relay contact Ry1S connects the primary winding Tr4a and the filament FL1b.

In any case, the inverter circuit 3 is not limited to the resonance type, but may be a separately excited type, or may be a push-pull type or any other type.

[0057]

According to the discharge lamp lighting device of the first aspect, the filament preheating inductor magnetically coupled to the inductor of the inverter circuit is provided, and the filament preheating inductor preheats the filament. The filament can be surely preheated and the discharge lamp can have a long life.

According to the discharge lamp lighting device of the second aspect,
The discharge lamp lighting device according to claim 1, further comprising a timer circuit for heating the filament for a predetermined time after the output of the inverter circuit, so that the filament is not preheated after the discharge lamp is started, so that the power consumption is further saved. be able to.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of a discharge lamp lighting device of the present invention.

FIG. 2 is a waveform diagram showing the same operation. (A) Voltage waveform diagram of capacitor C11 (b) Voltage waveform diagram of filament FL1a and filament FL1b of discharge lamp FL1 (c) Voltage waveform diagram of discharge lamp FL1 (d) Voltage waveform diagram of capacitor C12

FIG. 3 is a circuit diagram showing a part of a discharge lamp lighting device of another embodiment of the same as above.

FIG. 4 is a partial circuit diagram showing a part of a discharge lamp lighting device according to another embodiment of the present invention.

FIG. 5 is a circuit diagram showing a discharge lamp lighting device of still another embodiment of the same.

FIG. 6 is a partial circuit diagram showing a discharge lamp lighting device according to still another embodiment of the present invention.

FIG. 7 is a circuit diagram showing a conventional discharge lamp lighting device.

FIG. 8 is a circuit diagram showing another conventional discharge lamp lighting device.

[Explanation of symbols]

3 Inverter circuit 5 Timer circuit FL1 Discharge lamp FL1a, FL1b Filament Tr1b Secondary winding as inductor Tr1c Filament preheating power supply winding as filament preheating inductor

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Masahiro Sugiyama, 6-78 Minamimachi, Mishima-shi, Shizuoka Tokyo Electric Co., Ltd. Mishima factory (72) Shinichi Yamashita 6-78 Minami-machi, Mishima, Shizuoka Tokyo Electric Co., Ltd. Mishima factory

Claims (2)

[Claims] 1. A filament lamp of a discharge lamp is preheated with a preheating voltage, and then a voltage higher than the preheating voltage is applied to the discharge lamp to light the discharge lamp, and a discharge lamp is provided with an inverter circuit having an inductor. The discharge lamp lighting device according to claim 1, further comprising a filament preheating inductor that is magnetically coupled to the inductor and preheats the filament. 2. The discharge lamp lighting device according to claim 1, further comprising a timer circuit for heating the filament for a predetermined time after the output of the inverter circuit.