JP2000188193A - Discharge lamp lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a discharge lamp lighting device capable of protecting a discharge lamp when it is not suitable. SOLUTION: When power is turned on, a base drive circuit 5 starts to operate through a starting resistor R1 and makes a transistor Q1 perform a high-frequency switching operation. This resonates a parallel resonant circuit 3 and a voltage is induced in filament preheating windings Tr1d, Tr1e of an inverter transformer Tr1 so that filaments FL1, FL2 of a fluorescent lamp FL are preheated. A resonant voltage is induced in a secondary winding Tr1b so that the fluorescent lamp FL is lit with high-frequency waves. When the fluorescent lamp FL comes into a short-circuit state due to the termination period of its service life, a voltage is not induced in a power winding Tr1c close-coupled to the secondary winding Tr1b, so that no power source remains for the base drive circuit 5 and accordingly, the transistor Q1 cannot be driven. The inverter circuit 2 is prevented from successively operating and applying stress on the transistor Q1 and the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a discharge lamp lighting device for lighting a discharge lamp.

[0002]

2. Description of the Related Art Conventionally, as a discharge lamp lighting device of this type, for example, a configuration shown in FIG. 1 is known.

In the discharge lamp lighting device shown in FIG. 1, a full-wave rectifier circuit 1 is connected to a commercial AC power supply e, and an output terminal of the full-wave rectifier circuit 1 is connected to a smoothing capacitor C1. Is connected to an inverter circuit 2.

[0004] A parallel resonance circuit 3 is connected to the inverter circuit 2. This parallel resonance circuit 3
It has a resonance inductance circuit 4 for the primary winding Tr1a of the leakage flux type inverter transformer Tr1, and a resonance capacitor C2 that resonates with the resonance inductance circuit 4. A transistor Q1 is connected in series to the parallel resonance circuit 3. Further, a base drive circuit 5 as a drive means is connected to the transistor Q1,
The base drive circuit 5 has a power supply winding provided as a power supply provided in the starting resistor R1 and the inverter transformer Tr1.
Tr1c is connected.

[0005] The secondary winding of the inverter transformer Tr1
A load circuit 6 is connected to Tr1b. The load circuit 6 has a fluorescent lamp FL as a discharge lamp.
One end of each of the filaments FL1 and FL2 of the FL is connected, and each of the filaments FL1 and FL2 is connected to an inverter transformer Tr1.
Are connected to the filament preheating windings Tr1d and Tr1e.

As shown in FIGS. 9 and 10, the inverter transformer Tr1 has a square-shaped iron core 11, and a gap between the square-shaped iron cores 11 for forming a leakage magnetic path. The primary winding Tr1a and the power supply winding Tr1c are wound around one end of the square-shaped iron core 11, and the secondary winding Tr1b is wound around the other end. Therefore, the primary winding
Since Tr1a and the secondary winding Tr1b have a leakage magnetic flux φ3, the value differs between the magnetic flux φ1 and the magnetic flux φ2, the coupling coefficient is about 0.5 to 0.7, and the primary winding Tr1a and the power supply winding Tr1c Are the same magnetic flux φ1, and are tightly coupled with a coupling coefficient of 0.8 to 1.0.

Then, when the power is turned on, the starting resistor
The base drive circuit 5 starts operating via R1, the transistor Q1 is switched by the base drive circuit 5 at a high frequency, and the primary winding Tr1a of the inverter transformer Tr1 of the resonance inductance circuit 4 of the parallel resonance circuit 3;
Resonates with the resonance capacitor C2, and the inverter transformer Tr
A voltage is induced in the filament preheating windings Tr1d and Tr1e to preheat the filaments FL1 and FL2 of the fluorescent lamp FL, and a resonance voltage is generated in the secondary winding Tr1b to generate a fluorescent lamp.
FL is turned on at high frequency. In addition, the inverter transformer Tr1
The lighting of the fluorescent lamp FL is stabilized by the current limiting inductance generated by the leakage inductance of the fluorescent lamp FL.

[0008]

However, the above-described discharge lamp lighting device shown in FIG.
Is a leakage magnetic flux type and has leakage inductance. Therefore, when the filaments FL1 and FL2 of the fluorescent lamp FL are short-circuited at the end of life or the like, a state where a voltage is induced in the power supply winding Tr1c by the leakage inductance is maintained.
Since the base drive circuit 5 keeps switching the transistor Q1, a short-circuit current may flow through the inverter transformer Tr1.

The operating frequency of the transistor Q1 is set to be different for each type of the fluorescent lamp FL.

However, FLR4 tubes having almost the same length are used.
OSS / 36 and FHF32 mistakenly use the other fluorescent lamp
The FL may be inserted incorrectly and used. And F
When the correct fluorescent lamps FL are used for lamps designed for LR40S / 36 or FHF32, the lamp characteristics can be sufficiently extracted and used properly, whereas different fluorescent lamps FL can be used. In the case of using, there is a problem that the lamp characteristics cannot be sufficiently brought out and that a large stress may be applied to the discharge lamp lighting device and the discharge lamp itself.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above problems, and has as its object to provide a discharge lamp lighting device capable of protecting a discharge lamp when it is not appropriate.

[0012]

According to a first aspect of the present invention, there is provided a discharge lamp lighting device comprising: a primary winding; a secondary winding connected to the primary winding and a discharge lamp of a leakage flux type; Having a tightly coupled power supply winding having a coupling coefficient of 0.8 to 1.0, a resonance inductance circuit, a resonance capacitor resonating with the resonance inductance circuit, and a connection to the resonance inductance circuit And an inverter circuit having a switching element for generating a high-frequency voltage by a switching operation, and drive means for controlling the switching element driven by the power supply winding as a power supply. When the switching element is driven by driving means using the resonance of the resonance inductance circuit and the resonance capacitor and the power supply winding as a power source, the discharge lamp is turned on at a high frequency. Since the secondary winding and the power supply winding are of the completely coupled type, no voltage is induced in the power supply winding and power is not supplied to the drive means, so that the drive means does not operate the switching element and the inverter circuit is not operated. Prevent it from continuing to operate.

A discharge lamp lighting device according to a second aspect of the present invention includes a primary winding, a secondary winding connected to the primary winding and a discharge lamp of a leakage flux type having a coupling coefficient of 0.5 to 0.7, and a secondary winding. A transformer having a detection winding for outputting an output corresponding to the voltage of the discharge lamp in tight coupling with a coupling coefficient of 0.8 to 1.0 with the secondary winding, a resonance inductance circuit, and a resonance inductance circuit; A resonance capacitor that resonates, and an inverter circuit that is connected to the resonance inductance circuit and has a switching element that generates a high-frequency voltage by a switching operation; a drive unit that controls the switching element; A different lamp detecting means for detecting whether the discharge lamp is an appropriate discharge lamp or a different type of discharge lamp based on the voltage of the discharge lamp,
When the different lamp detecting means detects a different lamp, the driving means includes a control means for at least reducing the output of the inverter circuit. Then, the switching element is driven by the resonance of the resonance inductance circuit and the resonance capacitor and the driving means to drive the discharge lamp at high frequency. If a different discharge lamp is mounted, the lamp voltage of the discharge lamp is different. When the voltage is detected by the tightly coupled detection winding to the secondary winding to which the discharge lamp is connected, and when the different lamp detection means detects that the lamp voltage is different, the control means outputs the output of the inverter circuit to the drive means. At least to lower,
Prevent the inverter circuit from continuing to operate.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A discharge lamp lighting device according to one embodiment of the present invention will be described below with reference to the drawings.

The circuit configuration of the discharge lamp lighting device is the same as that of the conventional example. As shown in FIG. 1, a full-wave rectifier circuit 1 is connected to a commercial AC power supply e, and an output terminal of the full-wave rectifier circuit 1 is used for smoothing. , And an inverter circuit 2 is connected to the capacitor C1.

A parallel resonance circuit 3 is connected to the inverter circuit 2. This parallel resonance circuit 3
It has a resonance inductance circuit 4 for the primary winding Tr1a of the leakage flux type inverter transformer Tr1, and a resonance capacitor C2 that resonates with the resonance inductance circuit 4. A transistor Q1 is connected in series to the parallel resonance circuit 3. Further, a base drive circuit 5 as a drive means is connected to the transistor Q1,
The base drive circuit 5 has a power supply winding provided as a power supply provided in the starting resistor R1 and the inverter transformer Tr1.
Tr1c is connected.

Further, the secondary winding of the inverter transformer Tr1
A load circuit 6 is connected to Tr1b. The load circuit 6 has a fluorescent lamp FL as a discharge lamp.
One end of each of the filaments FL1 and FL2 of the FL is connected, and each of the filaments FL1 and FL2 is connected to an inverter transformer Tr1.
Are connected to the filament preheating windings Tr1d and Tr1e.

As shown in FIGS. 2 and 3, the inverter transformer Tr1 has a square-shaped iron core 11, and a gap between the square-shaped iron cores 11 for forming a leakage magnetic path. The primary winding Tr1a is wound around one end of the square-shaped iron core 11, and the secondary winding Tr1b and the power supply winding Tr1c are wound around the other end. Therefore, the primary winding Tr
Since 1a and the secondary winding Tr1b have a leakage magnetic flux φ3, the magnetic flux φ
1 and the magnetic flux φ2, the coupling coefficient is about 0.5 to 0.7, and since the secondary winding Tr1b and the power supply winding Tr1c have the same magnetic flux φ2, the coupling coefficient is 0.8 to 0.7. 1.
0 is a tight coupling.

In the inverter transformer Tr1, a primary winding Tr1a, a secondary winding Tr1b and a power supply winding Tr1c are mounted on a coil bobbin 15 as shown in FIGS. Terminal blocks 16 are formed at both ends of the coil bobbin 15, and an iron core 11 and an iron core 12 are mounted.

Next, the operation of the above embodiment will be described.

First, when the power is turned on, the base drive circuit 5 starts operating via the starting resistor R1, and the base drive circuit 5 causes the transistor Q1 to perform a high-frequency switching operation. Resonates with the primary winding Tr1a of the inverter transformer Tr1 and the resonance capacitor C2, and a voltage is induced in the filament preheating windings Tr1d and Tr1e of the inverter transformer Tr1 to preheat the filaments FL1 and FL2 of the fluorescent lamp FL. A resonance voltage is generated in the secondary winding Tr1b, and the fluorescent lamp FL is turned on at a high frequency. Further, the lighting of the fluorescent lamp FL is stabilized by the current limiting inductance generated by the leakage inductance of the inverter transformer Tr1.

If the fluorescent lamp FL is short-circuited at the end of its life, for example, no voltage is induced in the power supply winding Tr1c tightly coupled to the secondary winding Tr1b, and the base drive circuit 5 loses power. Since the transistor Q1 is no longer driven, it is possible to prevent the inverter circuit 2 from continuing to operate and giving stress to the transistor Q1 and the like.

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

The discharge lamp lighting device according to the embodiment shown in FIG. 8 is different from the discharge lamp lighting device according to the embodiment shown in FIG. 1 in that the secondary winding Tr1b is replaced with a coupling coefficient 0 in place of the power supply winding Tr1c. .8 to 1.0, a tightly coupled detection winding Tr1f is provided, and this detection winding Tr1f is connected to a detection circuit 21 as a different kind lamp detection means, and this detection circuit 21 is used as a control means and a drive means. And the transistor Q1 is controlled by the control circuit 22.

The inverter transformer Tr1 does not have the filament windings Tr1d and Tr1e, and a starting capacitor C5 is connected between the other ends of the filaments FL1 and FL2 of the fluorescent lamp FL.

Although the basic operation is the same as that of the discharge lamp lighting device shown in FIG. 1, for example, if the fluorescent lamp FL is not appropriate and a different fluorescent lamp FL is attached, the lamp voltage becomes lower. Unlike normal operation, the detection winding Tr1f is tightly coupled to the secondary winding Tr1b,
A voltage set by the ratio of the secondary winding Tr1b to the detection winding Tr1f is induced in 1f, and it is possible to detect that the fluorescent lamp FL is of a different kind.

That is, for example, if the inverter circuit 2
When the FLR40S / 36 is dedicated to the fluorescent lamp FL of the LR40S / 36 and a suitable FLR40S / 36 is mounted, a voltage of 100 V is induced in the secondary winding Tr1b, which is substantially equal to the lamp voltage VL of the fluorescent lamp FL. In the detection winding Tr1f, a voltage set by the ratio of the secondary winding Tr1b to the detection winding Tr1f is induced, and the control circuit 22 normally controls the detection circuit 21 as normal and the inverter circuit 2 Output normally.

However, if a fluorescent lamp FL of FHF32, which is a different kind of lamp, is used, in the case of FHF32, FL
The tube diameter is smaller than R40S / 36, the tube wall load is higher, and the lamp voltage is higher than that of FLR40S / 36 115
V, the detection winding Tr1c has FLR40S / 3
6, a voltage higher than normal is applied to the detection circuit 21, and the control circuit 22 changes or stops the switching of the transistor Q1 assuming that a different lamp is mounted and abnormal, and the inverter circuit 2 Output is reduced or stopped.

On the other hand, for example, if the inverter circuit 2
32, the secondary winding Tr1b is used when the appropriate lamp FHF32 is mounted.
Is approximately equal to the lamp voltage VL of the fluorescent lamp FL.
V voltage is induced, and the secondary winding Tr1b is connected to the detection winding Tr1f.
And a voltage set by the ratio of the detection winding Tr1f and the detection winding Tr1f,
In the detection circuit 21, the control circuit 22 performs normal control as normal and the inverter circuit 2 performs normal output.

However, when the FLR40S fluorescent lamp FL is used, the FLR40S has a larger tube diameter and lower tube wall load than the FHF32, and the lamp voltage becomes FLR4S.
Since the voltage is lower than in the case of 0S / 36, the detection winding
A voltage lower than that in the case of FHF32 is induced in Tr1f, a voltage lower than normal is applied to the detection circuit 21, and a different lamp is mounted, and the control circuit 22 changes or stops the switching of the transistor Q1, assuming that the lamp is abnormal, The output of the inverter circuit 2 is reduced or stopped.

[0031]

According to the discharge lamp lighting device of the first aspect, the switching element is driven by the drive means using the resonance of the resonance inductance circuit and the resonance capacitor and the power supply winding as a power supply to drive the discharge lamp to a high frequency. Lights up,
If the discharge lamp is short-circuited at the end of life, etc., the secondary winding and the power supply winding are completely coupled, so that no voltage is induced in the power supply winding and power is not supplied to the drive means. It is possible to prevent the drive unit from operating the switching element and the inverter circuit from continuing to operate.

According to the discharge lamp lighting device of the second aspect,
The switching element is driven by the resonance of the resonance inductance circuit and the resonance capacitor and the driving means to drive the discharge lamp at a high frequency.If a different discharge lamp is mounted, the lamp voltage of the discharge lamp differs. When the secondary winding to which the discharge lamp is connected is detected by the tightly-coupled detection winding and the different lamp detection means detects that the lamp voltage is different, the control means lowers the output of the inverter circuit to the drive means at least. Therefore, it is possible to prevent the inverter circuit from continuing to operate.

[Brief description of the drawings]

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

FIG. 2 is a circuit diagram showing a magnetic circuit of the inverter transformer.

FIG. 3 is an explanatory diagram showing states of a primary winding, a secondary winding, and a power supply winding of the inverter transformer.

FIG. 4 is a plan view showing an external appearance of the inverter transformer.

FIG. 5 is a front view showing the appearance of the inverter transformer.

FIG. 6 is a left side view showing the appearance of the inverter transformer.

FIG. 7 is a right side view showing an appearance of the inverter transformer.

FIG. 8 is a circuit diagram showing a discharge lamp lighting device according to another embodiment of the present invention.

FIG. 9 is a circuit diagram showing a magnetic circuit of a conventional inverter transformer.

FIG. 10 is an explanatory diagram showing states of a primary winding, a secondary winding, and a power supply winding of the inverter transformer.

[Explanation of symbols]

2 Inverter circuit 4 Resonance inductance circuit 5 Base drive circuit as drive means 21 Detection circuit as heterogeneous lamp detection means 22 Control circuit having functions as control means and drive means C2 Resonance capacitor FL Fluorescent lamp Tr1 as discharge lamp Tr1 Inverter transformer Tr1a Primary winding Tr1b Secondary winding Tr1c Power supply winding

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Masahiro Sugiyama 6-78, Minami-cho, Mishima-shi, Shizuoka F-term in Tec Mishima Plant (reference) 3K072 AA02 AB09 BA03 BB01 BC02 DB03 DB03 DC01 DD05 EA01 EB05 GA01 GB04 GC04 HB03

Claims (2)

[Claims] 1. A primary winding, a secondary winding to which a discharge lamp is connected to the primary winding and a leakage flux type, and a tight coupling of 0.8 to 1.0 having a coupling coefficient of 0.8 to 1.0 with the secondary winding. A transformer having a power supply winding, a resonance inductance circuit, a resonance capacitor that resonates with the resonance inductance circuit,
And an inverter circuit having a switching element connected to the resonance inductance circuit and generating a high-frequency voltage by a switching operation; and a drive unit driven by using the power supply winding as a power supply and controlling the switching element. Discharge lamp lighting device characterized by the above-mentioned. 2. A primary winding, a secondary winding connected to a discharge lamp of a leakage flux type having a coupling coefficient of 0.5 to 0.7 with the primary winding and a coupling coefficient with the secondary winding. 0.8
A transformer having a detection winding for outputting an output corresponding to the voltage of the discharge lamp in a tight coupling of 1.0, a resonance inductance circuit, a resonance capacitor resonating with the resonance inductance circuit, and the resonance inductance An inverter circuit that is connected to a circuit and has a switching element that generates a high-frequency voltage by a switching operation; a driving unit that controls the switching element; and an appropriate discharge lamp based on the voltage of the discharge lamp detected by the detection winding. A different lamp detecting means for detecting whether the discharge lamp is of a different type or a different kind of discharge lamp; and a control means for at least lowering the output of the inverter circuit in the drive means when the different kind of lamp is detected by the different kind of lamp detecting means. Discharge lamp lighting device characterized by the above-mentioned.