JPH05251189A - Electric discharge lamp lighting device - Google Patents

Abstract

PURPOSE:To provide a discharge lamp lighting device of a simple circuit constitution and a small loss and capable of early rising up a light output at the time of starting in the case where a discharge lamp is used for a head lamp or the like for a vehicle. CONSTITUTION:A bypass capacitor 4 is disposed in parallel to an electric discharge lamp 5. A secondary coil n2 of a pulse transformer 3 is provided inside a closed circuit between the discharge lamp 5 and the bypass capacitor 4. Pulse voltages generated at both ends of the secondary coil n2 of the pulse transformer 3 is supplied to the discharge lamp 5, which is thus started. A starting auxiliary power source 1 previously charges an electric charge to the bypass capacitor 4, and a large current is instantly discharged to the discharging lamp 5 almost simultaneously with a dielectric breakdown of the discharge lamp 5. Consequently, it is possible to provide a discharge lamp lighting device of a simple circuit constitution with a small loss and capable of rising up a light output early.

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 lighting a discharge lamp.

[0002]

2. Description of the Related Art In recent years, high pressure discharge lamps such as metal halide lamps have been widely used in automobiles or overhead projectors (generally OHP). At that time, the light output is required to rise early, which is a drawback of the high pressure discharge lamp.

Conventionally, in order to remedy this drawback, for example, there is one described in Japanese Patent Application Laid-Open No. 2-215093. However, this device requires a detection circuit and a switching element for detecting the dielectric breakdown of the discharge lamp, and has a problem that the circuit configuration becomes complicated and the steady loss of the detection unit increases.

[0004]

The problems to be solved are that the light output of the high-pressure discharge lamp rises early and that the circuit structure becomes complicated and the steady loss of the detector increases. Therefore, the object of the present invention is to
An object of the present invention is to provide a discharge lamp lighting device that has a simple circuit configuration and that allows an early rise of light output without an increase in loss.

[0005]

SUMMARY OF THE INVENTION The present invention is directed to a lighting circuit section for supplying electric power to a discharge lamp, a bypass capacitor connected in parallel with the discharge lamp, and a closing of the bypass capacitor and the discharge lamp. A secondary winding of a pulse transformer that is inserted in the circuit and generates a pulse voltage that causes dielectric breakdown of the discharge lamp,
In a discharge lamp lighting device comprising a pulse voltage supply unit for supplying a pulse voltage to a primary winding of a pulse transformer electromagnetically coupled to a secondary winding of the pulse transformer, the discharge lamp is applied with a pulse voltage. Is equipped with a starting auxiliary power supply for supplying a predetermined voltage required for starting to the bypass capacitor before dielectric breakdown and starting.

Further, the invention is characterized in that the pulse voltage supply section is shared as a starting auxiliary power source.

[0007]

According to the present invention, since the discharge lamp is equipped with a starting auxiliary power supply for supplying a predetermined voltage necessary for starting before the starting of the discharge lamp due to dielectric breakdown and application of the pulse voltage, the present invention has a circuit configuration. It is easy to perform, and there is an effect that the optical output can be raised early without increasing loss.

[0008]

1 is a basic circuit configuration diagram showing a first embodiment of the present invention. The configuration thereof includes a lighting circuit section (not shown) for supplying electric power to a discharge lamp 5 and the discharge lamp. 5, a bypass capacitor 4 connected in parallel with the bypass capacitor 4, and a secondary of a pulse transformer 3 that is inserted in a closed circuit of the bypass capacitor 4 and the discharge lamp 5 and that generates a pulse voltage that causes dielectric breakdown of the discharge lamp 5. A pulse voltage supply unit 1 that supplies a pulse voltage to the winding n2, the primary winding n1 of the pulse transformer 3 electromagnetically coupled to the secondary winding n2 of the pulse transformer 3, and the pulse voltage is applied and released. The electric lamp 5 is provided with a starting auxiliary power supply 2 for supplying a predetermined voltage required for starting the bypass capacitor 4 before the electric breakdown of the electric lamp 5 due to dielectric breakdown.

With this configuration, when the pulse voltage generated in the secondary winding n2 of the pulse transformer 3 is applied to the discharge lamp 5 and the discharge lamp 5 is dielectrically broken down, the bypass capacitor 4 is immediately connected. By instantly discharging the electric charge that has been charged up to the start, the startup can be performed smoothly and the light output can be quickly started up.

FIG. 5 shows a concrete example of the first embodiment. Here, the lighting circuit unit includes a high frequency lighting circuit INV that receives a DC voltage from the DC power source E and outputs a high frequency voltage, and may be a sine wave output, a rectangular wave output, or the like, or a push-pull inverter. Any inverter system such as a half-bridge type inverter and a full-bridge type inverter may be used as long as it can generate a high frequency output.

The pulse voltage supply unit 1 includes a tertiary winding n3 of a power transformer PT1 connected to an AC power source AC, and a diode D at both ends of the tertiary winding n3 of the power transformer PT1.
The capacitor C1 is connected via 2 and the primary winding n1 of the pulse transformer 3 is connected to both ends of the capacitor C1 via switch elements SW such as a discharge gap, triac and SSS.

The auxiliary starting power source 2 is a secondary winding n2 of a power transformer PT1 connected to an AC power source AC, and a diode D1 for supplying a DC voltage from the secondary winding n2 of the power transformer PT1 to a bypass capacitor 4. It is composed of

The operation state will be described below. First, when a DC voltage is supplied from the DC power source E, a high frequency voltage is generated at the output end of the high frequency lighting circuit unit INV.
This voltage is applied across the discharge lamp 5.

On the other hand, the pulse voltage supply unit 1 also starts operating. When the AC voltage is supplied from the AC power supply AC, the primary winding n1 is connected to both ends of the tertiary winding n3 of the power transformer PT1.
A voltage is generated according to the winding ratio of the above, and the capacitor C1 is charged via the diode D2. This capacitor C1
With the electric charge of 1 as a power source, a pulse voltage is generated at both ends of the primary winding n1 of the pulse transformer 3 by the on / off operation of the switch element SW. Then, this voltage is boosted according to the turn ratio and is generated as a pulse voltage VPT across the secondary winding n2 of the pulse transformer 3.

At the same time, the auxiliary starting power supply 2 also starts to operate. When the AC voltage is supplied from the AC power supply AC, a voltage according to the turn ratio with the primary winding n1 is generated across the secondary winding n2 of the power transformer PT1, and the diode D
The bypass capacitor 4 is charged via 1 to generate the charging voltage V4.

Next, the pulse voltage VPT from the pulse voltage supply unit 1 is set so that the capacitance of the bypass capacitor 4 is sufficiently large with respect to the resonance frequency of the pulse voltage VPT, so that the pulse voltage VPT is almost high voltage. It is applied to both ends of the discharge lamp 5. Then, when the high-pressure discharge lamp 5 undergoes a dielectric breakdown, a high-frequency voltage is supplied from the high-frequency lighting circuit unit INV, the glow discharge changes to an arc discharge, and a normal lighting state is obtained. When the voltage VL across the high-pressure discharge lamp 5 becomes lower than the charging voltage V4 of the bypass capacitor 4 due to the above-mentioned dielectric breakdown, the electric charge already charged from the bypass capacitor 4 is instantly discharged. If the charging voltage V4 is set to an appropriate predetermined voltage, the injection of the charging charge into the high-pressure discharge lamp 5 instantaneously makes the transition from glow discharge to arc discharge smooth and supplies a large current instantaneously. By doing so, the optical output can be raised quickly.

Therefore, it is possible to achieve an early rise of the optical output with a simple circuit configuration having a small loss, and as shown in FIG. 6, a pulse voltage VPT is applied to the voltage value VDC of the DC voltage V4 of the bypass capacitor 4. If the polarities are matched so as to be superposed, the predetermined peak value required for starting is obtained by the pulse voltage VPT + the DC voltage value VDC of the bypass capacitor 4 rather than the predetermined peak value required by the pulse voltage VPT alone. It is possible to reduce the size because it is possible to satisfactorily start even if the predetermined peak value is low.

FIG. 2 is a basic circuit configuration diagram showing a second embodiment of the present invention. The configuration different from the first embodiment described above is as follows.
The pulse voltage supply unit (FIG. 1) is provided so that the pulse voltage supply unit (1 shown in FIG. 1) can supply the bypass capacitor 4 with a predetermined voltage required for the start of the discharge lamp 5 before the dielectric breakdown occurs and before the start. 1) is shared with the auxiliary starting power source (2 shown in FIG. 1) to form a shared configuration 10.

With this configuration, the bypass capacitor 4 can be charged along with the operation of generating a voltage in the primary winding n1 of the pulse transformer 3, so that the configuration becomes simpler.

FIG. 7 shows a concrete example of the second embodiment. Here, the shared configuration 10 includes a secondary winding n2 of a power transformer PT1 connected to an AC power source AC, and a diode D at both ends of the power transformer PT1 secondary winding n2.
A capacitor C1 connected via a capacitor C1, a series of a primary winding n1 of a pulse transformer 3 connected to both ends of the capacitor C1 via a switching element SW2 such as a discharge gap, a triac, and SSS, and a bypass capacitor 4. It is composed of a circuit. An impedance Z for discharging the electric charge of the bypass capacitor 4 is connected in parallel with the bypass capacitor 4.

The operation state will be described below. First, when the AC voltage is supplied from the AC power supply AC, a voltage corresponding to the winding ratio with the primary winding n1 is generated across the secondary winding n2 of the power transformer PT1, and the diode D
The capacitor C1 is charged via 3. The charge of the capacitor C1 is used as the power supply voltage VC1 and the switch element S
The bypass capacitor 4 is charged through the primary winding N1 of the pulse transformer 3 by the on / off operation of W2. This charging action is performed by changing the charging voltage V4 to the capacitor C1 voltage VC1.
Will continue until. Then, when VC1 = V4, the switch SW2 is turned off. Next, when the voltage of the capacitor C1 is VC1> V4, the switch element SW2 is turned on. At this time,
VC1-V is provided at both ends of the primary winding n1 of the pulse transformer 3.
The voltage of 4 is applied, and this voltage is boosted according to the turn ratio, and is generated as a pulse voltage VPT across the secondary winding n2 of the pulse transformer 3. This pulse voltage VPT is generated by superimposing the DC voltage V4 from the previous operation as shown in FIG. When the high-voltage discharge lamp 5 is broken down and the voltage VL across the high-voltage discharge lamp 5 becomes lower than the charging voltage V4 of the bypass capacitor 4, the bypass capacitor 4 is instantly released.
The electric charge which has already been charged is discharged as shown in FIG.

FIG. 3 is a basic circuit configuration diagram showing a third embodiment of the present invention. The configuration different from that of the second embodiment is as follows.
The lighting circuit section 7 is composed of a high-frequency lighting circuit that receives a DC voltage from the DC power source E and outputs a high-frequency voltage, and is connected to the high-pressure discharge lamp 5 via a capacitor 6. Similar to the first embodiment, a sine wave output, a rectangular wave output, or the like may be used, and any inverter system such as a push-pull inverter, a half-bridge inverter, or a full-bridge inverter may be used. Any material that can generate a high frequency output may be used.

FIG. 4 is a basic circuit configuration diagram showing a fourth embodiment of the present invention. The configuration different from the third embodiment described above is as follows.
This is that a switch 8 for short circuit is connected in parallel with the capacitor 6 connected to the output end of the lighting circuit unit 7.

With this configuration, the state of the voltage applied to the discharge lamp 5 can be easily changed by turning on the switch 8 (high frequency lighting, rectangular wave lighting, etc.).

FIG. 9 shows a concrete example of the fourth embodiment. Here, the lighting circuit unit 7 is a so-called half-bridge type inverter, and includes the switching elements Q1,
Q2 is alternately turned on and off so that the voltages of the capacitors C2 and C3 are alternately supplied to the discharge lamp 5 as a high frequency voltage (for example, 70 KHz to several hundred KHz). Further, in the case of lighting with a rectangular wave, it can be easily obtained by turning on and off the switching element Q1 a predetermined number of times after turning on the switch SW3 which is the switch 8 shown in FIG. ..

Since the operating state is also the same as the configuration shown in FIG. 7 which is a concrete example of the second embodiment, the duplicated description will be omitted. The discharge loop of the bypass capacitor 4 is a loop indicated by I4 in the drawing, and the electric charge accumulated in the high pressure discharge lamp 5 is supplied to the discharge loop. Also, the capacitor C
The charges accumulated in 4 are also discharged to the high pressure discharge lamp 5.

FIG. 10 shows another specific example of the fourth embodiment. The configuration different from the specific example shown in FIG. 9 is that the lighting circuit unit 7 is configured by a so-called full-bridge type inverter, and the switching elements Q1 to Q4.
Respectively turn on and off to output a high frequency voltage or a rectangular wave voltage to the high voltage discharge lamp 5, and a bypass capacitor 4 in parallel with a series circuit of the secondary winding n2 of the pulse transformer 3 and the high voltage discharge lamp 5. Is connected to form a discharge loop of the bypass capacitor 4 as indicated by I4 in the figure. The lighting waveform can be changed by the switch SW3 as in the embodiment shown in FIG.

FIG. 11 is a circuit configuration diagram showing a fifth embodiment of the present invention. The configuration different from the embodiment of the second embodiment shown in FIG. 7 is a capacitor C1 (shown in FIG. 7). In the present embodiment, the capacitor C10 is configured to be charged by alternating current.

With this structure, the voltage VPT generated in the primary winding n1 of the pulse transformer 3 is generated by alternately changing the polarity, so that the high voltage discharge lamp 5 is not applied with the voltage only from one direction. By applying the voltage of 1, the adverse effect on the life is prevented. FIG. 12 shows the operation waveform of each part at that time.

[0030]

The present invention provides a lighting circuit section for supplying electric power to a discharge lamp, a bypass capacitor connected in parallel with the discharge lamp, and a bypass capacitor and a discharge lamp in a closed circuit. A pulse that supplies a pulse voltage to the secondary winding of a pulse transformer that is inserted into the secondary winding of the pulse transformer that generates a pulse voltage that causes dielectric breakdown of the discharge lamp and the primary winding of the pulse transformer that is electromagnetically coupled to the secondary winding of this pulse transformer. In a discharge lamp lighting device comprising a voltage supply unit, a starting auxiliary power supply for supplying a predetermined voltage required for starting to the bypass capacitor before a discharge lamp is applied with a pulse voltage to cause dielectric breakdown and start. Since it has, the circuit configuration is easy,
Moreover, there is a remarkable effect that the light output can be quickly started up without an increase in loss.

[Brief description of drawings]

FIG. 1 is a basic circuit configuration diagram showing a first embodiment of the present invention.

FIG. 2 is a basic circuit configuration diagram showing a second embodiment of the present invention.

FIG. 3 is a basic circuit configuration diagram showing a third embodiment of the present invention.

FIG. 4 is a basic circuit configuration diagram showing a fourth embodiment of the present invention.

FIG. 5 is a circuit configuration diagram showing a specific example of the first exemplary embodiment of the present invention.

FIG. 6 is an explanatory diagram showing waveforms for explaining the first embodiment of the present invention.

FIG. 7 is a circuit configuration diagram showing a specific example of a second exemplary embodiment of the present invention.

FIG. 8 is an explanatory diagram showing waveforms of various parts for explaining a second embodiment of the present invention.

FIG. 9 is a circuit configuration diagram showing a specific example of the fourth embodiment of the present invention.

FIG. 10 is a circuit configuration diagram showing another specific example of the fourth exemplary embodiment of the present invention.

FIG. 11 is a circuit configuration diagram showing a fifth embodiment of the present invention.

FIG. 12 is an explanatory diagram showing waveforms of various parts for explaining a fifth embodiment of the present invention.

[Explanation of symbols]

 1 pulse voltage supply unit 2 start auxiliary power supply 3 pulse transformer 4 bypass capacitor 5 discharge lamp 7 lighting circuit unit 10 pulse voltage supply unit, start auxiliary power supply n1 pulse transformer primary winding n2 pulse transformer secondary winding

Claims (2)

[Claims] 1. A lighting circuit unit for supplying electric power to a discharge lamp,
A bypass capacitor connected in parallel with the discharge lamp, and a secondary winding of a pulse transformer that is inserted in a closed circuit between the bypass capacitor and the discharge lamp to generate a pulse voltage that causes dielectric breakdown of the discharge lamp. In a discharge lamp lighting device comprising a pulse voltage supply unit for supplying a pulse voltage to a primary winding of a pulse transformer electromagnetically coupled to a secondary winding of the pulse transformer, a pulse voltage is applied and released. A discharge lamp lighting device comprising a starting auxiliary power supply for supplying a predetermined voltage required for starting to the bypass capacitor before the electric lamp is dielectrically broken down and before starting. 2. The starting auxiliary power supply is configured so that a predetermined voltage required for starting can be supplied from the pulse voltage supply unit to the bypass capacitor before the discharge lamp is dielectrically broken down and the starting is started. The discharge lamp lighting device according to claim 1.