JPH0419996A - Lighting device for high luminance discharge lamp - Google Patents

Abstract

PURPOSE:To obtain a low-cost device with simple circuit constitution which does not use a DC/DC converter by switching DC power supplied from a battery, and raising the voltage of the power at a transformer. CONSTITUTION:DC power supplied from a battery 1 is switched at a switching portion 3 and switching output is converted to a higher voltage by a transformer 7. The discharge maintenance voltage of a high luminance discharge lamp 5 is thereby obtained. A trigger circuit 4 is connected to the output coil 72 of the transformer 7 and the high luminance discharge lamp 5 is triggered by a trigger voltage supplied from the trigger circuit 4. After triggering discharge is maintained by the discharge maintenance voltage supplied from the transformer 7. A DC/DC converter is therefore unnecessary and a high luminance discharge lamp lighting device of simple, small circuit constitution is realized at low cost.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention mainly relates to a high-intensity discharge lamp lighting device used when an automobile headlamp is constructed of high-intensity discharge lamps, and relates to a high-intensity discharge lamp lighting device that uses direct current supplied from a battery. Switching the power supply and boosting the switching power using a transformer,
A trigger circuit provided in the output winding of the transformer supplies a trigger voltage to the high-intensity discharge lamp to trigger it, and after the trigger, a switching output appearing in the 8-power winding of the transformer is given to the high-intensity discharge lamp. , by sustaining the discharge, D
This makes it possible to provide an inexpensive high-intensity discharge lamp lighting device that does not use a C/DC converter.

<Prior Art> High-intensity discharge lamps are different from halogen lamps, which have traditionally been widely used as automobile headlights, because they generate light by discharging in a gas.
Although it consumes about 1/3 of the power of a lamp,
It can obtain four times the luminous flux, making it extremely useful as a headlamp for automobiles.

Although high-intensity discharge lamps have excellent characteristics as mentioned above, in order to turn them on, it is necessary to
A trigger voltage of about V must be applied to trigger. The power supply for automobiles is usually DC12V or DC24V.
Since the high-intensity discharge lamp is a V battery, it is necessary to generate a trigger voltage of 10 to 15 kV from 12 V DC or 24 V DC in order to use the high-intensity discharge lamp as a car headlight. In addition, since a voltage of about 200 to 500V is required to maintain the discharge, this discharge maintenance voltage is also DC12V.
Or it must be made from a 24V DC battery.

Conventionally, as a means to satisfy such conditions, first, the voltage of the battery is boosted using a DC/DC converter to about 200 to 500 μm, which is necessary to maintain discharge. Next, the DC voltage obtained by boosting is switched, and the LC
The trigger voltage was created using the resonance effect of a resonant circuit.

FIG. 8 is a circuit diagram of a conventional high-intensity discharge lamp lighting device.

In the figure, 1 is a battery, 2 is a DC/DC converter, 3 is a switching section, 4 is a trigger circuit, 5 is a high-intensity discharge lamp, and 6 is a capacitor for blocking direct current.

The switching unit 3 has switching elements 31, 32 which alternately perform switching operations. 33 and 34 are diodes.

The trigger circuit 4 is a series resonant circuit including a capacitor 41 and a coil device 42.

In the high-intensity discharge lamp 5, a rare gas, mercury, metal halide, etc. are contained in a tube 51 made of, for example, quartz glass, and electrodes 52 and 53 are placed opposite each other at a distance within the tube 51. It has a structure that allows Such a high intensity discharge lamp 5
is called a metal halide lamp.

During operation of the lamp, the voltage of battery 1 is set to D C/D.
After the C converter 2 boosts the voltage to 200 to 500V necessary to maintain discharge, the switch element 31.
Switching is performed by the switching section 3 constituted by 32. The switching frequency is determined by the switching element 31
．． 32 control electrodes 311, 321 by a control signal frequency applied to the 32 control electrodes 311, 321. With this frequency control, when the switching frequency reaches the resonant frequency of the capacitor 41 and the coil device 42, a large amplitude resonant voltage is obtained. This resonant voltage is the voltage of the high-intensity discharge lamp 5, 152-5
3, and the high intensity discharge lamp 5 is triggered.

As described above, when a high voltage pulse is applied between the electrodes 52-53, an arc discharge occurs, and the discharge occurs through the gas in the tube 51, and the heat generated by the discharge vaporizes the metal halide. , the maximum amount of light is emitted. After lighting, a relatively low switching output voltage is continuously applied from the switching unit 2 to the high-intensity discharge lamp 5 as a discharge sustaining voltage.

<Problems to be Solved by the Invention> However, the above-mentioned conventional high-intensity discharge lamp lighting device must be equipped with a DC70C converter to obtain a DC high voltage, resulting in a complicated and large-sized circuit configuration. There was a problem in that it caused problems and became expensive.

Therefore, an object of the present invention is to provide a system for solving the above-mentioned problems.
To provide an inexpensive high-intensity discharge lamp lighting device with a simple circuit configuration that does not use a C70C converter.

Means for Solving the Problems> In order to solve the above problems, the present invention provides a high-intensity discharge lamp lighting device including a battery, a switching section, a transformer, a high-intensity discharge lamp, and a trigger circuit. The switching section is a circuit that switches and outputs the DC power supplied from the battery, and the switching section is connected to an input winding of the transformer, and the voltage boosted from the output winding is connected to the transformer. The high-intensity discharge lamp is configured to take out a switching output, and the high-intensity discharge lamp has a pair of electrodes facing each other at a distance in a tube filled with gas,
A discharge lamp that emits light by a discharge between the pair of electrodes, having two different voltage values: a trigger voltage that causes discharge to occur in the pair of electrodes, and a discharge sustaining voltage that sustains the discharge after the trigger, the electrode is connected to the output winding side of the transformer, and the trigger circuit is connected to the output winding side of the transformer to apply the trigger voltage to the high intensity discharge lamp. It is characterized by

Function> DC power supplied from the battery is switched by the switching unit, and the switching output is boosted by the transformer. As a result, a discharge sustaining voltage necessary for maintaining discharge of the high-intensity discharge lamp can be obtained.

A trigger circuit for applying a trigger voltage to the high-intensity discharge lamp is connected to the output winding side of the transformer.

The high intensity discharge lamp is triggered by a trigger voltage applied from this trigger circuit. After the trigger, the discharge is sustained by the discharge sustaining voltage applied from the output winding of the transformer.

Therefore, a DC70C converter is not required, and a high-intensity discharge lamp lighting device with a simple and compact circuit configuration and low cost can be realized.

<Embodiment> FIG. 1 is a circuit diagram of a high-intensity discharge lamp lighting device according to the present invention. In the figure, the same reference numerals as in FIG. 8 indicate the same components. 7 is a transformer, and 8 is a control circuit that controls the switching section 3.

In the transformer 7, the switching section 3 is connected to an input winding 71, and a boosted switching output is taken out from an output winding 72. The switching voltage output from the output winding 72 is set to 200 to 50,000 to satisfy the discharge sustaining voltage condition.
Set to a range of about 00■. Input winding 71 of transformer 7
And the turns ratio of the output winding 72 is set to obtain this voltage. Specifically, when the number of turns of the input winding 71 is NP and the number of turns of the output winding 72 is N, when used as a car headlight, the range of 15≦Ns/Np≦35 is appropriate. be.

The trigger circuit 4 is connected to the output winding 72 and applies a trigger voltage of about 10 to 15 kV to the high intensity discharge lamp 5. The trigger voltage is given as a high voltage pulse.

In the lighting operation, the switching unit 3 switches the DC power supplied from the battery 1, and the switching output is boosted by the transformer 7. Thereby, the discharge sustaining voltage of the high-intensity discharge lamp 5 is obtained.

A trigger circuit 4 is connected to the output winding 72 of the transformer 7, and the high intensity discharge lamp 5 is triggered by the trigger voltage supplied from the trigger circuit 4. After the trigger, transformer 7
The discharge is sustained by the discharge sustaining voltage supplied from the

Therefore, a DC70C converter is not required, and a high-intensity discharge lamp lighting device with a simple and compact circuit configuration and low cost can be realized.

FIG. 2 shows a specific circuit diagram of the high intensity discharge lamp lighting device according to the present invention. In the figure, the same reference numerals as in FIG. 1 indicate the same components. A feature of this embodiment is that the trigger circuit 4 is a series resonant circuit including a capacitor 41 and a coil device 42.

The switching section 3 includes a switching element 31.3 such as a bipolar transistor or a field effect transistor.
It has 2. The main electrode circuits of each of the switching elements 31, 32 are connected to the battery 1 so as to form a closed loop. An output winding 342 and a resistor 313 of the transformer 34 and an output winding 352 and a resistor 323 of the transformer 35 are respectively connected to the control electrodes of the switching elements 31, 32 so as to form a closed loop. Connection 1 of switching elements 31 and 32 is capacitor 33
It is connected to the input winding 71 of the transformer 7 via. Input winding 341 of transformer 34 and input winding 3 of transformer 35
A control signal for alternately switching the switching elements 31, 32 is applied from the control circuit 8 to one end 311, 321 of each of the switching elements 31, 321.

FIG. 3 shows an example of operating waveforms for the embodiment shown in FIG. The switching section 3 is controlled by a control signal from the control circuit 8 so that the switching frequency gradually increases. With this frequency control, when the switching frequency of the switching section 3 reaches the resonant frequency f0 of the series resonant circuit of the capacitor 41 and the coil device 42 constituting the trigger circuit 4 at time t1, a large resonant voltage VP is obtained.

This resonance voltage (2) is applied to the high-intensity discharge lamp 5 as a trigger voltage, and the high-intensity discharge lamp 5 is triggered. After the high-intensity discharge lamp 5 is triggered, the switching unit 3 is controlled to have a switching frequency f1 of about 10 kHz, which is lower than the resonance frequency f0. After the trigger, a switching output voltage of 200 to 500 V at this frequency f1 is applied as a discharge sustaining voltage to the high-intensity discharge lamp 5 via the coil 42, and the discharge of the high-intensity discharge lamp 5 is sustained.

FIG. 4 shows a circuit diagram of another embodiment of the high intensity discharge lamp lighting device according to the present invention. In the figure, the same reference numerals as in FIG. 1 and Section 2 indicate the same components. Trigger circuit 4 includes a coil device 43 and a trigger voltage generation circuit 44. The coil device 43 has a first
It has a winding 431 and a second winding 432, and a first winding 431 and a second winding 432.
The winding 431 is connected between the output winding 72 of the transformer 7 and the high intensity discharge lamp 5.

Trigger voltage generation circuit 44 supplies a trigger voltage to second winding 432 of coil device 43 . The timing of supplying the trigger voltage can be set, for example, by turning on or off a switch built into the trigger voltage generation circuit 44.

When the trigger voltage is supplied from the trigger voltage generation circuit 44 to the second winding 432 of the coil device 43, the first winding 4
A trigger voltage determined by the turns ratio appears at 31. This trigger voltage is applied to the electrodes 52-53 of the high-intensity discharge lamp 5, and the high-intensity discharge lamp 5 is triggered.

After the high-intensity discharge lamp 5 is triggered, the supply of the trigger voltage from the trigger voltage generation circuit 44 is stopped. Then, the switching output voltage appearing in the output winding 72 of the transformer 7 is applied to the high-intensity discharge lamp 5 to continue discharging.

FIG. 5 is a more specific circuit diagram of the high intensity discharge lamp lighting device shown in FIG. 4. The transformer 7 has an input winding 71 divided into two windings 711.712;
The connection point is connected to the battery 1.

The switching section 3 includes a switching element 31.3 such as a bipolar transistor or a field effect transistor.
It has 2. The main electrode circuit of the switching element 31.32 is connected to each of the windings 711.712. The control electrodes 311, 321 of the switching elements 31, 32 receive control signals S1,
S2 is supplied.

The trigger voltage generation circuit 44 connects a capacitor 441 and a switch 442 in series to the second winding 432 of the coil device 43, and connects the second winding 432 and the capacitor 4 in series.
A unidirectional charging circuit including a resistor 443 and a diode 444 is connected between the connection point of 41 and the output winding 72 of the transformer 7. When the switch 442 is closed, the charge accumulated in the capacitor 441 is transferred to the coil device 4.
A high voltage pulse trigger voltage is induced in the first winding 431 which is discharged into the second winding 432 of the third winding 432 and is coupled to the second winding 432 .

Next, the operation of the high-intensity discharge lamp lighting device shown in FIG. 5 will be explained with reference to FIG. 6. Figure 6 shows high intensity discharge lamp 5
– terminal voltage waveform is shown.

First, a control signal S1 having a positive amplitude is supplied from the control circuit (reference numeral 8 in FIG. 4) to the control electrode 311 of the switching element 31. The frequency of the control signal S1 is usually 10
It is set to about kHz. During the positive half cycle of the control signal Sl, the switching element 31 is turned on and current flows from the battery 5 through the winding 711 of the transformer 7 to the switching element 31 . At this time, the second winding 4 of the transformer 7
A positive voltage vT is generated at 32. The positive voltage (7) is a voltage necessary to maintain discharge of the high-intensity discharge lamp 5, and is usually set at a peak value of about 100 to 250 (V). The turns ratio of the transformer 7 is 12 of the battery voltage.
(V) to this positive voltage vT. Further, this positive voltage A charges the capacitor 441 through a unidirectional charging circuit including a resistor 443 and a diode 444.

Next, a signal S2 delayed by half a cycle with respect to the control signal s1
is supplied to the control electrode 311 of the switching element 32, the switching element 32 is turned on during the positive half cycle of the control signal s2, and the winding 71 of the transformer 7 is switched on from the battery 5.
A current flows to the switching element 32 via the switch 2. At this time, the second winding 432 of the transformer 7 has a negative voltage (-V
T) occurs. The charge on capacitor 441 is blocked by diode 444 and is not discharged.

In this way, by alternately turning on and off the switching elements 31 and 32, a voltage for maintaining discharge of the high-intensity discharge lamp 5 is obtained in the second winding 432. Also,
Charging of the capacitor 441 is also completed in the first few cycles.

Next, consider the case where the high intensity discharge lamp 5 is turned on. As described above, since charging of the capacitor 441 is completed in the first few cycles, a high voltage can be generated in the first winding 431 of the coil device 43 at any time when the switch 442 is turned on. In FIG. 6, when the switch 442 is turned on at 71 o'clock while the switching element 31 is on, the charge accumulated in the capacitor 441 is discharged through the second winding 432 of the coil device 43. be done. At this time, the winding 431 of the coil device 43 has
A high voltage is generated according to the turns ratio.

Therefore, the high-intensity discharge lamp 5 has a second winding 4 of the transformer 7.
A voltage that is the difference between the voltage generated at the coil device 32 and the voltage generated at the winding 431 of the coil device 43 is applied. In this embodiment, in order to ensure that the high-intensity discharge lamp 5 starts discharging, the voltage
2 is set to about -15 (kV).

Switch 442 may be a manual switch or a semiconductor switch element.

After the discharge is started as described above, the switching output provided through the output winding 72 becomes the discharge sustaining voltage, and the discharge is maintained. By this, D C/D C
An inexpensive high-intensity discharge lamp lighting device that does not use a converter can be realized.

In the embodiment of FIG. 5, the output winding 72 of the transformer 7 is used as the energy supply source for the trigger circuit 4 in order to reduce the number of parts, but a separate power source may also be used. For example, the transformer 7 may be provided with a winding for a trigger circuit to serve as an energy supply source. Furthermore, the second coil device
The winding 432 may be directly connected to the battery 1. In this case, the turns ratio of the coil device is increased as necessary.

FIG. 7 is a circuit diagram showing still another embodiment of the high intensity discharge lamp device according to the present invention. The same reference numerals as in FIG. 5 indicate identical components. In this embodiment, the high-intensity discharge lamp 5 is connected to the output winding 72 of the transformer 7 and the first
and the first winding 431, and the first winding 431 is grounded. The first winding 431 of the coil arrangement 43 has opposite polarity to the second winding 432.

The trigger voltage applied to the high-intensity discharge lamp 5 is the voltage of the output winding 72 of the transformer 7 and the voltage of the first winding 4 of the coil device 43.
The voltage is the sum of the voltage of 31. Also in this example,
A high intensity discharge lamp lighting device that does not use a DC/DC converter can be provided.

<Effects of the Invention> As described above, the high intensity discharge lamp lighting device according to the present invention includes a battery, a switching section, a transformer, a high intensity discharge lamp, and a trigger circuit, and the switching section includes a battery, a switching section, a transformer, a high intensity discharge lamp, and a trigger circuit. The transformer switches and outputs the DC power supplied from the transformer, and the switching part is connected to the input winding, and the boosted switching output is taken out from the output winding. It is connected to the output winding side of the transformer, and the trigger circuit is connected to the output winding side of the transformer, so as to apply the trigger voltage to the high intensity discharge lamp, so it does not use a DC/DC converter. , it is possible to provide a compact and inexpensive high-intensity discharge lamp lighting device with a simple circuit configuration.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of a high intensity discharge lamp lighting device according to the present invention,
Figure 2 is a circuit diagram showing a more specific embodiment, and Figure 3 is a circuit diagram showing a more specific embodiment.
The figures are diagrams showing examples of operating waveforms in the embodiment of Fig. 2, and Fig. 4.
The figure is a circuit diagram showing another embodiment of the high-intensity discharge lamp lighting device according to the present invention, FIG. 5 is a circuit diagram showing still another embodiment, and FIG. 6 is a circuit diagram of the embodiment shown in FIG. FIG. 7 is a circuit diagram showing yet another embodiment of the high-intensity discharge lamp lighting device according to the present invention, and FIG. 8 is a circuit diagram showing a conventional high-intensity discharge lamp lighting device. be. 1...Battery 3...Switching section 4...
Trigger circuit 5...High intensity discharge lamp 7...Transformer diagram diagram diagram diagram diagram diagram

Claims (3)

[Claims] (1) A high-intensity discharge lamp lighting device including a battery, a switching unit, a transformer, a high-intensity discharge lamp, and a trigger circuit, wherein the switching unit switches DC power supplied from the battery. The switching unit is connected to the input winding of the transformer, and the boosted switching output is taken out from the output winding, and the high-intensity discharge lamp has the following characteristics: It has a pair of electrodes facing each other at a distance within a tube filled with gas,
A discharge lamp that emits light by a discharge between the pair of electrodes, having two different voltage values: a trigger voltage that causes discharge to occur in the pair of electrodes, and a discharge sustaining voltage that sustains the discharge after the trigger, connected to the output winding side of the transformer, and the trigger circuit is connected to the output winding side of the transformer so as to apply the trigger voltage to the high intensity discharge lamp. A high-intensity discharge lamp lighting device featuring: (2) The trigger circuit is a resonant circuit including an inductor and a capacitor, and is connected to the output winding of the transformer so that the resonant voltage is applied to the high-intensity discharge lamp as the trigger voltage. The high-intensity discharge lamp lighting device according to claim 1, characterized in that: (3) The trigger circuit includes a trigger voltage generation circuit and a coil device, and the coil device has a first winding and a second winding, and the first winding is The trigger voltage generation circuit is connected between the output winding of the transformer and the high-intensity discharge lamp, and the trigger voltage generation circuit supplies a trigger voltage to the second winding side of the coil device. The high intensity discharge lamp lighting device according to claim 1.