JP2000243584A - Discharge lamp lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the capacity of a charging circuit small, make the size small, and reduce the cost in an inverter device for lighting a discharge lamp with a DC power source. SOLUTION: The discharge lighting device has a commercial AC power source 1; a rectifier 2 for converting the commercial AC power source 1 into DC current; a DC power source 3 capable of charging; a charging circuit 4 for charging the DC power source 3 with the commercial AC power source 1; an inverter 6 which converts DC voltage outputted from a DC booster 5 into low frequency rectangular wave voltage and supplies it to the inverter part 6; an igniter 7 for applying high voltage pulse when starting a discharge lamp 8; a voltage detector 9 for detecting the voltage of the DC power source 3; and switches SW1, SW2 for supplying power for lighting the discharge lamp to the DC booster 5 from the commercial AC power source 1 through the rectifier 2, or from the DC power source 3, according to the voltage of the DC power source 3.

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, and more particularly to a portable HID ballast for lighting an HID lamp using a DC power source such as a battery.

[0002]

FIG. 12 is a circuit diagram of a conventional portable HID ballast. A portable HID ballast is designed to be small and lightweight so that it can be used for a search light for road construction, etc., and usually operates using a vehicle-mounted battery as a power source. Used by connecting an AC power supply. The AC voltage of the commercial AC power supply 1 is stepped down and rectified by the charging circuit unit 4 to charge the DC power supply 3 such as a battery. The DC voltage of the DC power supply 3 is
The voltage is boosted by the DC booster 5 to control the power supplied to the discharge lamp 8 as a load. The DC voltage boosted by the DC booster 5 is converted into a rectangular wave low-frequency AC voltage by the inverter 6 and supplied to the discharge lamp 8 as a load.
The igniter unit 7 applies a high-voltage pulse when starting the discharge lamp 8 as a load.

The operation of the conventional example will be described. When the discharge lamp 8, which is a load, is started, the output voltage of the DC booster 5 becomes 3
Boosted to a no-load secondary voltage of about 00V to 400V,
Apply the no-load secondary voltage to the load. At that time, the igniter unit 7 generates a high-voltage pulse of about 20 kV and applies it to the discharge lamp 8 to start discharge between the electrodes of the discharge lamp 8 and start the discharge.

[0004]

In the case of the conventional example, 100
It is necessary to once convert the battery voltage from the AC power supply 1 of V or 200 V system to a battery voltage of about 12 V, and then boost the voltage again to about 90 V, which is the stable lighting voltage of the discharge lamp 8, by the DC booster 5. However, in order to light the discharge lamp 8, the capacity of the charging circuit unit 4 becomes large, and the shape of the discharge lamp lighting device becomes large, so that there is a disadvantage that the cost becomes high. While charging the battery 3, the discharge lamp 8
In order to light the LED, the circuit efficiency was poor and a large heat sink was required to ensure reliability. For this reason,
There is a disadvantage that the shape of the discharge lamp lighting device is large and the cost is high.

The present invention has been made in view of the above points, and an object of the present invention is to provide a discharge lamp lighting device for lighting a discharge lamp with an inverter using a DC power supply, in which the capacity of a charging circuit is reduced. An object of the present invention is to realize size reduction and cost reduction by reducing the size.

[0006]

In order to solve the above-mentioned problems, in a discharge lamp lighting device according to the present invention, as shown in FIG. A rectifying unit 2 for conversion, a chargeable DC power supply 3, a charging circuit unit 4 for charging the DC power supply 3 with the commercial AC power supply 1, a DC boosting unit 5 for boosting a DC voltage, and output from the DC boosting unit 5. A discharge lamp lighting device including an inverter unit 6 that converts a DC voltage into a low-frequency rectangular wave voltage and supplies the same to the discharge lamp 8 and an igniter unit 7 that applies a high-voltage pulse when the discharge lamp 8 is started. A voltage detector 9 for detecting the voltage of the power supply 3 is provided, and is turned on when the voltage of the DC power supply 3 is lower than a predetermined value, and the discharge lamp is turned on from the commercial AC power supply 1 to the DC booster 5 via the rectifier 2. Switching switch that supplies power for Switch SW1 and a second switch SW2 that is turned on when the voltage of the DC power supply 3 is higher than a predetermined value and supplies power from the DC power supply 3 to the DC booster 5 for lighting the discharge lamp. It is a feature.

[0007]

(Embodiment 1) FIG. 1 is a block circuit diagram showing a configuration of Embodiment 1 of the present invention. In the figure, 1 is 1
It is a 00V or 200V commercial AC power supply. A rectifier 2 converts an AC voltage of the commercial AC power supply 1 into a DC voltage and outputs the DC voltage. Reference numeral 3 denotes a DC power supply, which here comprises a vehicle-mounted battery (about 10 V to 40 V). Reference numeral 4 denotes a charging circuit that charges the DC power supply 3 using the commercial AC power supply 1 as a power supply. Reference numeral 5 denotes a DC booster that boosts the output voltage of the rectifier 2 or the DC power supply 3 to control the power supplied to the discharge lamp 8 as a load. Reference numeral 6 denotes an inverter, which converts a DC voltage into a low-frequency rectangular wave AC voltage and supplies it to the discharge lamp 8. 7 is an igniter section,
This is a starting circuit that applies a high-voltage pulse when starting the discharge lamp 8 as a load. Reference numeral 8 denotes a discharge lamp, which is formed by an HID lamp here. Reference numeral 9 denotes a voltage detection unit that detects the voltage of the DC power supply 3 and controls the switches SW1 and SW2. 10
Denotes a control power supply, and includes a DC booster 5 and an inverter 6
Is a power source for driving the switching element.

[0008] A switch SW1 is connected between the commercial AC power supply 1 and the rectifying unit 2, and a DC power supply 3 and a DC boosting unit 5 are connected.
The switch SW2 is connected between the input section and the input section. FIG. 2 shows the switching timing of the switches SW1 and SW2. The switches SW1 and SW2 are switched according to the voltage V _IN of the DC power supply 3 so that one of them is on and the other is off. As the DC power supply 3 is charged by the charging circuit unit 4, its voltage _VIN gradually increases. The voltage V _IN of the DC power supply 3 is monitored by the voltage detection unit 9, and when the voltage V _IN of the DC power supply 3 is lower than a predetermined value Vth (for example, 14 V), the switch SW1 is turned on and the switch SW2 is turned off. When the voltage V _IN of the DC power supply 3 exceeds a predetermined value Vth, the switch SW1
Is off, and the switch SW2 is on.

When the discharge lamp 8 is turned on, and
When the AC power supply 1 is connected, power is supplied from the AC power supply 1 to the DC booster 5 via the rectifier 2 for lighting the discharge lamp without passing the DC power supply 3. In addition, the control power supply 10 of the DC booster 5 and the inverter 6 is supplied from at least the DC power supply 3, thereby minimizing unnecessary voltage conversion of supplied power and greatly improving circuit efficiency.
Thereby, a compact and low-cost discharge lamp lighting device can be provided. In particular, the size of the charging circuit unit 4 for charging the DC power supply 3 while the discharge lamp 8 is on can be reduced.

(Embodiment 2) FIG. 3 shows a specific configuration example of a DC booster 5 according to Embodiment 2 of the present invention. In the present embodiment, the core and the secondary side of the transformer T1 of the DC step-up unit 5 are shared, and the primary side is divided. The rectifier 2 includes a diode bridge DB and a smoothing capacitor C0, and an AC input terminal of the diode bridge DB is connected to the commercial AC power supply 1 via a switch SW1. A smoothing capacitor C0 is connected to a DC output terminal of the diode bridge DB. The primary winding of the transformer T1 is connected to both ends of the smoothing capacitor C0 via the switching element Q0. The DC power supply 3 is charged by the output of the charging circuit unit 4, and a capacitor C1 is connected to the DC power supply 3 via a switch SW2. Another primary winding of the transformer T1 is connected to both ends of the capacitor C1 via the switching element Q1. A capacitor C2 is connected to a secondary winding of the transformer T1 via a diode D1. In this way, by sharing the core and the secondary side of the transformer T1, it is possible to further reduce the size. Further, by securing the control power supply from the DC power supply 3, higher circuit efficiency can be obtained. This makes it possible to reduce the size and cost of the heat sink.

(Embodiment 3) FIG. 4 shows a configuration diagram of Embodiment 3 of the present invention. In this embodiment, when the discharge lamp lighting device is divided into two units, the DC booster 5 and the inverter 6
And is divided between In the conventional example of FIG. 12, normally, the DC booster 5 and the inverter 6 which share a control power supply are the same unit. However, in this case, when the restriction of radiation noise and the like is very strict, such as for a vehicle, a very large AC circuit is provided on the unit U1 side in order to reduce the radiation noise from the crossover between the units U1 and U2. A filter circuit is required. However, when the functional blocks are divided as shown in FIG. 4, only the DC voltage is applied to the crossover between the two units 11 and 12, so that there is an advantage that the filter circuit can be downsized. In particular, for a vehicle, it is desirable that the unit 12 shown in FIG. 4 be disposed inside the headlamp and the unit 11 be placed outside the headlight or inside the room.

FIG. 5 shows a circuit configuration of the igniter unit 7. A capacitor C3 is connected in parallel to an output terminal of the inverter unit 6, and a discharge lamp 8 is connected via a secondary winding N2 of the pulse transformer PT2. A capacitor C4 is connected to both ends of the capacitor C3 via a resistor R1. When the charging voltage of the capacitor C4 reaches a predetermined voltage, the voltage-responsive switch element S1 is turned on, a current flows through the primary winding n1 of the pulse transformer PT1, and is boosted to the secondary winding n2 of the pulse transformer PT1. A voltage is generated and charges the capacitor C5 via the diode D2. By repeating this operation, the capacitor C5
Rises step by step and exceeds the breakover voltage of the discharge gap G, the voltage of the capacitor C5 is discharged via the primary winding N1 of the pulse transformer PT2, and the secondary winding of the pulse transformer PT2 is discharged. A high voltage pulse of about 20 kV is generated in N2. This high-voltage pulse is applied to both ends of the discharge lamp 8 via the capacitor C3, discharge is started between the electrodes of the discharge lamp 8, and the discharge lamp 8 starts.

When the discharge lamp 8, which is a load, is started, the DC booster 5 supplies 300 V to 4 to the input terminal of the igniter 7.
The no-load secondary voltage boosted to about 00 V is applied via the inverter unit 6. To boost this voltage to about 20 kV, two-step boosting by the pulse transformers PT1 and PT2 is required. However, in this method,
Step-up transformer (transformer PT1 for charging the first-stage capacitor C5 and second-stage high-voltage pulse transformer PT
2) requires two, large size, high cost, and responds to the demand for miniaturization and thinning for mounting in the head lamp of a car like a discharge lamp lighting device for vehicles. Is difficult. Therefore, an embodiment for reducing the size of these step-up transformers will be described below.

(Embodiment 4) FIG. 6 is a circuit diagram of Embodiment 4 of the present invention. In the present embodiment, the core 14 occupying most of the cost and volume of the first-stage charging transformer and the second-stage high-voltage pulse transformer of the igniter unit 7 is integrally formed.
By weakening the magnetic coupling between the charging-side windings n1 and n2 and the high-voltage pulse windings N1 and N2, the first-stage charging at the time of high-voltage pulse generation can be performed while sharing the core of the two-stage step-up transformer. The stress on the side circuit is also reduced, and the igniter section 7
Can be provided at a small size and at low cost.

FIG. 7 is a sectional view of a transformer used in this embodiment. Windings n1, n2 and 2 of the first stage charging transformer
The windings N <b> 1 and N <b> 2 of the high-voltage pulse transformer at the stage are wound around the integrally formed core 14. The windings n1 and n2 and the windings N1 and N1, in order to weaken the magnetic coupling while securing the insulation distance between the first-stage charging transformer and the second-stage high-voltage pulse transformer in the integrally formed core 14, A constriction is provided in which the magnetic path area of the core between N2 and N2 is reduced. As a result, when a high-voltage pulse is generated, a larger current flows than when the first-stage charging circuit operates. Therefore, the magnetic path area of the core is reduced, the constriction is magnetically saturated, and the pulse on the high-voltage pulse transformer side is generated. The influence of the generation is less likely to be exerted on the charging transformer side. For example, the current flowing through the charging circuit is about 10 A,
The current flowing in the high-voltage pulse transformer circuit is about several hundreds of amperes, and a current that differs by one digit flows.

At this time, the windings n1, n of the charging transformer
2 and the magnetic coupling between the windings N1 and N2 of the high-voltage pulse transformer, assuming that the coupling coefficient when completely coupled is 1,
As shown in FIG. 8, 0.5 or less, preferably 0.2 to
By setting the value to 0.5, the influence (voltage stress) of the pulse generation on the high voltage pulse transformer side is less likely to be exerted on the charging transformer side.

(Embodiment 5) FIG. 9 is a circuit diagram of an igniter section according to Embodiment 5 of the present invention. In the present embodiment, as shown in FIG. 10, when the voltage V _{C4 of the} capacitor C4 exceeds a predetermined value, the voltage responsive switch element S1 is turned on, and the capacitor C5 is charged. When the voltage V _C5 of the capacitor C5 exceeds a predetermined value, high-voltage switching element S2 of the thyristor is turned on by the trigger circuit 13. At this time, a resonance current flows through the thyristor S2, and the resonance current also flows through the charging-side winding n2 and the diode D2. The current limiting resistor R2 is connected to the charging-side winding n2 so that the resonance current flowing through the charging-side winding n2 is reduced and the electric charge charged in the pulse generating capacitor C5 is used as much as possible for the generation energy of the pulse voltage. It has a circuit configuration inserted in series. In this embodiment, the current limiting resistor R2 is provided individually, but the resistance of the charging side winding n2 may be used.

(Embodiment 6) FIG. 11 shows a circuit diagram of Embodiment 6 of the present invention. In this embodiment, in addition to sharing the transformer for charging the capacitor C5 and the core unit 14 of the high-voltage pulse transformer, the transformer for the control power supply is also shared, so that the primary circuit of the charging transformer for the capacitor C5 can be used. The primary circuit of the transformer of the control power supply is also shared. The primary winding n1 of the transformer PT is connected to the switching element Q
6, the switching unit Q6 is turned on / off by the drive unit 15 to charge the capacitor C5 from the secondary winding n2 via the diode D2, Power can be supplied from the winding n3 to the control power supply 10 via the diode D4.
The control power supply 10 is a power supply for the DC booster 5 and the controller 16 of the inverter 6. Further, the primary winding N1 and the secondary winding N2 of the high-voltage pulse transformer are wound around the integrally formed core portion 14, but the other windings n1, n2, n3
The effect of the stress at the time of generating the high-voltage pulse on the other windings n1, n2, and n3 is reduced by weakening the magnetic coupling with the windings n1, n2, and n3.

In this embodiment, the secondary circuit for supplying power to the control power supply 10 is a forward circuit type.
The secondary circuit for charging the capacitor C5 employs a flyback circuit system. When pulse generation is necessary, the load on the control power supply 10 is relatively light. When power is supplied to the secondary circuit and the discharge lamp 8 is turned on after the pulse is generated, the load on the control power supply 10 becomes relatively heavy for stable lighting control. No power is supplied to the circuit. As a result, the core portion occupying most of the cost and volume of the transformer can be shared, and the transformer can be provided at a small size and at low cost.

[0020]

According to the first aspect of the present invention, in a lighting device for boosting a chargeable DC power supply such as a battery and lighting an AC discharge lamp by an inverter unit, when the voltage of the DC power supply is low, By supplying electric power for lighting the discharge lamp from the commercial AC power supply without passing through the charging circuit section or DC power supply, the charging circuit section can be significantly reduced in size, resulting in a small, low-cost An electric lighting device can be provided.

According to the second aspect of the present invention, since the secondary winding and the core of the transformer for voltage conversion of the DC booster are shared, the lighting device can be reduced in size and cost. According to the third aspect of the invention, when the discharge lamp lighting device is divided into two units, the discharge lamp lighting device is divided between the DC boosting unit and the inverter unit, so that the noise removing filter can be downsized. In addition, the size and cost of the lighting device can be reduced.

According to the fourth aspect of the present invention, the cost and cost of the two-stage step-up transformer constituting the igniter section, and the core portion occupying most of the volume, are integrally formed to weaken the magnetic coupling between the windings of each transformer. This has the effect of reducing the stress at the time of generating a high-voltage pulse while sharing the core of the step-up transformer, and providing the igniter unit at a small size and at low cost.

[Brief description of the drawings]

FIG. 1 is a block circuit diagram according to a first embodiment of the present invention.

FIG. 2 is an operation explanatory diagram of the first embodiment of the present invention.

FIG. 3 is a main part circuit diagram of a second embodiment of the present invention.

FIG. 4 is a block circuit diagram according to a third embodiment of the present invention.

FIG. 5 is a circuit diagram illustrating a detailed configuration of an igniter unit according to a third embodiment of the present invention.

FIG. 6 is a circuit diagram according to a fourth embodiment of the present invention.

FIG. 7 is a sectional view of a transformer used in Embodiment 4 of the present invention.

FIG. 8 is a characteristic diagram showing a relationship between a coupling coefficient of a transformer used in Example 4 of the present invention and a voltage stress.

FIG. 9 is a circuit diagram illustrating a detailed configuration of an igniter unit according to a fifth embodiment of the present invention.

FIG. 10 is an operation waveform diagram according to a fifth embodiment of the present invention.

FIG. 11 is a block circuit diagram according to a sixth embodiment of the present invention.

FIG. 12 is a block circuit diagram of a conventional example.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 commercial AC power supply 2 rectifier 3 DC power supply (battery) 4 charging circuit 5 DC booster 6 inverter 7 igniter 8 discharge lamp 9 voltage detector

Claims (4)

[Claims] 1. A commercial AC power supply, a rectifier for converting the commercial AC power into DC, a chargeable DC power, a charging circuit for charging the DC power with the commercial AC power, and a DC booster for boosting the DC voltage. Unit, an inverter unit that converts a DC voltage output from the DC boost unit to a low-frequency rectangular wave voltage and supplies the same to the discharge lamp, and an igniter unit that applies a high-voltage pulse when the discharge lamp is started. The lighting device includes a voltage detection unit that detects the voltage of the DC power supply, and is turned on when the voltage of the DC power supply is lower than a predetermined value, and is used to turn on the discharge lamp from the commercial AC power supply to the DC boosting unit via the rectifying unit. And a second switch for turning on the power supply when the voltage of the DC power supply is higher than a predetermined value and supplying power for lighting the discharge lamp from the DC power supply to the DC booster. Switch A discharge lamp lighting device comprising: 2. The DC booster according to claim 1, wherein the DC booster includes a voltage conversion transformer.
Discharge lamp lighting device, comprising: one primary winding, an output of a rectifier connected to one primary winding, and a DC power supply connected to the other primary winding. . 3. The discharge lamp lighting device according to claim 2, wherein the DC booster and the inverter are divided into two units. 4. The igniter section includes a first transformer for boosting an output voltage of the inverter section to charge a capacitor, and a second transformer for discharging a voltage of the capacitor to generate a high-voltage pulse. Equipped with a transformer, the first
And the core of the second transformer are integrally formed, and the magnetic coupling coefficient between the winding of the first transformer and the winding of the second transformer is in the range of 0.2 to 0.5. The discharge lamp lighting device according to claim 1, wherein