JP2000340374A - Discharge lamp lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a discharge lamp lighting device capable of stably, surely starting without making a shape large. SOLUTION: This discharge lamp lighting device has a DC power source 1; a DC-DC converter circuit 2 for boosting up DC input voltage from the DC power source 1; an inverter circuit 3 for converting voltage boosted up in the DC-DC circuit 2 into AC; and an igniter circuit 4 for generating a starting high voltage pulse from the AC wave from the inverter circuit 3 and applying it to a discharge lamp 5, and the igniter circuit 4 contains a pulse transformer 43; a switching element 42 for switching the primary side of the pulse transformer 43; and a trigger element 41 for controlling the switching element 42, and the trigger element 41 is arranged in the vicinity of the pulse transformer 43, and covered with a shield 44 at a potential lower than the switching voltage.

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 FIG. 7 shows a circuit configuration of a discharge lamp lighting apparatus of this type. A DC power supply 1, a DC-DC converter circuit section 2 for boosting a DC input voltage from the DC power supply 1, and
An inverter circuit section 3 for converting the voltage boosted by the DC-DC converter circuit section 2 into an alternating voltage, and a voltage (starting high-voltage pulse) for breaking down the alternating current from the inverter circuit section 3 by the discharge lamp 5. And an igniter circuit section 4 for applying a voltage to the discharge lamp 5. The igniter circuit unit 4 includes a booster circuit that boosts the AC wave from the inverter circuit unit 3, a pulse transformer that boosts the voltage boosted by the booster circuit to a voltage at which the discharge lamp 5 breaks down, and a primary side of the pulse transformer. And a trigger element for controlling the switching element.

Here, a trigger element having high sensitivity is used in order to surely operate the trigger element in a wide temperature range.

[0004]

However, in the above-described discharge lamp lighting device, for example, when it is used in a vehicle, a large current flows in an engine room and an environment in which noise is likely to be generated. Will be placed. In order to prevent the generation of noise and prevent intrusion, it is necessary to insert a large filter in the input / output unit or shield the entire igniter circuit unit 4, which has led to an increase in the size and cost.

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 capable of stably and reliably starting without increasing the size. It is in.

[0006]

According to the first aspect of the present invention,
A DC power supply unit, a DC-DC converter circuit unit for boosting a DC input voltage from the DC power supply unit, an inverter circuit unit for converting the voltage boosted by the DC-DC converter circuit unit into an AC, and the inverter circuit unit An igniter circuit for generating a high-voltage pulse for starting from an alternating current wave applied to the discharge lamp and applying the pulse to a discharge lamp, wherein the igniter circuit includes a pulse transformer and a switching element for switching the primary side of the pulse transformer. And a trigger element for controlling the switching element, wherein the trigger element is arranged near the pulse transformer, and the trigger element is shielded at a potential lower than the switching voltage. It is characterized by the following.

According to a second aspect of the present invention, in the first aspect of the present invention, the shield is covered with a wiring pattern covering the trigger element, and the wiring pattern has a potential lower than a switching voltage of the trigger element. It is a feature.

According to a third aspect of the present invention, in the second aspect of the present invention, the wiring pattern is connected to a potential lower than a switching voltage of the trigger element via a capacitor.

According to a fourth aspect of the present invention, in the first aspect, the shield is formed by a metal plate extending from a lid of a grounded metal igniter circuit case.
It is characterized in that it is made to cover the trigger element.

According to a fifth aspect of the present invention, in the fourth aspect of the present invention, the switching element is also radiated by the metal plate.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a circuit diagram of an igniter circuit unit according to a first embodiment of the discharge lamp lighting device of the present invention, and FIG. 2 is a schematic diagram showing a positional relationship between a trigger element and a pulse transformer.

The igniter circuit unit 4 according to the present embodiment comprises:
A booster circuit for boosting the AC wave from the inverter circuit unit 3, a pulse transformer 43 for boosting the voltage boosted by the booster circuit to a voltage at which the discharge lamp 5 breaks down, and a switching element for switching the primary side of the pulse transformer 43 42 and a trigger element 4 for controlling the switching element 42
1.

In the present embodiment, the trigger element 41 is arranged near the pulse transformer 43 and is shielded by covering the trigger element 41 with a wiring pattern 44. The wiring pattern 44 is connected to the circuit ground of the igniter circuit unit 4 and the trigger element 41
Has a lower potential than the switching voltage.

According to this embodiment, since the trigger element 41 is shielded by the wiring pattern 44 set to a potential lower than the switching voltage, malfunction of the trigger element 41 due to noise can be prevented. Are arranged near the pulse transformer 43, the wiring from the trigger element 41 to the pulse transformer 43 can be shortened, so that noise affecting this wiring can be reduced, and the discharge lamp 5 can be stably and reliably turned on. be able to.

FIG. 3 is a circuit diagram of an igniter circuit section according to a second embodiment of the discharge lamp lighting device of the present invention, and FIG. 4 is a schematic diagram showing a positional relationship between a trigger element and a pulse transformer.

In the present embodiment, the wiring pattern 44 is connected to the circuit ground of the igniter circuit section 4 via a capacitor 45 in the first embodiment.

According to this embodiment, the same effects as those of the first embodiment can be obtained. FIG. 5 is a schematic configuration diagram of an igniter circuit unit 4 according to a third embodiment of the discharge lamp lighting device of the present invention, and a metal case 46 of the igniter circuit unit 4.
The trigger element 4 is provided by a metal plate 47 extending from
1 is covered. The metal case 46 is grounded.

According to the present embodiment, the trigger element 41 is shielded by the metal plate 47 extending inside the metal case 46 of the igniter circuit section 4 set to a potential lower than the switching voltage. Trigger element 4
1 can be reduced, malfunction of the trigger element 41 due to noise can be prevented, and the discharge lamp 5 can be stabilized.
It can be lit reliably.

FIG. 6 is a schematic configuration diagram of an igniter circuit section 4 according to a fourth embodiment of the discharge lamp lighting device of the present invention.
In the third embodiment, the metal plate 4 of the metal case 46
7, the switching element 42 also functions as a heat sink. In addition, it is also possible to use it as a heat sink of other electronic components other than the switching element 42.

According to the present embodiment, in addition to the effect of the third embodiment, there is an effect that heat can be simultaneously radiated from the electronic components by the metal plate 47 of the metal case 46.

[0021]

As described above, according to the first to third aspects of the present invention, a DC power supply, a DC-DC converter circuit for boosting a DC input voltage from the DC power supply, An inverter circuit unit for converting the voltage boosted by the DC-DC converter circuit unit into an AC, and an igniter circuit unit for generating a high-voltage pulse for starting from an AC wave from the inverter circuit unit and applying the pulse to a discharge lamp. A discharge lamp lighting device including a pulse transformer, a switching element for performing switching on the primary side of the pulse transformer, and a trigger element for controlling the switching element in the igniter circuit unit. Since the trigger element is shielded at a potential lower than its switching voltage while being disposed near the transformer, a trigger caused by noise is provided. Prevents malfunction of the device, a discharge lamp stable and can be reliably provide the discharge lamp lighting device capable of lighting.

According to a fourth aspect of the present invention, in the first aspect, the shield is covered with a metal plate extending from a lid of a grounded metal igniter circuit unit case. As a result, the trigger element is shielded by the metal plate, malfunction of the trigger element due to noise can be prevented, and a discharge lamp lighting device capable of stably and reliably lighting the discharge lamp can be provided.

According to the fifth aspect of the present invention, in the fourth aspect of the present invention, the switching element is also radiated by the metal plate. The plate has an effect that heat can be radiated from the electronic components at the same time.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of an igniter circuit unit according to a first embodiment of the discharge lamp lighting device of the present invention.

FIG. 2 is a schematic diagram showing a positional relationship between a trigger element and a pulse transformer according to the first embodiment.

FIG. 3 is a circuit diagram of an igniter circuit unit according to a second embodiment of the discharge lamp lighting device of the present invention.

FIG. 4 is a schematic diagram showing a positional relationship between the trigger element and the pulse transformer according to the above.

FIG. 5 is a schematic configuration diagram of an igniter circuit unit according to a third embodiment of the discharge lamp lighting device of the present invention.

FIG. 6 is a schematic configuration diagram of an igniter circuit unit according to a fourth embodiment of the discharge lamp lighting device of the present invention.

FIG. 7 is a circuit configuration diagram of a discharge lamp lighting device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 DC power supply 2 DC-DC converter circuit part 3 Inverter circuit part 4 Igniter circuit part 5 Discharge lamp 41 Trigger element 42 Switching element 43 Pulse transformer 44 Wiring pattern 45 Capacitor 46 Metal case 47 Metal plate

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // H05B 41/24 H05B 41/24 DF term (Reference) 3K014 AA01 DA07 EA01 LA01 LB04 3K072 AA11 BA03 BA05 DD07 DD08 GB01 3K083 AA02 AA92 BA05 BA25 BA26 BC15 BC34 BC47 CA32

Claims (5)

[Claims] A DC power supply unit, a DC-DC converter circuit unit for boosting a DC input voltage from the DC power supply unit, and an inverter circuit unit for converting the voltage boosted by the DC-DC converter circuit unit into an AC. An igniter circuit for generating a high-voltage pulse for starting from an AC wave from the inverter circuit and applying the pulse to a discharge lamp. The igniter circuit includes a pulse transformer and a primary side of the pulse transformer. In a discharge lamp lighting device including a switching element for performing switching and a trigger element for controlling the switching element, the trigger element is arranged near the pulse transformer, and the trigger element is set at a potential lower than the switching voltage. A discharge lamp lighting device characterized by being shielded. 2. The discharge lamp lighting device according to claim 1, wherein the shield is covered with a wiring pattern covering the trigger element, and the wiring pattern has a potential lower than a switching voltage of the trigger element. 3. The discharge lamp lighting device according to claim 2, wherein the wiring pattern is connected to a potential lower than a switching voltage of the trigger element via a capacitor. 4. The discharge device according to claim 1, wherein the shield is configured to cover the trigger element with a metal plate extending from a lid of a grounded metal igniter circuit unit case. Lighting device. 5. The discharge lamp lighting device according to claim 4, wherein the switching element is also radiated by the metal plate.