JPH07106084A - Electronic lighting device for ultraviolet radiation discharge lamp - Google Patents

Abstract

PURPOSE:To obtain an electronic lighting device for rectangular-wave lighting a high-output ultraviolet radiation discharge lamp, which needs a high lighting voltage. CONSTITUTION:Each pair of IGBT 11, IGBT 12 and IGBT 13, IGBT 14 and IGBT 15, IGBT 16 and IGBT 17, IGBT 18 connected in series to each other is used as each polarity switching element, and they are connected in a full- bridge shape to form a full-bridge inverter 21. High tension direct current voltage is applied to this full-bridge inverter 21, and an ultraviolet discharge lamp 23 is connected to an output end of this inverter 21 to form an electronic lighting device for ultraviolet radiation discharge lamp.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic lighting device for lighting a high power ultraviolet radiation discharge lamp requiring a high lighting voltage in a rectangular wave.

[0002]

2. Description of the Related Art Conventionally, as a lighting device for a discharge lamp, a discharge lamp is lit by using a copper-iron type ballast such as a phase-advancing type ballast consisting of a leakage transformer and a main capacitor or a choke coil type ballast. Although the method has been used, in recent years, a lighting method using a high frequency inverter and an electronic lighting method for performing rectangular wave lighting have been used in order to reduce the size and weight.

FIG. 3 is a diagram showing a configuration example of a discharge lamp electronic lighting device for performing rectangular wave lighting. In FIG. 3, 1 is an AC power supply, 2 is a rectifying / smoothing circuit for converting the AC power from the AC power supply 1 into DC power, 3 is a step-down chopper circuit, which is a switching transistor TR1, a DC reactor L, a smoothing capacitor C, and the switching. The constant current feedback circuit 4 drives the transistor TR1. R1 is a current detection element for inputting a detection output to the constant current feedback circuit 4, and 5 is a full-bridge type low-frequency inverter composed of four switching transistors TR2 to TR5.
2 to TR5 are driven by a drive signal from the drive circuit 6. Reference numeral 7 is a discharge lamp connected to the output terminal of the low frequency inverter 5.

In the discharge lamp electronic lighting device configured as described above, the AC power from the AC power supply 1 is rectified by the rectifying / smoothing circuit 2, and the DC output is input to the step-down chopper circuit 3 for constant current control. The output of the chopper circuit 3 is input to the full-bridge inverter 5. By the operation of the inverter 5, a rectangular wave alternating voltage is applied to the discharge lamp 7, and a rectangular wave lighting with less flicker is performed.

[0005]

By the way, when lighting a high-power discharge lamp, especially a high-power ultraviolet radiation discharge lamp, a high lighting voltage is required. When an ultraviolet radiation discharge lamp that requires such a high applied voltage is to be lit using the above-described conventional rectangular wave lighting type discharge lamp electronic lighting device, a booster such as a DC-DC converter is provided in the preceding stage. The DC voltage applied to the full-bridge low-frequency inverter is increased, but the final-stage full-bridge low-frequency inverter uses a single bipolar transistor for each polarity switching element. A high lighting voltage (1000 to 1500 V) is directly applied to a single bipolar transistor when the polarity is switched.

However, since there is no polar transistor having a withstand voltage corresponding to such a high lighting voltage, the conventional rectangular wave lighting type discharge lamp lighting device is used as a discharge lamp for ultraviolet radiation which requires a high applied voltage. It is impossible to use it as a lighting device.

Further, in order to increase the breakdown voltage of each polarity switching switching element of the full bridge type low frequency inverter to which a high voltage DC voltage is applied, it is conceivable to use a pair of bipolar transistors connected in series. However, since it is used as a switching element, in order to saturate the bipolar transistor, it is necessary to keep flowing a base current above a certain level, so that the power consumption of the drive circuit is extremely large. Therefore, when a pair of bipolar transistors are connected in series, each bipolar transistor requires a driving power source having a high withstand voltage and a large power, and the entire drive circuit becomes extremely large. Further, the repetition frequency of the inverter for supplying alternating power is low at several hundred Hz, but a very high voltage is applied at the time of switching, so the dv / dt value becomes very large, and in consideration of malfunction of the drive circuit, There are many problems such as not only increasing the withstand voltage but also reducing the capacitance between circuits, and it is difficult to connect a pair of bipolar transistors in series to realize a high-voltage low-frequency inverter. .

The present invention has been made in order to solve the above problems in lighting a high-power ultraviolet radiation discharge lamp using a conventional rectangular-wave lighting type discharge lamp electronic lighting device. An object of the present invention is to provide an electronic lighting device for an ultraviolet radiation discharge lamp that can easily light an ultraviolet radiation discharge lamp.

[0009]

In order to solve the above problems, the present invention is for an ultraviolet radiation discharge lamp in which an ultraviolet radiation discharge lamp is connected to the output end of a full bridge type inverter to which direct current power is input. In the electronic lighting device, as each polarity switching element constituting the full bridge type inverter,
A plurality of insulated gate bipolar transistors (hereinafter abbreviated as IGBT) connected in series are used.

As described above, a plurality of I connected in series is used as each polarity switching element forming the full-bridge type inverter.
When the IGBT is used, the IGBT does not substantially require a current for driving, like the FET. Therefore, even if a plurality of IGBTs connected in series are used as the polarity switching element, power saving and downsizing of the drive circuit can be achieved. Can be planned. Also,
In the case of a FET, a high breakdown voltage element causes a large voltage drop and an increase in loss, which is a problem. However, although the IGBT is not as fast as the FET, the repetition frequency used is several hundreds.
Since it is as low as Hz, it can be sufficiently supported, and even when it is a high breakdown voltage element, the voltage drop is about the same as that of a bipolar transistor, so it is optimal as a polarity switching element of a high breakdown voltage inverter, high output that requires a high applied voltage The ultraviolet radiation discharge lamp can be easily turned on.

[0011]

EXAMPLES Next, examples will be described. FIG. 1 is a circuit configuration diagram showing an embodiment of an electronic lighting device for an ultraviolet radiation discharge lamp according to the present invention. The configuration up to the chopper circuit is the same as that of the conventional example shown in FIG. Since the parts are added, the illustration and the description thereof are omitted, and it is shown as a boosted DC power supply E necessary for lighting the ultraviolet radiation discharge lamp. In this embodiment, two IGBTs connected in series are used as the polarity switching elements forming the full bridge inverter. That is, in FIG. 1, 11 to 18 are IGBTs, and a pair of IGBT11 and IGBT12 connected in series,
IGBT13 and IGBT14, IGBT15 and IGBT16, I
The IGBT 17 and the IGBT 18 form a polarity switching element, are connected in a full bridge type, and a drive signal is applied to the gate of each IGBT from the drive circuit 22 to form a full bridge type low frequency inverter 21. Then, the DC voltage E boosted to the voltage required for lighting the ultraviolet radiation discharge lamp is applied to the full-bridge low-frequency inverter 21 configured as described above through the chopper circuit 6, and the output terminal is exposed to the ultraviolet light. A radiation discharge lamp 23 is connected.

FIG. 2 is a circuit configuration diagram showing a configuration example of the drive circuit 22. In FIG. 2, reference numeral 31 is a drive circuit power source, and a high frequency switching power source is used because the power for driving the IGBT can be small. Reference numerals 32 and 33 are pulse transformers connected to the high frequency power supply 31 and having a small inter-winding capacitance, which are connected in series to increase the withstand voltage and reduce the inter-circuit capacitance. The output of the pulse transformer 33 is rectified, and the control signal C applied via the photo coupler 34.
The ONT supplies a drive signal to the gate of the IGBT 36 through the gate control circuit 35.

Next, a full-bridge type low-frequency inverter of the electronic lighting device for an ultraviolet radiation discharge lamp constructed as described above.
The operation of 21 will be described. An ON signal is sent from the drive circuit 22 to a pair of IGBT11 and IGBT12, and IGBT17 and I.
The gates of the GBT 18 are input to turn them on at the same time, the boosted DC voltage E is applied to the ultraviolet radiation discharge lamp 23 to light it, and a current is passed in the direction of the arrow. Next, the pair of IGBT11 and IGBT12, and IGBT17 and IGBT
The pair of T18 is turned off to stop the operation and the opposite pair, that is, the pair of IGBT13 and IGBT14 and the pair of IGBT15 and IG.
An on signal is input from the drive circuit 22 to each gate of the pair of BT16 to turn them on at the same time, and a current in the opposite direction to the above case flows. After that, the above operation is repeated to keep the ultraviolet radiation discharge lamp 23 lit.

By the way, a ramp voltage is applied to each of the pair of IGBTs constituting each polarity switching element in the full bridge type low frequency inverter 21 which alternately operates in this way during each switching operation. However, since the pair of IGBTs forming each polarity switching element is configured by connecting two IGBTs in series, only a voltage divided by the IGBTs connected in series is included in a single IGBT. Will be applied. Therefore, it becomes possible to turn on a high-output ultraviolet radiation discharge lamp having a lamp voltage higher than the withstand voltage of a single IGBT, for example, a lamp voltage of several thousand and several hundred volts.

In the above embodiment, the two IGBTs connected in series are used as the polarity switching elements constituting the full bridge type low frequency inverter, but three or more IGBTs connected in series are used. A polarity switching element can also be configured, and a discharge lamp with a higher lamp voltage can be turned on.

[0016]

As described above on the basis of the embodiments,
According to the present invention, since a plurality of IGBTs connected in series are used as the polarity switching elements forming the full-bridge type inverter, it is possible to easily realize an electronic lighting device for a high-power ultraviolet radiation discharge lamp having a high lamp voltage. can do.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram showing a main part of an embodiment of an electronic lighting device for an ultraviolet radiation discharge lamp according to the present invention.

FIG. 2 is a circuit configuration diagram showing a configuration example of a drive circuit in the electronic lighting device shown in FIG.

FIG. 3 is a circuit configuration diagram showing a configuration example of a conventional discharge lamp electronic lighting device of a rectangular wave lighting system.

[Explanation of symbols]

 1 AC power supply 2 Rectification smoothing circuit 3 Step-down chopper circuit 4 Constant current feedback circuit 5,21 Full bridge type inverter 6,22 Drive circuit 7 Discharge lamp 23 Ultraviolet radiation discharge lamp

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuaki Miyata 1-18-1 Takada, Toshima-ku, Tokyo Inside Origin Electric Co., Ltd. (72) Inventor Shigenori Kobayashi 3-12-4, Shiba, Minato-ku, Tokyo No. Iwasaki Electric Co., Ltd. (72) Inventor Akira Ogawa 3-12-4 Shiba, Minato-ku, Tokyo Iwasaki Electric Co., Ltd.

Claims (1)

[Claims] 1. An electronic lighting device for an ultraviolet radiation discharge lamp in which an ultraviolet radiation discharge lamp is connected to an output terminal of a full bridge type inverter to which direct current power is input, and each polarity switching element constituting the full bridge type inverter, An electronic lighting device for an ultraviolet radiation discharge lamp, comprising a plurality of insulated gate bipolar transistors connected in series.