JPH0536484A - Discharge lamp lighting apparatus - Google Patents

Abstract

PURPOSE:To provide a starting circuit able to generate starting pulses with a wide pulse width and high pulse energy for a rectangular wave lighting-type discharge lamp lighting apparatus. CONSTITUTION:A starting circuit is composed of an inductor 11 connected with a metal halide lamp 10 in series and a nonlinear capacitor 12 connected with the lamp 10 in parallel wherein the starting circuit is in a rectangular wave lighting-type discharge lamp lighting apparatus composed of a commercial electric power source 1, a current rectifying device 2, a filter 3, a voltage lowering type chopper circuit 4 for current control, and a full bridge-type inverter 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a lighting device for a high-intensity discharge lamp such as a metal halide lamp, which is lit by a rectangular wave using an inverter.

[0002]

2. Description of the Related Art In recent years, high-intensity discharge lamps such as metal halide lamps have begun to spread as various light sources. Lighting devices for such discharge lamps are also used in conventional phase-advancing ballasts such as leakage transformers and main capacitors. From a method of lighting a lamp using an iron ballast to a method using a high frequency inverter,
Furthermore, the rectangular wave lighting system using an inverter is being reduced in size and weight.

FIG. 4 is a diagram showing an example of the configuration of a conventional rectangular wave lighting type lighting device, in which 1 is a commercial power source, 2 is a rectifying element, and 3 is a rectifier.
Is a smoothing circuit composed of a smoothing capacitor, 4 is a step-down chopper circuit for controlling current, 5 is a full bridge inverter, 6 is a starting pulse transformer, and 7 is between the output terminals of the full bridge inverter 5. A bidirectional two-terminal semiconductor switching element (SSS) 9 connected through a resistor 8 was connected between the intermediate tap of the starting pulse transformer 6 and a connection point between the semiconductor switching element 7 and the resistor 8. A capacitor, a starting pulse transformer 6, a semiconductor switching element 7, and a resistor 8
The capacitor 9 and the capacitor 9 constitute a starting circuit. Reference numeral 10 is a metal halide lamp connected to the output terminal of the full-bridge inverter 5 via the starting circuit.

In the lighting device configured as described above, the commercial power source 1 is rectified by the rectifying element 2, and the full bridge inverter 5 is passed through the smoothing circuit 3 and the chopper circuit 4.
Entered in. Then, by the operation of the inverter 5, a rectangular wave alternating voltage is supplied to the metal halide lamp 10 via the starting circuit.
Applied to. When a rectangular wave alternating voltage is applied to the starting circuit, the capacitor 9 starts charging, and when the charging voltage exceeds the breakover voltage of the semiconductor switching element 7, the semiconductor switching element 7 is turned on and the capacitor 9 The discharge current suddenly flows into the pulse transformer 6 via the semiconductor switching element 7. As a result, a high-voltage pulse is generated in the pulse transformer 6 and applied to the metal halide lamp 10, the lamp 10 is started, and rectangular wave lighting is performed. In this rectangular wave lighting method, since a rectangular wave is applied, flicker of the lamp is reduced and good lighting is performed.

[0005]

By the way, in the discharge lamp lighting device of the rectangular wave lighting type as described above, good lighting is performed by applying the rectangular wave after starting, but at the time of starting, the pulse transformer 6 is used. The width of the starting pulse generated in the starting circuit consisting of the semiconductor switching element 7, the resistor 8 and the capacitor 9 is narrow, and therefore the starting pulse energy is small and the starting is difficult.

The starting pulse width can be widened by increasing the inductance L of the pulse transformer 6 and the capacitance C of the capacitor 9, but the purpose is to increase the size of the lighting device and to reduce the size and weight of the inverter. Will be contrary to. Further, due to the limitation of the current capacity of the semiconductor switching element 7, the capacity of the capacitor 9 cannot be so large.
The larger the number of starting pulses generated, the easier the starting. However, since the number of starting pulses generated in the above-mentioned starting circuit is determined by the breakover voltage of the semiconductor switching element and the time constant of the capacitor and the resistor, the pulse width is wide. In order to increase the number of start-up pulses generated, the resistance value must be reduced because the capacitor is enlarged corresponding to the pulse width, and a high wattage resistance is required, resulting in an increase in size. Occurs.

The present invention has been made in order to solve the above problems in the discharge lamp lighting device of the conventional rectangular wave lighting system, and is provided with a starting circuit capable of generating a starting pulse with a large pulse energy and is easy to start. An object is to provide a discharge lamp lighting device.

[0008]

In order to solve the above-mentioned problems, the present invention inputs direct current to a step-down chopper circuit for current control and inputs the output of the step-down chopper circuit to an inverter, A discharge lamp lighting device for connecting a discharge lamp to an output terminal of the inverter and lighting a rectangular wave, wherein a starting circuit including an inductor connected in series to the discharge lamp and a non-linear capacitor connected in parallel to the discharge lamp is provided. Is.

In the discharge lamp lighting device provided with the starter circuit having such a configuration, when the rectangular wave AC voltage output from the inverter changes greatly at rising and falling, a charging current rapidly flows through the non-linear capacitor, The charge immediately saturates and reaches the saturation voltage of the non-linear capacitor, and the charge current rapidly drops to zero. At this time, a high voltage pulse having the same polarity as the rectangular wave AC voltage is generated by the series inductor and applied to the discharge lamp. This high-voltage pulse has a large pulse width due to the characteristics of the non-linear capacitor, and therefore the discharge lamp does not require a semiconductor switching element and can be easily started by a pulse of large energy.

[0010]

EXAMPLES Next, examples will be described. FIG. 1 is a circuit configuration diagram showing an embodiment of the discharge lamp lighting device according to the present invention, and the same or corresponding members as those of the conventional discharge lamp lighting device shown in FIG. The description is omitted. The starting circuit in the present invention is an inductor 11 inserted in series with a circuit for applying a rectangular wave AC voltage from the output terminal of the full-bridge inverter 5 to the metal halide lamp 10.
And a non-linear V connected in parallel to the metal halide lamp 10.
Non-linear capacitor 12 made of ferroelectric material having -Q characteristic
It consists of and.

Next, the operation of the discharge lamp lighting device having the starting circuit configured as described above will be described. When the rectangular-wave AC voltage output from the full-bridge inverter 5 is applied to the starting circuit, a charging current suddenly flows through the nonlinear capacitor 12 when the rectangular-wave AC voltage changes greatly at rising and falling, and the charging charge is increased. Is immediately saturated and reaches the saturation voltage of the non-linear capacitor 12, and the charging current suddenly becomes zero. At this time, as shown in FIG.
As a result, a high-voltage pulse P having the same polarity as the rectangular wave AC voltage is generated and applied to the metal halide lamp 10. In FIG. 2, for comparison, a starting pulse P ′ generated in the conventional discharge lamp lighting device shown in FIG. 4 is shown by a wavy line. This high-voltage starting pulse P is applied to the nonlinear capacitor 12
3A, the pulse width is larger than that of the high-pressure starting pulse P'of the conventional device shown in the enlarged view of FIG. 3B, and the metal halide lamp 10 is easy to use. To start.

As described above, in the present invention, the combination of the rectangular wave lighting system and the starting circuit composed of the non-linear capacitor, unlike the normal commercial power supply voltage, causes the same time when the rectangular wave AC voltage rapidly rises and falls. A pulse with a large polarity pulse width is generated. Therefore, without the need for a semiconductor switching element, a high-voltage pulse with a large amount of energy is generated reliably in each cycle, the lamp can be easily started, and the starting circuit can be made smaller and smaller.
The weight can be reduced.

[0013]

As described above on the basis of the embodiments,
According to the present invention, since the starting circuit in the discharge lamp lighting device of the rectangular wave lighting system is composed of the inductor and the non-linear capacitor, a starting pulse having a wide pulse width can be generated in each cycle, and the discharge lamp in the rectangular wave lighting system is generated. Can be easily started.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram showing an embodiment of a discharge lamp lighting device according to the present invention.

FIG. 2 is a diagram showing how a high-voltage starting pulse is generated by a starting circuit in the embodiment shown in FIG.

FIG. 3 is an enlarged partial view of FIG.

FIG. 4 is a circuit configuration diagram showing a configuration example of a conventional discharge lamp lighting device.

[Explanation of symbols]

 1 Commercial power supply 2 Rectifier element 3 Smoothing circuit 4 Step-down type chopper circuit 5 Full bridge type inverter 10 Metal halide lamp 11 Inductor 12 Non-linear capacitor

Front Page Continuation (72) Ichiro Terayama, Inventor Ichiro Terayama 212-10 Akagidai, Kawasato-mura, Kita-Saitama-gun, Saitama I-Liting System Saitama Factory (72) Inventor Shunichi Sasaki 1-1, Iriyama-cho, Gyoda-shi, Saitama Iwasaki Electric Co., Ltd. Saitama Factory

Claims (1)

[Claims] 1. A discharge lamp for inputting direct current to a step-down chopper circuit to control current, inputting an output of the step-down chopper circuit to an inverter, and connecting a discharge lamp to an output end of the inverter to illuminate a rectangular wave. A discharge lamp lighting device, comprising: a starting circuit including an inductor connected in series to the discharge lamp and a non-linear capacitor connected in parallel to the discharge lamp.