JP2001345198A - Lighting device and lighting device - Google Patents

Abstract

(57) [Summary] To provide a lighting device for a high-pressure discharge lamp that reliably lights a discharge lamp without using an igniter or the like. The output of a step-down chopper (4) for applying a voltage to a metal halide lamp (DL) is several hundred volts necessary for intermittently glow-discharging the lamp to a DC voltage of about 100 V, which is the voltage required for glow arc transition of the discharge lamp. The step-up chopper 3 and the step-down chopper 4 are controlled by the control circuit 6 so as to have a waveform to which the pulse voltage is applied.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lighting device for lighting a high-pressure discharge lamp and the like, and a lighting device.

[0002]

2. Description of the Related Art Conventionally, a high-pressure discharge lamp, particularly a metal halide lamp, etc. has a very high starting voltage, and the lamp is turned on by applying a high-voltage pulse. For this reason, an igniter has been used to generate a high-voltage pulse necessary for lighting the lamp.

However, application of such a high-voltage pulse not only deteriorates the electrodes in the arc tube, but also causes deterioration of components due to the high-voltage pulse and the secondary voltage, causes of ambient noise, and the risk of electric shock to the user. there were.

For this reason, Japanese Unexamined Patent Publication No. Hei 7-201484 discloses a high effective voltage (ie, a high effective voltage boosted by a step-up transformer at the time of lamp lighting) as a lighting device for starting a high pressure discharge lamp without applying a high voltage pulse. A lighting device for a discharge lamp (conventional example 1) for applying a voltage of about several hundred volts at a low frequency is described.

[0005]

However, in the case of the prior art 1, since a high voltage is output as a secondary voltage, a special case is required when installing a lighting device incorporating such a discharge lamp lighting device. Grounding must be applied. In other words, the electrical equipment standards stipulate that lighting equipment with an effective output voltage (2 seconds or more) of 300 V or more and a lamp current of 1 A or more be provided with special third-class grounding. Therefore, in the case of Conventional Example 1, the special third type grounding is often required. The necessity of such grounding alone increases the cost of the lighting equipment and complicates the installation work.

In order to reduce the complexity of grounding work and the like, Japanese Unexamined Patent Application Publication No. Hei 8-102378 discloses a method in which an igniter is used in order to reduce the effective value of the output voltage of a discharge lamp lighting device to less than 300 V. A discharge lamp that is lit by intermittently applying a high-voltage pulse voltage generated from the igniter to a high-pressure discharge lamp by using an igniter mainly composed of a voltage doubler rectifier circuit and control means for supplying a voltage to the igniter discontinuously. A lighting device (conventional example 2) is described.

However, in the conventional example 2, since the high-voltage pulse voltage is intermittently applied to the discharge lamp,
Even if it contributes to the glow discharge of the high-pressure discharge lamp, it does not shift to the arc discharge, that is, a problem such as that the lamp is easily extinguished may occur.

Accordingly, an object of the present invention is to provide a lighting device and a lighting device which reliably light a high-pressure discharge lamp without using a special igniter device, and which eliminates complexity such as grounding work.

[0009]

A lighting device according to a first aspect of the present invention comprises a DC power supply; a variable output chopper circuit which is supplied with a voltage from the DC power supply and outputs a predetermined DC voltage; and an output of the chopper circuit. Control means for outputting a voltage in which a pulse voltage is intermittently superimposed on a DC voltage when the lamp is started, and outputting a continuous DC voltage after the lamp is turned on.

A lighting device according to a second aspect of the present invention is a lighting device comprising: a DC power supply; a variable output chopper circuit which is supplied with a voltage from the DC power supply and outputs a predetermined DC voltage; A polarity reversing circuit for converting the voltage to a voltage that reverses the polarity and supplying the voltage to the lamp; controlling the output of the chopper circuit to output a voltage in which a pulse voltage is intermittently superimposed on the DC voltage when the lamp is started, and after the lamp is turned on. And control means for outputting a continuous DC voltage.

In the present invention and each of the following inventions, definitions and technical meanings of terms are as follows unless otherwise specified.

The DC power supply may be either a rectified DC power supply in which AC is rectified or a battery power supply.

As the discharge lamp, a mercury lamp, a metal halide lamp, a ceramic metal halide lamp and the like are allowed.

The chopper circuit allows a step-up chopper and a step-down chopper, and also includes, for example, a current limiting inductance as ballast means for compensating for the load characteristics of the discharge lamp.

An AC lighting discharge lamp can be used as a load at the output end of the chopper circuit by using a polarity inversion circuit. The polarity inversion circuit allows to form a full bridge circuit and a half bridge circuit, and the switching elements forming these circuits are field effect transistors (FE).
T) can be used. It is also possible to use a DC lighting discharge lamp as a load without using a polarity inversion circuit.

A portion including a current limiting inductance may be connected in series to a discharge lamp as a load at an output terminal of the polarity inversion circuit.

The control means has, for example, a function of detecting the output voltage of the chopper circuit to determine whether the power is turned on and whether or not the lamp is turned on. In addition, it includes a function of outputting a voltage obtained by intermittently superimposing a pulse voltage as a DC voltage of the chopper circuit after power-on and when there is no load, and a function of continuously outputting a DC voltage as an output voltage after the lamp is turned on. . The power supply of the control means allows the output end of the DC power supply or the output end of the step-up chopper to be divided or changed in voltage via a transformer, and also to be supplied from a separate power supply.

The control means can determine whether the lamp is lit or not, for example, by detecting the output voltage of the chopper circuit. When the lamp is not lit, the output of the chopper circuit appears as it is, but when the lamp is lit, the lamp voltage appears. In addition, the presence or absence of lighting of the lamp can be detected by detecting current, light, heat, and the like.

After the power is turned on and when there is no load, the control means intermittently causes the output of the chopper circuit to glow discharge the discharge lamp to a voltage required for glow arc transition of the discharge lamp, for example, a DC voltage of about 100 V. Control is performed so that a pulse voltage, for example, a voltage obtained by intermittently superimposing several hundred volts is output for about 2 msec. By applying a voltage to the lamp in this way, the lighting of the discharge lamp can be ensured. After the lamp is lit, the output voltage of the chopper circuit is controlled so that the discharge lamp can be lit stably.
For example, by continuously applying a voltage to the discharge lamp so as to be about 100 V, the discharge lamp can be stably lit.

The peak value and width required for starting the discharge lamp vary depending on the type of the discharge lamp. Although the above example is an example of a pulse required for lighting a metal halide lamp rated at 250 W, it is known that a higher pulse voltage is required when lighting a high-pressure sodium lamp. , The type of lamp, and the like.

Further, by using a microcomputer for the control means, the circuit can be simplified and downsized. Also,
By using the microcomputer, it is possible to monitor the power supply voltage, detect an abnormality in the circuit, and stop the step-down chopper, and also to protect the lighting device.

According to the first aspect of the present invention, at the time of starting the discharge lamp, a pulse voltage intermittently superimposed on the DC voltage can be applied. By applying such a voltage to the discharge lamp, a glow discharge is generated between the electrodes of the discharge lamp by the superimposed high-voltage pulse, and the transition from the glow discharge to the arc discharge by the potential of the DC voltage can be ensured. The discharge lamp can be turned on.

Further, since it is not necessary to apply a high voltage pulse more than necessary, it is possible to reduce the deterioration of components due to the high voltage pulse, the surrounding noise and the risk of electric shock to the user.

According to the invention of claim 2, according to claim 1,
In addition to the effects of the invention, the present invention is effective for a lighting device of a discharge lamp of AC lighting.

A lighting device according to a third aspect of the present invention is the lighting device according to the first or second aspect, wherein the control means controls the output voltage of the chopper circuit to have an effective value of less than 300V.

According to the present invention, in addition to the effects of the first and second aspects, the output of the lighting device is controlled so as to have an effective value of less than 300 V, so that special grounding is unnecessary or simplified. Can be.

A lighting device according to a fourth aspect of the present invention includes a lighting device main body; and the lighting device according to any one of claims 1 to 3 supported by the lighting device main body.

In the present invention, the lighting device means any device utilizing the light emission of a discharge lamp, and includes, for example, a lighting fixture, a backlight such as a liquid crystal, a headlight for an automobile, and the like.

According to the fourth aspect of the present invention, since the lighting device according to any one of the first to third aspects is used, the discharge lamp can be reliably turned on, and special grounding work is unnecessary or simple. A lighting device that can perform the lighting.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a lighting device according to the present invention will be described with reference to the drawings. FIG. 1 is a circuit diagram of a lighting device, and FIG.
FIG. 3 is a diagram showing a circuit operation waveform.

In the lighting circuit diagram of FIG. 1, a rectifier circuit 2, a step-up chopper 3, a step-down chopper 4, and a load circuit 5 are sequentially connected to the secondary side of an AC power supply 1.

The AC power supply 1 is a commercial 200 V AC power supply.

Although not shown, the rectifier circuit 2 includes a noise prevention circuit, a bridge type full-wave rectifier circuit, a smoothing circuit, etc., and rectifies a commercial AC power supply and outputs a DC power supply.

In the step-up chopper 3, a series circuit of an inductance L3 and a switching element Q3 is connected to the rectifier circuit 2. A smoothing capacitor C3 is connected to both ends of the switching element Q3 via a backflow preventing diode D3. The switching element Q3 uses a field effect transistor (FET),
The drain of the transistor 3 is connected between the inductance L3 and the diode D3, and the source of the FET Q3 is connected to one end of the capacitor C3 and the negative output terminal of the rectifier circuit 2. FET Q3
Are connected to the control means 6. The step-up chopper 3 controls the output of the voltage applied to the capacitor C3 by controlling the switching frequency and the ON period of the switching element Q3.

When the FET Q3 is turned on, a current flows from the rectifier circuit 2 to the inductance L3 to accumulate energy, and when the FET Q3 is turned off, an induced electromotive force is generated in the inductance L3, which is superimposed on the output of the rectifier circuit 2. And the capacitor C via the diode D3
3 is charged. Therefore, the capacitor C3 is charged with a DC voltage obtained by boosting the output voltage of the rectifier circuit 2. By controlling the ON / OFF time of the switching of the FET Q3, it is possible to output a boosted voltage by controlling the accumulation of energy of the inductance L3.

The step-down chopper 4 is constructed by connecting a diode D4 between the FET Q4 and the inductance L4 connected in series, between the FET Q4 and the inductance L4, and at the other end of the output of the step-up chopper 3. Step down the voltage to the desired voltage. In addition, in order to prevent flickering during lighting of the high-pressure discharge lamp, the high-frequency discharge lamp has a function of superimposing a high frequency on a DC voltage by switching the FET Q4.

The output end of the step-down chopper-4 is
Voltage dividing resistors R41 and R42 for voltage detection are connected in series to the other end of the inductance L4 and the negative terminal of the diode D4. The inductance L4 of the step-down chopper 4 is also used as a current limiting inductance for stably lighting the lamp.

A load circuit 5 including a high-pressure discharge lamp DL is provided at the output end of the step-down chopper 4. Load circuit 5
Is composed of a full-bridge circuit 51 including four field-effect transistors (FETs) Q51, Q52, Q53, and Q54 as a polarity inversion circuit, and a high-pressure discharge lamp DL connected to an output terminal of the full-bridge circuit 51. I have.

Q5 of the FETs of the full bridge circuit 51
1, when Q53 is turned on and Q52 and Q54 are turned off, a DC voltage appears at the output terminal of the full bridge circuit 51, then Q51 and Q53 are turned off, and Q52 and Q5 are turned off.
When 4 is on, a reverse voltage appears as before. Further, a noise prevention capacitor C2 is connected in parallel with the high-pressure discharge lamp DL.

The control means 6 uses a microcomputer. The power of the control means 6 is supplied from the output of the step-up chopper 3 via the transformer T.

The output of the step-down chopper 4 is input to the control means 6 through the voltage dividing resistor R2 to determine whether the high-pressure discharge lamp DL is turned on and whether the AC power supply 1, the step-up chopper 3 and the step-down chopper 4 are abnormal or normal. And so on.

The control means 6 controls the connected FETs Q3, Q
4 has a function of controlling the output of the step-up chopper 3 and the step-down chopper 4 by controlling the switching. Further, the full bridge circuit 51 is controlled by the control means 6.
Field-effect transistors (FETs) Q51, Q5
2, by outputting signals to the gates of Q53 and Q54, respectively, so that the FETs Q51, Q52, Q53 and Q54
By performing the switching control, the operation of the full bridge circuit 51 is controlled.

Each output waveform diagram of FIG. 2 is shown. The boost chopper 3 outputs a DC voltage of 600 V until the lighting of the lamp is confirmed by the control means 6 after the power is turned on. Further, the step-down chopper 4 converts the DC voltage of 100V to 60V.
The pulse voltage of 0 V (pulse width 2 msec) is output so that the pulse interval becomes about 100 Hz. At this time, the full bridge circuit 51 is also operated at about 100 Hz.
The output of the full bridge circuit operates as shown.

When the high-pressure discharge lamp DL is turned on, a lamp voltage appears at the output terminal of the step-down chopper 4, so that the output voltage of the step-down chopper 4 decreases. This voltage is detected by the voltage dividing resistor R42, and lighting of the high-pressure discharge lamp DL is confirmed. Thereafter, the control means 6 reduces the output of the boost chopper 3 to 400 V, and the step-down chopper 4 controls the output voltage to be the rated voltage of the high-pressure discharge lamp DL. The full bridge circuit 5 includes Q51, Q
53 and Q52, Q54 are alternately switched to apply a rectangular wave of about 100 Hz to the high-pressure discharge lamp DL.

Using such a lighting device, a rating of 250
When the W metal halide lamp was turned on, it was confirmed that all 10 lamps were turned on within 2 seconds. When the lighting device is operated in this way, the effective value of the secondary voltage of the lighting device is 200 Vrms before lighting, and 100 Vrms after lighting, and the effective value of the secondary voltage of the lighting device is less than 300 V. Therefore, grounding can be simplified.

A second embodiment of the present invention will be described with reference to FIG. FIG. 3 shows a lighting device 7 in which a metal halide lamp DL having a rating of 250 W is mounted on the lighting device 73 of the first embodiment.

The lighting device 7 includes a reflection shade 71, a socket 72
And a lighting device 73. The base 4 of the metal halide lamp DL is used by being mounted on a socket 72 of a lighting device. A secondary output terminal of a lighting device 73 is connected to the socket 72 to supply power to the metal halide lamp DL. The lighting device 7 is supported by a ceiling surface 70.

In the lighting device thus configured, there is no need for special third-class grounding work, and the grounding work can be simplified.

[0048]

According to the first or second aspect of the present invention, without using a complicated circuit such as an igniter and applying an excessive pulse voltage to a lamp as in the related art,
A lighting device for reliably lighting a discharge lamp can be provided.

According to the third aspect of the invention, in addition to the effect of the first aspect, the effective value of the output voltage of the lighting device is 300
Since it is less than V, no special grounding is required, so that installation work and the like can be simplified.

According to the fourth aspect of the present invention, it is possible to provide a lighting device having the effect of the first aspect of the present invention.

[Brief description of the drawings]

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

FIG. 2 is a diagram showing circuit operation waveforms of the lighting device according to the first embodiment of the present invention.

FIG. 3 shows a lighting device according to a second embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 commercial AC power supply 2 rectifier circuit 3 step-up chopper 4 step-down chopper 5 load circuit 51 full-bridge circuit DL high-pressure discharge lamp 6 control means

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Isao Abe 4-3-1 Higashishinagawa, Shinagawa-ku, Tokyo Toshiba Litec Co., Ltd. F-term (reference) 3K072 AA13 BA05 BB10 DD02 DD03 DD06 EA07 EB05 GA02 GB12 GB18 GC04 3K082 AA55 AA76 BA06 BA19 BA43 BC23 BD03 BD23 BD26 BD32 BE10 CA33

Claims (4)

[Claims] A DC power supply; a variable output chopper circuit supplied with a voltage from the DC power supply and outputting a predetermined DC voltage; controlling an output of the chopper circuit, and intermittently converting to a DC voltage when the lamp is started. Control means for outputting a voltage on which a pulse voltage is superimposed and outputting a continuous DC voltage after the lamp is turned on. 2. A DC power supply device; a variable output chopper circuit which is supplied with a voltage from the DC power supply device and outputs a predetermined DC voltage; and receives an output voltage of the chopper circuit and converts it into a voltage whose polarity is alternately inverted. A polarity reversing circuit for supplying the lamp to the lamp; controlling the output of the chopper circuit to output a voltage in which a pulse voltage is intermittently superimposed on the DC voltage when the lamp is started, and to output a continuous DC voltage after the lamp is turned on. Control means for controlling the lighting device. 3. The lighting device according to claim 1, wherein the control means controls the output voltage of the chopper circuit to have an effective value of less than 300V. 4. A lighting device comprising: a lighting device main body; and the lighting device according to claim 1 supported by the lighting device main body.