JP3310314B2 - Lighting device for high pressure discharge lamp - Google Patents

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 a high pressure discharge lamp for starting and lighting a high pressure discharge lamp such as a metal halide lamp, a mercury lamp and a high pressure sodium lamp.

[0002]

2. Description of the Related Art FIG. 8 shows a typical example of a lighting circuit for a high-pressure discharge lamp. This circuit has four switching elements Q _{1 to} Q ₄
And an igniter unit IGN for generating a high-voltage pulse voltage for starting the lamp L, which is a high-pressure discharge lamp.

[0003] Switching element Q₁~ Q_FourOperation of FIG.
As shown in FIG. _ThreeAnd Q_FourBut
For example, it operates at a low frequency of 100 to several hundred Hz (FIG. 9).
(C) (d)), switching element Q₁And Q_TwoBut an example
For example, it operates at a high frequency of about several tens KHz (FIG. 9A)
(B)). Switching element Q₁~ Q_FourBehavior of the timing
The switching element Q shown in FIG._ThreeIs on
When the switching element Q_TwoRepeats on / off operation,
Conversely, switching element Q_FourIs switched on when
Element Q₁Repeats the on / off operation.

As a result, the lamp L is shown in FIG.
Such a switching element Q_Three, Q _FourSame frequency as low
Frequency lamp current I_LFlows. Next, FIG.
The operation will be described. Switching element Q at start₁
~ Q_FourIs also the same as during the lighting described above. However
Before the lamp L is turned on, the lamp current I_LFlows
Therefore, the peak value of both ends of the lamp L is almost
Source voltage V₁A rectangular wave voltage close to the above is generated.

Next, the switch SW of the igniter section IGN
_{When 2} is turned on, the power supply voltage V ₂ is boosted by the booster circuit 1 to charge the capacitor C ₂ . As the charging of the capacitor C ₂ progresses, the voltage across V _C2 of the capacitor C ₂ rises as shown in Figure 10 (a). When the voltage V _C2 reaches the discharge starting voltage V _GAP of the discharge gap GAP, the electric charge stored in the capacitor C ₂ is discharged through the primary winding of the pulse transformer PT.
Has a high-voltage pulse voltage Vp corresponding to the turns ratio.
Occurs.

The high-voltage pulse Vp is applied to both ends of the lamp L via a bypass capacitor C ₁ ,
Starts. As an example, in order to start the lamp L, a pulse voltage of about 2000 to 4000 V is usually required. In addition, while this type of lamp is lit, the pressure in the lamp tube has reached several atmospheres or more. Immediately after the lamp is turned off, a high-voltage pulse voltage of about 10 KV to several tens of KV is required to immediately relight the lamp. Become.

As an igniter for generating such a high voltage, a circuit configuration using a discharge gap GAP as shown in FIG. 8 is often used. For example, the discharge gap GA
If the discharge start voltage of P is set to several KV and the turns ratio of the pulse transformer PT is set to about 1:10, a high-voltage pulse voltage of about tens of KV can be obtained at the output of the pulse transformer PT.

[0008]

In an igniter section IGN using a discharge gap GAP as shown in FIG. 8, normally, as shown in FIG.
Is repeated, and a pulse voltage is continuously generated until the lamp L is started. However, the discharge gap GAP
The arc extinction performance of the discharge gap GAP is reduced due to its own characteristic variation, change over time, ambient environment such as temperature and humidity, etc., and as shown in FIG. (FIG. 11A), the high-voltage pulse voltage Vp may be generated only in the first shot (FIG. 11B).

The lamp L is driven by the first high-voltage pulse V
If the engine does not start at p, not only does the faulty state continue, but if this state continues for a long time, the discharge gap GAP is almost short-circuited, so that the discharge gap GAP deteriorates due to abnormal heat generation and the booster circuit 1 is overloaded. And may cause a failure. Also, there is a circuit filed by the applicant that operates the igniter intermittently to prevent sustained discharge.However, the control circuit is complicated, and a stop circuit is required to stop the operation of the igniter after the lamp is turned on. Problem.

There is also a method of detecting the pulse voltage and stopping the igniter for a certain period of time, but the configuration becomes complicated. The present invention has been made in view of the above points, and provides a lighting device for a high-pressure discharge lamp which has a simple configuration and is intended to prevent a sustained discharge of a discharge gap of an igniter operated by an output of an inverter. Is what you do.

[0011]

SUMMARY OF THE INVENTION The present invention provides at least two
An inverter circuit that consists of one or more switching elements and outputs a high-frequency voltage to light the discharge lamp is provided, a booster circuit that charges the capacitor when the discharge lamp is started, and a capacitor charging voltage that reaches the discharge start voltage of the discharge gap in a high pressure discharge lamp lighting device provided with an igniter portion comprising a pulse transformer for applying a high pulse voltage to the discharge lamp when the intermittent from the inverter circuit power to the igniter portion
It was supplied, the power supply from the inverter circuit to the igniter portion
It is a supply stop period of what was set to be longer than the arc-extinguishing time of the discharge gap.

According to the second aspect, the output of the inverter circuit is provided.
Igniter section from the power through a diode for half-wave rectification
During the period when the output of the inverter circuit is a positive half-wave,
During which the output of the inverter circuit is a negative half-wave
Is the supply suspension period . Further, claim 3
Then, from the output of the inverter circuit, a diode for full-wave rectification
Of the inverter circuit to the igniter
Supply power during both periods when the output is a positive or negative half-wave,
The dead time between the two periods is determined by the supply suspension period.
It was something between . In claim 4, when no load is applied,
DC power from the motor circuit to the igniter
Things.

[0013]

Therefore, even if the discharge gap is continuously discharged , the supply of power from the inverter circuit to the igniter section is stopped.
Since the stop period is set to be longer than the arc extinguishing time of the discharge gap, the sustained discharge of the discharge gap can be stopped. Can provide a lighting device for a high-pressure discharge lamp with a good performance.

According to a second aspect of the present invention, a power supply for the igniter unit is provided.
From the inverter circuit through the diode for half-wave rectification
Supply and the period when the output of the inverter circuit is a negative half-wave.
Being set longer than the arc extinction time of the discharge gap
During the negative half-wave period of the inverter circuit.
Since the operation of the iter part has been stopped,
Continuous discharge can be stopped, and therefore, with a simple configuration
Sustained discharge in the discharge gap of the igniter can be prevented,
It is possible to provide a lighting device for high pressure discharge lamps with good mobility.
Wear. According to the third aspect of the present invention , the power of the igniter unit is supplied from the inverter circuit via the diode bridge, and the dead time of the inverter circuit is set to be longer than the extinction time of the discharge gap. Since the operation of the igniter section is stopped during the period, the continuous discharge of the discharge gap can be stopped, and therefore, the sustained discharge of the discharge gap of the igniter section can be prevented with a simple configuration, and the high voltage with good startability can be prevented. A lighting device for a discharge lamp can be provided.

Furthermore, in the fourth aspect, the DC power from the inverter circuit when no load is intermittently supplied to the igniter portion,
Power supply stop period from inverter circuit to igniter section
By setting the interval to be longer than the arc extinguishing time of the discharge gap, the sustained discharge can be stopped even if the discharge gap is sustained, so that the discharge gap of the igniter section can be sustained with a simple configuration. Can be prevented and a lighting device for a high pressure discharge lamp having good startability can be provided.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a circuit configuration of the present embodiment, FIG. 2 shows an operation waveform diagram, and FIG. The circuit of FIG. 1 is the same as the four-bridge full-bridge circuit shown in the conventional example, and the igniter unit IGN is configured to operate with the voltage between the outputs a and b of the bridge circuit.

At the time of starting (at the time of no load), a rectangular wave voltage Vab as shown in FIG. If rectifies the square wave voltage Vab by the diode D _5, the voltage of point c rectangular wave voltage Vcb next half-wave as shown in FIG. 2 (b), the rectangular wave voltage Vcb to the boosting circuit 1 of the igniter portion IGN input. As a result, the igniter unit IGN operates only during the period T ₁ of the FIG. In this T ₁ becomes period, charges are accumulated in the capacitor C _2,
As shown in FIG. 2 (c), the both-ends voltage V _C2 rises, and when it reaches the discharge starting voltage V _GAP of the discharge gap GAP, the discharge gap GAP is discharged. On the secondary side, a high-voltage pulse voltage Vp is generated and applied to the lamp L as shown in FIG.

[0018] At this time, event, even the discharge gap GAP is sustained arc, at T ₂ becomes the period (period power supply to the booster circuit 1 is stopped), since stopping the operation of the igniter portion IGN, Naturally, the continuous discharge of the discharge gap GAP also stops. This operation is repeated until the lamp L is turned on, so that the lamp L can be started immediately. Incidentally, T ₂ becomes time, the discharge gap GAP
Is set to a value sufficient to stop the sustained discharge of.

FIG. 3 shows a specific example of the booster circuit 1.
This circuit is commonly known as a one-stone self-excited
Live-back converter (RCC: Ringing choke)
 Converter). This behavior is very general
Since the circuit is a typical circuit, the details are omitted,
explain. DC voltage between inputs a and b
Q_FiveHigh frequency switching with flyback transformer F
BT tertiary winding n_ThreeAt both ends of the primary winding n ₁And tertiary winding n
_ThreeA high voltage corresponding to the turns ratio of the
Code D₇Rectified by the capacitor C_TwoDC high voltage
Circuit for

The flyback transformer FBT has 2
The winding n ₂ is provided, and a switching element Q ₅ so as to operate in self-excited. At no load, the voltage between a and b is
Although the igniter unit IGN operates at approximately the input voltage V ₁ , the voltage between a and b becomes approximately the lamp voltage after the lamp L is turned on, and decreases to ２〜 to １ ／ of the input voltage V ₁ . since the switching element Q ₅ does not start by the action of the Zener diode ZD ₁ of the booster circuit 1, the lamp L
After the lighting, the operation of the igniter unit IGN automatically stops, the generation of the pulse stops, and the lamp L keeps lighting stably.

(Embodiment 2) FIG. 4 shows a circuit diagram of Embodiment 2.
FIG. 5 shows an operation waveform diagram thereof. Points of this embodiment
Is the switching element Q₁~ Q_FourDead time T_Dof
When the continuous discharge of the discharge gap GAP is stopped during the period
At the time. Generally this type of full bridge circuit
The switching element Q₁, Q_ThreeAnd Q_Two, Q_FourIs the same
When it is turned on sometimes, the power supply V₁Short-circuited and the switch
Ching element Q₁~ Q_FourDestroys. To prevent this
The switching element Q_ThreeAnd Q _FourSwitching the operation of
The switching element Q₁~ Q_FourAll will be turned off
Good time T_DIn general, a certain period is provided.

[0022] In this embodiment, positively utilizing the dead time T _D becomes period, is set more than the time required to extinguishing of the dead time T _D becomes period a discharge gap GAP, duration of the discharge gap GAP Discharge is stopped. In the circuit of FIG. 4, a diode bridge circuit DB is provided in the input section, and is operated by full-wave rectification.
As a result, more pulses can be generated than in the previous embodiment, and the starting performance can be further improved.

The circuit configuration of the bridge and the booster circuit 1
May be the same as in the previous embodiment. (Embodiment 3) Embodiment 3 is shown in FIG. In this embodiment, the switching elements Q ₆ and Q ₇ are used instead of the full bridge configuration.
In addition, a half-bridge circuit configuration is formed by the capacitors C ₅ and C _{6 and the} like. Note that the configuration and operation of the igniter unit IGN are the same as those in the first and second embodiments, and thus description thereof will be omitted.

(Embodiment 4) In Embodiment ₄ , the operation of the switching elements Q _{1 to} Q ₄ at the time of no load in the circuit of FIG. 1 is operated as shown in FIG. That is, the switching elements Q ₂ and Q ₃ are always off (FIGS. 7 (b) and 7 (c)), the switching element Q ₄ is always on (FIG. 7 (d)), and the switching element Q ₁ is in a certain idle period T _D. Is provided (FIG. 7A), and an on / off operation is performed at a high frequency of about several tens KHz.

[0025] At this time, the output voltage Vab of the inverter is as shown in FIG. 7 (e), to operate step-up circuit 1 at this voltage, as described in Example 1, is charged capacitor C _2, When the voltage V _C2 reaches the discharge starting voltage V _GAP , a high-voltage pulse voltage Vp is generated (FIGS. 7F and 7G). At this time, the discharge gap GAP is unlikely even if the sustained discharge, by providing the stoppage period T _D, it is possible to stop the sustained discharge, can be generated continuously and stably high pulse voltage Vp was Becomes After the lamp L is turned on, if the operation of the switching elements Q _{1 to} Q ₄ is switched as in the _first embodiment, a rectangular wave current alternating at the same frequency as the switching elements Q ₃ and Q ₄ flows through the lamp L. Maintain stable lighting.

[0026]

As described above, according to the present invention, there is provided an inverter circuit which is composed of at least two or more switching elements, outputs a high-frequency voltage to light a discharge lamp, and charges a capacitor when the discharge lamp is started. igniter when, in the high pressure discharge lamp lighting device provided with an igniter portion comprising a pulse transformer for applying a high pulse voltage to the discharge lamp when the charging voltage of the capacitor reaches the discharge starting voltage of the discharge gap, the power from the inverter circuit Intermittent in the department
It is supplied to, the power supply from the inverter circuit to the igniter portion
Since the supply suspension period is set to be longer than the arc extinguishing time of the discharge gap, even if the discharge gap is continuously discharged, the continuous discharge of the discharge gap can be stopped. It is possible to prevent a sustained discharge in the discharge gap of the igniter section, and to provide a lighting device for a high-pressure discharge lamp with good startability.

According to a second aspect of the present invention, a power supply for the igniter unit is provided.
From the inverter circuit through the diode for half-wave rectification
Supply and the period when the output of the inverter circuit is a negative half-wave.
Being set longer than the arc extinction time of the discharge gap
During the negative half-wave period of the inverter circuit.
Since the operation of the iter part has been stopped,
Continuous discharge can be stopped, and therefore, with a simple configuration
Sustained discharge in the discharge gap of the igniter can be prevented,
It is possible to provide a lighting device for high pressure discharge lamps with good mobility.
Wear. According to the third aspect of the present invention , the power of the igniter unit is supplied from the inverter circuit via the diode bridge, and the dead time of the inverter circuit is set to be longer than the extinction time of the discharge gap. Since the operation of the igniter section is stopped during the period, the continuous discharge of the discharge gap can be stopped, and therefore, the sustained discharge of the discharge gap of the igniter section can be prevented with a simple configuration, and the high voltage with good startability can be prevented. A lighting device for a discharge lamp can be provided.

Furthermore, in the fourth aspect, the DC power from the inverter circuit when no load is intermittently supplied to the igniter portion,
Power supply stop period from inverter circuit to igniter section
By setting the interval to be longer than the arc extinguishing time of the discharge gap, the sustained discharge can be stopped even if the discharge gap is sustained, so that the discharge gap of the igniter section can be sustained with a simple configuration. Can be prevented and a lighting device for a high pressure discharge lamp having good startability can be provided.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of an embodiment of the present invention.

FIG. 2 is an operation waveform diagram of FIG.

FIG. 3 is a specific circuit diagram of the booster circuit.

FIG. 4 is a block circuit diagram of an igniter according to the second embodiment.

FIG. 5 is an operation waveform diagram of FIG.

FIG. 6 is a circuit diagram of a third embodiment of the present invention.

FIG. 7 is an operation waveform diagram of the fourth embodiment.

FIG. 8 is a circuit diagram of a conventional example.

FIG. 9 is an operation waveform diagram of FIG.

FIG. 10 is an operation waveform diagram of the above.

FIG. 11 is an operation waveform diagram when a sustained discharge is generated as in the first embodiment.

[Explanation of symbols]

1 booster circuit Q ₁ switching element Q ₂ switching element Q ₃ switching element Q ₄ switching elements L lamp C ₂ capacitors PT pulse transformer D ₅ diodes IGN igniter unit

Claims (4)

(57) [Claims] An inverter circuit comprising at least two switching elements for outputting a high-frequency voltage and lighting a discharge lamp is provided, a booster circuit for charging a capacitor when the discharge lamp is started, and a charging voltage for discharging the capacitor. in a high pressure discharge lamp lighting device provided with an igniter portion comprising a pulse transformer for applying a high pulse voltage to the discharge lamp when reaching the discharge start voltage of the gap, or the inverter circuit
A lighting device for a high-pressure discharge lamp, characterized in that power is intermittently supplied to the igniter section, and a period in which the supply of power from the inverter circuit to the igniter section is stopped is set to be longer than an arc extinguishing time of the discharge gap. 2. An output from an inverter circuit for half-wave rectification.
The inverter circuit is connected to the igniter via a diode.
Supply power during the period when the output is a positive half-wave, and
The lighting device for a high pressure discharge lamp according to claim 1, wherein a period during which the output of the circuit is a negative half-wave is defined as the supply suspension period . 3. An output of an inverter circuit for full-wave rectification.
Inverter to igniter section via diode bridge
Power supply during both periods when the output of the
And the dead time between the two
The lighting device for a high-pressure discharge lamp according to claim 1, wherein the supply suspension period is set. 4. A DC power supply from an inverter circuit when there is no load.
Supply intermittently to the igniter section
The lighting device for a high pressure discharge lamp according to claim 1.