JPH06275385A - Discharge lamp lighting device - Google Patents

Abstract

PURPOSE:To provide a discharge lamp lighting device capable of preventing the deterioration of a winding, etc., due to overcurrent by detecting the drop of lamp voltage due to the leakage of enclosed gas in a very short time to extinguish a discharge lamp. CONSTITUTION:A high-pressure pulse generator 1 is constituted so as to generate a high-pressure pulse having pulse energy lower than pulse energy required for lighting a normal lamp and higher than pulse energy required for lighting a life lamp for a fixed duration after a power source is turned on. Also a pulse control circuit 5 is constituted so as to detect the pulse energy of the high- pressure pulse generator 1 at the moment of the lighting of a discharge lamp LA based on the output of a control circuit 3 controlling the high-pressure pulse generator 1 and the output of a lamp current detection circuit 4. A relay contact Ry1 is constituted so as to interrupt electric power feeding to a discharge lamp 1A when the discharge lamp LA is lit within fixed duration after a power source is turned on based on the output of the pulse control circuit 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is started by a high-pressure pulse, the gas enclosed in the arc tube is gradually released (slow leak), and the lamp voltage is kept lower than the rated value at the end of its life. The life of discharge lamps that have a life mode in which overcurrent flows to the lighting device, and the pulse energy required for starting will be lower than normal when in the life mode, for example, high color rendering small metal halide lamps The present invention relates to a discharge lamp lighting device capable of detecting a mode and turning off a discharge lamp.

[0002]

2. Description of the Related Art FIG. 6 shows a conventional discharge lamp lighting device of this type.
A basic circuit diagram is shown. This discharge lamp lighting device
Source V_SAnd the power switch S₁And Cho, which is a current limiting element
Inductance element L such as coil₁And the pulse tran
PT₁, Capacitor C₁, C ₂, Resistance R₁And both
Tropic thyristor Q₁High-voltage pulse generator 1 consisting of
It is a general lighting device including an electric lamp LA.

[0003] high-voltage pulse generator 1, the energy stored in the capacitor C ₁ by a time constant circuit of the capacitor C ₁ and resistor R _1, to turn on the bidirectional thyristor Q ₁ in phase with the commercial power supply V _S The capacitor C _1- primary winding of the pulse transformer PT _1- capacitor C ₂ -bidirectional thyristor Q ₁ -capacitor C ₁ is discharged in a closed circuit, at which time ₁ of the pulse transformer PT ₁ is discharged.
Due to the electromotive force generated in the secondary winding, the pulse transformer PT ₁
A high-voltage pulse corresponding to the winding ratio is generated in the secondary winding of the discharge coil LA, and the discharge lamp LA is started and turned on.

The control power source 2 is a commercial power source V._SStep down / adjust
DC power supply voltage V_CCIs also applied to other circuits
So the step-down transformer T₁, Full wave rectifier DB₁,resistance
R₂, R ₃, Diode D₁And capacitor C₃From
Become. The control circuit 3 receives the DC power supply voltage V from the control power supply 2.
_CCIs applied and operates, the bidirectionality of the high-voltage pulse generator 1
Thyristor Q₁For general-purpose timers
Product circuit (eg NEC's μPC617) IC₁,
Anti-R_Four~ R₈， Pulse transformer PT₂, Capacitor C_Four
~ C₆, Diode D₂, D₃And transistor Q₂
Bidirectional thyristor Q₁Against
A bidirectional thyristor Q is generated by intermittently generating a trigger pulse.₁
Conducts and transistor Q ₂Turned on
Stop trigger pulse generation.

The general-purpose timer integrated circuit IC ₁ is triggered near the voltage of the commercial power source V _S , which is approximately 0 V, and its output terminal (3
The output of the No. pin) becomes high level for a certain period of time determined by the time constant of the resistor R ₄ and the capacitor C ₄ . Then, at the moment when the output of the 3rd pin changes from the high level to the low level after the lapse of the certain time, the energy stored in the capacitor C ₅ by the series circuit of the resistor R ₅ , the capacitor C ₅ and the diode D ₃ is transferred to the capacitor C _5. C ₅ -Diode D ₂
- third pin for universal timer integrated circuit IC ₁ - 1 winding of the pulse transformer PT ₂ - emitted by closed-circuit of the capacitor C _5, causing that the moment generated in the primary winding of the pulse transformer PT ₂ voltage is transferred to the secondary winding of the pulse transformer PT _2, and triggers the bidirectional thyristor Q _1, to conduct a bidirectional thyristor Q _1.

The lamp current detection circuit 4, which is a lighting discrimination circuit for discriminating the lighting of the discharge lamp LA, judges that the discharge lamp LA has been lit when the discharge lamp LA has lit and the lamp current has flowed above a certain value. The operation of the control circuit 3 is stopped and the generation of the high voltage pulse from the high voltage pulse generator 1 is stopped, and the current transformer PT ₃ , the full wave rectifier DB ₂ , the capacitor C ₇ , the reference voltage source E ₁ and It is composed of a comparator IC ₂ , and when the lamp current flows above a certain value, the output of the comparator IC ₂ outputs the transistor Q.
₂ is turned on to stop the generation of the trigger pulse from the control circuit 3.

Specifically, a comparator IC _{2 including an} operational amplifier converts a lamp current into a voltage by a current transformer PT ₃ , a full-wave rectifier DB ₂ and a capacitor C ₇ and a voltage of a reference voltage source E _1. This is a configuration for comparison, and when the discharge lamp LA is turned on and the lamp current flows above a certain value, the output terminal a of the comparator IC ₂ becomes high level, and it is determined that the discharge lamp LA is turned on.

When the output terminal a of the comparator IC ₂ becomes high level, the transistor Q ₂ in the control circuit 3 is driven through the resistor R ₈ and becomes conductive, and the integrated circuit IC for general-purpose timer IC.
The fourth pin ₁ is set to low level to stop the oscillation operation of the general-purpose timer integrated circuit IC ₁ . 7 (a) to 7 (d) show waveform diagrams of the respective portions of FIG. FIG (a) shows a voltage waveform applied to the second pin of the integrated circuit IC ₁ for general-purpose timer (input trigger), the (b) shows an integrated circuit IC ₁ for general-purpose timer
3C shows the voltage waveform of the output of the third pin, FIG. 7C shows the voltage waveform of the output of the comparator IC ₂ , and FIG. 7D shows the trigger current I flowing in the primary winding of the pulse transformer PT _2. The waveform of _T is shown. That is, only during the low level period of the output of the comparator IC _2, the output of the third pin of the general-purpose timer integrated circuit IC ₁ changes to the low level at a predetermined phase every half cycle of the commercial power supply V _S , and the pulse transformer The trigger current I _T will flow through PT ₁ .

[0009]

By the way, as described above, depending on the type of the discharge lamp LA, the gas enclosed in the arc tube escapes and the lamp voltage is lower than the rated value. There is a life mode in which an overcurrent flows. FIG. 8 shows the load characteristics of the lighting device. In FIG. 8, normally, stable lighting is performed at point A, but when gas is released as described above, it is stable at point B, and a larger current than usual continues to flow, causing inductance element L ₁ and pulse transformer P to flow.
The inconvenience arises that a large stress is applied to T ₁ .
Incidentally, V ₀₂ is the voltage at no load, I _S is the current during a short circuit, V _1, I ₁ is the voltage of the point A, current,
V ₂ and I ₂ are the voltage and current at point A.

Therefore, as a proposal example, as shown in FIG. 9, the thermal protector TP _{1 is connected} to the pulse transformer PT ₁
The secondary winding, the inductance element L _{1 and the} like are mounted on a portion where the temperature rises significantly, and when the temperature rises above a certain temperature, the thermal protector TP ₁ opens to shut off the power. is there. However, even in the configuration of FIG. 9, when the temperature drops after the power is turned off and the thermal protector TP ₁ is closed again, overcurrent continues to flow for a relatively long time until the thermal protector TP ₁ operates again. The temperature of the secondary winding of the pulse transformer PT _1, the inductance element L _1, etc. rises. As described above, in the proposed example, the opening / closing operation of the thermal protector TP ₁ is repeated and the cycle thereof is relatively long, so the windings and the like are gradually deteriorated, and the protection function cannot be said to be sufficient.

Therefore, an object of the present invention is to detect a drop in the lamp voltage due to the escape of the enclosed gas in a very short time and turn off the discharge lamp to prevent the deterioration of the winding or the like due to an overcurrent. An object of the present invention is to provide an electric lamp lighting device.

[0012]

SUMMARY OF THE INVENTION The present invention detects a drop in lamp voltage due to escape of a sealed gas in a very short time and turns off a discharge lamp to prevent deterioration of a winding due to an overcurrent. is there. For example, in a discharge lamp that has a life mode in which it is started with a high-pressure pulse and has a low lamp voltage due to a leak of a sealed gas, such as a high color rendering type small metal halide lamp, once the sealed gas leaks to a low lamp voltage, There is a phenomenon that it is easier to start with a pulse energy that is much less than the pulse energy required for normal starting.

The present invention utilizes the above phenomenon to determine that a discharge lamp started with a very small pulse energy has a low lamp voltage (life mode) and shuts off the power source to make a defect. Is. That is, claim 1
The discharge lamp lighting device described is a discharge lamp, a current limiting inductance element for limiting a lamp current supplied to the discharge lamp, and a high-voltage pulse capable of switching pulse energy for generating a high-voltage pulse for starting the lamp from low to high. In a discharge lamp lighting device including a generator and a lighting determination circuit for detecting lighting of a discharge lamp, pulse energy for detecting pulse energy of a high-voltage pulse generator at the moment when the discharge lamp lights based on the output of the lighting determination circuit. A detection circuit,
And a switch element for cutting off the power supply to the discharge lamp when the amount of pulse energy detected by the pulse energy detection circuit is lower than the lighting energy of the normal lamp.

A discharge lamp lighting device according to a second aspect is the discharge lamp lighting device according to the first aspect, in which a pulse energy required for lighting a normal lamp is lower than a pulse energy for a certain period after power-on.
In addition, the high-voltage pulse generator is configured to generate a high-voltage pulse having a pulse energy higher than the pulse energy required to light the life lamp, and the output of the control circuit that controls the high-voltage pulse generator and the output of the lighting determination circuit The pulse energy detection circuit is configured to detect the pulse energy of the high-voltage pulse generator at the moment when the discharge lamp lights up, and the discharge lamp lights up within a certain period after the power is turned on based on the output of the pulse energy detection circuit. The switch element is configured so as to cut off the power supply to the discharge lamp when this occurs.

A discharge lamp lighting device according to a third aspect of the present invention is the discharge lamp lighting device according to the first aspect, wherein the high voltage pulse generator is configured to gradually increase the pulse energy of the high voltage pulse after the power is turned on.

[0016]

According to the structure of the present invention, in the case of a life lamp,
The normal lamp is lit with a high-voltage pulse having a pulse energy lower than the pulse energy with which the normal lamp is lit. At this time, the switch element is opened to stop the power supply to the discharge lamp and turn off the discharge lamp.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, this discharge lamp lighting device is opened and closed according to the output of the pulse control circuit 5 and the pulse control circuit 5 having a pulse energy detection circuit in addition to the one shown in FIG. 6 to discharge from the commercial power supply V _S. A relay contact Ry ₁ which is a switch element for connecting and disconnecting the power supply to the lamp LA is added, and other configurations are similar to those of the discharge lamp lighting device of FIG. 6.

FIG. 2 shows a specific configuration of the pulse control circuit 5. The pulse control circuit 5 is a general-purpose timer integrated circuit IC.
₃ (same as IC ₁ ), resistor R ₉ and capacitor C ₈ constitute a timer circuit. C ₉ is a capacitor.
The output terminal (3rd pin) of the general-purpose timer integrated circuit IC ₃ is at a high level for a certain period after the power is turned on, and the transistor Q ₃ is made conductive through the inverting circuit IC ₄ for that period. The series circuit of the transistor Q ₃ and the resistor R ₁₀ is the resistor R _{4 of the} control circuit 3.
Connected in parallel to the general-purpose timer integrated circuit IC ₃ and shortens the high-level period of the general-purpose timer integrated circuit IC _{1 while} the output terminal (pin 3) of the general-purpose timer integrated circuit IC ₃ is at a high level (a certain period after power-on).

FIG. 3 shows an operation waveform diagram of each part of the circuit of FIG.
You FIG. 1A shows a general-purpose timer integrated circuit IC₁No. 2 pin
The voltage waveform of (input) is shown.
Product circuit IC₁The voltage waveform of the 3rd pin (output) of
Figure (c) shows a general-purpose timer integrated circuit IC₃Pin 3 of (exit
Force) voltage waveform, and FIG.₁of
Terminal voltage V_C1The waveform of the discharge lamp L is shown in FIG.
Lamp voltage V applied to A _LAShows the waveform of.

As described above, the output terminal of the general-purpose timer integrated circuit IC ₃ is at a high level as shown in FIG. 3C for a certain period after the power is turned on, and the general-purpose timer integrated circuit IC ₃ is in the meantime.
The output terminal of ₁ has a short high level period as shown in FIG. That is, the trigger phase of the bidirectional thyristor Q ₁ advances, and the energy stored in the capacitor C ₁ decreases, so that the pulse energy of the high-voltage pulse decreases as shown in FIGS. 3D and 3E.

On the other hand, when the output end of the general-purpose timer integrated circuit IC ₃ becomes low level after the above-mentioned certain period of time has passed, the high-level period of the output end of the general-purpose timer integrated circuit IC ₁ becomes longer and the capacitor C ₁ becomes The energy storage amount of the pulse energy also increases, and the pulse energy also increases. That is, for a certain period after the power is turned on, a low energy pulse that can start only a life lamp having a low lamp voltage is output, and after a certain period of time, a high energy pulse that can start a normal lamp is generated.

Further, an inverting circuit IC_FourOutput and lamp power
The output (a) of the flow detection circuit 2 is applied to the inverting circuit IC₆Flipped at
Output and NOR gate IC_FiveInput to NOR gate I
C_FiveRelay excitation winding L at the output end of_RYAre connected. N
OR gate IC_FiveIs output for a certain period (IC
_FourOutput lamp is at the low level), the discharge lamp LA is on.
When the lamp is turned on, the output (a) of the lamp current detection circuit 2 becomes high level.
In other words, inversion circuit IC ₆When the output of becomes low level
Only when it becomes high level, the relay excitation winding is momentarily excited.
Normally closed relay contact Ry₁Open the discharge lamp L
Let A disappear.

When the relay contact Ry ₁ is closed after the discharge lamp LA is extinguished, the same operation is repeated again. This repetition period is very short. As described above, when the discharge lamp LA is lit while the pulse energy is relatively low within a certain period after the power is turned on, it is determined that the life mode has been described above, the discharge lamp LA is extinguished early, and the pulse transformer PT ₁ and the inductance are reduced. It is possible to protect the lighting device by preventing deterioration of the winding of the element L ₁ .

A second embodiment of the present invention will be described with reference to FIG. This discharge lamp lighting device is different from the circuit of FIG.
A thermal protector TP ₁ similar to that of the proposed example of FIG. 9 is inserted in series with a power switch S ₁ to provide a thermal protector TP 1.
Close to _1, for example secondary winding of the pulse transformer PT ₁ (or inductance element L ₁ and the like) are arranged, the secondary winding of the pulse transformer PT ₁ (or inductance element L _1, etc.) is a certain temperature or higher and In this case, the thermal protector TP ₁ is opened to shut off the power supply, and other configurations are the same as those of the discharge lamp lighting device of FIG. 1.

In the first embodiment shown in FIG. 1, the discharge lamp LA cannot be extinguished if it is in the life mode while the discharge lamp LA is being lit. By providing the protector TP ₁ , when the life mode is entered during lighting of the discharge lamp LA, _first , the life protector is detected by the thermal protector TP ₁ to temporarily shut off the power source to turn off the discharge lamp LA. After that, when the temperature drops and the thermal protector TP ₁ closes again, this time, before the thermal protector TP ₁ operates, the same operation as in the first embodiment is repeated to open and close the relay contact Ry ₁ to discharge. The operation of turning on / off the lamp LA is repeated at high speed to protect the lighting device and prevent the winding of the pulse transformer PT ₁ and the inductance element L ₁ from being deteriorated.

A third embodiment of the present invention will be described with reference to FIG. The discharge lamp lighting apparatus, instead of the relay L _Ry of 2, using a latching relay LR _1, to connect the set winding L _S of the latching relay LR ₁ to the output terminal of the NOR circuit IC _5, a latching relay LR ₁ Reset winding L
_R is connected to the control power supply voltage V _CC via a capacitor C ₁₀ , and other configurations are the same as those of the embodiment of FIG. 1 or FIG.
It is similar to the embodiment of.

According to the structure of this embodiment, when the power is turned on, the reset winding L _R of the latching relay LR ₁ is excited via the capacitor C ₁₀ , the relay contact Ry ₁ is turned on, and the discharge lamp LA is connected to the discharge lamp LA. Power can be supplied. The discharge lamp LA lights up until a certain period of time passes after the power is turned on (the pulse energy is small), and when the output terminal of the NOR circuit IC ₅ becomes a high level for a moment, the latching relay LR.
The set winding L _{S of 1} is excited, the relay contact Ry ₁ is turned off, and the discharge lamp LA is extinguished. This state continues until the control power supply is reset, the relay contact Ry ₁ remains off, and once the discharge lamp LA goes off, the power switch S ₁ is turned off and then turned on again. The extinguished state of the LA will continue. As a result, the discharge lamp LA is not repeatedly turned on and off at the end of its life, and the lighting device can be reliably protected.

The function and effect other than the above are the same as those of the first and second embodiments. It should be noted that the pulse energy of the high-voltage pulse generator that generates the high-voltage pulse for lamp starting can be switched from low to high, and the pulse energy of the high-voltage pulse generator at the moment when the discharge lamp lights up is detected based on the output of the lighting determination circuit. As a specific configuration of a pulse energy detection circuit that performs, and a switch element that shuts off the power supply to the discharge lamp when the amount of pulse energy detected by the pulse energy detection circuit is lower than the lighting energy of the normal lamp,
In the above-mentioned embodiment, by using the timer means, a high-voltage pulse having a pulse energy lower than the pulse energy required to light the normal lamp and higher than the pulse energy required to light the life lamp for a certain period after the power is turned on. Pulse voltage of the high voltage pulse generator at the moment when the discharge lamp lights up based on the output of the control circuit controlling the high voltage pulse generator and the output of the lighting determination circuit. The pulse energy detection circuit is configured to perform, and the switch element is configured to cut off the power supply to the discharge lamp when the discharge lamp is lit within a certain period after the power is turned on based on the output of the pulse energy detection circuit. However, for the high-voltage pulse generator, instead of the above, gradually increase the pulse energy of the high-voltage pulse after the power is turned on. It may be configured to.

The lighting of the discharge lamp LA can be determined not only by detecting the lamp current, but also by detecting the lamp power, the light of the lamp, or the like.

[0030]

According to the discharge lamp lighting device of the present invention, the pulse energy of the high-voltage pulse generator at the moment when the discharge lamp is lit is detected, and the discharge is performed when the detected amount of pulse energy is lower than the lighting energy of the normal lamp. Since the power supply to the lamp is cut off by the switch element, the gas filled in the arc tube gradually leaks and maintains lighting at a lower lamp voltage than usual, and in a discharge lamp with a life mode in which an overcurrent state exists, Since the life mode can be detected in a very short period of time and the discharge lamp can be extinguished, deterioration of the lighting device itself can be prevented.

[Brief description of drawings]

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

FIG. 2 is a circuit diagram showing a specific configuration of a main part of the discharge lamp lighting device of FIG.

FIG. 3 is a waveform chart of each part showing the operation of the discharge lamp lighting device of FIGS. 1 and 2.

FIG. 4 is a circuit diagram showing a configuration of a discharge lamp lighting device according to a second embodiment of the present invention.

FIG. 5 is a circuit diagram of essential parts showing a configuration of a discharge lamp lighting device according to a third embodiment of the present invention.

FIG. 6 is a circuit diagram showing a configuration of an example of a conventional discharge lamp lighting device.

7 is a waveform chart of each part showing the operation of the discharge lamp lighting device of FIG.

FIG. 8 is a lamp voltage-lamp current characteristic diagram of the discharge lamp.

FIG. 9 is a circuit diagram showing a configuration of a discharge lamp lighting device of a proposed example of the discharge lamp lighting device.

[Explanation of symbols]

1 high voltage pulse generator 2 for controlling the power supply 3 control circuit 4 lamp current detection circuit (lighting discrimination circuit) 5 pulse control circuit (pulse energy detector) V _S commercial power S ₁ Power switch L ₁ inductance element LA discharge lamp Ry ₁ relays Contact (switch element)

Claims (3)

[Claims] 1. A discharge lamp and a current limiting inductance element for limiting a lamp current supplied to the discharge lamp,
In a discharge lamp lighting device comprising a high-voltage pulse generator capable of switching pulse energy for generating a high-voltage pulse for lamp starting from low to high, and a lighting determination circuit for detecting lighting of the discharge lamp, the lighting determination circuit A pulse energy detection circuit for detecting the pulse energy of the high-voltage pulse generator at the moment when the discharge lamp is lit based on the output of, and when the amount of pulse energy detected by the pulse energy detection circuit is lower than the lighting energy of a normal lamp. A discharge lamp lighting device, comprising: a switch element for cutting off power supply to the discharge lamp. 2. The high-voltage pulse generator generates a high-voltage pulse having a pulse energy lower than the pulse energy required to light a normal lamp for a certain period after the power is turned on and higher than the pulse energy required to light a life lamp. The pulse energy detection circuit is configured to generate the pulse energy of the high-voltage pulse generator at the moment when the discharge lamp is lit based on the output of the control circuit that controls the high-voltage pulse generator and the output of the lighting determination circuit. The switch element is configured to cut off the power supply to the discharge lamp when the discharge lamp is lit within a certain period after the power is turned on based on the output of the pulse energy detection circuit. Item 1. The discharge lamp lighting device according to item 1. 3. The discharge lamp lighting device according to claim 1, wherein the high-voltage pulse generator is configured to gradually increase the pulse energy of the high-voltage pulse after the power is turned on.