JP2562816B2 - Discharge lamp lighting device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a discharge lamp lighting device having a high-pressure discharge lamp that requires a high-voltage pulse for starting as a load.

(Background Art) FIG. 5 is a circuit diagram for explaining the principle of a conventional high pressure discharge lamp lighting device. A high pressure discharge lamp DL is connected to the AC power source V ₁ via a choke coil L ₁ which is a current limiting element. The choke coil L ₁ has a tap in the middle of the winding and also serves as a pulse transformer for generating a high-voltage pulse for starting the high-pressure discharge lamp DL. The windings N ₁ and N ₂ correspond to the primary winding and the secondary winding of the pulse transformer, respectively. The primary winding N ₁ is connected to the AC power supply V ₁ via the capacitor C ₁ and the triac Q ₁ . A series circuit of a resistor R ₁ and a capacitor C ₂ is connected to both ends of the high pressure discharge lamp DL. Q ₂
Is a voltage response switching element, which becomes conductive when the charging voltage of the capacitor C ₂ becomes a predetermined value or more and triggers the gate of the triac Q ₁ .

The operation of the circuit shown in FIG. 5 will be briefly described with reference to the waveform chart of FIG. FIG. 6 (a) shows the voltage across the high-pressure discharge lamp DL, and FIG. 6 (b) shows the charging voltage of the capacitor C _2. The solid line shows the state before the high-pressure discharge lamp DL is started, and the broken line shows the high-pressure discharge lamp. It shows the state when the DL is steadily lit.

Before the high-pressure discharge lamp DL is started, a voltage substantially equal to the power supply voltage of the AC power supply V ₁ (referred to as V ₁ for convenience) is applied to both ends of the high-pressure discharge lamp DL, and the capacitor C ₂ has a power supply voltage V ₁
It is charged via the resistor R ₁ from the initial of each half cycle of the charging voltage of the capacitor C ₂ reaches the response voltage of the voltage response switching element Q _2, and conducts voltage response switching element Q _2, the capacitor C ₂ electric charge is discharged to the gate of the triac Q _1, triac Q ₁ is triggered. Thereby, the triac Q ₁ is conductive, the AC power source V _1, the primary winding N ₁ of the choke coil L _1, a closed circuit of the capacitor C ₁ is formed, steep current flows through the primary winding N ₁ As a result, a pulsed voltage is generated. This pulsed voltage is also induced in the secondary winding N ₂ , superposed on the power supply voltage V _1, and applied to both ends of the high pressure discharge lamp DL as a high voltage pulse for starting. After that, the voltage response switching element Q ₂ maintains the conductive state until the end of the half cycle of the power supply voltage V ₁ . Then, at the end of the half cycle, the polarity of the power supply voltage V ₁ is reversed, so that the voltage response switching element Q ₂ becomes non-conductive. Also in the next half cycle of the power supply voltages V _1, the above operation is repeated, the the high-pressure discharge lamp DL, superimposed high-voltage pulses for one by one starting in each half-cycle of the supply voltage V ₁ is the power supply voltages V ₁ The applied voltage is applied in a fixed form (see the solid line in FIG. 6 (a)).

When the high pressure discharge lamp DL is started by the above high voltage pulse for starting, the voltage across the high pressure discharge lamp DL becomes as shown by the broken line in FIG. Generally, the voltage across the high-pressure discharge lamp DL in the lit state is about half of the power supply voltage V ₁ , so the charging voltage of the capacitor C ₂ does not reach the response voltage of the voltage response switching element Q ₂ and the sixth As shown by the broken line in the figure (b), therefore, the triac Q ₁ is not triggered in the lighting state of the high-pressure discharge lamp DL, and the above-mentioned high-voltage pulse for starting is not generated.

The circuit of FIG. 5 operates as described above,
The high-pressure pulse generation circuit (so-called igniter IGN) for starting the high-pressure discharge lamp DL stops its operation only when the high-pressure discharge lamp DL is turned on. Therefore, even when the high pressure discharge lamp DL is disconnected from the discharge lamp lighting device (so-called no-load state), the high pressure discharge lamp DL
Even though the high pressure discharge lamp DL is connected due to the life of the DL, etc., the igniter IGN continues to operate even when the high pressure discharge lamp DL is in a state where it cannot shift to steady lighting, and the AC power supply V ₁ is turned on. During that time, the high-pressure pulse is continuously applied to both ends of the high-pressure discharge lamp DL.

The operation of the igniter IGN over such a long time causes a continuous generation of electric noise, and there is a problem that the possibility of adverse effects on audio equipment and computer equipment increases. Further, in the circuit of FIG. 5, when the feed wiring (so-called tube light circuit) is interposed between the igniter IGN and the high pressure discharge lamp DL, the continuous high voltage pulse generated by the igniter IGN is applied. There was a possibility that the feed wiring would be deteriorated or, in the worst case, burned out.

Therefore, it is possible to use a timer to forcibly stop the operation of the igniter IGN instead of making the operation of the igniter IGN respond to the state of the high-pressure discharge lamp DL. By the way, in the case of a high-pressure discharge lamp, if it goes out for some reason (typically, a momentary power failure) after it enters the steady lighting state, it takes about 5 to 20 minutes before restarting. Generally it takes. This is because the arc tube is extremely hot during steady lighting of the high pressure discharge lamp, and until the arc tube temperature falls to a sufficiently low temperature, the high pressure pulse for starting described above starts the high pressure discharge lamp. Because it cannot be done.
Therefore, as a certain fixed time until the aforementioned igniter IGN is stopped, it is appropriate that the time is typically about 20 minutes. However, if the application of the high-voltage pulse is continued for as long as 20 minutes, it is not possible to sufficiently solve the above-mentioned problems such as continuous generation of electrical noise and deterioration / burnout of the feed wiring.

Therefore, a timer that operates the igniter IGN only for a sufficient time for the initial start of the high-pressure discharge lamp DL (in order to distinguish it from the restart immediately after the extinguishment is referred to as “initial start”) is provided, and It is conceivable to periodically repeat the igniter operation. The operating time of the igniter IGN, which is sufficient for the initial start of the high pressure discharge lamp DL, is typically 7 to 1
It is 0 seconds, and this short igniter operation is
It is considered that the above-mentioned restart can be sufficiently dealt with by repeating every two minutes. However, even with such a system, when there is no load, the intermittent generation of electrical noise for 7 to 10 seconds is repeated every 2 minutes forever, and the above-mentioned deterioration of the feed wiring also occurs. ,
Although the short-term effective stress is reduced, it cannot be said that it is necessarily effective if the stress due to the high voltage pulse application is integrated over a long period of time.

(Object of the Invention) The present invention has been made in view of the above points, and an object of the present invention is to provide a discharge lamp lighting device that eliminates the inconvenience caused by continuous application of a high-voltage pulse for starting a high-pressure discharge lamp. To provide.

DISCLOSURE OF THE INVENTION In the discharge lamp lighting device according to the present invention, in order to achieve the above object, as shown in FIGS. 1 to 4, a high pressure discharge lamp DL requiring a high pressure pulse for starting is provided. In a discharge lamp lighting device equipped with an igniter IGN for generating the high-voltage pulse as a load, at least a time sufficient for the initial start of the high-pressure discharge lamp DL is timed, and the igniter IGN can be operated only during the timed time. A first timer TM ₁ and a second timer TM ₂ for repeatedly operating the first timer TM ₁ ,
At least a sufficient time for restarting the high-pressure discharge lamp DL is timed, and a third timer TM ₃ for prohibiting the operation of the igniter IGN is provided after the timed time has elapsed.

That is, in the present invention, while maximizing the respective features of the concept of forcibly releasing the high-voltage pulse application described above, by making the pulse generation period the minimum possible value, the above-mentioned difficulties are eliminated. The time required to start the high pressure discharge lamp DL for the first time (typically 10
The first timer TM ₁ for counting the seconds) provided to work intermittently, a second timer TM ₂ is provided in the first timer TM ₁ is constant period (2 minutes typically), These first and second timers TM ₁ and TM ₂ are at least high pressure discharge lamps.
A third timer TM ₃ is provided to operate for a sufficient time (typically 20 minutes) for restarting the DL, and the igniter IGN is turned on only during the time when the first timer TM ₁ is counting. The igniter IGN is operated so that the igniter IGN is not operated after the lapse of the time measured by the third timer TM ₃ .

Therefore, in the present invention, in the case where the arc tube of the high pressure discharge lamp DL is restarted from a hot state after the lamp disappears due to some cause (for example, momentary power failure) while the high pressure discharge lamp DL is in the lighting state, However, since high-voltage pulses for starting the high-pressure discharge lamp DL are generated intermittently, audio equipment and computer equipment that generate electrical noise are more difficult than the conventional method of continuously generating high-voltage pulses until restarting. The probability of adverse effects on the igniter IGN can be reduced.
Feeding wiring between the high pressure discharge lamp DL and the high pressure discharge lamp (so-called tube light circuit)
The possibility of deterioration and burnout can be reduced. Not only that, even if the high-pressure discharge lamp DL falls into a state in which it cannot be started and restarted (for example, a bulb burnout), the presence of the timer TM ₃ causes the intermittent high-pressure pulse to restart. It will not last longer than the time required.

 Examples of the present invention will be described below.

Embodiment 1 FIG. 1 is a circuit diagram of one embodiment of the present invention. In the circuit of FIG. 1, parts having the same functions as those of the conventional example of FIG. 5 are designated by the same reference numerals, and duplicate description will be omitted.
The power supply voltage of the AC power supply V ₁ is stepped down by the power supply transformer Tf _1, rectified and smoothed by the full-wave rectifier circuit DB ₁ and the capacitor C _3, and used for controlling the _{first to third} timers TM _{1 to} TM ₃ . The power supply voltage is obtained.

The first timer TM ₁ is composed of a general-purpose timer ICtm ₁ (for example, NEC's μPC1555), resistors R ₁₁ , R ₁₂ and capacitors C ₁₁ , C ₁₂ , C ₁₃ which are control elements of this timer ICtm _1. There is.

The second timer TM ₂ is composed of a general-purpose timer ICtm ₂ (for example, National AN6780) and a resistor R ₂₁ and capacitors C ₂₁ and C ₂₂ which are control elements of this timer ICtm ₂ .

The third timer TM ₃ is composed of a general-purpose timer ICtm ₃ (for example, National AN6780), resistors R ₃₁ , R ₃₂ and capacitors C ₃₁ , C ₃₂ , C ₃₃ which are control elements of this timer ICtm ₃ . .

Connect the AC side terminal of the full-wave rectifier circuit DB _{2 to} the trigger capacitor C ₂ of the triac Q ₁ and connect the output of the first timer TM ₁ to the DC side terminal of the full-wave rectifier circuit DB _2. The ends are connected. Trigger for the start of operation of the timer TM ₁ is performed by the second output of the timer TM _2, the trigger for the start of the operation of the timer TM _2, the third timer TM ₃
Output.

FIG. 2 is an operation waveform diagram for explaining an operation state of the igniter IGN in the circuit of FIG.

FIG. 2 (a) is a waveform diagram of the output signal of the timer TM ₃ obtained from the output terminal (6th pin) of the timer IC tm ₃ , showing the resistance R ₃₁ and the capacitor C ₃₁ after the power supply voltage V ₁ is turned on.
It indicates that the output signal of timer TM ₃ is generated until time t ₃ determined by. Timer ICtm ₃ has a high-level stop terminal (pin 2) and a reset terminal (pin 3)
There oscillates under the condition of "High" level, the reset terminal (pin 3) is connected to the output terminal (6 pin), after turned the power source voltage V _1, the output terminal at time t ₃ ( Oscillation is stopped when pin 6) is at the "Low" level, and then that state is maintained.

FIG. 2 (B) is a waveform diagram of the output signal of the timer TM ₂ obtained from the output terminal (pin 6) of the timer IC tm ₂ , showing the resistance R ₂₁ and the capacitor C ₂₂ after the power supply voltage V ₁ is turned on. Indicates that the output signal is generated at the oscillation cycle T ₂ determined by the value of. Stop pin (pin 2) is always "High" level, the reset terminal (pin 3) maintains the "High" level until the timing of the aforementioned time t _3.

Figure 2 (c) is a waveform diagram of the output signal of the timer TM ₁ obtained from the timer ICTM ₁ output terminal (pin 3), after turned the power supply voltage V _1, the timer ICTM ₁ trigger pin ( Every time (Pin 2) drops to "Low" level, resistance R ₁₂
"The output signal at determined time T ₁ by the value of capacitor C ₁₃ and Hig
The output of the timer ICtm ₂ immediately after the power supply voltage V ₁ is turned on is at the “High” level, but due to the presence of the resistor R ₁₁ and the capacitor C ₁₁ , the capacitor C ₁₁ Terminal voltage is extremely short (until capacitor C ₁₁ is charged to 1/3 or more of timer IC tm ₁ power supply voltage)
Since has become "Low" level, immediately after turning on the power voltage V _1, the timer ICTM ₁ is triggered, during the time T _1, the output terminal of the timer ICTM ₁ (3 pin) becomes "High" level .

The timers TM _{1 to} TM _{3 in the} circuit shown in FIG. 1 operate as described above, but when the focus is on the trigger circuit of the triac Q ₁ which is composed of the resistor R ₁ , the capacitor C _2, and the voltage response switching element Q ₂ , the timer TM _While the output of ₁ is at "Low" level, both ends of the capacitor C ₂ are shorted due to the presence of the bypass circuit between the output terminal (3rd pin) of the timer ICtm ₁ and the ground terminal (1st pin). Therefore, the capacitor C ₂ is not charged via the resistor R ₁ ,
The charging voltage of the capacitor C ₂ does not rise. Therefore, the triac Q ₁ maintains the non-conducting state, and the high pressure pulse for starting does not occur in any state of the high pressure discharge lamp DL. Further, while the output of the timer TM ₁ is at the "High" level, the trigger circuit operates in the same manner as the above-mentioned conventional example, and when the high pressure discharge lamp DL is started, the high pressure discharge lamp DL at that time is started. The generation of the high pressure pulse for starting is stopped, and if the high pressure discharge lamp DL is practically removed from the lighting device, it is possible to start the high pressure discharge lamp DL even in the so-called no-load state. The high-voltage pulse is generated only in the period T ₁ of FIG. 2C,
Moreover, at least after the time t _{3 in} FIG. 2A, the high pressure starting pulse is not generated in any state of the high pressure discharge lamp DL.

Embodiment 2 FIG. 3 is a circuit diagram of another embodiment of the present invention. In this embodiment, parts having the same functions as those of the circuit shown in FIG. 1 are designated by the same reference numerals, and redundant description will be omitted. The difference between this embodiment and the circuit of FIG. 1 is that in the circuit of FIG. ₁ , the series circuit of the resistor R ₁ and the capacitor C ₂ is connected to both ends of the high pressure discharge lamp DL. In the circuit of FIG. 3, the series circuit of the resistor R ₁ and the capacitor C ₂ is connected to both ends of the power source V ₁ . If such a circuit configuration is adopted, the high pressure discharge lamp DL can be started and restarted under the condition that
At least during the period determined by the timer TM ₁ after the high pressure discharge lamp DL is started, regardless of whether or not the high pressure discharge lamp DL is started,
A high-voltage pulse for starting the high-pressure discharge lamp DL is generated, but when the high-pressure discharge lamp DL is incapable of starting and restarting, the presence of the timers TM ₃ , TM ₂ and TM ₁ causes Performs the same operation.

In the circuit configuration shown in FIG. 3, the high pressure discharge lamp DL is connected to the resistor R _1.
Since the high voltage pulse for starting is not applied, it is superior to the case of using the circuit configuration of FIG. ₁ in that consideration of the withstand voltage of the resistor R ₁ is unnecessary.

Embodiment 3 FIG. 4 is a circuit diagram of still another embodiment of the present invention.
In this embodiment, parts having the same functions as those of the circuit shown in FIG. 1 are designated by the same reference numerals, and redundant description will be omitted.
In the circuit of Fig. 1, when the high-voltage discharge lamp DL goes out due to an instantaneous power failure of the power supply voltage V ₁ , the timer TM ₃
However, if the high-pressure discharge lamp DL goes out due to a sudden decrease in the power supply voltage V ₁ , the timer TM ₃ will not be reset, and the AC power supply V ₁ will be turned off once. Until then, the high-pressure discharge lamp DL remains unlit. In consideration of this point, the circuit of FIG. 4 has the reset element A of the timer TM ₃ added to the circuit of FIG. The reset element A sends a reset signal to the timer TM ₃ only when the high-pressure discharge lamp DL changes from the lighting state to the non-lighting state when the AC power source V ₁ is turned on. Therefore, in the circuit of FIG. 4, when the high-pressure discharge lamp DL shifts from the lighting state to the non-lighting state with the AC power supply V ₁ turned on, it is possible to prevent the non-lighting state from continuing. .

(Effects of the Invention) As described above, the present invention enables the igniter operation for a sufficient time for the initial start of the high pressure discharge lamp to be repeated within a time sufficient for the restart of the high pressure discharge lamp. There is an effect that the restart is reliably performed, and the possibility of occurrence of electrical noise and deterioration of wiring can be reduced as much as possible.

[Brief description of drawings]

1 is a circuit diagram of one embodiment of the present invention, FIG. 2 is an operation waveform diagram of the same as above, FIG. 3 is a circuit diagram of another embodiment of the present invention, and FIG.
FIG. 5 is a circuit diagram of still another embodiment of the present invention, FIG. 5 is a circuit diagram of a conventional example, and FIG. 6 is an operation waveform diagram of the same. DL is a high pressure discharge lamp, IGN is an igniter, and TM _{1 to} TM ₃ are timers.

Claims (1)

(57) [Claims] 1. A discharge lamp lighting device equipped with a high-pressure discharge lamp that requires a high-voltage pulse for starting and having an igniter for generating the high-voltage pulse, at least a time sufficient for initial starting of the high-pressure discharge lamp is measured, A first timer that allows the igniter to operate only during the time counting time, a second timer that repeatedly operates the first timer, and at least a time sufficient for restarting the high pressure discharge lamp, and the time counting A discharge lamp lighting device, comprising: a third timer for prohibiting the operation of the igniter after a lapse of time.