JP2002313590A - Discharge lamp lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the startability of a discharge lamp while reducing damage to electrodes to extend the life of the discharge lamp by allowing smooth shift from a glow discharge to an arc discharge of the discharge lamp after breakdown. SOLUTION: This discharge lamp lighting device includes a DC power supply E, a down converter 1 for controlling the power of the discharge lamp La, a smoothing capacitor C1 connected to the output of the down converter, a startability improving circuit 2 connected in series with the capacitor, and an igniter Ig. The startability improving circuit 2 comprises a diode D2, a resistance R1 and a switch means SW1 connected in parallel with one another and the timing of opening and closing of the switch means SW1 is controlled by a control means 3. The control means 3 switches the switch means SW1 from an open state to a closed state at predetermined timing from a reference point defined during a period after the supply of power until the discharge lamp La reaches a stable lighted state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge lamp lighting device, and more particularly to an improvement in the starting performance of a discharge lamp and a longer life of the discharge lamp.

[0002]

2. Description of the Related Art FIG. 2 is a circuit diagram of a general discharge lamp lighting device. In the figure, reference numeral 1 denotes a down converter, which includes a switching element Q1, an inductor L1, and a diode D1.
When the switching element Q1 is turned on and off at a high frequency, a voltage obtained by reducing the voltage supplied from the DC power supply E by a known step-down chopper operation is stored in the smoothing capacitor C1. Then, a high-voltage pulse is applied to the discharge lamp La by the igniter Ig, causing dielectric breakdown between the electrodes and starting discharge. Thereafter, the electric charge stored in the smoothing capacitor C1 flows into the discharge lamp La at a stretch. After that, the lamp voltage Vla and the lamp current Ila of the discharge lamp La are detected by the voltage detection circuit 4 and the current detection circuit 5, respectively.
And the power calculation circuit 6 calculates the power to be supplied to the discharge lamp La, feeds it back to the downconverter 1 via the PWM control circuit 7, controls the pulse width of the downconverter 1, and supplies a predetermined value to the discharge lamp La. Supply power. The discharge lamp La is, for example, a high-pressure discharge lamp.

The capacitor C1 is a smoothing capacitor for reducing high-frequency ripple current generated by the downconverter 1. This is to prevent acoustic resonance from occurring due to the ripple and frequency of the current flowing through the discharge lamp La, and prevent the arc between the electrodes of the discharge lamp La from fluctuating and appearing as flickering. Generally, the capacity of the capacitor C1 is several hundred n-
Several μF are used. The larger the capacitance, the lower the current ripple.

However, when the discharge lamp La is started, since there is almost no impedance in the discharge path of the capacitor C1, an inrush current having a width of several tens A and a width of several tens to several hundreds of μs is applied to the discharge lamp La immediately after breakdown. It flows in and damages the electrode. As the capacity of the capacitor C1 increases, the rush current to the discharge lamp La increases, and the degree of damage to the electrodes also increases. When the discharge lamp La is started, the transition from glow discharge to arc discharge may fail after breakdown depending on the internal state of the discharge lamp La, and a dozen high-voltage pulses are applied. An inrush current flows from C1 to the discharge lamp La, damaging the electrodes.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and makes it possible to smoothly transition from glow discharge to arc discharge after breakdown of a discharge lamp, thereby improving startability. It is an object of the present invention to provide a discharge lamp lighting device which can improve and suppress a rush current from a capacitor to a discharge lamp immediately after a breakdown, thereby suppressing electrode deterioration of the discharge lamp and extending the life of the discharge lamp.

[0006]

As shown in FIG. 1, the discharge lamp lighting device according to the present invention comprises a DC power supply E, a down converter 1 for controlling the power of the discharge lamp La, a smoothing capacitor C1, A startability improving circuit 2 and an igniter Ig are provided. When the discharge lamp La is started, the startability improvement circuit 2 includes a capacitor C1 after the breakdown by the igniter Ig.
The resistor R1 is connected in series with the capacitor C1 in order to suppress a rush current from flowing into the discharge lamp La. In this state, the charging of the capacitor C1 from the downconverter 1 is delayed. Therefore, in order to quickly charge the capacitor C1, the diode D2 is connected in series with the capacitor C1 so that the charging direction of the capacitor C1 is forward. R1 is connected in parallel. In this state, after the discharge lamp La shifts to the arc discharge, when the capacitor C1 is discharged, a loss due to the resistor R1 always occurs due to the discharge current, so that the circuit efficiency deteriorates. Therefore, the switch SW1 is connected in parallel with the resistor R1, the switch SW1 is kept open before the arc discharge, the rush current to the discharge lamp La is suppressed by the resistor R1, and the switch SW1 is closed after the shift to the arc discharge. The loss generated by the resistor R1 is suppressed. The timing of opening and closing the switch SW1 is performed by the timing control circuit 3. It is characterized by the above circuit configuration. Although the converter 1 is illustrated as a down converter in the illustrated circuit, the converter 1 is not limited to this, and any converter that can control the power of the discharge lamp La may be used. Further, the DC power supply E may be a rectified and smoothed commercial power supply.

Assuming that a current as indicated by Ila1 in FIG. 3 flows through the discharge lamp in the circuit configuration of the prior art, in the circuit configuration of claim 1, the voltage across the capacitor C1 before breakdown of the discharge lamp La is determined. Vc and the resistance value of the resistor R1 is R, the inrush current is Ip2 = Vc / R,
It is reduced from p1 to Ip2. Then, the suppressed inrush current becomes the indentation current, and it is possible to smoothly shift from glow discharge to arc discharge.

A discharge lamp lighting device according to a second aspect of the present invention is the lighting device according to the first aspect, in which the power supply is turned on, that is, from the moment when a lighting signal for starting the down converter 1 is turned on until the discharge lamp La reaches stable lighting. In the meantime, in order to determine the closing timing from the open state of the switch SW1, a certain reference point is set, and the closing condition and timing of the switch SW1 are set from the reference point. The term “stable lighting” as used herein refers to a lighting state after transition from glow discharge to arc discharge, and includes the moment immediately after transition to arc discharge and immediately after.

According to a third aspect of the present invention, in the lighting apparatus of the second aspect, as shown in FIG. 4, the reference point is set to a moment when a lighting signal for starting the down converter 1 is applied, and from that moment a predetermined point is set. After the elapse of time t, switch SW
1 is closed.

According to a fourth aspect of the present invention, in the lighting device of the second aspect, as shown in FIG. 5, the discharge lamp La is switched to the igniter Ig after a lighting signal for starting the down converter 1 is applied to the reference point. Set until break down. This determination is made by detecting the lamp voltage of the discharge lamp La. The reference point is a time point at which the detected voltage detected by the voltage detection circuit 4 is compared with a threshold voltage serving as a determination reference set in the timing control circuit 3, and the detected voltage becomes higher than the threshold voltage. The switch SW1 is closed after a lapse of a predetermined time t from that point.

According to a fifth aspect of the present invention, in the lighting device of the second aspect, as shown in FIG. 6, after the lighting signal for starting the down converter 1 is applied to the reference point,
It is set after the discharge lamp La breaks down due to the igniter Ig. This determination is made by detecting the lamp voltage of the discharge lamp La. The reference point compares the detection voltage detected by the voltage detection circuit 4 with a threshold voltage serving as a determination criterion set in the timing control circuit 3, and is set as a time point at which the detection voltage becomes lower than the threshold voltage. A predetermined time t from that point
The switch SW1 is closed after the lapse of.

According to a sixth aspect of the present invention, in the lighting device of the second aspect, as shown in FIG. 7, the reference point is set at a point after a lighting signal for starting the down converter 1 is input.
It is set after the discharge lamp La breaks down due to the igniter Ig. This determination is made by detecting the lamp current of the discharge lamp La. The reference point compares the detection voltage detected by the current detection circuit 5 with a threshold voltage serving as a criterion set in the timing control circuit 3, and is set as a time point at which the detection voltage becomes higher than the threshold voltage. A predetermined time t from that point
The switch SW1 is closed after the lapse of.

According to a seventh aspect of the present invention, in the lighting device of the first aspect, after the discharge lamp La is lit and the switch SW1 is closed once, the discharge lamp La is lit according to a certain lighting determination criterion.
Is determined to have disappeared, the switch SW1 is changed from the closed state to the open state. When it is determined that the discharge lamp La is turned on, the switch is changed from the open state to the closed state. That is, the lighting state of the discharge lamp La is detected, and the lighting determination is performed based on the detected value and the lighting determination reference value. When the lighting state of the discharge lamp La is off, the switch SW1 is changed from the closed state to the open state, In the case of lighting, the state is changed from an open state to a closed state.

According to an eighth aspect of the present invention, in the lighting device of the seventh aspect, the detection voltage detected by the voltage detection circuit 4 and a threshold voltage which is a lighting determination reference set in the timing control circuit 3 are used. It is characterized by comparing and determining the lighting state.

According to a ninth aspect of the present invention, in the lighting apparatus of the eighth aspect, as shown in FIG. 8, the lighting determination criterion is closed from the open state of the switch SW1 set in the timing control circuit 3. Threshold voltage a for setting the state and threshold voltage b for setting the switch SW1 from the closed state to the open state
When the detected voltage detected by the voltage detection circuit 4 becomes lower than the threshold voltage a, the lighting is determined, and when the detected voltage becomes higher than the threshold voltage b, the light is turned off.

According to a tenth aspect of the present invention, there is provided a discharge lamp lighting device according to the seventh aspect.
9, the detection voltage detected by the current detection circuit 5 is compared with a threshold voltage serving as a lighting determination reference set in the timing control circuit 3, as shown in FIG.
Lighting is determined when the detected voltage is higher than the threshold voltage, and light-off is determined when the detected voltage is lower than the threshold voltage.

According to the eleventh aspect of the present invention, there is provided a discharge lamp lighting device according to the first aspect.
As shown in FIG. 10, the discharge lamp La
Lights up, and once the switch SW1 is closed, the detection voltage detected by the voltage detection circuit 4 and the timing control circuit 3
Is compared with the threshold voltage set as the lighting determination reference, and when the detected voltage becomes higher than the threshold voltage, it is determined that the light is turned off, and the switch SW1 in the closed state is opened. The switch SW1 is closed after a lapse of a predetermined time t from that point.

According to a twelfth aspect of the present invention, there is provided a discharge lamp lighting device according to the first aspect.
As shown in FIG. 11, the discharge lamp La
Is turned on, and once the switch SW1 is closed, the detection voltage detected by the current detection circuit 5 and the timing control circuit 3
Is compared with a threshold voltage set as a lighting determination reference, and when the detected voltage becomes lower than the threshold voltage, it is determined that the light is turned off, and the switch SW1 in the closed state is opened. The switch SW1 is closed after a lapse of a predetermined time t from that point.

[0019]

(Embodiment 1) FIG. 12 is a circuit diagram of Embodiment 1 of the present invention. Voltage detection circuit 4
Is composed of resistors R2 and R3, and detects the voltage of the discharge lamp La by the voltage division of the resistors R2 and R3. Current detection circuit 5
Is composed of a resistor R4, an operational amplifier OPA, and resistors R5 and R6. The resistance R4 is set to 0.1 in order to minimize the loss due to the current of the discharge lamp. Current-voltage conversion is performed using a resistance of several Ω to detect the current of the discharge lamp La. However, since the detection voltage is too low in this state, the operational amplifier OPA
And an amplifier circuit using the resistors R5 and R6 to amplify the detection voltage. The power calculation circuit 6 is configured by a general multiplication circuit using, for example, NJM4200 manufactured by New Japan Radio Co., Ltd. The PWM control circuit 7 is, for example, a μPC10 manufactured by NEC.
It is composed of a general regulator control circuit using the H.94. Further, a relay is used for the switch means SW1. In this embodiment, a relay is used as the switch means SW1, but a transistor may be used instead of the relay. The above-described circuit is the same in other embodiments.

The ON / OFF switching timing control circuit 3 for the switch means SW1 comprises a comparator COMP1, resistors R7, R8, R9, R10 and a capacitor C2, and sets a predetermined time for switching the switch means SW1. The time chart is as shown in FIG.
The capacitor C2 is charged via the resistor R10 from the moment when the lighting signal for activating the down converter 1 is inputted. When the charged voltage exceeds the reference voltage created by the resistors R7 and R8, the output of the comparator COMP1 is changed. It reverses and switches the switch means SW1 from OFF to ON. It goes without saying that the length of the predetermined time t in FIG. 4 is designed to be an appropriate length by the time constant of the resistor R10 and the capacitor C2 or the voltage division ratio of the resistors R7 and R8.

(Embodiment 2) FIG. 13 is a circuit configuration diagram of Embodiment 2 of the present invention. In this embodiment, the ON / OFF switching timing control circuit 3 of the switch means SW1 is partially different from that of FIG. 12, and the lamp voltage detection voltage of the voltage detection circuit 4 is set by resistors R10 and R11. A predetermined threshold voltage is compared with the comparator COMP2, and the comparison output voltage is used as the input voltage of the comparator COMP1. When the lamp voltage detection voltage by the resistors R2 and R3 rises and exceeds a predetermined threshold voltage determined by the voltage dividing ratio of the resistors R10 and R11, the comparator COMP2
Output from Low level (short with ground) to High
Switch to level (open). Thereby, the resistance R
When the capacitor C2 is charged via 10 and its charged voltage exceeds the reference voltage created by the resistors R7 and R8, the output of the comparator COMP1 is inverted and the switch SW1 is switched from OFF to ON.

(Embodiment 3) FIG. 14 is a main part circuit configuration diagram of Embodiment 3 of the present invention. In FIG. 14, the ON / OFF switching timing control circuit 3 of the switch means SW1 is shown.
13 is shown, and other circuit configurations are shown in FIG.
Is the same as The polarity of the input terminal of the comparator COMP2 is different from the circuit configuration of FIG. That is, in the circuit configuration of FIG. 13, the lamp voltage detection voltage by the resistors R2 and R3 of the voltage detection circuit 4 is applied to the plus input terminal of the comparator COMP2, and the predetermined threshold voltage set by the resistors R10 and R11 is compared with the comparator COMP2. However, in the circuit configuration of FIG. 14, on the other hand, the lamp voltage detection voltage by the resistors R2 and R3 of the voltage detection circuit 4 is applied to the minus input terminal of the comparator COMP2, and the resistance R10 , R11 are applied to the positive input terminal of the comparator COMP2.

(Embodiment 4) FIG. 15 is a circuit configuration diagram of Embodiment 4 of the present invention. In this embodiment, the ON / OFF switching timing control circuit 3 of the switch means SW1 is partially different from that of FIG. 12, and the lamp current detection voltage of the current detection circuit 5 is set by resistors R10 and R11. A predetermined threshold voltage is compared with the comparator COMP2, and the comparison output voltage is used as the input voltage of the comparator COMP1. Other configurations are the same as those in FIG.

(Embodiment 5) FIG. 16 is a circuit diagram showing a main part of a fifth embodiment of the present invention. In FIG. 16, the ON / OFF switching timing control circuit 3 of the switch means SW1 is shown.
13 is shown, and other circuit configurations are shown in FIG.
Is the same as In this embodiment, the lamp voltage detection voltage based on the voltage division of the resistors R2 and R3 is compared with the comparator COMP.
1, the lighting state of the discharge lamp is determined by comparing it with a predetermined threshold value, but the predetermined threshold value used as a reference for voltage comparison of the comparator COMP1 is switched by the diode D3 and the resistor R19. Comparator COMP
When the output of No. 1 is Low level (short circuit with ground),
Since the diode D3 is turned on, the comparator COM
The threshold voltage of P1 is determined by the parallel circuit of the resistors R8 and R19 and the resistor R
7 (threshold voltage a in FIG. 8). When the output of the comparator COMP1 is at the high level (open), the diode D3 is turned off, and the threshold voltage of the comparator COMP1 is set to the resistors R7 and R7.
8 (threshold voltage b in FIG. 8). The transistor Q3, the resistor R21, and the capacitor C3 are circuits for turning off the switch SW1 until the voltage of the capacitor C1 rises after the input of the lighting signal. That is, since the voltage of the capacitor C3 is low immediately after the power is turned on, the transistor Q3 is turned on, and the exciting current of the relay is bypassed by the transistor Q3, so that the switch means SW1 as a contact is turned off. When the capacitor C3 is charged by the lighting signal via the resistor R21, the transistor Q3 is turned off. At this time, the lamp voltage detection voltage in FIG. 8 is higher than the lower threshold voltage a, and thereafter. 8, the threshold voltage of the comparator COMP1 switches.

(Sixth Embodiment) FIG. 17 is a circuit diagram of a main part of a sixth embodiment of the present invention. In FIG. 17, the ON / OFF switching timing control circuit 3 of the switch means SW1 is shown.
15 is shown, and the other circuit configuration is shown in FIG.
Is the same as In this embodiment, the lamp current detection voltage is adjusted by the voltage division ratio of the resistors R17 and R18, and is input to the comparator COMP1 and compared with a threshold voltage determined by the voltage division ratio of the resistors R7 and R8. The time chart is as shown in FIG. When the lamp current detection voltage is higher than the threshold voltage, the output of the comparator COMP1 becomes High level (open), and the exciting current of the relay flows through the resistor R9, so that the switch means SW1 as a contact is turned on. When the lamp current detection voltage becomes lower than the threshold voltage, the output of the comparator COMP1 becomes Lo.
When the level becomes w level (short circuit with the ground) and the exciting current of the relay stops flowing, the switch means SW1 as a contact thereof is turned off.

(Seventh Embodiment) FIG. 18 is a circuit diagram of a main part of a seventh embodiment of the present invention. In FIG. 18, the ON / OFF switching timing control circuit 3 of the switch means SW1 is shown.
13 is shown, and other circuit configurations are shown in FIG.
Is the same as The time chart is as shown in FIG. In this embodiment, the counter COUNT1 counts the number of times the output of the comparator COMP2 has become Low level. In other words, the switch SW
The number of times 1 changes from on to off is counted.
In this example, the count of ON → OFF of the switch means SW1 is set to two times, and thereafter, the switch means SW1 is closed after a predetermined time t has elapsed. First, since the output q2 of the counter COUNT1 is at the low level, the transistors Q2 and Q3 are both off. The comparator COMP2 has a predetermined threshold voltage determined by the voltage division ratio of the resistors R10 and R11, and the lamp voltage V determined by the resistors R2 and R3.
It is compared with a lamp voltage detection voltage obtained by dividing la.
When the lamp voltage detection voltage exceeds a predetermined threshold voltage and the output of the comparator COMP2 changes from the high level to the low level, the first output q1 of the counter COUNT1 changes from the low level to the high level. At this time, since the transistor Q3 is turned off, the output of the comparator COMP1 is at the Low level like the output of the comparator COMP2, and the switching means SW1
Turns off.

When the discharge of the discharge lamp La starts and the lamp voltage detection voltage becomes lower than a predetermined threshold voltage, the output of the comparator COMP2 returns from the low level to the high level. Also at this time, since the transistor Q3 is off, the output of the comparator COMP1 is at the High level, similarly to the output of the comparator COMP2, and the switch SW1 is on. When the discharge lamp La fails to shift from the glow discharge to the arc discharge and the discharge stops, the lamp voltage detection voltage rises again and exceeds a predetermined threshold voltage, so that the output of the comparator COMP2 changes from the high level to the low level. When it changes, the second output q2 of the counter COUNT1 changes from the Low level to the H level.
changes to the high level. As a result, a base current flows through the transistor Q2 via the resistor R12.
10 and R13 are connected in parallel, and the threshold voltage rises as shown in FIG. As a result, the output of the comparator COMP2 is always open (high impedance state).
However, the second output q2 of the counter COUNT1
Becomes high level, a base current flows to the transistor Q3 via the resistor R14, so that the voltage of the plus side input terminal of the comparator COMP1 is
2 to ground level. Therefore, the output of the comparator COMP1 is at the low level, and the switch SW1 is turned off. Capacitor C2
Is charged via the resistor R15, the voltage of the capacitor C2 increases. After a lapse of a predetermined time t in FIG.
When the voltage exceeds a predetermined voltage determined by the voltage dividing ratio, the output of the comparator COMP1 becomes High level, and the switch means SW1 is turned on.

(Eighth Embodiment) FIG. 20 is a circuit diagram showing a main part of an eighth embodiment of the present invention. In FIG. 20, the ON / OFF switching timing control circuit 3 of the switch means SW1 is shown.
15 is shown, and the other circuit configuration is shown in FIG.
Is the same as The time chart is as shown in FIG. In this example, ON → OFF of the switch means SW1
Is counted once, and then the switch means SW1 is closed after a predetermined time t has elapsed. Compared with the circuit of FIG. 20 and the circuit of FIG. 18, the point that the output of the counter COUNT1 controlling the transistors Q2 and Q3 uses the first output q1 instead of the second output q2, and the input of the comparator COMP2 is The point that the lamp current detection voltage is used instead of the lamp voltage detection voltage and the series circuit of the resistor R13 and the transistor Q2 is a comparator C
OMP2 threshold voltage (divided voltage of resistors R10 and R11)
Is connected so as to pull up the lamp current detection voltage. When the transistor Q2 is turned on, the plus input terminal of the comparator COMP2 is pulled up via the resistor R13.
, Which is always higher than the threshold voltage based on the voltage division ratio of R11,
The output of the comparator COMP2 is always at the high level. Other operations are the same as those of the circuit of FIG.

[0029]

According to the present invention, a discharge lamp is provided in a parallel circuit of a diode interposed in a charge path of a smoothing capacitor connected in parallel with an output of a converter for controlling power of a discharge lamp and a resistor interposed in a discharge path. Since the switch means that changes from the open state to the closed state after the start of the discharge is connected in parallel, the transition from the glow discharge to the arc discharge after the breakdown of the discharge lamp is smoothly performed, and the startability is improved,
Damage to the electrodes can be reduced, and the life of the discharge lamp can be prolonged.

[Brief description of the drawings]

FIG. 1 is a circuit configuration diagram of a discharge lamp lighting device according to claim 1;

FIG. 2 is a circuit configuration diagram of a conventional general discharge lamp lighting device.

FIG. 3 is a waveform diagram for explaining a difference between an inrush current of the discharge lamp lighting device of the first embodiment and a conventional general discharge lamp lighting device.

FIG. 4 is an operation explanatory diagram showing an on / off operation of switch means in the discharge lamp lighting device according to claim 3;

FIG. 5 is an operation explanatory diagram showing an on / off operation of switch means in the discharge lamp lighting device according to claim 4;

FIG. 6 is an operation explanatory diagram showing an on / off operation of switch means in the discharge lamp lighting device of claim 5;

FIG. 7 is an operation explanatory diagram showing an on / off operation of switch means in the discharge lamp lighting device of claim 6;

FIG. 8 is an operation explanatory diagram showing the on / off operation of the switch means in the discharge lamp lighting device of claim 9;

FIG. 9 is an operation explanatory diagram showing an on / off operation of switch means in the discharge lamp lighting device according to claim 10;

FIG. 10 is an operation explanatory view showing the on / off operation of the switch means in the discharge lamp lighting device according to claim 11;

FIG. 11 is an operation explanatory diagram showing the on / off operation of the switch means in the discharge lamp lighting device of claim 12;

FIG. 12 is a circuit configuration diagram according to the first embodiment of the present invention.

FIG. 13 is a circuit configuration diagram according to a second embodiment of the present invention.

FIG. 14 is a main part circuit configuration diagram of a third embodiment of the present invention.

FIG. 15 is a circuit configuration diagram according to a fourth embodiment of the present invention.

FIG. 16 is a main part circuit configuration diagram according to a fifth embodiment of the present invention.

FIG. 17 is a main part circuit configuration diagram of a sixth embodiment of the present invention.

FIG. 18 is a main part circuit configuration diagram according to a seventh embodiment of the present invention.

FIG. 19 is an operation explanatory diagram showing on / off operations of switch means according to Embodiment 7 of the present invention.

FIG. 20 is a main part circuit configuration diagram of an eighth embodiment of the present invention.

FIG. 21 is an operation explanatory diagram showing on / off operations of switch means according to Embodiment 8 of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Down converter 2 Startability improvement circuit 3 Timing control circuit 4 Voltage detection circuit 5 Current detection circuit 6 Power calculation circuit 7 PWM control circuit SW1 Switch means La Discharge lamp Ig Igniter C1 Smoothing capacitor R1 Resistance D2 Diode E DC power supply

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3K072 AA11 BB04 CA16 DA00 DD06 DE02 DE04 DE06 DE07 EA06 EA07 HA09 HB03

Claims (12)

[Claims] 1. A DC power supply, a converter for controlling power of a discharge lamp using the DC power as an input, a smoothing capacitor connected to an output of the converter, a diode interposed in a charge path of the capacitor, and a discharge path. A discharge lamp lighting device comprising: a parallel circuit with a resistor interposed in the discharge lamp lighting device; and an igniter, wherein a switch circuit that changes from an open state to a closed state after the discharge lamp starts discharging is provided in parallel with the diode and the resistance parallel circuit. Discharge lamp lighting device characterized by being connected. 2. The discharge lamp lighting device according to claim 1, wherein
A discharge lamp lighting device characterized in that the switch means is switched from an open state to a closed state at a predetermined timing from a reference point determined from the time when the power is turned on until the discharge lamp reaches stable lighting. 3. The discharge lamp lighting device according to claim 2,
A discharge lamp lighting device, characterized in that the reference point is when the power is turned on. 4. The discharge lamp lighting device according to claim 2,
A discharge lamp lighting device characterized in that a reference point is a time when a lamp voltage reaches a predetermined voltage after power-on. 5. The discharge lamp lighting device according to claim 2,
A discharge lamp lighting device, characterized in that the reference point is a time after the power is turned on and a time when the lamp voltage of the discharge lamp becomes a voltage immediately after discharge. 6. The discharge lamp lighting device according to claim 2,
A discharge lamp lighting device, characterized in that the reference point is a time after the power is turned on and a time when the lamp voltage of the discharge lamp becomes a current immediately after discharge. 7. The discharge lamp lighting device according to claim 1, wherein
When the discharge lamp is determined to be turned off after the switch is closed, the switch is changed from the closed state to the open state, and after the switch is opened, the discharge lamp is determined to be on. A discharge lamp lighting device characterized in that the switch means is changed from an open state to a closed state at the time. 8. The discharge lamp lighting device according to claim 7,
The lighting state of the discharge lamp is determined by comparing the lamp voltage with a predetermined threshold value. 9. The discharge lamp lighting device according to claim 8, wherein
A threshold value when the switch means is changed from the closed state to the open state,
A discharge lamp lighting device, wherein a threshold value when changing from an open state to a closed state is different. 10. The discharge lamp lighting device according to claim 7, wherein the lighting state of the discharge lamp is determined by comparing the lamp current with a predetermined threshold value. 11. The discharge lamp lighting device according to claim 1, wherein the switch means is turned off from the closed state when the discharge lamp is determined to be off by detecting the lamp voltage after the switch means is closed. A discharge lamp lighting device, wherein the switch means is changed from an open state to a closed state after a lapse of a predetermined time. 12. The discharge lamp lighting device according to claim 1, wherein the switch means is turned off from the closed state if the discharge lamp is determined to be off by detecting lamp current after the switch means is closed. A discharge lamp lighting device, wherein the switch means is changed from an open state to a closed state after a lapse of a predetermined time.