JP2001307897A - Discharge lamp lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a discharge lamp lighting device which has a small size and a low cost and which is suitable for on board in which a high voltage pulse can be generated at the time of starting without reducing the number of pulse generation per unit time over wide temperature ranges. SOLUTION: In the discharge lamp lighting device composed of a direct- current power source, a direct-current voltage step-up circuit to elevate the direct-current voltage and to control a supply power to the discharge lamp which is a load, an inverter circuit to convert the step-upped direct voltage into an alternating current voltage and to supply it to the discharge lamp which is the load, an ignitor circuit to apply a high voltage pulse in starting of the discharge lamp which is the load, and the discharge lamp which is the load, have self extinction type element of arc at a switching element Q for the high pressure pulse generation at the time of starting of ignitor circuit, and when the discharge lamp does not start after the self extinction type element of arc has been on, a breaker circuit is equipped to break a current supply to the ignitor circuit during at least the necessary time for the self extinction type element of arc to surely self extinct of arc.

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, such as a discharge lamp for a headlight mounted on a vehicle, which is required to have a wide operating temperature range and to start the discharge lamp in a short time. It is.

[0002]

2. Description of the Related Art FIG. 18 shows a circuit configuration of a conventional discharge lamp lighting device. In the figure, E denotes a DC power supply, which is composed of a vehicle-mounted battery or the like. Reference numeral 1 denotes a DC boosting circuit that boosts the DC power supply E and controls the power supplied to the discharge lamp LP, which is a load, and includes a switching element Q1, a transformer T1, a diode D0, and a capacitor C0. Reference numeral 2 denotes an inverter circuit for converting a DC voltage to an AC voltage, and is configured by a full bridge circuit of switching elements Q2 to Q5. Reference numeral 3 denotes an igniter circuit that applies a high-voltage pulse when the discharge lamp LP as a load is started. The igniter circuit 3 includes a charging circuit 31 and a pulse generation circuit 32.
The charging circuit 31 is composed of diodes D1 and D2 for voltage doubling, capacitors C1 and C2, and a resistor R for limiting charging current. The pulse generation circuit 32 includes a pulse transformer PT and a self-extinguishing type switching element Q.

FIG. 19 shows operation waveforms of the conventional igniter circuit 3. Charging circuit 31 of the igniter circuit 3 is constituted by a voltage doubler rectifier circuit, the charging current I _R flowing when the polarity of the input voltage Vo of the igniter circuit 3 alternates, the voltage of the capacitor C1 V1, the voltage of the capacitor C2 To V2
Then, when the battery is charged like the charging voltage V1 + V2 in FIG. 19, and when the charging voltage is charged to a predetermined voltage, the self-extinguishing type switching element Q (here, a reverse blocking three-terminal thyristor (SCR)) is used. But the triac,
The same applies to the discharge gap, etc.), and a pulse is generated via the pulse transformer PT. When the discharge lamp LP starts immediately after the pulse is generated, the inverter output voltage Vo decreases and the igniter circuit 3 stops. However, when the discharge lamp LP does not start, the inverter output voltage Vo does not decrease and the charging current I _R again. Flows.

Assuming that the discharge lamp lighting device is used even in a high temperature environment, as shown in FIG. 20, when the holding current I _H of the self-extinguishing type switching element Q which is the main switch of the igniter circuit 3 is high, to lower, it can not be turned off self extinguishing type switching element Q and a large peak value of the charging current I _R. Then, there is a problem that the next pulse cannot be generated. Therefore, conventionally, the peak value of the charging current I _R has been designed to be equal to or less than the holding current I _H in the entire operating temperature range, thereby realizing reliable pulse generation. However, naturally, the charging current I
_{Since R} decreases, the number of pulses generated per unit time decreases.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a small and low-cost start-up high-voltage pulse that can be generated over a wide temperature range without reducing the number of pulse generations per unit time. An object of the present invention is to provide a discharge lamp lighting device suitable for in-vehicle use.

[0006]

According to the present invention, in order to solve the above-mentioned problems, as shown in FIG. 18, a DC power supply E and a discharge lamp LP as a load by boosting the DC power supply E. DC booster circuit 1 that controls the power supplied to the inverter, an inverter circuit 2 that converts the boosted DC voltage into an AC voltage and supplies the AC voltage to the discharge lamp LP that is a load, and a high-voltage pulse when the discharge lamp LP that is a load is started. As shown in FIG. 1, a self-extinguishing type switching element Q for generating a high-voltage pulse at the start of the igniter circuit is provided in a discharge lamp lighting device including an igniter circuit 3 for applying a voltage and a discharge lamp LP as a load. If the discharge lamp LP does not start after the self-arc-extinguishing element is turned on and the self-arc-extinguishing element is turned on, the current supply to the igniter circuit is cut off at least for the time necessary for the self-arc-extinguishing element to reliably self-extinguish. To shut off It is characterized in further comprising a road SW.

[0007]

(Embodiment 1) FIG. 1 shows the configuration of Embodiment 1 of the present invention. In the figure, E denotes a DC power supply, which is composed of a vehicle-mounted battery or the like. Reference numeral 12 denotes a quadrature converter, which includes a DC booster circuit that boosts the DC power supply E and controls power supplied to the discharge lamp LP as a load, and an inverter circuit that converts the boosted DC voltage to an AC voltage. ing. Reference numeral 31 denotes a charging circuit that charges the capacitor C of the pulse generation circuit 32 for generating pulse energy. Reference numeral 32 denotes a pulse generation circuit, which includes a capacitor C charged by the charging circuit 31, a pulse transformer PT, and a self-extinguishing type switching element Q (SCR, triac,
Discharge gap). The primary winding of the pulse transformer PT is connected to both ends of the capacitor C via a self-extinguishing type switching element Q. When the switching element Q is turned on, the electric charge of the capacitor C is released to the primary winding of the pulse transformer PT, and a high-voltage pulse is generated in the secondary winding of the pulse transformer PT. The secondary winding of the pulse transformer PT is connected to the output of the orthogonal transformer 12 and the discharge lamp L.
It is connected in series between P.

A cutoff circuit SW is inserted in series between the output of the orthogonal transformer 12 and the input of the charging circuit 31,
When the discharge lamp LP does not start after the self-extinguishing type switching element Q of the pulse generation circuit 32 that applies the high-voltage pulse at the time of starting is turned on, at least the self-extinguishing type switching element Q is required to surely extinguish itself. During the predetermined time T1,
This is to stop charging the capacitor C of the pulse generation circuit 32 with pulse energy. In this example, after the control circuit 4 sends a trigger signal to the self-extinguishing type switching element Q of the pulse generation circuit 32 to turn on the switching element Q and generate a pulse, the cutoff circuit SW is turned off for a predetermined time T1. The operation is performed so that the voltage Vc of the capacitor C does not rise. The operation is shown in FIG. In the present embodiment, the charging current I _R can be increased without being limited to the holding current I _{H as} in the related art.
It becomes possible to increase the number of times of generation of the pulse and to improve the startability.

(Embodiment 2) FIGS. 3 to 6 show the configuration of Embodiment 2 of the present invention. 3 shows the configuration of the DC booster circuit 1, FIG. 4 shows the configuration of the inverter circuit 2, FIG. 5 shows the configuration of the igniter circuit 3, and FIG. The output of the DC booster circuit 1 is connected to the input of the inverter circuit 2 at terminals A1 and A2.
The output of the inverter circuit 2 is connected to the input of the igniter circuit 3 at terminals B1 and B2. Further, the terminals a to j of the control circuit 4 are connected to the terminals a to j of the DC booster circuit 1 and the inverter circuit 2, respectively.

First, the configuration of the DC booster circuit 1 shown in FIG. 3 will be described. The positive terminal of the DC power supply E is connected to one end of the primary winding of the step-up transformer T1. The other end of the primary winding of the step-up transformer T1 is connected to the drain of a switching element Q1 composed of a MOSFET. The source of the switching element Q1 is connected to the ground GND and to the negative electrode of the DC power supply E. A resistor R2 is connected between the gate and source of the switching element Q1. The gate of the switching element Q1 is connected to the drive signal input terminal c via the resistor R1. The input terminal of the control power supply circuit 5 is connected to the drain of the switching element Q1 via the anode and the cathode of the diode D3. One end of the secondary winding of the step-up transformer T1 is connected to the ground GND, and the other end is connected to the cathode of the diode D0. The anode of the diode D0 is connected to one end of the output capacitor C0 and to one DC output terminal A1. Output capacitor C0
Is connected to ground GND and to the other DC output terminal A2 via a small resistor R4 for detecting output current. The one DC output terminal A1 is connected to an output voltage detection terminal f via an output voltage detection resistor R3, and the other DC output terminal A2 is connected to an output current detection terminal g.

Next, the configuration of the inverter circuit 2 shown in FIG. 4 will be described. The inverter circuit 2 is connected between a pair of DC output terminals A1 and A2 of the DC booster circuit 1 described above.
Four switching elements Q2 to Q made of MOSFET
5, a first state in which switching elements Q2 and Q5 are on and Q3 and Q4 are off, and a second state in which switching elements Q2 and Q5 are off and switching elements Q3 and Q4 are on. Is alternately inverted by the drive circuit 21. Note that when the first state and the second state alternate, a dead-off time may be provided in which all the switching elements Q2 to Q5 are simultaneously turned off. The drive circuit 21 includes a control signal for turning on and off the switching elements Q2 and Q5 from a control circuit 4 described later, and a switching element Q
Control signals for turning on and off 3 and Q4 are supplied. The operating power of the drive circuit 21 is supplied from a capacitor C3 connected to the control power circuit 5 of the DC booster circuit 1. The connection point between the switching elements Q2 and Q3 is one output terminal B1 of the inverter circuit 2, and the connection point between the switching elements Q4 and Q5 is the other output terminal B2 of the inverter circuit 2.

Next, the configuration of the igniter circuit 3 shown in FIG. 5 will be described. A capacitor C4 is connected in parallel between the pair of output terminals B1 and B2 of the inverter circuit 2, and a discharge lamp LP is connected via a secondary winding of the pulse transformer PT. When the pulse transformer PT generates a high-voltage pulse, the high-voltage pulse is applied to both ends of the discharge lamp LP via the capacitor C4. A primary circuit of the pulse transformer PT is provided with a series circuit of capacitors C1 and C2 for storing energy for pulse generation, and constitutes a voltage doubler rectifier circuit with the diodes D1 and D2. That is, when one output terminal B1 of the inverter circuit 2 is at a high potential, the diode D1, the charging current limiting resistor R5, the capacitor C1, and the cutoff circuit S
A charging current flows through the path of W and the other output terminal B2 of the inverter circuit 2, and a charging voltage V1 is obtained in the capacitor C1. Also, the other output terminal B2 of the inverter circuit 2
Is high potential, the shutoff circuit SW, the capacitor C2,
A charging current flows through the path of the charging current limiting resistor R6, the diode D2, and one output terminal B1 of the inverter circuit 2, and a charging voltage V2 is obtained at the capacitor C2. The voltage (V1 + V) obtained in the series circuit of the capacitors C1 and C2
2) is divided by the resistors R7 and R8 and the capacitor C
When the voltage exceeds the breakover voltage of the trigger element Q6, the trigger element Q6 conducts,
A trigger signal is supplied to the gate of the thyristor Q via the gate resistor R9 to turn on the thyristor Q, and the charges of the capacitors C1 and C2 are discharged to the primary winding of the pulse transformer PT, and the primary winding and the secondary winding A high-voltage pulse voltage corresponding to the step-up ratio of the line is generated in the secondary winding. The thyristor Q is connected in parallel with a diode D4 for flowing an oscillating current in the reverse direction.

In this embodiment, as shown in FIG. 5, a cutoff circuit SW is inserted in a path through which the charging current I _R of the capacitors C1 and C2 flows, and after the thyristor Q is turned on by the control circuit 4 described later, the thyristor Q is turned on. Is controlled so as to turn off the cutoff circuit SW for a predetermined time T1 required for self-extinguishing. The cutoff circuit SW may be inserted into the path through which the charging current I _R of the capacitor C1, C2, but inserting a blocking circuit in the path between the diode D1, one output terminal B1 of the connection point between the inverter circuit 2 of D2 Then, since a high-voltage pulse is applied to the cutoff circuit, a high withstand voltage element is required as the cutoff circuit. As shown in FIG.
1 and C2 and the other output terminal B2 of the inverter circuit 2 by inserting a cutoff circuit SW into the discharge lamp L
Since it is connected to the low-voltage side terminal LV of P, the shutoff circuit S
As W, a low breakdown voltage element can be used. Also,
By providing the cutoff circuit SW in the charging current path of the capacitors C1 and C2, an element having a relatively low current capacity can be used. As the cutoff circuit SW, M
A separately-excited switching element that can be turned on and off by a drive signal, such as an OSFET or a bipolar transistor, is used. However, when driven directly from the control power supply 5, an insulating element such as a photo MOS relay is used.

Next, the configuration of the control circuit 4 shown in FIG. 6 will be described. The control circuit 4 controls the operation of the DC booster circuit 1 shown in FIG. 3 and the inverter circuit 2 shown in FIG. 4, and has an arithmetic and logic circuit 40 for controlling the switch element of the cutoff circuit SW. Reference numeral 41 denotes an ILA detecting unit which detects a current output from the DC booster circuit 1 to the inverter circuit 2 by the resistor R4 in FIG. 3 and inputs the detected current to the arithmetic and logic circuit 40 as a detected value of the lamp current ILA. Reference numeral 42 denotes a VLA detector, which is a DC booster 1
The voltage of the smoothing capacitor C0 is detected via the resistor R3 in FIG. 3 and is input to the arithmetic and logic circuit 40 as a detected value of the lamp voltage VLA. Reference numeral 43 denotes a primary side detection unit which detects a timing at which the energy of the transformer T1 is released by detecting a voltage between both ends of the switching element Q1 of the DC booster circuit 1, and inputs the timing to the arithmetic and logic circuit 40. A power command value setting unit 44 sets lamp power and inputs the power to the arithmetic and logic circuit 40. The calculation and logic circuit 40 calculates the lamp power from the lamp current detected by the ILA detection unit 41 and the lamp voltage detected by the VLA detection unit 42, and matches the lamp power set by the power command value setting unit 44. Thus, the control signal for the switching element Q1 of the DC booster circuit 1 is created. This control signal is output via the primary drive circuit 45,
The voltage is divided by the resistors R1 and R2 and supplied between the gate and source of the switching element Q1. Reference numeral 46 denotes an input voltage detection unit which monitors the input voltage when the DC power supply E has a voltage fluctuation like a vehicle-mounted battery. 4
Reference numeral 7 denotes a secondary drive circuit, which supplies a pair of control signals to the drive circuit 21 of the inverter circuit 2 based on a low-frequency signal output from the arithmetic and logic circuit 40. Reference numeral 48 denotes an IC power supply unit, which is supplied with a low DC voltage from the control power supply 5 of the DC booster circuit 1 and serves as an operation power supply of the arithmetic and logic circuit 40 and operates the primary drive circuit 45 and the secondary drive circuit 47. Power supply. The arithmetic and logic circuit 40 outputs an ON / OFF control signal to the switch element of the cutoff circuit SW.

FIG. 7 is a waveform chart for explaining the operation of this embodiment. As shown in FIG. 7, immediately after the self-extinguishing type switching element Q of the pulse generating circuit is turned on, a predetermined time T
By turning off the cutoff circuit SW during the period of 1, the self-turn-off type switching element Q can be turned off without fail. As a result, the charging current I _R can be increased without being limited to the holding current I _H of the self-extinguishing type switching element Q or less as in the related art. Thus, it is possible to improve the startability.

(Embodiment 3) FIG. 8 shows a main configuration of Embodiment 3 of the present invention. In the present embodiment, a blocking circuit SW is provided on the ground side of the DC voltage input in the inverter circuit of the second embodiment shown in FIG. Instead, the igniter circuit 3 of the present embodiment is as shown in FIG. 9, and the igniter circuit 3 of the second embodiment shown in FIG. Other configurations are the same as in the first embodiment. That is, in the present embodiment, the DC booster circuit 1 shown in FIG. 3, the inverter circuit 2 shown in FIG.
It comprises the igniter circuit 3 shown in FIG. 9 and the control circuit 4 shown in FIG.

FIG. 10 shows waveforms for explaining the operation of the present embodiment.
FIG. As shown in FIG. 10, the pulse generation circuit
At a predetermined time immediately after the self-extinguishing type switching element Q is turned on
By turning off the cutoff circuit SW during the interval T1,
The self-extinguishing type switching element Q can be reliably turned off.
it can. As a result, the charging current I _R
Is the holding current I of the self-extinguishing type switching element Q._HAnd
Can be increased without any restrictions
To increase the number of high-voltage pulses generated during operation to improve startability
It becomes possible.

Further, by providing the cutoff circuit SW on the ground side of the DC voltage input of the inverter circuit 2, the drive circuit of the cutoff circuit SW can be downsized. Further, it can also be used as a cutoff switch at the time of a short circuit failure of the full bridge circuit of the inverter circuit 2.

(Embodiment 4) FIG. 11 shows a configuration of a main part of Embodiment 4 of the present invention. In this embodiment, the second embodiment shown in FIG.
In the control circuit 4, the control signal to the switch element of the cutoff circuit SW is omitted, and the switching elements Q2 to Q5 of the inverter circuit 2 are also used as the switch elements of the cutoff circuit SW. For other configurations, see Example 2,
Same as 3. That is, in the present embodiment, the DC booster circuit 1 shown in FIG. 3, the inverter circuit 2 shown in FIG.
The igniter circuit 3 shown in FIG. 11 and the control circuit 4 shown in FIG.
It is composed of

FIG. 10 is a waveform chart for explaining the operation of this embodiment. As shown in FIG. 10, the shut-off circuit SW is turned off for a predetermined time T1 immediately after the self-extinguishing type switching element Q of the pulse generation circuit is turned on. That is, in this embodiment, all the switching operations of the inverter circuit 2 are performed. Element Q
By turning off Q2 to Q5 for a predetermined time T1,
The self-extinguishing type switching element Q can be reliably turned off. This allows the charging current I
_{Since R} can be increased without being limited to the holding current I _H of the self-extinguishing type switching element Q or less, it is possible to increase the number of high voltage pulses generated at the time of startup and improve the startability. Further, by using the switching elements of the cutoff circuit SW as the switching elements Q2 to Q5 of the inverter circuit 2, the drive circuit of the cutoff circuit SW can also be used as the drive circuit 21 of the inverter circuit 2.

(Embodiment 5) FIG. 12 is a waveform diagram for explaining the operation of Embodiment 5 of the present invention. This embodiment is similar to the fourth embodiment.
Similarly, the switching elements Q2 to Q2 of the inverter circuit 2
Q5 is also used as a switch element of the cutoff circuit SW. The DC booster circuit 1 shown in FIG. 3, the inverter circuit 2 shown in FIG. 4, the igniter circuit 3 shown in FIG.
The control circuit 4 shown in FIG.

As described above, when the switching elements Q2 to Q5 of the full bridge circuit of the inverter circuit 2 are also used as the switching elements of the cutoff circuit SW, FIG.
As shown in the figure, the dead-off time when the ON / OFF of the switching elements Q2 to Q5 of the full bridge circuit of the inverter circuit alternately changes to a predetermined time T1 when no load is applied (the arc-extinguishing time of the self-extinguishing type switching element Q). With the above, the self-extinguishing type switching element Q can be reliably turned off.

As a result, the charging current I _R can be increased without being limited to the holding current I _H of the self-extinguishing type switching element Q or less, unlike the related art.
It is possible to increase the number of high voltage pulses generated at the time of starting, and to improve the startability. The switching elements of the cutoff circuit SW are replaced with the switching elements Q2 to Q5 of the inverter circuit 2.
The drive circuit of the inverter circuit 2 can also serve as the drive circuit of the cutoff circuit SW. Also,
In this embodiment, the control of the inverter circuit 2 is simplified as compared with FIG.

(Embodiment 6) FIG. 13 is a waveform diagram for explaining the operation of Embodiment 6 of the present invention. This embodiment is also similar to the fourth embodiment.
Similarly, the switching elements Q2 to Q2 of the inverter circuit 2
Q5 is also used as a switch element of the cutoff circuit SW. The DC booster circuit 1 shown in FIG. 3, the inverter circuit 2 shown in FIG. 4, the igniter circuit 3 shown in FIG.
The control circuit 4 shown in FIG.

As described above, when the switching elements Q2 to Q5 of the full bridge circuit of the inverter circuit 2 are also used as the switching elements of the cutoff circuit SW, as shown in FIG. As shown in FIG. 13, instead of charging the capacitor in alternate cycles, the capacitor is charged in multiple cycles of the inverter output polarity, and then ON / OFF of the switching elements Q2 to Q5 of the full bridge circuit of the inverter circuit. Is set to a predetermined time T1 (the arc-extinguishing time of the self-extinguishing type switching element Q) when no load is applied,
The self-extinguishing type switching element Q can be reliably turned off.

As a result, the charging current I _R can be increased without being limited to the holding current I _H of the self-extinguishing type switching element Q or less as in the prior art.
It is possible to increase the number of high voltage pulses generated at the time of starting, and to improve the startability. The switching elements of the cutoff circuit SW are replaced with the switching elements Q2 to Q5 of the inverter circuit 2.
The drive circuit of the inverter circuit 2 can also serve as the drive circuit of the cutoff circuit SW. Also,
In the present embodiment, the control for changing the output polarity of the full bridge circuit of the inverter circuit becomes simpler than in FIG.

Although a voltage doubler charging circuit is used as a charging circuit for the igniter circuit 3 in FIG. 9, a half-wave rectifying circuit or a full-wave rectifying circuit may be used, and there is no particular limitation. Further, the voltage may be increased or decreased by a transformer method.

(Embodiment 7) FIG. 14 shows Embodiment 7 of the present invention. Hereinafter, the circuit configuration will be described. The DC power supply E is composed of a battery or the like, and is connected to a series circuit of the primary winding of the step-up transformer T1 of the DC step-up circuit 1 and the switching element Q1. A capacitor C0 is connected to a secondary winding of the step-up transformer T1 via a diode D0. The DC voltage charged in the capacitor C0 is converted into a low-frequency AC voltage by the inverter circuit 2 and applied to the discharge lamp LP via the secondary winding of the pulse transformer PT. A pulse energy charging capacitor C is connected to the primary side of the pulse transformer PT via a self-extinguishing type switching element Q. In order to charge the capacitor C, an auxiliary winding is provided in the secondary winding of the step-up transformer T1 of the DC step-up circuit 1. The capacitor C is charged via the diode D and the resistor R by the voltage obtained on the auxiliary winding and the secondary winding of the step-up transformer T1.
ON / OFF of switching element Q1 of DC booster circuit 1
A control circuit 4 for controlling the input voltage of the inverter circuit 2 monitors the input voltage of the inverter circuit 2.
It is possible to determine whether or not is lit.

FIG. 15 is a diagram for explaining the operation of this embodiment. In the present embodiment, a part of the charging circuit of the igniter circuit 3 and a part of the DC booster circuit 1 are shared, and the switching element Q1 of the DC booster circuit 1 is also used as a switch element of the cutoff circuit. Switching element Q1 of DC booster circuit 1
Is turned on and off at a high frequency, the capacitor C for charging pulse energy of the igniter circuit 2 is charged. When the charging voltage Vc reaches the breakover voltage of the self-extinguishing type switching element Q, the capacitor C
Is discharged to the primary winding of the pulse transformer PT, a high-voltage pulse voltage is generated in the secondary winding of the pulse transformer PT, and applied to the discharge lamp LP. When the discharge lamp LP is turned on, the input voltage of the inverter circuit 2 decreases. Therefore, a change in the voltage is monitored by the control circuit 4 to determine the lighting.
When it is determined that the discharge lamp LP is turned on, the switching element Q1 of the DC booster circuit 1 is kept on and off.
When it is determined that the discharge lamp LP is not lit, the on / off operation of the switching element Q1 of the DC booster circuit 1 is temporarily stopped for a predetermined time T1 (the arc extinguishing time of the self-extinguishing type switching element Q or longer). ), The charging current to the pulse energy charging capacitor C of the igniter circuit 3 is stopped, and the self-extinguishing type switching element Q is reliably turned off. Then, after a predetermined time T1 has elapsed,
The operation of charging the capacitor C of the igniter circuit 2 is repeated by turning on and off the switching element Q1 of the DC booster circuit 1 at a high frequency again.

As a result, the charging current I _R can be increased without being limited to the holding current I _H of the self-extinguishing type switching element Q or less as in the conventional case.
It is possible to increase the number of high voltage pulses generated at the time of starting, and to improve the startability. Further, by using the switching element of the cutoff circuit as the switching element Q1 of the DC booster circuit 1, the drive circuit of the cutoff circuit can also be used as the drive circuit of the DC booster circuit.

(Embodiment 8) FIG. 16 shows a main part of an embodiment 8 of the present invention. In the present embodiment, the second embodiment shown in FIG.
In the DC booster circuit 1 of this embodiment, a cutoff circuit SW is provided at a DC voltage input unit. Instead, the igniter circuit 3 of the present embodiment is as shown in FIG. 9, and the igniter circuit 3 of the second embodiment shown in FIG.
In the igniter circuit 3 described above, the cutoff circuit SW is short-circuited. Other configurations are the same as in the first embodiment. That is, the present embodiment includes the DC booster circuit 1 shown in FIG. 16, the inverter circuit 2 shown in FIG. 4, the igniter circuit 3 shown in FIG. 9, and the control circuit 4 shown in FIG. . The control power supply 5 is configured to be able to supply a current directly from the DC power supply E without passing through the cutoff circuit SW.

In the present embodiment, the shut-off circuit SW is turned off for a predetermined time T1 immediately after the self-turn-off type switching element Q of the pulse generation circuit is turned on, so that the self-turn-off type switching element Q is turned off without fail. Can be done.
As a result, the charging current I _R can be increased without being limited to the holding current I _H of the self-extinguishing type switching element Q or less as in the related art. Thus, it is possible to improve the startability.

Further, by providing the cutoff circuit SW at the DC voltage input portion of the DC booster circuit 1, the drive circuit of the cutoff circuit SW can be reduced in size as compared with the second embodiment. Further, it can also be used as a cutoff switch at the time of a short-circuit failure of the DC booster circuit 1 or the like.

(Embodiment 9) FIG. 17 shows the configuration of Embodiment 9 of the present invention. In the figure, E denotes a DC power supply, which is composed of a vehicle-mounted battery or the like. Reference numeral 12 denotes an orthogonal transformer, which includes a DC booster circuit that boosts the DC power supply E and controls power supplied to a discharge lamp as a load, and an inverter circuit that converts the boosted DC voltage into an AC voltage. I have. Numeral 31 denotes a parallel charging / series discharging charging circuit which charges the capacitor C1 in parallel with the diode D1 and the capacitor C2 in parallel with the diode D2 when the discharging switch S is off, and turns on the discharging switch S. In this state, the capacitors C1 and C2 can be discharged in series. SW is a switch element of the cutoff circuit. When the parallel charging of the capacitors C1 and C2 is completed, the switch SW is turned off, the discharge switch S is turned on, and the self-extinguishing type switching element Q is triggered. Discharge C2 in series. Thereafter, the discharge switch S is turned off, and when the discharge lamp is not lit, after a predetermined time T1 (equal to or longer than the arc extinguishing time of the self-extinguishing type switching element Q) has elapsed,
By turning on the switch element of the cutoff circuit SW, the capacitors C1 and C2 are charged again in parallel. Thus, it is possible to reliably turn off the self extinguishing type switching element Q, as in the prior art, the charging current I _R without being limited to not more than the holding current I _H of the self extinguishing type switching elements Q Since it can be increased, it is possible to increase the number of occurrences of the high voltage pulse at the time of starting, and to improve the startability. In addition, according to the configuration of the present embodiment, a charging circuit of a parallel charging / series discharging method is used to charge a high voltage to a capacitor for charging pulse energy, so that a voltage doubler rectifier circuit is used. In addition, it is not necessary to invert the polarity of the input voltage, and therefore, it is not necessary to operate the inverter circuit 2 until the discharge lamp is started, so that the control is simplified.

[0035]

According to the present invention, a DC power supply, a DC booster circuit for boosting the DC power supply and controlling power supplied to a discharge lamp as a load, and converting the boosted DC voltage to an AC voltage. In a discharge lamp lighting device including an inverter circuit for supplying a discharge lamp as a load, an igniter circuit for applying a high-voltage pulse at the time of starting the discharge lamp as a load, and a discharge lamp as a load, when the igniter circuit is started. If the discharge lamp does not start after the self-arc-extinguishing element is turned on and the self-arc-extinguishing element is turned on, at least the self-extinguishing element is necessary to ensure self-extinguishing. For a short period of time, a shut-off circuit for cutting off the current supply to the igniter circuit is provided. The pulse in generating possible small it is possible to provide a discharge lamp lighting device suitable for low-cost vehicles.

[Brief description of the drawings]

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

FIG. 2 is a waveform chart for explaining the operation of the first embodiment of the present invention.

FIG. 3 is a circuit diagram of a DC booster circuit unit according to a second embodiment of the present invention.

FIG. 4 is a circuit diagram of an inverter circuit unit according to a second embodiment of the present invention.

FIG. 5 is a circuit diagram of an igniter circuit unit according to a second embodiment of the present invention.

FIG. 6 is a circuit diagram of a control circuit unit according to a second embodiment of the present invention.

FIG. 7 is a waveform chart for explaining the operation of the second embodiment of the present invention.

FIG. 8 is a circuit diagram of an inverter circuit unit according to a third embodiment of the present invention.

FIG. 9 is a circuit diagram of an igniter circuit unit according to a third embodiment of the present invention.

FIG. 10 is a waveform chart for explaining the operation of the third embodiment of the present invention.

FIG. 11 is a circuit diagram of a control circuit unit according to a fourth embodiment of the present invention.

FIG. 12 is a waveform chart for explaining the operation of the fifth embodiment of the present invention.

FIG. 13 is a waveform chart for explaining the operation of the sixth embodiment of the present invention.

FIG. 14 is a circuit diagram of a seventh embodiment of the present invention.

FIG. 15 is a flowchart for explaining the operation of the seventh embodiment of the present invention.

FIG. 16 is a circuit diagram of a DC booster circuit unit according to an eighth embodiment of the present invention.

FIG. 17 is a circuit diagram of a ninth embodiment of the present invention.

FIG. 18 is a circuit diagram of a conventional example.

FIG. 19 is a waveform chart for explaining the operation of the conventional example.

FIG. 20 is a characteristic diagram for explaining the operation of the conventional example.

[Explanation of symbols]

 SW cutoff circuit LP discharge lamp 31 charging circuit 32 pulse generation circuit C capacitor for pulse generation Q switching element (self-extinguishing type) PT pulse transformer

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoshiyuki Inada 1048 Kazumasa Kadoma, Osaka Prefecture Matsushita Electric Works, Ltd. Reference) 3K072 AA01 BA05 CA16 DD07 DE05 GA03 GB18 GC04 3K083 AA05 AA27 AA49 AA62 BA02 BC03 BC33 BC43 BD15 BD22 BE05 BE09 BE13 CA32

Claims (9)

[Claims] A DC power supply; a DC booster circuit for boosting the DC power supply to control power supplied to a discharge lamp as a load;
It is composed of an inverter circuit that converts the boosted DC voltage into an AC voltage and supplies it to the discharge lamp that is a load, an igniter circuit that applies a high-voltage pulse at the time of starting the discharge lamp that is a load, and a discharge lamp that is a load. If the discharge lamp does not start after the self-extinguishing element has been turned on, the self-extinguishing element must be at least turned off. A discharge lamp lighting device, comprising: a cutoff circuit for cutting off a current supply to an igniter circuit for a time necessary for the mold element to surely extinguish itself. 2. The discharge lamp lighting device according to claim 1, wherein said cut-off circuit is provided in a charging circuit for charging a capacitor for generating a high-voltage pulse at the time of starting the igniter circuit. 3. The discharge lamp according to claim 1, wherein said shutoff circuit comprises a switching element inserted into an input portion of said inverter circuit and a control circuit for shutting off said switching element for a predetermined time. Lighting device. 4. The discharge lamp lighting device according to claim 1, wherein the switching circuit comprises a switching element forming an inverter circuit and a control circuit for cutting off the switching element for a predetermined time. 5. The discharge lamp lighting device according to claim 1, wherein said shut-off circuit is constituted by a switching element constituting a DC booster circuit and a control circuit for shutting off the switching element for a predetermined time. 6. The discharge lamp lighting device according to claim 1, wherein the switching element constituting the shutoff circuit is a separately-excited switching element. 7. A charging circuit according to claim 1, wherein the charging circuit for charging the capacitor for generating a high-voltage pulse at the time of starting the igniter circuit is a circuit that double-rectifies an AC voltage output from the inverter circuit. A discharge lamp lighting device, comprising: 8. The method according to claim 4, wherein the dead-off time of the switching element constituting the inverter circuit is set to be at least longer than a time required for the self-extinguishing element to reliably self-extinguish under no load. Discharge lamp lighting device characterized by the above-mentioned. 9. The lighting device according to claim 5, wherein a lighting determination is performed immediately after the pulse is generated, and when the discharge lamp is not started, at least a self-extinguishing type element assures self-extinguishing of a switching element constituting the DC boosting circuit. A discharge lamp lighting device characterized in that the discharge lamp lighting device is turned off for a time necessary for the discharge.