JP3218721B2 - Discharge lamp lighting device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lighting device for a discharge lamp.

[0002]

2. Description of the Related Art There is known a discharge lamp lighting device in which when a discharge lamp cannot be started within a predetermined time, it is determined that the lamp cannot be turned on and power supply to the discharge lamp is stopped (for example, Japanese Utility Model Application Laid-Open No. HEI 3-103). No. 118595).

FIG. 12 shows the structure of this type of discharge lamp lighting device. When the light switch 2 is turned on, the booster circuit 1 boosts the voltage of the battery 3 and outputs a high DC voltage.
The inverter 4 converts a DC voltage output from the booster circuit 1 into an AC voltage, and applies the AC voltage to the discharge lamp 5 to light it.
The starting circuit 6 generates a high-voltage pulse for a predetermined time after the light switch 2 is turned on, applies the high-voltage pulse to the discharge lamp 5, and starts the discharge lamp 5. When the power of the battery 3 is supplied via the light switch 2, the control circuit 7 controls the booster circuit 1, the inverter 4 and the starting circuit 6 to control the lighting of the discharge lamp 5.

FIG. 13 shows details of external wiring from the lighting device to the discharge lamp and the discharge lamp. A discharge lamp lighting device 10 including a booster circuit 1, an inverter 4, a starter circuit 6, and a control circuit 7 is connected to the discharge lamp 5 via a high-voltage cable 8a, a connector 9, and a high-voltage cable 8b. Discharge lamp 5
Has a discharge lamp bulb 5b enclosed in an outer tube 5a.

FIG. 14 is a flowchart showing the operation of the conventional discharge lamp lighting device. In step S1, it is determined whether or not the light switch 2 is turned on. When the light switch 2 is turned on, the process proceeds to step S2, where the booster circuit 1 is turned on.
In addition, the discharge lamp 5 is activated by activating the inverter 4 and the activation circuit 6. Subsequent step S3
It is determined whether or not the discharge lamp 5 is turned on, and if it is turned on, the process proceeds to step S4, and if not, the process proceeds to step S7.
In step S4, the discharge lamp 5 is stably turned on by controlling the booster circuit 1 and the inverter 4. In step S5, it is determined whether or not the light switch 2 is turned off. If the light switch 2 is turned off, the process proceeds to step S6.
Return to 4. In step S6, the operations of the booster circuit 1 and the inverter 4 are stopped, and the discharge lamp 5 is turned off.

If the discharge lamp 5 has not been turned on in step S3, the operation proceeds to step S7, where it is determined whether or not a predetermined time has elapsed. If it has elapsed, the operation proceeds to step S8, and if not, the operation returns to step S2. In step S8, the operations of the booster circuit 1, the inverter 4, and the starter circuit 6 are stopped, and the process proceeds to step S9. In step S9, it is determined whether or not the light switch 2 has been turned off. When the light switch 2 has been turned off, the lighting control of the discharge lamp 5 ends.

Further, a lighting device (for example, see Japanese Utility Model Application Laid-Open No. 2-54657) that detects damage to the lens of the discharge lamp and turns off the light, and a lighting device that stops supplying power to the lighting device when the connector is disconnected (for example, A lighting device that stops supplying power to a lighting device when an abnormality such as an output voltage or an output current of a circuit is detected (see, for example, Japanese Patent Application Laid-Open No. 3-179694). Etc. are known.

[0008]

However, in the above-described conventional discharge lamp lighting device, when the discharge lamp is not lit, a high-voltage pulse is applied for a predetermined time and the startup is repeated. If the lamp does not turn on due to some failure, even a normal circuit or device may be damaged if the startup is forcibly repeated.

[0009] Further, abnormalities in the output voltage and output current of the circuit cannot be detected unless the lighting device is actually operated. However, although the discharge lamp itself or the external wiring from the lighting device to the discharge lamp has a failure, operating the lighting device may damage even normal circuits and devices.

An object of the present invention is to detect a faulty circuit or device without damaging a normal circuit or device.

[0011]

The present invention will be described with reference to FIG. 1 which is a diagram corresponding to the claims. A first aspect of the present invention is a lighting circuit 101 for lighting a discharge lamp 100, a discharge lamp 100 and a lighting circuit. The present invention is applied to a discharge lamp lighting device including a failure diagnosis circuit 102 for diagnosing a failure of the discharge lamp 101. The failure diagnosis circuit 102 performs failure diagnosis of the discharge lamp 100 and external wiring from the lighting circuit 101 to the discharge lamp 100. If not, the above object is achieved by performing a failure diagnosis of the lighting circuit 101. Further, according to the invention of claim 2, the failure diagnosis device 102A diagnoses the external wiring from the discharge lamp 100 and the lighting circuit 101 to the discharge lamp 100, and if the discharge lamp 100 is not damaged and the external wiring is not broken, the lighting circuit 101 Is diagnosed as to whether or not the output is short-circuited. If the output is not short-circuited, the lighting circuit 101 is operated to make a diagnosis.

[0012]

When the failure diagnosis of the discharge lamp 100 and the lighting circuit 101 is performed, first, the failure diagnosis of the external wiring from the discharge lamp 100 and the lighting circuit 101 to the discharge lamp 100 is performed. Perform failure diagnosis. As a result, when the discharge lamp 100 is damaged, or when there is a failure such as disconnection, contact failure, or short circuit in the external wiring, the lighting circuit 101 is activated to damage a normal circuit or device. Absent.

[0013]

FIG. 2 is a block diagram showing the configuration of one embodiment. It should be noted that the same devices as those in FIG. 12 described above are denoted by the same reference numerals, and the description will focus on differences. Control circuit 11
When the power of the battery 3 is supplied via the light switch 2, the controller controls the booster circuit 1, the inverter 4 and the starter circuit 6 to control the lighting of the discharge lamp 12, and receives a command signal from the failure detection circuit 13. The failure diagnosis operation of each circuit is performed based on the circuit. The failure detection circuit 13 detects a failure of the booster circuit 1, the inverter 4, the starting circuit 6, and the discharge lamp 12, and when a failure is found, a failure indicator lamp 14 corresponding to each of the circuits 1, 4, 6, and the discharge lamp 12. To 17 are turned on. The indicator lamp 18 is a warning lamp for urging the replacement of the discharge lamp 12.

FIG. 3 shows a main circuit of the discharge lamp lighting device 20. The outline of each circuit will be described with reference to FIG. The booster circuit 1 includes a well-known chopper circuit and the like, and includes a battery 3
The DC voltage supplied from is converted to an AC voltage once, boosted, converted to a DC voltage again, and output. When the PWM control signal Sg1 is supplied from the control circuit 11 to the gate of the FET 6, the charge of the capacitor C1 is
Discharge through the primary winding of R2 and FET6, PWM
An alternating current having the frequency of the control signal Sg1 flows. As a result, an AC high voltage corresponding to the turn ratio is induced in the secondary winding of the transformer TR2. This AC high voltage is a diode D
1 and smoothed by a capacitor C2 to generate a DC high voltage Vdc.

The inverter 4 comprises four FETs 1 to 4 and the like. The FET 1 and the FET 4 and the FET 2 and the FET 3 are turned on alternately according to a control signal Sg 2 from the control circuit 11. As a result, the polarity of the DC high voltage Vdc applied to the discharge lamp 12 is periodically switched. That is, an AC high voltage is applied to the discharge lamp 12. The starting circuit 6
T5, capacitor C4, transformer TR1, etc.
When a pulse train control signal Sg3 is supplied from the control circuit 11 to the gate of the FET 5, the charge of the capacitor C4 charged via the diode D2 is discharged through the primary winding of the transformer TR1 and the FET 5, and the pulse train primary current is discharged. Flows. As a result, a high-voltage pulse train corresponding to the turn ratio is induced in the secondary winding of the transformer TR1, and these pulse voltages are superimposed on the DC high voltage Vdc described above and applied to the discharge lamp 12 as the starting voltage Vbd. Is done.

In this embodiment, the self-diagnosis of the discharge lamp 12 and the lighting device 20 at the time of startup is performed in the following procedure. (1) Is the outer tube of the discharge lamp 12 damaged? Is the high-voltage cable broken? Check for loose connectors and poor contact. (2) Is there a short circuit failure in the output of the lighting device 20? (3) Does the booster circuit 1 operate normally? (4) Do the inverter 4 and the start circuit 6 operate normally? These diagnoses are executed by the failure detection circuit 13 and the control circuit 11, and when any one of the failures is detected, the corresponding failure indicator lamps 14 to 18 are turned on.

Of the above diagnostic items, items (1) and (2) are serious faults in which the normal circuit and equipment are damaged when the discharge lamp 12 is started, and the faulty portion is enlarged. Then, the diagnosis of the items (3) and (4) is stopped, and the activation of the discharge lamp 12 is prohibited. As a result of the diagnosis of the items (1) and (2), if there is no abnormality, the process proceeds to the diagnosis of the item (3).
In the diagnosis of the item (3), it is determined whether or not the output voltage Vdc of the booster circuit 1 is equal to or more than a specified value. However, when the output voltage Vdc is lower than the specified value, it is highly likely that the output voltage Vdc is caused by the voltage drop of the battery 3 as described above, and the discharge lamp 12 and the lighting device 20 determine in the diagnosis of the items (1) and (2). Since it has been diagnosed that there is no failure in the external wiring up to the discharge lamp 12, the discharge lamp 12 is started as it is, and the diagnosis of the following item (4) is executed. In the diagnosis of the item (4), it is checked whether or not the starting voltage Vbd of the inverter 4 and the starting circuit 6 is equal to or more than a specified value. However, even if the starting voltage Vbd is lower than the specified value, it may be caused by the voltage drop of the battery 3.
Since it has been diagnosed in (1) and (2) that there is no failure in the discharge lamp 12 and the external wiring from the lighting device 20 to the discharge lamp 12, the startup is continued as it is.

First, the diagnosis circuit and the diagnosis method of the item (1) will be described. FIG. 4A shows details of a part of the lighting device, the discharge lamp, and the external wiring between them, and FIG.
FIG. 4 is an arrow view of the discharge lamp 12 shown in FIG. The discharge lamp 12 has a discharge lamp bulb 12b sealed in an outer tube 12a, and a conductive line 12c deposited on the inner surface of the outer tube 12a.
The high pressure cable 2 from the starting circuit 6 is connected to the discharge lamp bulb 12b.
1, a drive voltage is applied via the connector 22 and the high-voltage cable 23.

On the other hand, the conductive line 12c of the discharge lamp 12 is connected to a failure detection circuit 13 through a high voltage cable 23, a connector 22, and a high voltage cable 21.
From the power supply Vcc to the resistor R2 → the signal line 21a → the connector 22 → the signal line 23a → the conductive line 12c → the signal line 23
A signal current flows through a path of b → connector 22 → signal line 21b → resistor R4 → base of transistor T1 → T1 emitter → ground, and transistor T1 turns on, and its collector potential V1 becomes low level. Now, the outer tube 12a of the discharge lamp 12 is damaged and the conductive line 12c is disconnected,
If the high-voltage cables 21 and 23 are disconnected,
Is disconnected or the connector 22 has a contact failure, the path becomes non-conductive and the signal current becomes zero, or the contact failure increases the impedance of the circuit and decreases the signal current. As a result, the transistor T1 is turned off or close to off, and the collector potential V1 becomes high level. This collector potential V1
Is measured, and if it exceeds a preset value, it is determined that there is damage to the discharge lamp 12, disconnection of the high-voltage cables 21, 23, poor contact of the connector 22, or disconnection. If the lighting device 20 is activated in spite of such a serious failure, a normal circuit or equipment may be damaged. When this failure is detected, the operation of the lighting device 20 is prohibited and the failure indicator 14 is turned off. Lights and warns.

Next, the diagnosis procedure of item (2) will be described with reference to FIG. From the control circuit 11 to the inverter 4
To the FETs 1 and 4 and the FE
One of the T2 and T3, for example, the FETs 1 and 4 are kept on, and the low frequency PWM control signal S
g1 is supplied to output a low DC voltage Vdc. If the bulb 12b of the discharge lamp 12 or the high voltage cable 2
When the output of the lighting device 20 such as 1, 23 is short-circuited,
FET1 → TR by DC output voltage Vdc of booster circuit 1
The current flows through the secondary winding of No. 1, the discharge lamp 12, the FET 4, and the resistor 5, and a voltage proportional to the current flowing to one terminal A of the resistor R5 is generated. Thereby, the lighting device 2
A zero output short circuit fault is detected. Activating the lighting device 20 in spite of such a serious failure may damage a normal circuit or equipment. When this failure is detected, the operation of the lighting device 20 is prohibited, and the failure indicator 15 Lights to warn.

The diagnosis of the item (3) is performed as follows. As a result of the diagnosis in the item (2), it was confirmed that the output of the lighting device 20 was not short-circuited. Therefore, the normal PWM control signal Sg1 was supplied from the control circuit 11 to the booster circuit 1 to operate the booster circuit 1. And whether the output DC voltage Vdc is equal to or higher than a specified value. If the DC output voltage Vdc is equal to or higher than the specified value, it is determined that the booster circuit 1 operates normally. As described above, even if the output voltage Vdc is lower than the specified value, it is highly likely that the output voltage Vdc is caused by the voltage drop of the battery 3, and the diagnosis of the above items (1) and (2) causes the discharge lamp 12 and the external wiring to fail. Since there is no diagnosis, the diagnosis of the following item (4) is executed.

Next, the diagnosis procedure of the item (4) will be described. As described above, the inverter 4 and the activation circuit 6 determine that the activation voltage Vbd is normal if the activation voltage Vbd is equal to or higher than the specified value. However, the starting voltage Vbd is as high as, for example, 10 kV to 20 kV, which is difficult to measure. In addition, if such a high voltage measuring circuit is added, the load may be adversely affected. The method diagnoses the inverter 4 and the starting circuit 6.

FIG. 5 shows the details of the start-up circuit 6, and FIG. 6 shows changes in the voltage and current of each part of the start-up circuit 6 shown in FIG.
The starter circuit 6 generates a pulse train current in the primary winding circuit of the transformer TR1 as described above, induces a pulse train voltage on the secondary side of the transformer TR1, superimposes the pulse train voltage on the DC voltage Vdc, and generates a starter voltage Vbd. Therefore, the transformer TR
If a pulse train current having a specified current value flows through one primary winding circuit, it can be estimated that the starting voltage Vbd is equal to or higher than the specified voltage. During the startup period of the discharge lamp 12, the capacitor C4 of the startup circuit 6 is charged by applying the voltage Vg1 from the power supply (not shown) via the diode D2. A pulse train control signal Sg3 is supplied to the gate of the FET5,
5 is turned on, the charge of the capacitor C4 is discharged, a current Io of the cycle of the pulse train signal flows through the primary winding of the transformer TR1, and a high-voltage pulse voltage with the same cycle flows through the secondary winding of the transformer TR1. That is, the starting voltage Vbd is generated. The starting voltage Vbd is proportional to the primary winding current Io of the transformer TR1, and the voltage value increases as the current Io increases. The primary winding current Io is proportional to the terminal voltage Vchg of the capacitor C4, and the higher the terminal voltage Vchg, the larger the current Io. That is, since the starting voltage Vbd is proportional to the terminal voltage Vchg of the capacitor C4, the starting voltage Vbd can be estimated by detecting the terminal voltage Vchg.

The control signal Sg3 in the form of a pulse train from the control circuit 11 is also supplied to the base of the transistor T2 via a resistor R9.
Turns on. A voltage obtained by dividing the terminal voltage Vchg of the capacitor C4 by the resistors R6 and R7 is applied to the collector of the transistor T2. Each time the transistor T2 is turned on, the divided voltage is applied to the capacitor C4 via the resistor R8.
5 to charge the capacitor C5. As a result, the terminal voltage V2 of the capacitor C5 increases with the period of the pulse train signal, and increases as the terminal voltage Vchg of the capacitor C4 increases. In this embodiment, three pulse control signals Sg3 are supplied from the control circuit 11, the terminal voltage V2 immediately after the generation of the three start-up voltage pulses Vbd is detected, and if the voltage V2 is equal to or more than a predetermined threshold value, It is determined that the normal starting voltage Vbd is applied to the discharge lamp 12, and the inverter 4 and the starting circuit 6 are operating normally.

FIG. 7 shows a modification of the starting circuit, and FIG. 8 shows changes in voltage and current of each part of the circuit. In the starting circuit 6A of this modification, the discharge gap GAP is used instead of the FET5.
Use 1. The discharge gap GAP1 discharges when the voltage between both ends reaches a predetermined value. Thyristor T during startup
When the gate signal Vg2 is applied to the gate of HY1, the thyristor THY1 is turned on, and the DC voltage Vdc of the booster circuit 1 is applied to the capacitor C4 via the thyristor THY1 to be charged, the terminal voltage Vchg of the capacitor C4 increases. When the terminal voltage Vchg reaches the discharge voltage of the discharge gap GAP1, a discharge occurs in the discharge gap GAP1, and the charge stored in the capacitor C4 is discharged, so that the transformer TR
The current Io flows through the primary winding circuit 1, and a starting voltage Vbd is generated on the secondary side of the transformer TR1. Discharge gap GA
When P1 is discharged and the current Io flows through the primary winding circuit, the terminal voltage Vchg of the capacitor C4 drops, the discharge of the discharge gap GAP1 stops, and the primary winding current Io also becomes zero. Thereafter, the capacitor C4 is charged again, and the above operation is repeated.

Since the starting voltage Vbd is proportional to the terminal voltage Vchg of the capacitor C4 as described above, this terminal voltage Vchg is used to measure the terminal voltage of the capacitor C4.
Is divided by resistors R11 and R12, and the capacitor C6 is charged through the diode D3 and the resistor R10. The terminal voltage V3 of the capacitor C6 increases rapidly as the terminal voltage Vchg of the capacitor C4 increases, and is sufficient to start the discharge lamp 12 when the terminal voltage V3 reaches a predetermined threshold value within a predetermined time after starting. The start-up voltage Vbd is applied, and it is determined that the inverter 4 and the start-up circuit 6 are normal.

According to the flowcharts shown in FIGS.
The operation of the embodiment will be described. In step S21, it is determined whether or not the light switch 2 has been turned on. If the light switch 2 has been turned on, the process proceeds to step S22, where the failure detection circuit 13 causes damage to the outer tube 12a of the discharge lamp 12, damage to the high voltage cables 21, 23, and damage to the connector 22. It is determined whether there is no disconnection, poor contact, or the like. As described above, when the voltage V1 of the failure detection circuit 13 shown in FIG. 4 exceeds a preset value, it is determined that there is any failure, and the process proceeds to step S23. Otherwise, the process proceeds to step S27. When these serious faults are detected, the operation of the booster circuit 1, the inverter 4, and the starting circuit 6 is prohibited in step S23, and the process proceeds to step S24 to turn on the fault indicator lamp 14 to warn. Thereafter, in step S25, it is determined whether or not the light switch 2 has been turned off. If the light switch 2 has been turned off, the process proceeds to step S26; otherwise, the process returns to step S23. In step S26, the failure indicator lamp 14 is turned off, and the lighting control of the discharge lamp 12 ends.

If it is determined in step S22 that there is no failure in the discharge lamp 12 and the external wiring, a low frequency PWM control signal Sg1 is output from the control circuit 11 to the booster circuit 1 in step S27. DC voltage Vdc
And test run. In the subsequent step S28, it is determined whether or not the output of the lighting device 20 is short-circuited. If a voltage is generated at one terminal A of the resistor R5 shown in FIG. Is determined to have a short circuit, and the process proceeds to step S29. Since the output short circuit of the lighting device 20 is a serious failure, the operation of the booster circuit 1, the inverter 4, and the starter circuit 6 is prohibited in step S29,
In the following step S30, the failure indicator lamp 15 is turned on. Thereafter, in step S31, it is determined whether or not the light switch 2 has been turned off. If the light switch 2 has been turned off, the process proceeds to step S26; otherwise, the process returns to step S29.

If it is determined in step S28 that the output of the lighting device 20 is not short-circuited, the process proceeds to step S35 in FIG. 10, in which the control circuit 11 outputs a normal PWM control signal Sg1 to the booster circuit 1, and the booster circuit 11 Perform a normal boost operation. In a succeeding step S36, it is determined whether or not the booster circuit 1 is normal. If the output voltage Vdc of the booster circuit 1 is equal to or more than the specified value, it is determined that the voltage is normal, and the process proceeds to step S38. Otherwise, the process proceeds to step S37 to set the failure flag F1 of the booster circuit 1.

If the output voltage Vdc of the booster circuit 1 is lower than the specified value and it is determined that there is a failure, the cause may be that the voltage of the battery 3 is low.
Since it is confirmed that there is no abnormality in the external wiring, the inverter 4 and the starting circuit 6 are operated to start the discharge lamp 12 in step S38. Then, in a step S39, it is determined whether or not the inverter 4 and the starting circuit 6 are normal. As described above, the terminal voltage V2 of the capacitor C5 of the starting circuit 6 shown in FIG. 5 exceeds the threshold value, or the capacitor C5 of the starting circuit 6A shown in FIG.
If the terminal voltage V3 exceeds the threshold value, it is determined that the inverter 4 and the start-up circuit 6 are normal, and step S4
Go to step 1, otherwise go to step S40. In step S40, a failure flag F2 of the inverter 4 and the starting circuit 6 is set.

In step S41, it is determined whether or not the discharge lamp 12 has been turned on. If the discharge lamp 12 has been turned on, the process proceeds to step S41A; otherwise, the process proceeds to step S45. Step S
After resetting the flags F1 and F2 in 41A, the booster circuit 1 and the inverter 4 are controlled to stably light the discharge lamp 12 in step S42. In a succeeding step S43, it is determined whether or not the light switch 2 is turned off. If the light switch 2 is turned off, the process proceeds to a step S44.
Return to 42. In step S44, the operations of the booster circuit 1 and the inverter 4 are stopped to turn off the discharge lamp 12, and the lighting control is ended.

If it is determined in step S41 that the lamp is not turned on, it is determined in step S45 whether or not a predetermined time has elapsed. If the predetermined time has elapsed, the flow proceeds to step S46, and if not, the flow returns to step S36. In step S46, the operations of the booster circuit 1, the inverter 4, and the starting circuit 6 are stopped, and the process proceeds to step S51 in FIG. In step S51 of FIG. 11, it is determined whether or not the failure flag F1 has been set. If so, the process proceeds to step S52, and if not, the process proceeds to step S53. In step S52, the failure indicator 16 of the booster circuit 1 is turned on. In a succeeding step S53, it is determined whether or not the failure flag F2 is set. If the failure flag F2 is set, the process proceeds to a step S54, and if not, the process proceeds to a step S55.
In step S54, the fault indicator lamp 17 of the inverter 4 and the starting circuit 6 is turned on. In step S55, as a result of the self-diagnosis, the failure in the above-described items (1) to (4) was not detected, and the discharge lamp 12 did not turn on. The warning indicator lamp 18 is turned on to prompt replacement. Thereafter, if the light switch 2 is turned off in step S56, the process proceeds to step S57, in which the flags F1 and F2 are reset, the indicators 14 to 18 are turned off, and the lighting control ends.

As described above, the discharge lamp 12 and the lighting device 2
When performing the fault diagnosis of 0, the fault diagnosis is performed according to a predetermined procedure. That is, first, the discharge lamp 12 and the lighting device 2
Diagnosis of failure of the external wiring from 0 to the discharge lamp 12 is performed, and if there is no failure such as breakage, disconnection, poor contact, etc.
It is diagnosed whether or not the output is short-circuited. If not, it is diagnosed whether the booster circuit 1 operates normally. If the booster circuit 1 operates normally, the inverter 4 and the starting circuit 6 are operated to discharge the discharge lamp 12. Is started to diagnose whether the inverter 4 and the starting circuit 6 operate normally, so that a faulty circuit or device can be detected without damaging the normal circuit or device.

The lighting circuit and the failure diagnosis circuit are not limited to the above embodiment.

In the configuration of the above embodiment, the booster circuit 1, the inverter 4, and the starter circuit 6 constitute a lighting circuit, and the failure detection circuit 13 and the control circuit 11 constitute a failure diagnosis circuit.

[0036]

As described above, according to the present invention, failure diagnosis of the external wiring from the discharge lamp and the lighting circuit to the discharge lamp is performed, and if there is no failure, the failure diagnosis of the lighting circuit is performed. A faulty circuit or device can be detected without damaging a normal circuit or device.

[Brief description of the drawings]

FIG. 1 is a diagram corresponding to claims.

FIG. 2 is a block diagram showing a configuration of one embodiment.

FIG. 3 is a circuit diagram showing a main circuit of one embodiment.

FIG. 4 is a diagram showing a part of a lighting device, a discharge lamp, and external wiring.

FIG. 5 is a circuit diagram showing details of a starting circuit.

FIG. 6 is a time chart showing changes in voltage and current of each part of the starter circuit shown in FIG. 5;

FIG. 7 is a circuit diagram showing a modified example of the starting circuit.

FIG. 8 is a time chart showing changes in voltage and current of each part of the starting circuit shown in FIG. 7;

FIG. 9 is a flowchart showing the operation of one embodiment.

FIG. 10 is a flowchart showing the operation of the embodiment following FIG. 9;

FIG. 11 is a flowchart showing the operation of the embodiment following FIG. 10;

FIG. 12 is a block diagram showing a configuration of a conventional discharge lamp lighting device.

FIG. 13 is a diagram showing external wiring and a discharge lamp of a conventional lighting device.

FIG. 14 is a flowchart showing the operation of a conventional discharge lamp lighting device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Step-up circuit 2 Light switch 3 Battery 4 Inverter 6 Starting circuit 11 Control circuit 12, 100 Discharge lamp 12a Outer tube 12b Discharge lamp valve 12c Conductive line 13 Failure detection circuit 14-18 Indicator lamp 20 Discharge lamp lighting device 21, 23 High voltage cable 21a, 21b, 23a, 23b Signal line 22 Connector 101 Lighting circuit 102 Failure diagnosis circuit R1 to R12 Resistor FET1 to 6 FET TR1 to TR2 Transformer T1 to T2 Transistor D1 to D3 Diode C1 to C6 Capacitor THY1 Thyristor GAP1 Discharge gap

Claims (2)

(57) [Claims] 1. A discharge lamp lighting device comprising: a lighting circuit for lighting a discharge lamp; and a failure diagnosis circuit for diagnosing a failure of the discharge lamp and the lighting circuit, wherein the failure diagnosis circuit comprises: A discharge lamp lighting device, wherein a failure diagnosis of an external wiring from a lighting circuit to the discharge lamp is performed, and if there is no failure, a failure diagnosis of the lighting circuit is performed. 2. The discharge lamp lighting device according to claim 1, wherein the failure diagnosis circuit diagnoses the discharge lamp and an external wiring from the lighting circuit to the discharge lamp, and damages the discharge lamp and the external circuit. A discharge lamp lighting device characterized by diagnosing whether the output of the lighting circuit is short-circuited if there is no disconnection of the wiring, and activating and diagnosing the output if not short-circuited.