JPH1167475A - Discharge lamp lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To elongate the life of a discharge lamp by lighting out or reducing the power supply upon the rapid detection of the erroneous mounting of the discharge lamp by detecting the voltage of the discharge lamp to read it every predetermined period and comparing lice voltage with a predetermined threshold value after several seconds elapsed since the start of the lighting of the discharge lamp. SOLUTION: An alternating voltage from an a.c. power source 1 is boosted and converted to d.c. voltage by an A/F2 and then limited by a current limiting circuit 3 and supplied to an inverter 4 to convert to low frequency power and thereafter, supplied to a discharge lamp 24 by way of an igniter 5 to which a starting pulse is applied. In addition, the voltage and the current of the power supply to the discharge lamp 24 is detected by a current detection circuit 6 and a voltage detection circuit 7 respectively so that the power is controlled by a control circuit 8. In the discharge lamp lighting circuit, the voltage detected by the voltage detection circuit 7 is read every predetermined period with the control circuit 8. When this read voltage exceeds a predetermined threshold value at the time several seconds has elapsed since the start of the lighting of the discharge lamp, it is judged by the inverter 4 that a low capacity discharge lamp is erroneously mounted.

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 provided with control means for quickly detecting an erroneous attachment of a discharge lamp to a discharge lamp lighting device and controlling the lighting operation of the discharge lamp.

[0002]

2. Description of the Related Art FIG. 8 is a block diagram showing a circuit configuration of a conventional discharge lamp lighting device disclosed in Japanese Patent Application Laid-Open No. Hei 5-226090. In FIG. 8, reference numeral 20 denotes a battery,
21 is a DC-D for boosting the DC voltage from the battery 20
C converter, 22 is a DC-AC inverter that converts the DC voltage boosted by the DC-DC converter 21 into AC voltage, 23 is a high-voltage pulse generating circuit that applies a high-voltage pulse for starting to the discharge lamp 24, and 25 is a DC- A voltage abnormality detection circuit that detects an abnormality in the voltage of the discharge lamp 24 from the output of the DC converter 21. The voltage division circuit 26 divides the output of the DC-DC converter 21. A comparison circuit 27 for comparing with a reference voltage, a timer circuit 29 in which a predetermined time until the voltage of the discharge lamp 24 is sufficiently stabilized is set in advance, and an output from the comparison circuit 27 after a predetermined time set in the timer circuit 29 And an OR circuit 30 that outputs a voltage abnormality signal based on the Reference numeral 31 denotes an abnormality display unit that performs an abnormality display based on the voltage abnormality signal output from the OR circuit 30, or a lighting stop circuit that stops the discharge lamp 24.

FIG. 9 shows an example of a voltage characteristic of the discharge lamp 24. In FIG. 9, for example, when a discharge lamp having an appropriate capacity, that is, a 150 W discharge lamp 24 is mounted on a 150 W discharge lamp lighting device, the voltage of the discharge lamp 24 gradually increases with the lapse of time (see FIG. 9). A pattern). Then, at the time point of the elapsed time t (minutes), the voltage of the discharge lamp 24 reaches the V1 level, and thereafter is stable. Next, when a discharge lamp having an inappropriate capacity, that is, a 70 W discharge lamp 24 is erroneously mounted on a 150 W discharge lamp lighting device, the voltage of the discharge lamp 24 gradually increases with the lapse of time (see FIG. 9). B pattern). Then, at the time point of the elapsed time t (minute), the voltage of the discharge lamp 24 becomes V
Reached level 2 and is stable thereafter. Discharge lamp 24
The rise (gradient) of the voltage and the magnitude of the absolute value of the stable voltage are as follows.
Is apparent from the voltage characteristics shown in FIG. This is because the magnitude of the impedance of the discharge lamp 24 is smaller than that of the discharge lamp 24 of 150 W <70 W.

Next, the operation of the discharge lamp lighting device will be described with reference to FIG. After the DC voltage from the battery 20 is boosted by the DC-DC converter 21,
The AC voltage is converted into AC voltage, that is, AC power by the AC inverter 22, and the AC power is supplied to the discharge lamp 24. When the discharge lamp 24 is started, a high-voltage pulse generated from the high-voltage pulse generation circuit 23 is applied to the discharge lamp 24, whereby the discharge lamp 24 starts lighting. In the voltage abnormality detection circuit 25, the reference voltage of the reference power supply 28 input to one of the comparison circuits 27 is set to a predetermined value (V2 in FIG. 9).
Level). When the 70 W discharge lamp 24 is erroneously mounted on the 150 W discharge lamp lighting device, the OR circuit 30 outputs a voltage abnormality signal based on the predetermined output from the timer circuit 29 and the predetermined output from the comparison circuit 27. Thereby, the abnormality of the voltage of the discharge lamp 24 is displayed from the abnormality display section 31, and the replacement of the discharge lamp 24 can be notified. Further, the discharge lamp 24 can be turned off by sending the voltage abnormality signal output from the OR circuit 30 to the lighting stop circuit 31.

[0005]

The conventional discharge lamp lighting device detects erroneous mounting of a discharge lamp having an inappropriate capacity when the voltage of the discharge lamp is sufficiently stabilized as described above. For this,
For example, when a 70 W discharge lamp is erroneously attached to a 150 W discharge lamp lighting device, excessive electric power is supplied to this discharge lamp only for several minutes until the erroneous attachment is detected. Therefore, there is a problem that the life of the discharge lamp is significantly shortened.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem. Immediately after lighting, erroneous mounting of a discharge lamp having an inappropriate capacity is quickly detected, and the discharge lamp is turned off or supplied to the discharge lamp. It is an object of the present invention to provide a discharge lamp lighting device capable of significantly extending the life of a discharge lamp by reducing power to a predetermined level.

[0007]

A discharge lamp lighting device according to the present invention includes a discharge lamp lighting device having a discharge lamp and an inverter circuit for supplying low frequency power to the discharge lamp. Voltage detecting means for reading the voltage of the discharge lamp detected by the voltage detecting means at predetermined time intervals is provided, and the voltage of the discharge lamp read by the voltage reading means has passed several seconds immediately after the start of lighting of the discharge lamp. When a predetermined threshold value is exceeded at a point in time, a judgment means for judging that a low-capacity discharge lamp is erroneously attached to the inverter circuit is provided.

Further, in a discharge lamp lighting device provided with a discharge lamp and an inverter circuit for supplying low-frequency power to the discharge lamp, voltage detection means for detecting the voltage of the discharge lamp is provided, and the discharge detected by the voltage detection means is provided. Voltage reading means for reading the voltage of the lamp at predetermined time intervals is provided, and calculating means for calculating a voltage gradient from the voltage of the discharge lamp read at predetermined time intervals by the voltage reading means is provided, and the voltage gradient calculated by the calculating means is a predetermined value. In the case of exceeding, the judgment circuit for judging that the low capacity discharge lamp is erroneously attached to the inverter circuit is provided.

In addition, the low frequency power supplied to the discharge lamp is cut off or the inverter circuit is controlled to reduce the low frequency power to a predetermined level based on the output from the determination means.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. FIG. 1 is a circuit block diagram illustrating an embodiment of a discharge lamp lighting device according to the present invention. In FIG. 1, reference numeral 1 denotes an AC power supply, 2 denotes an A / F (active filter) that boosts an AC voltage from the AC power supply 1 and converts the AC voltage into a DC voltage, and 3 denotes a current limiting circuit that limits a current flowing through the discharge lamp 24. , 4 is a DC voltage from the A / F2 is a low frequency voltage,
That is, an inverter for converting to low-frequency power, and 5 is a discharge lamp 24
An igniter for applying a starting pulse to the lamp; 6 a current detection circuit for detecting a current flowing through the discharge lamp 24; 7 a voltage detection circuit for detecting the voltage of the discharge lamp 24; 8 a discharge lamp current detected by the current detection circuit 6; A control circuit for controlling the current limiting circuit 3, the inverter 4, and the igniter 5 based on the discharge lamp voltage detected by the voltage detection circuit 7, respectively.
This is a lighting switch that turns N / OFF.

Next, the operation of the discharge lamp lighting device according to the present invention will be described with reference to the operation flowcharts shown in FIGS. In the main flowchart shown in FIG. 2, when the lighting switch 9 is turned on (step S10), the flag of the control circuit 8 is set to "1" (step S2).
0). Then, the inverter 4 starts driving (step S30), and thereafter, the igniter 5 starts driving (step S40), whereby a state where a start pulse is applied to the discharge lamp 24 is obtained. Next, the current A flowing through the discharge lamp 24 detected by the current detection circuit 6 is read (step S50), and the magnitude of the current A is compared with a predetermined value α (step S60). Note that the predetermined value α is the discharge lamp 24
This is a threshold value for judging the quality of the start. Here, if the condition of current A> predetermined value α is not satisfied, N
It is determined as O, and in this case, it is determined that the starting of the discharge lamp 24 is not successfully performed, and the driving of the igniter 5 is continued (step S40). Thereafter, the above operation is repeated. If the condition of current A> predetermined value α is satisfied, it is determined as YES. In this case, it is determined that the discharge lamp 24 has been successfully started, and T = n is set in the timer stored in the control circuit 8. Is performed (step S70).
Then, T = n set in this timer is instantaneously (in the order of ms) by an interrupt means described later every predetermined time.
Counted down to When the timer counts down, the operation of the main flowchart shown in FIG. 2 is interrupted.

Next, the voltage VL of the discharge lamp 24 detected by the voltage detecting circuit 7 is read (step S80).
Thereafter, it is determined whether the flag satisfies the condition of "1" (step S90). Here, if the above condition is satisfied, it is determined as YES, and it is determined whether T set in the timer satisfies the condition of T = 0 (step S100). When this condition is not satisfied, the determination is NO, and the current I of the discharge lamp corresponding to the magnitude of the voltage VL of the discharge lamp 24 is determined (step S13).
0), the control circuit 8 controls the current limiting circuit 3 so that the current I at the target level is obtained. As a result, predetermined power is supplied to the discharge lamp 24. Then, the voltage VL of the discharge lamp 24 is read again (step S80), and thereafter, the above operation is repeated.

Next, after the flag satisfies the condition of "1" and is determined as YES (step S90), when T set in the timer counts down and reaches T = 0, it is determined as YES. (Step S100). As a result, "0" is set in the flag (step S1).
10). Then, the magnitude of the voltage VL of the discharge lamp 24 and the predetermined value λ are compared (step S120), and if the discharge lamp 24 having an appropriate capacity is mounted on the lighting device, that is, 150W
When the 150 W discharge lamp 24 is mounted on the lighting device, the condition of voltage VL <predetermined value λ is satisfied, and thus the determination is YES. Note that the predetermined value λ is set to
Is a threshold value for determining whether or not is mounted.
Thereafter, the current I of the discharge lamp according to the magnitude of the voltage VL of the discharge lamp 24 is determined (step S130), and the current limiting circuit 3 is controlled by the control circuit 8 so that the current I at the target level is obtained. As a result, predetermined electric power is supplied to the discharge lamp 24. Next, the voltage VL of the discharge lamp 24 is read again (step S80), and thereafter, it is determined whether or not the flag satisfies the condition of "1" (step S9).
0). Here, since it is determined as NO, the current I of the discharge lamp according to the magnitude of the voltage VL of the discharge lamp 24 is determined again (step S130), and the control circuit 8 sets the current I to the target level. The current limiting circuit 3 is controlled. Subsequent operations are the same as described above.

Further, the magnitude of the voltage VL of the discharge lamp 24 and the predetermined value λ are compared (step S120), and if the discharge lamp 24 having an improper capacity is erroneously attached to the lighting device, ie, 15
If the 70 W discharge lamp 24 is erroneously attached to the 0 W lighting device, the condition of voltage VL <predetermined value λ is not satisfied, and thus the determination is NO. As a result, the driving of the inverter 4 is stopped to turn off the discharge lamp 24, or the inverter 4 is controlled so as to reduce the power supplied to the discharge lamp 24 to a predetermined level (step S140).

Next, the countdown operation of T = n set in the timer of the control circuit 8 will be described with reference to the interrupt flowchart shown in FIG. 3, the operation of the main flowchart shown in FIG. 2 is interrupted at predetermined time intervals to execute an interrupt operation (step S200), and thereafter, it is determined whether T set in the timer is T = 0. (Step S210). Here, when the condition of T = 0 is not satisfied, it is determined as NO, and T = n set in the timer is counted down by "1" (step S2).
20), after which the interrupt operation is interrupted (step S2)
30). Such an operation is repeated every predetermined time. When T set in the timer satisfies the condition of T = 0, it is determined as YES, and the interrupt operation ends (step S240).

FIG. 4 is a timing chart showing the temporal relationship between the operation of the main flowchart and the operation of the interrupt flowchart. In FIG. 4, during the operation of the main flowchart, the operation of the interrupt flowchart is interrupted and executed every predetermined time X (s) after the lighting switch 9 is turned on. The interruption time is instantaneous Y (ms), at which time the operation of the main flowchart is interrupted. Here, for example, when T = n (5) is set in the timer, the countdown reaches T = 0 at the fifth countdown, so that the erroneous mounting of the discharge lamp 24 is determined, and the interrupt operation ends at the sixth count.

FIG. 5 shows a pattern of the voltage characteristics of the discharge lamp 24. The voltage gradually increases with the lapse of time. Here, for example, when T = n (5) is set in the timer, the voltage is increasing, that is, t in FIG.
At the time of (seconds) × 5 (the number of interruptions), whether the discharge lamp 24 is correctly mounted or not is determined. Note that the predetermined time X is set so that t is set to several seconds or less not including zero seconds.
(Seconds) or the number of interrupts n can be arbitrarily variably adjusted. At the same time, the predetermined value λ is
It is configured to be variably set according to. A series of control programs related to the operations of the main flowchart and the interrupt flowchart are stored in the control circuit 8 in advance.

As described above, since the erroneous mounting determination function for quickly and accurately detecting whether or not the capacity of the discharge lamp 24 mounted on the lighting device is appropriate is provided.
When the 70W discharge lamp 24 is incorrectly mounted on the 0W lighting device,
The drive of the inverter 4 can be immediately stopped to turn off the discharge lamp 24, or the inverter 4 can be controlled to reduce the power supplied to the discharge lamp 24 to a predetermined level. Therefore, it is possible to provide a discharge lamp lighting device in which excessive power is not supplied to the 70 W discharge lamp 24 and the life of the discharge lamp 24 can be significantly extended.

Embodiment 2 6 and 7 are operation flowcharts for explaining another embodiment of the discharge lamp lighting device according to the present invention. Note that the block diagram showing the circuit configuration is the same as that of the first embodiment, and a description thereof will not be repeated.

Next, the operation of the discharge lamp lighting device according to the present invention will be described with reference to the operation flowcharts shown in FIGS. In the main flowchart shown in FIG. 6, when the lighting switch 9 is turned on (step S300), the inverter 4 starts driving (step S310), and then the igniter 5 starts driving (step S32).
0). As a result, a starting pulse is applied to the discharge lamp 24. Then, the current A flowing through the discharge lamp 24 detected by the current detection circuit 6 is read (step S330), and thereafter, the magnitude of the current A flowing through the discharge lamp 24 and a predetermined value α are compared (step S340). Here, if the condition of current A> predetermined value α is not satisfied, it is determined to be NO, and it is determined that the starting of the discharge lamp 24 is not performed properly.
Is continued (step S320). The definition of the predetermined value α is the same as in the first embodiment. Thereafter, the above operation is repeated.

If the condition of current A> predetermined value α is satisfied, the determination is YES, and it is determined that the discharge lamp 24 has been started successfully. Then, the data X is applied to the voltage gradient K.
Is set (step S350), and thereafter, the voltage VL of the discharge lamp 24 detected by the voltage detection circuit 7 is read (step S360). Next, the current I of the discharge lamp corresponding to the magnitude of the voltage VL of the discharge lamp 24 is determined (step S37).
0), the control circuit 8 controls the current limiting circuit 3 so that the current I at the target level is obtained. As a result, predetermined electric power is supplied to the discharge lamp 24. Then, the magnitude of the voltage gradient K is compared with the predetermined value β (step S380), and since the data X is set in the voltage gradient K in advance, the condition of voltage gradient K <predetermined value β is satisfied here. become.
Thereby, since it is determined as YES, the voltage VL of the discharge lamp 24 is read again (step S360), and the subsequent operation is the same as described above. The predetermined value β is a threshold value for determining whether or not the discharge lamp 24 having an appropriate capacity is mounted on the lighting device.

The data set in the voltage gradient K is updated by a later-described interrupt means after a predetermined time.
Here, if the discharge lamp 24 having an appropriate capacity is attached to the lighting device, that is, the 150 W discharge lamp 24 is attached to the 150 W lighting device.
Is attached, the voltage gradient K of the voltage VL, that is, the voltage change amount of the voltage VL per a predetermined time is relatively small. Therefore, when the magnitude of voltage gradient K is compared with predetermined value β (step 380), the condition of voltage gradient K <predetermined value β is satisfied and YES is determined. Then, the voltage VL of the discharge lamp 24 is read again (step S360), and the subsequent operation is the same as described above.

Further, the discharge lamp 24 having an improper capacity is not provided in the lighting device.
Is wrongly mounted, that is, when the 70 W discharge lamp 24 is wrongly mounted on the 150 W lighting device, the voltage gradient K of the voltage VL becomes large. Therefore, when the magnitude of the voltage gradient K is compared with the predetermined value β (step S380), the voltage gradient K <
NO is determined because the condition of the predetermined value β is not satisfied. Then, driving of the inverter 4 is stopped to turn off the discharge lamp 24, or the inverter 4 is controlled so as to reduce the power supplied to the discharge lamp 24 to a predetermined level (step S390).

Next, a method of calculating the voltage gradient K of the voltage VL of the discharge lamp 24 by the interrupt means will be described with reference to an interrupt flowchart shown in FIG. After the lighting switch 9 is turned on during the operation of the main flowchart shown in FIG. 6 (step S300), the operation of the interrupt flowchart shown in FIG. 7 is interrupted and executed at predetermined time intervals (step S400). The interruption time is instantaneous (on the order of ms), and at this time, the operation of the main flowchart is interrupted. As a result, the data X previously set to the voltage gradient K
Is cleared (step S410), and the VLN read in the previous interrupt process is set as VLO (step S420). Next, the voltage VL of the discharge lamp 24 at the time of interruption
N is read (step S430), and thereafter, the voltage gradient K = (VLN-VLO) / predetermined time is calculated (step S440), and the operation of the interrupting unit ends (step S450). Then, the operation of the main flowchart shown in FIG. 6 (steps S360 to S39)
0) starts again, and at the same time, the data K calculated by the above-described calculation formula is newly set in the voltage gradient K. A series of control programs related to the operations of the main flowchart and the interrupt flowchart are stored in the control circuit 8 in advance.

As described above, the erroneous mounting determination function for quickly and accurately detecting whether or not the capacity of the discharge lamp 24 mounted on the lighting device is appropriate is provided. A discharge lamp lighting device having the same effect can be provided.

[0026]

Since the present invention is configured as described above, it has the following effects.

A discharge lamp lighting device according to the present invention is a discharge lamp lighting device comprising a discharge lamp and an inverter circuit for supplying low-frequency power to the discharge lamp, wherein a voltage detecting means for detecting a voltage of the discharge lamp is provided. A voltage reading means for reading the voltage of the discharge lamp detected by the voltage detection means at predetermined time intervals, and a predetermined threshold when a few seconds have elapsed from the start of lighting of the discharge lamp when the voltage of the discharge lamp read by the voltage reading means has elapsed. When the value exceeds the value, the inverter circuit is provided with a judging means for judging that the low-capacity discharge lamp is erroneously mounted, so that it is possible to quickly determine whether the capacity of the discharge lamp mounted on the lighting device is appropriate. , And with high accuracy. Therefore, a discharge lamp lighting device capable of significantly extending the life of the discharge lamp can be obtained.

Also, in a discharge lamp lighting device provided with a discharge lamp and an inverter circuit for supplying low-frequency power to the discharge lamp, voltage detection means for detecting the voltage of the discharge lamp is provided, and the discharge detected by the voltage detection means is provided. Voltage reading means for reading the voltage of the lamp at predetermined time intervals is provided, and calculating means for calculating a voltage gradient from the voltage of the discharge lamp read at predetermined time intervals by the voltage reading means is provided, and the voltage gradient calculated by the calculating means is a predetermined value. In the case where the discharge lamp exceeds the limit, a judgment means for judging that the low-capacity discharge lamp is erroneously mounted in the inverter circuit is provided. And it can detect with high precision. Therefore, a discharge lamp lighting device capable of significantly extending the life of the discharge lamp can be obtained.

Further, since the low-frequency power supplied to the discharge lamp is cut off or the inverter circuit is controlled so as to reduce the low-frequency power to a predetermined level based on the output from the judgment means, for example, 150 W If a 70W discharge lamp is incorrectly mounted on the device, the inverter may be stopped immediately to turn off the discharge lamp, or the inverter may be controlled to reduce the power supplied to the discharge lamp to a predetermined level. it can. Therefore, a discharge lamp lighting device can be obtained in which no excessive power is supplied to the 70 W discharge lamp and the life of the discharge lamp can be significantly extended.

[Brief description of the drawings]

FIG. 1 is a circuit block diagram showing Embodiment 1 of a discharge lamp lighting device according to the present invention.

FIG. 2 is a main flowchart showing the operation of the first embodiment.

FIG. 3 is an interrupt flowchart showing the operation of the first embodiment.

FIG. 4 is a timing chart showing the operation of the first embodiment.

FIG. 5 is a diagram illustrating an example of voltage characteristics of the discharge lamp according to the first embodiment.

FIG. 6 is a main flowchart showing the operation of the second embodiment.

FIG. 7 is an interrupt flowchart showing the operation of the second embodiment.

FIG. 8 is a circuit block diagram showing a conventional discharge lamp lighting device.

FIG. 9 is a diagram illustrating an example of a voltage characteristic of a discharge lamp in a conventional discharge lamp lighting device.

[Explanation of symbols]

Reference Signs List 1 AC power supply, 2 A / F, 3 current limiting circuit, 4 inverter, 5 igniter, 6 current detection circuit, 7 voltage detection circuit, 8 control circuit, 9 lighting switch, 20 battery, 21 DC-DC converter, 22 DC- AC
Inverter, 23 High-voltage pulse generating circuit, 24 Discharge lamp, 25 Voltage abnormality detecting circuit, 26 Voltage dividing circuit, 27
Comparison circuit, 28 reference power supply, 29 timer circuit, 30
OR circuit, 31 error display section.

Claims (3)

[Claims] In a discharge lamp lighting device including a discharge lamp and an inverter circuit for supplying low-frequency power to the discharge lamp, voltage detection means for detecting a voltage of the discharge lamp, and voltage detected by the voltage detection means. A voltage reading means for reading the voltage of the discharge lamp every predetermined time, and when the voltage of the discharge lamp read by the voltage reading means exceeds a predetermined threshold several seconds after the start of lighting of the discharge lamp, A determination means for determining that a low-capacity discharge lamp has been erroneously attached to the inverter circuit. 2. A discharge lamp lighting device comprising a discharge lamp and an inverter circuit for supplying low-frequency power to the discharge lamp, a voltage detector for detecting a voltage of the discharge lamp, and a voltage detected by the voltage detector. Voltage reading means for reading the voltage of the discharge lamp every predetermined time; calculating means for calculating a voltage gradient from the voltage of the discharge lamp read every predetermined time by the voltage reading means; A discharge lamp lighting device comprising: a judgment unit for judging that a low-capacity discharge lamp is erroneously mounted on the inverter circuit when the value exceeds the value. 3. The method according to claim 1, wherein the low frequency power supplied to the discharge lamp is cut off or the low frequency power is controlled to a predetermined level based on an output from the determination means. The discharge lamp lighting device according to claim 1 or 2, wherein: