JP4092531B2 - Lighting device and lighting device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a lighting device and a lighting device that perform light control by PWM control.
[0002]
[Prior art]
When a lighting device using a high-pressure discharge lamp is used in a building, there is a case where a plurality of lighting devices are dimmed with one dimmer. That is, a PWM signal is transmitted to each lighting device from one dimmer, and the lighting device performs light control by PWM-controlling the power supplied to the high-pressure discharge lamp with this PWM signal.
[0003]
[Problems to be solved by the invention]
However, in general, high-pressure discharge lamps are often installed in high places. Since there are many cases where it is installed in a high place, when a PWM signal is supplied from the outside and dimming the high-pressure discharge lamp by PWM control, it becomes necessary to lengthen the signal cable, resulting in a voltage drop or the like It is easy to cause a problem that the light is accidentally turned off, and it takes time to turn on again because of the high-pressure discharge lamp, and the light-off time continues for a long time.
[0004]
An object of the present invention is to maintain the lighting drive of a high-pressure discharge lamp even when an external PWM signal is interrupted due to an unexpected cause such as a voltage drop.
[0005]
An object of the present invention is to enable power saving for an external dimmer that transmits a PWM signal to control a desired dimming ratio.
[0006]
An object of the present invention is to enable accurate dimming even if a PWM signal is momentarily interrupted.
[0007]
An object of the present invention is to enable accurate dimming when the supply of the PWM signal from the outside is interrupted, when it is resumed later.
[0008]
An object of the present invention is to make it possible to distinguish between those that perform dimming and those that do not, only by PWM signals, even if PWM signals are supplied to a plurality of lighting devices using the same cable.
[0009]
[Means for Solving the Problems]
The invention according to claim 1 is a DC power supply; a step-down chopper that steps down a direct current output from the DC power supply; an inverter that converts the output of the step-down chopper into an alternating current that lights a high-pressure discharge lamp; and a signal cable Input means for receiving an input of an external PWM signal transmitted through the terminal ; counting means for counting an elapsed time from when the external input of the PWM signal is interrupted; at least the PWM signal input in advance Latching means for latching for a set reference time ; PWM control of the chopping switching element of the step-down chopper based on the duty ratio of the input PWM signal, thereby supplying the high pressure discharge lamp the first light control means and for adjusting dimming power; when the input of the PWM signal is interrupted, the count When the time has elapsed that is counted by the step becomes greater than a predetermined reference time, it reads the PWM signals latched by PWM controlling the switching device based on a duty ratio of the read PWM signal And a second dimming means for dimming the high-pressure discharge lamp.
[0010]
Therefore, even if the external PWM signal is interrupted due to an unexpected cause such as a voltage drop, the lighting drive of the high-pressure discharge lamp can be maintained based on the latched PWM signal. In addition, an optimum dimming ratio can be maintained even if the dimmer is turned off after transmitting a PWM signal from an external dimmer to control it to a desired dimming ratio, which can contribute to power saving. .
[0012]
Further, even if the PWM signal is momentarily interrupted, it is possible to perform dimming using the PWM signal supplied from the outside, and thus dimming can be performed accurately.
[0013]
According to a second aspect of the invention, in the lighting device according to claim 1, when the input of the PWM signal after dimming based on the PWM signal being latched has started is resumed, the first tone Resuming means for resuming light control by the light means is provided.
[0014]
Therefore, even if lighting driving based on the PWM signal latched due to interruption of the supply of the PWM signal from the outside is performed, if the supply of the PWM signal from the outside resumes thereafter, the light control is performed based on the PWM signal Therefore, dimming can be performed accurately.
[0015]
A third aspect of the present invention is the lighting device according to the first or second aspect , further comprising frequency detection means for detecting a frequency of the input PWM signal; the first dimming means is the frequency detection When the frequency detected by the means reaches a preset value, the light control is performed by the PWM control.
[0016]
Therefore, even if PWM signals are supplied to a plurality of lighting devices using the same cable, it is possible to distinguish between those that perform dimming and those that do not, using only the PWM signals.
[0017]
Invention of Claim 4 is an illuminating device provided with the illuminating device main body; The lighting device as described in any one of Claims 1-3 provided in this illuminating device main body.
[0018]
Therefore, the same operation and effect as the invention according to any one of claims 1 to 3 can be achieved.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described.
[0020]
An illuminating device according to an embodiment of the present invention illuminates using a high-pressure discharge lamp, and the lighting device main body is provided with a lighting device that drives and drives the high-pressure discharge lamp.
[0021]
FIG. 1 is a circuit diagram of the lighting device. As shown in FIG. 1, the lighting device 1 includes a DC power source 2, a step-down chopper 3 that is connected to an output line of the DC power source 2 and steps down a direct current output from the DC power source 2, and an output side of the step-down chopper 3. And an inverter 5 for supplying the output of the step-down chopper 3 to the high-pressure discharge lamp 4 with a predetermined alternating current, and a starter 6 for starting the lighting of the high-pressure discharge lamp 4.
[0022]
The inverter 5 is configured by a full bridge circuit of four switching elements Q1 to Q4. A predetermined alternating current can be applied to the high-pressure discharge lamp 4 by driving the inverter 5 in a known manner.
[0023]
The step-down chopper 3 includes a switching element Q5 that chops a direct current output from the DC power source 2, and a smoothing coil C that smoothes the output of the switching element Q5.
[0024]
The control circuit 7 includes a microcomputer, receives a PWM signal from the outside, and performs PWM control of the switching element Q5 via the drive circuit 8 based on the PWM signal.
[0025]
Next, a specific processing procedure of PWM control performed by the control circuit 7 will be described with reference to the flowchart of FIG.
[0026]
As shown in FIG. 2, when the CPU of the control circuit 7 accepts an external PWM signal input (Y in step S1), the CPU sets the predetermined flag to “1” and receives the input. The PWM signal is latched in the RAM of the control circuit 7 (step S2). The input means is realized by step S1, and the latch means is realized by step S2. Then, the frequency of the input PWM signal is detected (step S3). The frequency detection means is realized by step S3.
[0027]
Then, the detected frequency value is compared with a reference value set in advance in the ROM of the control circuit 7 (step S4). The first dimming means is realized by step S4. If the detected frequency value is equal to the reference value (Y in step S4), the duty ratio of the input PWM signal is detected (step S5). Then, the ON / OFF timing of the switching element Q5 is adjusted via the drive circuit 8 so that the output of the DC power source 2 has a power value corresponding to the duty ratio of the PWM signal detected in step S5. Dimming control is performed (step S6). The first dimming means is realized by steps S5 and S6. When the frequency value detected in step S2 is different from the reference value (N in step S4), the process of FIG. 2 is returned.
[0028]
When there is no external PWM signal input (N in step S1), the value of the flag is determined (step S7). When this flag is “1” (Y in step S7), it indicates that the input of the PWM signal from the outside was accepted in the previous determination (Y in step S1), and when it is “0” (in step S7) N), indicating that there was no external PWM signal input in the previous determination (N in step S1). When it is “1” (Y in step S7), a predetermined counter is reset (step S8), and when it is “0”, this counter is incremented by +1 without being reset (step S9). . Counting means is realized by steps S8 and S9.
[0029]
Then, the value of the counter is compared with a reference value set in advance in the ROM of the control circuit 7 (step S10). When the counter value reaches the reference value (Y in step S10), the PWM signal previously latched in step S2 is read at least by this reference value (step S11), and the switching element is connected via the drive circuit 8. The dimming control is performed so that the output of the DC power source 2 becomes a power value according to the duty ratio of the PWM signal by adjusting the ON / OFF timing of Q5 (step S12). The second dimming means is realized by steps S10, S11, and S12. After step S12, the determination of Y in step S1 is made, and the processing of steps S5 and S6 is performed, thereby realizing the restarting means. When the value of the counter does not reach the reference value (N in Step S10), the process of FIG. 2 is returned.
[0030]
The control circuit 7 has a system configuration that does not accept a PWM signal, which is a dimming signal, from the outside during the period from the start of lighting of the high-pressure discharge lamp 4 to the stable lighting (generally about 20 minutes). desirable. This is because the lamp voltage of the high-pressure discharge lamp 4 is not stable immediately after starting lighting until stable lighting, and it is difficult to perform dimming. Moreover, in order to enable the high-pressure discharge lamp 4 to shift to stable lighting at an early stage from immediately after the start of lighting to stable lighting, a configuration is adopted in which high power is applied and the temperature of the arc tube is quickly raised. Is desirable.
[0031]
According to the illuminating device described above, even if the external PWM signal is interrupted due to an unexpected cause such as voltage drop (N in Step S1), the high pressure discharge lamp 4 is latched based on the PWM signal latched (Step S2). Can be maintained (steps S11 and S12).
[0032]
In addition, after the PWM signal is transmitted from the external dimmer and controlled to a desired dimming ratio, the optimum dimming ratio can be maintained even if the dimmer is turned off (N in step S1) ( Steps S11 and S12) can also contribute to power saving.
[0033]
In this case, even if the PWM signal is momentarily interrupted (Y in step S1 after N in step S10), dimming can be performed using the PWM signal supplied from the outside (step S6). ) And can be adjusted accurately.
[0034]
Further, even if the supply of the PWM signal from the outside is interrupted (N in Step S1) and the lighting drive is performed based on the latched PWM signal (Steps S11 and S12), the supply of the PWM signal from the outside is thereafter performed. Is resumed (Y in step S1, S2), dimming is performed based on the PWM signal (step S6), so that dimming can be performed accurately.
[0035]
Further, only when the frequency value of the input PWM signal is equal to the reference value (Y in step S4), dimming is performed using the PWM signal supplied from the outside (step S6), so that the external dimmer Thus, even if PWM signals are supplied to a plurality of lighting devices 1 using the same cable, it is possible to distinguish between those that perform dimming and those that do not, by using only the PWM signals.
[0036]
【The invention's effect】
According to the first aspect of the present invention, even when the external PWM signal is interrupted due to an unexpected cause such as a voltage drop, the high voltage discharge lamp can be driven to be driven based on the latched PWM signal. In addition, an optimum dimming ratio can be maintained even if the dimmer is turned off after transmitting a PWM signal from an external dimmer to control it to a desired dimming ratio, which can contribute to power saving. .
[0037]
Furthermore, even if the PWM signal is momentarily interrupted, it is possible to perform dimming using the PWM signal supplied from the outside, and therefore dimming can be performed accurately.
[0038]
According to a second aspect of the present invention, in the lighting device according to the first aspect , even when the lighting drive based on the PWM signal latched by interruption of the supply of the PWM signal from the outside is performed, the lighting device from the outside thereafter When the supply of the PWM signal is resumed, the light is adjusted based on the PWM signal, so that the light can be accurately adjusted.
[0039]
According to a third aspect of the present invention, in the lighting device according to the first or second aspect , even if the PWM signal is supplied to a plurality of lighting devices by the same cable, the light control is performed and the light control is not performed. It can be distinguished only by the signal.
[0040]
The invention according to claim 4 can exhibit the same operations and effects as the invention according to any one of claims 1 to 3 .
[Brief description of the drawings]
FIG. 1 is a circuit diagram of a lighting device used in a lighting device according to an embodiment of the present invention.
FIG. 2 is a flowchart for explaining a specific processing procedure of PWM control performed by a control circuit of the lighting device.
[Explanation of symbols]
1 lighting device 2 DC power source 3 step-down chopper 4 high pressure discharge lamp 5 inverter S1 input means S2 latch means S3 frequency detection means S4 first dimming means S5 first dimming means S6 first dimming means S8 counting means S9 Count means S10 Second light control means S11 Second light control means S12 Second light control means

Claims (4)

DC power supply;
A step-down chopper for stepping down the direct current output from the DC power supply;
An inverter that converts the output of the step-down chopper into an alternating current that lights a high-pressure discharge lamp;
Input means for receiving an external PWM signal input transmitted via a signal cable ;
Counting means for counting an elapsed time from a point when the external input of the PWM signal is interrupted;
During the reference time that is at least pre-set the PWM signal input is a latch means for latching;
A first dimming means for adjusting the power supplied to the high-pressure discharge lamp to perform dimming by PWM-controlling the chopping switching element of the step-down chopper based on the duty ratio of the input PWM signal; ;
When the input of the PWM signal is interrupted , the latched PWM signal is read when the elapsed time counted by the counting means exceeds a predetermined reference time, and the duty of the read PWM signal is read. Second dimming means for dimming the high-pressure discharge lamp by PWM controlling the switching element based on the ratio;
Lighting device equipped with. After said dimming based on the PWM signal being latched has started when the input of the PWM signal is resumed, according to claim 1, further comprising resuming resuming means by dimming the first light control means Lighting device. Frequency detection means for detecting the frequency of the input PWM signal;
The first dimming unit performs dimming by the PWM control when the frequency detected by the frequency detection unit reaches a preset value;
The lighting device according to claim 1 or 2 . A lighting device body;
The lighting device according to any one of claims 1 to 3 , provided on the lighting device body;
A lighting device.

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