JP2003068495A - Illumination control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an illumination control device in which light control ranges of discharge lamps respectively corresponding to plural discharge-lamp lighting devices can be made nearly the same in a simple and inexpensive constitution. SOLUTION: In the illumination control device provided with a signal-emitting means 2, a converter 3 to form a direct-current signal corresponding to a duty, a signal generator 5 capable of controlling a switching frequency in accordance with a level of the direct current signal, the plural discharge-lamp lighting devices capable of controlling the switching frequency of the discharge lamp lighting devices, and the discharge lamp LA light-controlled by the changes of the switching frequency of the discharge-lamp lighting devices, this is constituted so that the converter 3 is provided with the direct-current control means 4 to change the level of the direct current signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lighting control device for performing dimming control of a discharge lamp that is lit at a high frequency, and more particularly to a lighting control device for performing dimming control of a discharge lamp by a PWM signal. It is a thing.

[0002]

2. Description of the Related Art As a conventional example of this type, there is, for example, the one disclosed in Japanese Patent Laid-Open No. 2000-1227. This is a PWM signal source for generating a PWM signal, and a P
DC voltage conversion means for generating a DC voltage based on the WM signal, voltage dividing means capable of controlling the switching frequency based on the level of the DC voltage, and discharge lamp lighting that operates based on the switching frequency from the voltage dividing means A lighting control device comprising: a device; and a discharge lamp that is dimmed by a change in switching frequency of the discharge lamp lighting device.

In this conventional example, a so-called C including a resistor and a capacitor is included in order to convert a PWM signal into a DC voltage.
Since the R smoothing circuit is used, even if the PWM signal changes discontinuously, the DC voltage and the switching frequency change continuously, and therefore the flicker does not occur in the discharge lamp even when the dimming control is performed. With such a simple circuit configuration, the flicker of the discharge lamp can be prevented. For example, in order to suppress the flicker, the cost is high, but the PWM can be controlled by a high-speed and high-resolution signal sending means capable of fine duty control.
No need to generate a signal.

[0004]

However, when the lighting control device shown in the prior art is adapted to a plurality of discharge lamp lighting devices of different models, the circuit of the discharge lamp lighting device is different between the discharge lamp lighting devices of different models. Since the constants and the like are different, the variation range of the DC signal for making the dimming ranges of the discharge lamps corresponding to the respective discharge lamp lighting devices approximately the same differs depending on the model.

Therefore, in order to make the dimming ranges of the respective discharge lamp lighting devices substantially the same, for example, as shown in FIG. 11, the AC power source is set to Vac and the respective discharge lamp lighting devices INV are set.
If the discharge lamps corresponding to 1 to INV5 and the signal transmission means are LA1 to LA5 and μ1 to μ5, respectively, the signal transmission means μ1 to μ5 are provided for each model, and the DC signal is changed by changing the duty of the PWM signal. I had to change. As the signal transmission means, for example, a microcomputer can be cited, but the cost of the microcomputer is high, so that the cost of the entire lighting control device is increased.

In order for one microcomputer to correspond to the plurality of discharge lamp lighting devices INV1 to INV5, each discharge lamp lighting device I has to be connected to the microcomputer.
A plurality of storage devices corresponding to NV1 to INV5 must be provided. Therefore, even with this method, the cost of the entire lighting control device increases.

The present invention has been made in view of the above problems, and its object is a simple and inexpensive structure.
It is an object of the present invention to provide an illumination control device capable of making the dimming ranges of discharge lamps corresponding to a plurality of discharge lamp lighting devices substantially the same.

[0008]

According to a first aspect of the present invention, there is provided a lighting control device including a signal transmitting means for transmitting a PWM signal with variable duty, a converter for generating a DC signal according to the duty, and a DC signal level. A signal generator capable of controlling the switching frequency according to the present invention, a plurality of discharge lamp lighting devices capable of controlling the switching frequency, and a discharge lamp that is dimmed by a change in the switching frequency of the discharge lamp lighting device are provided. In the lighting control device, the converter is provided with DC signal control means for changing the level of the DC signal,
It is characterized in that the dimming ranges of the discharge lamps corresponding to the plurality of discharge lamp lighting devices are made substantially the same.

In such a lighting control device, even with the lighting control device comprising one signal sending means, the dimming ranges of the discharge lamps corresponding to the plurality of discharge lamp lighting devices can be made substantially the same. Therefore, the cost of the lighting control device can be reduced.

A lighting control device according to a second aspect of the present invention is the first aspect.
In the lighting control device, the lighting control device is adapted to a plurality of discharge lamp lighting devices, and among the duty change widths of the plurality of discharge lamp lighting devices corresponding to a certain dimming range, the change width is the smallest. It is characterized in that the other discharge lamp lighting devices are dimming-controlled by the duty change width.

In such an illumination control device, even with the illumination control device comprising one signal transmitting means, dimming control can be performed without turning off all the discharge lamps of the plurality of discharge lamp lighting devices.

A lighting control device according to a third aspect of the present invention is the illumination control device according to the first aspect.
In the above lighting control device, the duty control and the DC signal level control are simultaneously controlled.

In such a lighting control device, even in a discharge lamp lighting device in which the step size of the dimming change is not constant in order to prevent the human eye from feeling uncomfortable, the level of the DC signal is changed accordingly. Therefore, the dimming control can be performed without making the human eyes feel uncomfortable.
Therefore, the lighting control device including one signal sending unit can be applied to the above discharge lamp lighting device, and the cost of the lighting control device can be reduced.

[0014]

DETAILED DESCRIPTION OF THE INVENTION A first embodiment of the present invention corresponding to claim 1 will be described below with reference to FIGS.

The discharge lamp lighting device (for example, an inverter) shown in FIG. 1 is a combination of a chopper circuit and a half bridge circuit, and includes a chopper circuit inductor L1 in parallel with a diode bridge DB for rectifying an AC power supply Vac. The smoothing capacitor C1 and the switching elements Q2 and Q3 (for example, field effect transistors) are connected via the high-speed diode D1. Further, the switching element Q1 (for example, a field effect transistor) is provided between the connection point between the inductor L1 and the anode of the diode D1 and the source of the switching element Q3.
Are connected. The switching element Q1 is controlled by the control circuit 1. Further, a series circuit of a resonance inductor L2 and a resonance capacitor C2 is connected between a connection point between the switching elements Q2 and Q3 and a source of the switching element Q3. Then, the discharge lamp LA (for example,
Fluorescent lamp) is connected. Since the operating principle of this inverter is well known, it will be omitted.

Next, the control unit for controlling the switching frequencies of the switching elements Q2 and Q3 will be described. The control unit is a signal sending means 2 for generating a PWM signal.
A converter 3 for converting the PWM signal of the signal sending means 2 into a direct current signal; a direct current signal control means 4 for controlling the level of the direct current signal; A signal generator 5 for generating a control signal. Further, FIG. 2 shows a detailed circuit diagram of the DC signal control means 4, in which the PWM inputted to the CR smoothing circuit composed of the resistor RA and the capacitor CA.
The signal is converted into a DC signal by the CR smoothing circuit, and the amplifier E
A is amplified.

Here, as explained in the prior art,
Since the PWM signal input to the DC signal control means 4 is smoothed by the CR smoothing circuit, even if the PWM signal becomes discontinuous during the dimming control, the switching frequency f continuously changes, so that the discharge lamp LA It does not flicker.

The switch SA is connected in series with the amplifier EA.
Are connected, and the DC signal amplified by the amplifier EA is transmitted when the switch SA is in the ON state. Resistance R
DC signal control means including B, capacitor CB, amplifier EB, and switch SB and DC signal control means including resistance RC, capacitor CC, amplifier EC, and switch SC are also the resistance RA, capacitor CA, amplifier EA, and switch S.
The configuration and operation are exactly the same as the DC signal control means consisting of A, but the amplification factors of the amplifiers EA, EB, and EC are different from each other.

Next, the operation of the first embodiment will be described.

The signal sending means 2 changes the ON duty of the PWM signal (ON period of the PWM signal shown in FIG. 2) by receiving the dimming signal sent by the serial signal, for example. As shown in FIG. 3, when the PWM signal with the on-duty changed from duty2 → duty1 is sent from the signal sending means 2, the DC signal DC of the converter 3 becomes DC1 →
Change to DC2. In response to this change in DC signal DC,
As shown in FIG. 4, the switching frequency f generated by the signal generator 5 changes from f1 to f2. That is, since the switching frequency f changes in a high direction from f1 to f2, the discharge lamp LA is dimmed.

Here, in the present embodiment, as an example, three different types of inverters INVA, INVB, INVC are used.
think of. These inverters are the target discharge lamp LA
And an inductor L2 for resonance and a capacitor C2 for resonance
, Etc. are different circuit constants.

Three different types of inverters INVA, IN
In VB and INVC, as in the case shown in FIG.
When the on-duty is changed from duty2 to duty1, the DC signal DC is DC1a as shown in FIG.
→ DC2a, DC1b → DC2b, DC1c → DC2c
Change to each. At this time, the switching frequency f
As shown in FIG. 6, f1a → f2a, f1b → f2
b, f1c → f2c, respectively. However, the inverter IN operating at the switching frequency f2a
The dimming level is generally different between the inverter INVB operating at VA and the switching frequency f2b and the inverter INVC operating at the switching frequency f2c. That is, even if the change width of the on-duty is substantially the same, the dimming level is different because the circuit constants of the inverters are different.

Therefore, in order to make the dimming range of each discharge lamp (the ratio of the light output at a certain switching frequency when the light output during normal lighting of each discharge lamp is 100%) substantially equal, Change the DC level. That is, in the DC signal control means 4 shown in FIG.
When VA is connected, the switch SA is turned on. When the inverter INVB and the inverter INVC are connected, the switch SB and the switch SC are turned on. Since the amplification factors of the amplifiers EA, EB, and EC are different from each other, the dimming range of the discharge lamp corresponding to each inverter can be made substantially the same by changing the level of the DC signal DC.

In such a lighting control device, the single signal sending means 2 can make the dimming ranges of the discharge lamps corresponding to the respective inverters substantially the same. Each inverter INVA, INV
Since it is not necessary to separately provide signal transmitting means corresponding to B and INVC, the cost of the entire lighting control device can be reduced.

In the present embodiment, the case where the discharge lamps targeted by the three different types of inverters INVA, INVB, INVC are different is considered, but the target is targeted by the three types of inverters INVA, INVB, INVC. It goes without saying that even if the discharge lamps are the same, the dimming range of each discharge lamp can be made substantially the same by using the above lighting control device. Needless to say, the number of inverter models is not limited to three and may be two or more.

Further, in the present embodiment, a combination of a chopper circuit and a half-bridge circuit is shown as an inverter, but the inverter is not limited to this, and for example, a one-stone type, JP-A-2000-. 100
The inverter disclosed in Japanese Patent No. 587 may be used, and any inverter may be used as long as it is dimmable by changing the switching frequency.

Furthermore, in the present embodiment, attention was paid to the change in the on-duty of the PWM signal.
The dimming control may be performed by changing the off-duty of the WM signal, or the DC signal control means 4 may be one that increases the DC signal DC with the change of the on-duty.

A second embodiment of the present invention corresponding to claim 2 will be described below with reference to FIGS. 7 and 8.

In this embodiment, the circuit configuration of the inverter and the configuration of the control circuit 1 and the like are the same as those of the first embodiment, but the circuit configuration of the DC signal control means 4 shown in FIG.
2 and FIG. 2 are different. That is, in the DC signal control means 4 shown in FIG. 8, the duty width switching means 6 is provided in front of the resistor RC, and one DC signal control means (duty width switching means 6, resistor RC, capacitor CC and amplifier EC). The direct current signal control means) is used to control the dimming of two different types of inverters INVA and INVC.

Next, the operation of this embodiment will be described.

Similar to FIG. 5 of the first embodiment, FIG. 7 shows the relationship between the DC signal DC and the on-duty. In the present embodiment, as shown in FIG. 7, the variation width of the DC signal DC for making the dimming range substantially the same is determined by the inverter INVC.
Is larger than the inverter INVA. In the inverter INVC, the DC signal DC is changed from DC1c to DC
To change to 2c, the on-duty is set to duty.
Change from 2c to duty1c. At this time, in the inverter INVA, the DC signal DC is changed from DC1a to DC2a in order to make the dimming range substantially the same as that of the inverter INVC.
It must be changed to. In this case, as shown in FIG. 7, the on-duty is duty2a → duty.
It may be changed to 1a.

Here, the resistance RC, the capacitor CC and the amplifier EC are constants corresponding to the inverter INVC, and the duty width switching means 6 sets the change width of the on-duty to duty2a.fwdarw.duty1a.
Then, when the inverter INVA is connected, the discharge lamp LA can be dimmed within a normal dimming range (the range of the DC signal DC is DC1c → DC2c), and when the inverter INVC is connected, DC signal DC is DC1
Since it changes only from a to DC2a, the discharge lamp LA is dimmed in a dimming range narrower than the normal dimming range, but the dimming is made too deep and the discharge lamp LA flickers, moving stripes and disappears. Can be prevented from occurring. That is, the deepest dimming level of the inverter INVC (DC signal DC within the range of change of DC signal DC1a → DC2a)
Is equivalent to DC2c), and dimming control can be performed.

Further, when considering the dimming of only the inverter INVC, the duty width switching means 6
The change width of the on-duty is duty2c → duty1c
It goes without saying that the inverter INVC can perform dimming in the normal range when switched to.

Furthermore, in the present embodiment, the number of inverter models is considered to be two, but the number of inverter models is not limited to two, and even if there are two or more inverters,
With the DC signal control means of the inverter having the maximum width of the DC signal DC (using the circuit constant designed for that inverter), the duty width switching means 6 switches the duty width, and the on-duty dimming control suitable for each inverter is performed. it can.

The circuit configurations, operations, effects and the like not particularly mentioned in the above description are the same as those in the first embodiment.

A third embodiment of the present invention corresponding to claim 3 will be described below with reference to FIGS. 9 and 10.

In this embodiment, the circuit configuration of the inverter and the configuration of the control circuit 1 and the like are the same as those of the first embodiment, but the circuit configuration of the DC signal control means 4 shown in FIG.
0 and FIG. 2 are different. That is, in the DC signal control means 4 shown in FIG. 10, the duty width switching means 6 is provided in front of the resistor RA, and the signal from the duty width switching means 6 is fed back to the amplifier EA to amplify the amplification factor of the amplifier EA. Is changed.

In some inverters, when light is dimmed by continuously changing the frequency, flicker or moving fringes may occur depending on the dimming range, which may cause discomfort to the human eye. In such a case, it may be more natural for human eyes to change the step size of the dimming change during dimming.

Such an inverter is called an inverter INV
Let be D. As shown in FIG. 9, the level of the DC signal DC is changed between the on-duty change widths of duty1 → duty3 and duty3 → duty2. That is, when the on-duty becomes duty3, the level of the DC signal DC is changed by changing the amplification factor of the amplifier EA. In this way, when the frequency is continuously changed and dimming is performed, it causes discomfort to the human eye.
Even in the NVD, by changing the step size of the dimming change, dimming control can be performed without causing discomfort to the human eyes.

For comparison, FIG. 9 also shows the characteristics of the inverter INVA shown in FIG. 5, but of course, when the inverter INVA is connected, the amplification factor of the amplifier EA must be changed. It goes without saying that the inverter INVA can be dimming-controlled as in the first embodiment.

All the circuit configurations, operations, effects and the like not specifically mentioned in the above description are the same as those in the first embodiment.

[0042]

As described in detail above, in the lighting control device according to the first aspect, the dimming range of the same discharge lamp of the plurality of discharge lamp lighting devices is made substantially the same by changing the level of the DC signal. Therefore, even with the lighting control device including one signal transmitting means, the dimming ranges of the plurality of discharge lamp lighting devices can be made substantially the same, and the cost of the lighting control device can be reduced.

In the lighting control device according to claim 2,
The lighting control device according to claim 1, wherein a change width of the plurality of discharge lamp lighting devices corresponding to a certain dimming range has the smallest change width, and the other discharge lamp lighting device is dimmed with the duty change width. Since it is controlled, dimming control can be performed without turning off all the discharge lamps of the plurality of discharge lamp lighting devices.

In the lighting control device according to claim 3,
The lighting control device according to claim 1, wherein the duty change and the DC signal level change are controlled at the same time, so that the step size of the dimming change is not constant in order not to make human eyes feel uncomfortable. Even in the lighting device, the level of the DC signal is changed accordingly, and the dimming control can be performed without making the human eyes feel uncomfortable. Therefore, the lighting control device including one signal sending unit can be applied to the above discharge lamp lighting device, and the cost of the lighting control device can be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram showing an illumination control device according to a first embodiment.

FIG. 2 is a block diagram showing a DC signal control means of FIG.

FIG. 3 is an explanatory diagram showing an operation of the first embodiment.

FIG. 4 is another explanatory diagram showing the operation of the first embodiment.

FIG. 5 is still another explanatory diagram showing the operation of the first embodiment.

FIG. 6 is still another explanatory diagram showing the operation of the first embodiment.

FIG. 7 is an explanatory diagram showing the operation of the second embodiment.

FIG. 8 is a block diagram showing a DC signal control means of a second embodiment.

FIG. 9 is an explanatory diagram showing the operation of the third embodiment.

FIG. 10 is a block diagram showing a DC signal control means of a third embodiment.

FIG. 11 is a block diagram showing a conventional example.

[Explanation of symbols]

2 Signal transmission means 3 converter 4 DC signal control means 5 signal generator LA discharge lamp

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Naruo Goto             1048, Kadoma, Kadoma-shi, Osaka Matsushita Electric Works Co., Ltd.             Inside the company F term (reference) 3K098 CC24 CC41 CC42 CC60 CC70                       DD22 DD35 DD37 EE13 EE14                       EE17 EE18 EE27 EE31 EE32                       EE40

Claims (3)

[Claims] 1. A signal transmitting means for transmitting a PWM signal with variable duty, a converter for generating a DC signal according to a duty, and a signal generator capable of controlling a switching frequency according to the level of the DC signal. In a lighting control device including a plurality of discharge lamp lighting devices capable of controlling a switching frequency and a discharge lamp that is dimmed by a change in switching frequency of the discharge lamp lighting device, a converter changes a level of a DC signal. An illumination control device, characterized in that the dimming range of the discharge lamps corresponding to each of the plurality of discharge lamp lighting devices is made substantially the same by including the DC signal control means. 2. A lighting control device adapted to a plurality of discharge lamp lighting devices, wherein the duty width of the plurality of discharge lamp lighting devices corresponding to a certain dimming range has the smallest change width. The lighting control device according to claim 1, wherein the other discharge lamp lighting device is dimming-controlled by the change width. 3. The lighting control device according to claim 1, wherein the change of the duty and the change of the level of the DC signal are controlled at the same time.