JP7172770B2 - Lighting device and lighting device - Google Patents

Description

The present invention relates to a lighting device and a lighting device.

Patent Literature 1 discloses a dimmer that controls dimming by receiving a dimming signal from a dimming table that transmits dimming data substantially periodically. The dimmer itself measures the time until reception of the next dimmer data. Also, the dimmer determines the number of times of dimming and the dimming value after receiving the dimming data. The dimmer performs dimming step by step to the determined target dimming value within the time until receiving the next dimming data.

Japanese Patent No. 5008463

In Japanese Patent Application Laid-Open No. 2002-200000, the fade time for stepwise dimming is determined by the reception interval of dimming data transmitted substantially periodically. Therefore, the fade time cannot be freely set.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a lighting device and a lighting device in which the fade time can be freely set.

A lighting device according to the present invention includes a lighting circuit for lighting a light source, and a control section for controlling the lighting circuit according to a PWM signal input from the outside. Alternatively, when the OFF time changes from the first time to the second time, the fade time is obtained from the sustain time, which is the period during which the ON time or the OFF time was the first time, and the dimming of the light source is performed during the fade time. change the rate.

A lighting device according to the present invention includes a lighting circuit that lights a light source, and a control unit that controls the lighting circuit according to a PWM signal input from the outside. A fade time is obtained, and the dimming rate of the light source is changed at the fade time.

In the lighting device according to the present invention, the fade time can be freely set from the sustain time, which is the period in which the ON time or the OFF time is the first time.
In the lighting device according to the present invention, the fade time can be freely set from the period of the PWM signal.

1 is a circuit block diagram of a lighting device according to Embodiment 1; FIG. 4 is a flow chart showing the operation of a control unit according to Embodiment 1; It is a figure which shows the time change of the dimming rate which concerns on a comparative example. FIG. 5 is a diagram showing temporal changes in a dimming rate according to Embodiment 1; 9 is a flow chart showing the operation of a control unit according to Embodiment 2; 10 is a flow chart showing the operation of a control unit according to Embodiment 3;

A lighting device and a lighting device according to embodiments of the present invention will be described with reference to the drawings. The same reference numerals are given to the same or corresponding components, and repetition of description may be omitted.

Embodiment 1.
FIG. 1 is a circuit block diagram of lighting device 100 according to Embodiment 1. As shown in FIG. The lighting device 100 includes a lighting device 1 , a dimming device 19 and an LED module 11 .

The LED module 11 has a plurality of light sources 11a. The light source 11a is an LED. The light source 11a is not limited to an LED, and may be an organic EL. A plurality of light sources 11a are connected in series. Not limited to this, the plurality of light sources 11a may be connected in parallel or in series-parallel.

The lighting device 1 includes a rectifier circuit 3 that rectifies AC power from an AC power supply 2 into DC power. A boost chopper circuit 4 is connected between both output terminals of the rectifier circuit 3 . The boost chopper circuit 4 boosts the pulsating voltage, which is the output voltage of the rectifier circuit 3, by turning on and off the switching element, and outputs a DC high voltage. A control unit 16 to be described later controls the boost chopper circuit 4 .

A step-down chopper circuit 5 is connected between both output terminals of the step-up chopper circuit 4 . The step-down chopper circuit 5 is supplied with the output voltage of the step-up chopper circuit 4 and supplies a constant current to the LED module 11 . The boost chopper circuit 4 and the step-down chopper circuit 5 constitute a lighting circuit for lighting the light source 11a.

The step-down chopper circuit 5 has a switching element 6 . A drain terminal of the switching element 6 is connected to the high potential side of the boost chopper circuit 4 . A source terminal of the switching element 6 is connected to a cathode terminal of the diode 8 and one end of the inductor 7 . The other end of inductor 7 is connected to one end of capacitor 9 . The negative terminal of capacitor 9 is connected to one end of resistor 10 . The other end of resistor 10 is connected to the anode terminal of diode 8 and the low potential side of boost chopper circuit 4 . An LED module 11 is connected between the two poles of the capacitor 9 .

An output current supplied from the step-down chopper circuit 5 to the LED module 11 flows through the resistor 10 . Resistor 10 constitutes an output current detection circuit. The voltage applied to resistor 10 corresponds to the output current of step-down chopper circuit 5 . Thus, resistor 10 outputs an output current detection signal corresponding to the output current of step-down chopper circuit 5 .

One end of the resistor 10 is connected to the control section 16 . The control unit 16 converts the output current of the step-down chopper circuit 5 into a voltage applied to the resistor 10 and detects it. The control unit 16 controls the step-down chopper circuit 5 based on the value detected by the output current detection circuit.

The lighting device 1 also includes a dimming circuit 17 that receives a PWM (Pulse Width Modulation) signal from the outside. The dimming circuit 17 transmits the received PWM signal to the control section 16 . The dimmer 19 comprises a dimmer 18 . The dimmer 18 transmits the PWM signal to the controller 16 via the dimmer circuit 17 . The dimmer 18 may transmit the PWM signal wirelessly or by wire.

As the control unit 16, for example, a microcomputer, a DSP (Digital Signal Processor), or the like can be used as appropriate. An example of the control unit 16 is shown in FIG. In FIG. 1, the control section 16 includes a drive circuit 12, an A/D conversion circuit 13, a processing device 14 and a storage section 15 which are connected to each other via an internal bus.

The drive circuit 12 outputs a PWM signal for switching the switching element 6 . An A/D conversion circuit 13 is connected to one end of the resistor 10 . The A/D conversion circuit 13 converts the voltage applied to the resistor 10 corresponding to the lamp current flowing through the LED module 11 into a digital value. This digital value is input to the processor 14 .

The processing device 14 analyzes the PWM signal input from the dimming circuit 17 . The processor 14 determines the target current based on the on-time or off-time of the input PWM signal. The processing device 14 turns on and off the switching element 6 so that the target current and the lamp current flowing through the LED module 11 match. The processing device 14 adjusts the ON time and the like in the switching control of the switching element 6 . Thereby, the processing unit 14 controls the step-down chopper circuit 5 to have a constant current.

The storage unit 15 is, for example, a nonvolatile memory. The storage unit 15 stores a calculation program to be executed by the processing device 14 and various data used for the calculation. Thus, the control unit 16 controls the lighting circuit according to the PWM signal input from the outside.

FIG. 2 is a flow chart showing the operation of the control section 16 according to the first embodiment. The operation of lighting device 100 will be described with reference to FIG. First, as shown in step S101, the control unit 16 initializes a maintenance time, which will be described later.

Next, as shown in step S<b>102 , the controller 16 measures the ON time of the PWM signal transmitted from the dimmer 18 . At this time, it is assumed that the ON time of the PWM signal is the first time. In addition, the control unit 16 counts the time that has elapsed since the ON time reached the first time. That is, the control unit 16 measures the time that has elapsed since the ON time of the PWM signal changed from the previous value to the first time.

In addition, as shown in step S103, the control unit 16 determines whether or not the ON time has changed from the first time. If the ON time of the PWM signal has changed from the previously measured first time, the process proceeds to step S104. Here, it is assumed that the ON time of the PWM signal has changed from the first time to the second time. In addition, when it has not changed, it transfers to step S102.

Here, the sustain time is the time from when the ON time reaches the first time until it changes to another value, the second time. That is, the sustain time is the period during which the ON time was the first time.

Next, as shown in step S<b>104 , the processing device 14 reads the target current value corresponding to the second time, which is the new ON time, from the storage unit 15 . Note that the storage unit 15 stores in advance the correspondence relationship between the ON time of the PWM signal and the target current value of the lamp current flowing through the light source 11a.

Next, in step S105, the control unit 16 controls the lighting circuit so that the current value detected by the output current detection circuit and the target current value match. At this time, the control unit 16 obtains the fade time, which is the time required for the lamp current to reach the target current value, from the sustain time. In the present embodiment, the control unit 16 sets the fade time to the sustain time measured in step S102.

The controller 16 changes the dimming rate of the light source 11a with a fade time equal to the sustain time. That is, the control unit 16 controls the lighting circuit so that the dimming rate of the light source 11a changes from the dimming rate corresponding to the first time to the dimming rate corresponding to the second time over the fade time.

The controller 16 continuously increases or decreases the dimming rate of the light source 11a during the fade time. Also, the control unit 16 may change the dimming rate of the light source 11a stepwise during the fade time. The control unit 16 may change the dimming rate so that the rate of change per hour is constant during the fade time. The change rate of the dimming rate per hour may not be constant.

The fade control by the control unit 16 is fade-in control when the light control rate corresponding to the second time is higher than the light control rate corresponding to the first time. Also, the fade control is fade-out control when the dimming rate corresponding to the second time is smaller than the dimming rate corresponding to the first time.

After setting the fade time to the sustain time, the control unit 16 clears the sustain time as shown in step S106. Next, the control unit 16 moves to step S102 again.

Next, the effects of this embodiment will be described. FIG. 3 is a diagram showing temporal changes in the dimming rate according to the comparative example. FIG. 4 is a diagram showing temporal changes in the dimming rate according to Embodiment 1. FIG. Here, it is assumed that the ON time of the PWM signal from the dimmer 18 changes at regular time intervals. The fixed time interval is n seconds and corresponds to the maintenance time in this embodiment. 3 and 4 show, as an example, a case where the on-time of the PWM signal decreases every n seconds, so that the target dimming rate corresponding to the on-time decreases by 10% every n seconds.

In FIG. 3, the fade time is shorter than the sustain time. In this case the lamp current reaches the target current value before receiving the next dimming rate. At this time, the light output becomes stepwise and flickers occur.

In FIG. 4, the solid line indicates the dimming rate of the present embodiment, and the dashed line indicates the dimming rate of the comparative example. In this embodiment, the fade time is equal to the sustain time. Therefore, the lamp current reaches the target current value at the timing of receiving the next dimming rate. Therefore, compared with the comparative example, the change in light output can be smoothed, and flickering can be suppressed.

Further, it is conceivable that the dimming signal corresponding to the same dimming rate is received multiple times from the dimmer 18 during the maintenance time in which the ON time is kept constant. In this case, for example, if the reception interval of the dimming signal is set to the fade time, the target dimming rate is reached before the new dimming rate is received.

In contrast, in the present embodiment, the sustain time is set to the fade time. Therefore, even if the PWM signal corresponding to the same dimming rate is received multiple times during the sustain time, the dimming rate of the light source 11a is made to reach the target dimming rate at the timing of receiving the next dimming rate. be able to.

Further, the dimmer 18 of the present embodiment maintains the ON time at the first time for a period of time corresponding to the target value of the fade time, and then changes the ON time to the second time. In the present embodiment, the next fade time is the maintenance time, which is the time during which the ON time is maintained in the state of the first time. Therefore, the fade time from the dimming rate corresponding to the first time to the dimming rate corresponding to the second time can be freely set from the dimmer 18 . In addition, flickering of the light source 11a can be suppressed even if the fade time is set freely.

Also, in the present embodiment, the controller 16 measures the ON time of the PWM signal. Not limited to this, the control unit 16 may measure the OFF time of the PWM signal. When the OFF time of the PWM signal changes from the first time to the second time, the control unit 16 changes the dimming rate of the light source 11a with a fade time equal to the sustain time, which is the period during which the OFF time was the first time. You can let me.

Also, in this embodiment, the fade time is equal to the sustain time. The fade time is not limited to this, and may be any value determined by the sustain time. In this case, the storage unit 15 stores the correspondence relationship between the sustain time and the fade time. In step S105, the processing device 14 reads the fade time corresponding to the sustain time from the storage unit 15, and changes the dimming rate of the light source 11a according to the read fade time. In this case also, the fade time can be freely set from the dimmer 18 by adjusting the sustain time.

Further, in this embodiment, the PWM signal is used to determine the fade time to control the lighting circuit. Here, the PWM signal of the present embodiment may be any signal that has an ON time that is in a High state and an OFF time that is in a Low state. The PWM signal is composed of, for example, a square wave. Further, in this embodiment, the ON time or OFF time of the PWM signal corresponds to the dimming ratio. At this time, the duty ratio of the PWM signal does not have to correspond to the dimming rate. Alternatively, the processing device 14 may determine the target current based on the on-duty ratio or off-duty ratio of the PWM signal.

These modifications can be appropriately applied to lighting devices and lighting devices according to the following embodiments. A lighting device and a lighting device according to the following embodiment have many points in common with the first embodiment, so the explanation will focus on the points of difference from the first embodiment.

Embodiment 2.
FIG. 5 is a flow chart showing the operation of the control section 16 according to the second embodiment. The operation of lighting device 100 of the present embodiment will be described with reference to FIG. Steps 201 to 204 are the same as steps 101 to 104 in the first embodiment.

In step S205, the control unit 16 determines whether or not the maintenance time is longer than a predetermined time. If the maintenance time is equal to or shorter than the predetermined time, the process proceeds to step S207. When the maintenance time is longer than the predetermined time, the control unit 16 replaces the maintenance time with a predetermined specified time as shown in step S206. A value equal to or less than a predetermined time is set in the specified time.

In step S207, the control unit 16 sets the fade time to the sustain time. If the sustain time is longer than the predetermined time in step S205, the fade time becomes the specified time. Step S208 is the same as step S106 of the first embodiment.

In Embodiment 1, the time during which the previous on-time was maintained is taken as the fade time until the next dimming rate. Here, it is conceivable that after the series of first dimming control from the dimmer 18 is completed, it takes a long time until the second dimming control. In this case, the maintenance time during which the on-time is kept constant between the first dimming control and the second dimming control becomes longer. At this time, the initial fade time of the second dimming control may become unnecessarily long.

On the other hand, in the present embodiment, it is possible to determine the start of dimming. In step S205, if the maintenance time is longer than the predetermined time, the control unit 16 determines to start dimming, and proceeds to step S206. As a result, the fade time is set to the designated time. Further, if the maintenance time is equal to or less than the predetermined time, the control unit 16 determines that the dimming is being performed, and proceeds to step S208.

As described above, it is possible to prevent the initial fade time from becoming too long after the dimming rate is maintained constant for a long period of time.

As a modification of the present embodiment, the control unit 16 designates the fade time when the difference between the sustain time measured this time in step S202 and the sustain time measured last time is greater than a predetermined value. You can set the time. In this case, the storage unit 15 stores the last measured maintenance time. Also in the modified example, the control unit 16 can distinguish between the start of dimming and the midway of dimming, thereby shortening the fade time at the start of dimming.

Embodiment 3.
FIG. 6 is a flow chart showing the operation of the control section 16 according to the third embodiment. The operation of lighting device 100 of the present embodiment will be described with reference to FIG. First, in step S301, the control section 16 initializes the fade time.

Next, as shown in step S302, the control unit 16 measures the ON time and OFF time of the PWM signal. Also, the control unit 16 calculates the period of the PWM signal from the sum of the ON time and the OFF time.

Next, as shown in step S303, the control unit 16 determines whether or not the period of the PWM signal has changed from the period measured last time. If the period has changed, the process proceeds to step S304. If the cycle has not changed, the process proceeds to step S302.

In step S<b>304 , the processing device 14 reads out the target current value corresponding to the ON time of the PWM signal from the storage unit 15 .

Next, in step S305, processor 14 obtains the fade time from the period of the PWM signal. The processing device 14 reads the fade time corresponding to the period of the PWM signal from the storage unit 15 . Here, the correspondence relationship between the period of the PWM signal and the fade time is stored in advance in the storage unit 15 .

Next, as shown in step S306, the control unit 16 sets the fade time from the current current value to the target current value to the value read in step S305. Thereby, the control unit 16 controls the lighting circuit so that the dimming rate of the light source 11a changes to the dimming rate corresponding to the ON time of the PWM signal over a fade time corresponding to the cycle of the PWM signal.

Next, as shown in step S307, the control section 16 clears the fade time and proceeds to step S302.

The control unit 16 of this embodiment changes the dimming rate of the light source 11a with a fade time corresponding to the cycle of the PWM signal. A PWM signal has an on-time and an off-time. In this embodiment, the ON time corresponds to the target current value. On the other hand, the period that is the sum of the ON time and the OFF time corresponds to the fade time.

The dimmer 18 adjusts the OFF time of the PWM signal so that the cycle of the PWM signal corresponds to the target value of the fade time. Further, the dimmer 18 transmits a PWM signal having a period corresponding to the target value of the fade time to the control section 16 . As described above, the fade time can be freely set from the dimmer 18 .

Also, the dimmer 18 may change the ON time of the PWM signal in accordance with the timing of the end of the fade. As a result, the control unit 16 can receive the next dimming rate in time with the end of the fade. Therefore, flickering of the light source 11a can be suppressed.

Also, the OFF time of the PWM signal may correspond to the target current value. In this case, the dimmer 18 adjusts the on-time of the PWM signal so that the period of the PWM signal corresponds to the target value of the fade time.

The technical features described in each embodiment may be combined as appropriate.

Reference Signs List 1 lighting device 2 AC power supply 3 rectifier circuit 4 step-up chopper circuit 5 step-down chopper circuit 6 switching element 7 inductor 8 diode 9 capacitor 10 resistor 11 LED module 11a light source 12 drive circuit 13 A/D conversion circuit 14 processing device 15 storage unit 16 control unit 17 light control circuit 18 light control device 19 light control device 100 illumination device

Claims (10)

a lighting circuit for lighting the light source;
a control unit that controls the lighting circuit according to a PWM signal input from the outside;
with
When the on-time or off-time of the PWM signal changes from a first time to a second time, the controller controls a fade time from a sustain time, which is a period in which the on-time or off-time was the first time, to a fade time. and changing the dimming rate of the light source in the fade time. 2. The lighting device according to claim 1, wherein said fade time is equal to said sustain time. The control unit controls the lighting circuit so that the dimming rate of the light source changes from the dimming rate corresponding to the first time to the dimming rate corresponding to the second time over the fade time. The lighting device according to claim 1 or 2, characterized in that: 4. The control unit according to any one of claims 1 to 3, wherein when the sustain time is longer than a predetermined time, the control unit sets the fade time to a predetermined designated time. lighting device. When the difference between the sustain time measured this time and the sustain time measured last time is larger than a predetermined value, the control unit sets the fade time to a predetermined specified time. The lighting device according to any one of claims 1 to 4. A dimmer for transmitting the PWM signal to the control unit,
6. The dimmer maintains the on-time or the off-time at the first time for a period of time corresponding to the target value of the fade time. The lighting device according to . a lighting circuit for lighting the light source;
a control unit that controls the lighting circuit according to a PWM signal input from the outside;
with
The lighting device, wherein the control unit obtains a fade time from the period of the PWM signal, and changes a dimming rate of the light source according to the fade time. The control unit controls the lighting circuit such that the dimming rate of the light source changes to a dimming rate corresponding to the ON time or OFF time of the PWM signal over the fade time. The lighting device according to claim 7. 9. The lighting device according to claim 7, further comprising a dimmer that transmits the PWM signal having a period corresponding to the target value of the fade time to the control unit. the light source;
a lighting device according to any one of claims 1 to 9;
A lighting device comprising:

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