JP2020155215A - Lighting device and illumination device - Google Patents

Abstract

To obtain a lighting device and an illumination device whose fade time can be freely set.SOLUTION: The lighting device includes: a lighting circuit for lighting a light source; and a control unit for controlling the lighting circuit in response to a PWM signal input from an outside. When an on-time or off-time of the PWM signal changes from a first time to a second time, the control unit calculates a fade time from a maintenance time, which is a period during which the on-time or the off-time is the first time to change a dimming rate of the light source by the fade time.SELECTED DRAWING: Figure 1

Description

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

Patent Document 1 discloses a dimmer that receives a dimming signal from a dimming table that transmits dimming data substantially periodically and controls dimming. The dimmer measures itself the time until the next dimming data is received. Further, the dimmer determines the number of dimming times and the dimming value after receiving the dimming data. The dimmer gradually adjusts the dimming value to the determined target dimming value within the time until the next dimming data is received.

Japanese Patent No. 5008463

In Patent Document 1, the fade time for stepwise dimming is determined by the reception interval of dimming data transmitted substantially periodically. Therefore, the fade time cannot be set freely.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to obtain a lighting device and a lighting device in which a fade time can be freely set.

The lighting device according to the present invention includes a lighting circuit for lighting a light source and a control unit for controlling the lighting circuit in response to a PWM signal input from the outside, and the control unit includes an on-time of the PWM signal. Alternatively, when the off time changes from the first hour to the second hour, the fade time is obtained from the maintenance time, which is the period during which the on time or the off time was the first hour, and the dimming of the light source is performed at the fade time. Change the rate.

The lighting device according to the present invention includes a lighting circuit for lighting a light source and a control unit for controlling the lighting circuit in response to a PWM signal input from the outside, and the control unit starts from the period of the PWM signal. The fade time is obtained, and the dimming rate of the light source is changed by the fade time.

In the lighting device according to the present invention, the fade time can be freely set from the maintenance time, which is the period during which the on time or the off time is the first hour.
In the lighting device according to the present invention, the fade time can be freely set from the period of the PWM signal.

It is a circuit block diagram of the lighting apparatus which concerns on Embodiment 1. FIG. It is a flowchart which shows the operation of the control part which concerns on Embodiment 1. FIG. It is a figure which shows the time change of the dimming rate which concerns on a comparative example. It is a figure which shows the time change of the dimming rate which concerns on Embodiment 1. It is a flowchart which shows the operation of the control part which concerns on Embodiment 2. It is a flowchart which shows the operation of the control part which concerns on Embodiment 3.

The lighting device and the lighting device according to the embodiment of the present invention will be described with reference to the drawings. The same or corresponding components may be designated by the same reference numerals and the description may be omitted.

Embodiment 1.
FIG. 1 is a circuit block diagram of the lighting device 100 according to the first embodiment. 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 the LED, and may be an organic EL. The plurality of light sources 11a are connected in series. Not limited to this, a plurality of light sources 11a may be connected in parallel or in series and parallel.

The lighting device 1 includes a rectifier circuit 3 that rectifies AC power from AC power supply 2 into DC power. A step-up 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 the switching element on and off, and outputs a high DC voltage. The control unit 16 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 step-up chopper circuit 4 and the step-down chopper circuit 5 form a lighting circuit for lighting the light source 11a.

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

The output current supplied by the step-down chopper circuit 5 to the LED module 11 flows through the resistor 10. The resistor 10 constitutes an output current detection circuit. The voltage applied to the resistor 10 corresponds to the output current of the step-down chopper circuit 5. In this way, the resistor 10 outputs an output current detection signal corresponding to the output current of the step-down chopper circuit 5.

One end of the resistor 10 is connected to the control unit 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.

Further, the lighting device 1 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 unit 16. The dimmer 19 includes a dimmer 18. The dimmer 18 transmits a PWM signal to the control unit 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 appropriately used. FIG. 1 shows an example of the control unit 16. In FIG. 1, the control unit 16 includes a drive circuit 12, an A / D conversion circuit 13, a processing device 14, and a storage unit 15 connected to each other via an internal bus.

The drive circuit 12 outputs a PWM signal for switching the switching element 6. The 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 processing device 14.

The processing device 14 analyzes the PWM signal input from the dimming circuit 17. The processing device 14 determines the target current based on the on-time or off-time of the input PWM signal. The processing device 14 turns on / 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. As a result, the processing device 14 controls the step-down chopper circuit 5 with a constant current.

The storage unit 15 is, for example, a non-volatile memory. The storage unit 15 stores an arithmetic program to be executed by the processing device 14 and various data used for the arithmetic. In this way, the control unit 16 controls the lighting circuit according to the PWM signal input from the outside.

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

Next, as shown in step S102, the control unit 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. Further, the control unit 16 counts the time elapsed since the on-time becomes the first time. That is, the control unit 16 measures the time elapsed from the time when the on-time of the PWM signal changes from the previous value to the first time.

Further, the control unit 16 determines whether or not the on-time has changed from the first time as shown in step S103. If the on-time of the PWM signal has changed from the first time measured last time, the process proceeds to step S104. Here, it is assumed that the on-time of the PWM signal changes from the first time to the second time. If it has not changed, the process proceeds to step S102.

Here, the maintenance time is the time from when the on-time becomes the first time to when it changes to another value, the second time. That is, the maintenance time is the period during which the on-time was the first hour.

Next, as shown in step S104, the processing device 14 reads out the target current value corresponding to the second on-time, which is the new on-time, from the storage unit 15. The storage unit 15 stores in advance the correspondence 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 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 until the lamp current reaches the target current value, from the maintenance time. In the present embodiment, the control unit 16 sets the fade time to the maintenance time measured in step S102.

The control unit 16 changes the dimming rate of the light source 11a with a fade time equal to the maintenance 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 control unit 16 continuously increases or decreases the dimming rate of the light source 11a during the fade time. Further, 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 rate of change in the dimming rate per hour does not have to be constant.

The fade control by the control unit 16 is a fade-in control when the dimming rate corresponding to the second time is larger than the dimming rate corresponding to the first time. Further, the fade control is a 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 maintenance time, the control unit 16 clears the maintenance time as shown in step S106. Next, the control unit 16 shifts to step S102 again.

Next, the effect of this embodiment will be described. FIG. 3 is a diagram showing the time change of the dimming rate according to the comparative example. FIG. 4 is a diagram showing a time change of the dimming rate according to the first embodiment. 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, which corresponds to the maintenance time of this embodiment. In FIGS. 3 and 4, as an example, a case where the on-time of the PWM signal decreases every n seconds causes the target dimming rate corresponding to the on-time to decrease by 10% every n seconds.

In FIG. 3, the fade time is shorter than the maintenance 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 stepped and flicker occurs.

In FIG. 4, the dimming rate of the present embodiment is shown by a solid line, and the dimming rate of the comparative example is shown by a broken line. In this embodiment, the fade time is equal to the maintenance time. Therefore, the lamp current reaches the target current value at the timing of receiving the next dimming rate. Therefore, the change in the light output can be smoothed and the flicker can be suppressed as compared with the comparative example.

Further, it is conceivable that the dimming signal corresponding to the same dimming rate is received a plurality of times from the dimmer 18 during the maintenance time in which the on-time is maintained 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.

On the other hand, in the present embodiment, the maintenance time is set to the fade time. Therefore, even if the PWM signal corresponding to the same dimming rate is received a plurality of times during the maintenance time, the dimming rate of the light source 11a reaches the target dimming rate at the timing of receiving the next dimming rate. be able to.

Further, the dimmer 18 of the present embodiment changes the on-time to the second time after maintaining the state of the on-time of the first hour for a time corresponding to the target value of the fade time. In the present embodiment, the maintenance time, which is the time during which the on-time is maintained in the state of the first hour, is the next fade time. Therefore, the fade time from the dimming rate corresponding to the first hour to the dimming rate corresponding to the second hour can be freely set from the dimmer 18. Further, even if the fade time is freely set, the flicker of the light source 11a can be suppressed.

Further, in the present embodiment, the control unit 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 maintenance time, which is the period during which the off time was the first time. You may let me.

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

Further, in the present embodiment, the fade time is determined by using the PWM signal, and the lighting circuit is controlled. Here, the PWM signal of the present embodiment may be a signal having an on time in the High state and an off time in the Low state. The PWM signal is composed of, for example, a square wave. Further, in the present embodiment, the on-time or off-time of the PWM signal corresponds to the dimming rate. At this time, the duty ratio of the PWM signal and the dimming rate do not have to correspond to each other. Not limited to this, the processing device 14 may determine the target current based on the on-duty ratio or the off-duty ratio of the PWM signal.

These modifications can be appropriately applied to the lighting device and the lighting device according to the following embodiments. Since the lighting device and the lighting device according to the following embodiments have much in common with the first embodiment, the differences from the first embodiment will be mainly described.

Embodiment 2.
FIG. 5 is a flowchart showing the operation of the control unit 16 according to the second embodiment. The operation of the 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 of the first embodiment.

In step S205, the control unit 16 determines whether or not the maintenance time is longer than a predetermined predetermined time. If the maintenance time is less than or equal to 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 designated time as shown in step S206. A value equal to or less than a predetermined time is set for the specified time.

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

In the first embodiment, the time during which the previous on-time was maintained was defined as the fade time until the next dimming rate. Here, after the series of the first dimming control from the dimmer 18 is completed, it is conceivable that there will be a long time until the second dimming control. In this case, the maintenance time during which the on-time is kept constant becomes long between the first dimming control and the second dimming control. At this time, the first fade time of the second dimming control may be unnecessarily long.

On the other hand, in the present embodiment, the start of dimming can be determined. If the maintenance time is longer than a predetermined time in step S205, the control unit 16 determines that dimming has started and proceeds to step S206. As a result, the fade time is set to the specified time. If the maintenance time is less than or equal to a predetermined time, the control unit 16 determines that dimming is in progress and proceeds to step S208.

From the above, it is possible to prevent the initial fade time after the dimming rate is kept constant for a long time from becoming too long.

As a modification of the present embodiment, the control unit 16 specifies a fade time when the difference between the maintenance time measured this time in step S202 and the maintenance time measured last time is larger than a predetermined value. It may be set to the time. In this case, the storage unit 15 stores the previously measured maintenance time. Even in the modified example, the control unit 16 can discriminate between the start of dimming and the middle of dimming, and the fade time at the start of dimming can be shortened.

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

Next, as shown in step S302, the control unit 16 measures the on time and the off time of the PWM signal. Further, 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 cycle has changed, the process proceeds to step S304. If the cycle has not changed, the process proceeds to step S302.

In step S304, 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, the processing device 14 obtains the fade time from the period of the PWM signal. The processing device 14 reads out the fade time corresponding to the period of the PWM signal from the storage unit 15. Here, the storage unit 15 stores in advance the correspondence between the period of the PWM signal and the fade time.

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. As a result, 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 the fade time corresponding to the period of the PWM signal.

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

The control unit 16 of the present embodiment changes the dimming rate of the light source 11a with a fade time corresponding to the period of the PWM signal. The 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 cycle, which 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 period 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 unit 16. From the above, the fade time can be freely set from the dimmer 18.

Further, the dimmer 18 may change the on-time of the PWM signal according to the timing of the end of the fade. As a result, the control unit 16 can receive the next dimming rate at the timing of the end of the fade. Therefore, the flicker of the light source 11a can be suppressed.

Further, 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 used in combination as appropriate.

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 dimming circuit, 18 dimmer, 19 dimming device, 100 lighting device

Claims (10)

A lighting circuit that lights the light source and
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 the first time to the second time, the control unit sets the fade time from the maintenance time, which is the period during which the on-time or the off-time was the first time. A lighting device characterized in that the dimming rate of the light source is changed according to the fade time. The lighting device according to claim 1, wherein the fade time is equal to the maintenance 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, wherein the lighting device is provided. The control unit according to any one of claims 1 to 3, wherein when the maintenance time is longer than a predetermined time, the control unit sets the fade time to a predetermined designated time. Lighting device. The control unit is characterized in that when the difference between the maintenance time measured this time and the maintenance time measured last time is larger than a predetermined value, the fade time is set to a predetermined designated time. The lighting device according to any one of claims 1 to 4. A dimmer for transmitting the PWM signal to the control unit is provided.
The dimmer, any one of claims 1 to 5, characterized in that the on-time or the off-time maintains the state of the first time for a time corresponding to the target value of the fade time. The lighting device described in. A lighting circuit that lights the light source and
A control unit that controls the lighting circuit according to a PWM signal input from the outside,
With
The control unit is a lighting device characterized in that a fade time is obtained from the period of the PWM signal and the dimming rate of the light source is changed by the fade time. The control unit is characterized in that the lighting circuit is controlled so that the dimming rate of the light source changes to the dimming rate corresponding to the on time or the off time of the PWM signal over the fade time. The lighting device according to claim 7. The lighting device according to claim 7 or 8, 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. With the light source
The lighting device according to any one of claims 1 to 9,
A lighting device characterized by being provided with.

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