JP2015103503A - Illuminating fixture, and lighting device used for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a stress from being added to a semiconductor light-emitting element and a switching element at switching, in an illuminating fixture and a lighting device that switch in time division a plurality of light sources having luminous colors different from each other to lighten them.SOLUTION: In a switching element Q2, an operation time period in which a chopping operation is performed and a pause time period in which the chopping operation is paused are alternately formed, and the switching element Q2 is kept in an off state in the pause time period. In an operation of one cycle, four chopping time periods and four pause time periods are included. A timing when each light source switch Q3, Q4, Q5, Q6 is switched is set to after a start time point of the pause time period (a termination point of the chopping operation) to before a termination time point of the pause time period (a start point of the next chopping operation).

Description

  The present invention relates to a lighting fixture that emits light by turning on a plurality of light sources having different emission colors, and a lighting device used therefor.

2. Description of the Related Art In recent years, light fixtures including a light source unit having a plurality of LED (Light Emitting Diode) groups having different emission colors, such as green light, blue light, and red light, and a lighting device that turns on the light source unit have been used. .
In this lighting fixture, by adjusting the intensity of the light emitted from each LED group and adjusting the intensity of the light emitted from each LED group, the chromaticity or intensity of the emitted mixed light can be adjusted. It has become.

The lighting device includes a DC power supply circuit and a plurality of constant current circuits provided in series with respect to each LED group. The switching element of each constant current circuit is controlled by a PWM (Pulse Width Modulation) method, What adjusts the light emission amount of LED group is known.
On the other hand, as disclosed in Patent Document 1, a switching element is connected to two LED groups having different color temperatures, and the duty ratio is adjusted, while the duty ratio is adjusted, and the light is emitted alternately by a time division method. A technique for adjusting the color temperature is also known. If the amount of light emitted from each color LED group is adjusted by this method, it is not necessary to provide a constant current circuit for each LED group, so that the circuit in the lighting device can be reduced in size and cost.

JP2011-258517A

  However, as described above, in the case of the time division method in which the duty ratio is adjusted and lighted in a time division manner, when the LED groups that supply power are sequentially switched, stress is applied to the switching elements, or current starts to flow immediately after the switching. An excessive inrush current may flow to the LED group. In an LED group in which an excessive inrush current is generated, the LED group or the switching element may be damaged, which may cause the life of the lighting fixture to be shortened.

  In view of the above-described problems, the present invention can prevent a semiconductor light emitting element and a switching element from being stressed at the time of switching in a lighting apparatus and a lighting device that switches on and lights a plurality of light sources having different emission colors in a time division manner. The purpose is to do.

In order to achieve the above object, a lighting device according to one embodiment of the present invention lights a light source unit having a plurality of light sources having different emission colors. Here, each light source comprises a semiconductor light emitting element.
The lighting device includes a direct current power supply circuit, an output adjustment circuit that adjusts an output current by a chopping operation of a chopping switch provided in a power line extending from the direct current power supply circuit to the light source unit, and a plurality of light sources one by one. And a plurality of light source switches that are connected in series to form a series load circuit, and a control unit that controls a time for supplying a current to each light source. Each of the series load circuits is connected in parallel to the output terminal of the output adjustment circuit.

Then, the control unit operates the output adjustment circuit so as to repeat the operation period for performing the chopping operation and the pause period for suspending the chopping operation, and also sequentially switches the plurality of light source switches so as to be turned on. Thus, switching of the plurality of light source switches is performed at a point in time after the start of the suspension period.
In order to achieve the above object, a lighting fixture according to one embodiment of the present invention includes a light source unit including a plurality of light sources having different emission colors, each light source including a semiconductor light emitting element, and the lighting device. Prepare
In the lighting apparatus and the lighting device, the following may be performed.

The control unit changes the time length of the chopping operation in the output adjustment circuit to control the time length for the plurality of light sources to emit light.
The output adjustment circuit is provided with a capacitor that smoothes the chopped pulsating current, and the time from the start point of the rest period to the time when the plurality of light source switches are switched is discharged from the capacitor to the series load circuit side during the rest period. Set more than the time constant when.

A discharge circuit is provided in parallel with the plurality of series load circuits at the output end of the output adjustment circuit.
The control unit performs switching of the plurality of light source switches before the end of the suspension period.
The control unit further sets a target current value based on an instruction from the outside, and the output adjustment circuit performs a chopping operation so that the output current matches the target current value.

In the lighting device and the lighting fixture according to the above aspect, the output adjustment circuit is operated to repeat the operation period in which the chopping operation is performed and the suspension period in which the chopping operation is suspended, and the chopping switch is turned off in the suspension period. The plurality of light source switches are alternatively switched on.
Therefore, the power output from the DC power supply circuit through the output adjustment circuit is sequentially supplied to the plurality of light sources, and the plurality of light sources are turned on in a time division manner so that the ON periods do not overlap each other.

In addition, since the switching operation of the plurality of light source switches is performed at the time when the time has elapsed from the start point of the suspension period during the suspension period, the plurality of light sources are switched when the current flowing through the series load circuit is small. The switch is switched.
Therefore, stress applied to the semiconductor light emitting element and the light source switch constituting the series load circuit can be reduced.

FIG. 3 shows a circuit configuration of the lighting fixture 100 according to Embodiment 1. The flowchart which shows the control action which the control part 20 of the lighting fixture 100 performs. In the lighting fixture 100, the wave form diagram which shows the voltage input into each gate of switching element Q2, switching element Q3, Q4, Q5, the current I1 output from the DC voltage conversion circuit 12, and voltage IC1. It is a wave form diagram explaining the effect by burst control, Comprising: (a) Example which performs burst control, (b) is a comparative example which does not perform burst control. (A)-(d) is a figure which shows the tables T1-T4 with which the control part 20 is provided. (A) is a figure which shows a specific example of table T1, (b) is a figure which shows a specific example of table T2. (A), (b) is a timing chart which shows a mode that the electric current I1 output to the light source unit 1 is adjusted with the magnitude | size of the output control current data IA. The figure which shows the circuit structure of the lighting fixture 200 concerning Embodiment 5. FIG. 10 is a flowchart showing a control operation of the control unit 20 according to the sixth embodiment. In the lighting fixture of Embodiment 6, the wave form diagram which shows the current I1 output from the gate voltage of light source switch Q3, Q4, Q5, the gate voltage of the switching element Q2, and the electric power unit 10. FIG. (A)-(c) is a figure which shows the illuminating devices 100a-100c to which the lighting fixture 100 is applied.

<Embodiment 1>
A lighting apparatus 100 according to Embodiment 1 will be described with reference to FIGS.
1. Overall Configuration of Lighting Fixture 100 As shown in FIG. 1, the lighting fixture 100 includes a light source unit 1 having a plurality of light sources (LED groups 3, 4, 5, and 6) having different emission colors, and an LED group 3 of the light source unit 1. , 4, 5 and 6 are provided with a lighting device 2 which is driven by passing a current. The emission colors of the LED groups 3, 4, 5, and 6 are red (R), green (G), blue (B), and white (W).

In the light source unit 1 shown in FIG. 1, each of the LED groups 3, 4, 5, and 6 is configured by connecting LEDs having the same emission color and the same characteristics in series. However, the LED group 3 may be composed of one red LED, the LED group 4 may be one green LED, the LED group 5 may be one blue LED, and the LED group 6 may be one white LED.
The lighting device 2 periodically repeats the operation of sequentially lighting the LED groups 3, 4, 5, and 6 at such a high speed that blinking cannot be visually recognized by human vision. Thereby, mixed light in which the light from the LED groups 3, 4, 5, 6 is mixed is emitted from the light source unit 1.

  The lighting device 2 includes a plurality of light source switches Q3, Q4, Q5, Q6 connected in series to the LED groups 3, 4, 5, 6 of the light source unit 1, and a power unit that outputs DC power to the light source unit 1. 10 and a control unit 20 that controls the time for current to flow through the LED groups 3, 4, 5, and 6 of the light source unit 1. When the LED groups 3, 4, 5, and 6 are turned on, the color and intensity of the mixed light can be adjusted by adjusting the light emission time.

Here, a series load circuit 30 is formed by connecting the LED group 3 and the light source switch Q3 in series. Similarly, LED group 4 and light source switch Q4 are connected in series, LED group 5 and light source switch Q5 are connected in series, LED group 6 and light source switch Q6 are connected in series Is a series load circuit 40, 50, 60.
The power unit 10 includes a DC power supply circuit 11 including a full-wave rectifier circuit 11a and a smoothing circuit 11b, and a DC voltage conversion circuit 12 that adjusts an output current supplied from the DC power supply circuit 11 to the light source unit 1. The four series load circuits 30, 40, 50 and 60 are connected in parallel to each other on the output side of the DC voltage conversion circuit 12.

The DC voltage conversion circuit 12 controls the switching element Q2 for turning on / off the power path from the DC power supply circuit 11 to the light source unit 1, and controls the on / off operation of the switching element Q2 to output a constant current. A semiconductor element IC1 and a current detection circuit 13 are provided.
The control unit 20 is input with a dimming toning signal that specifies the emission color of light emitted from the light source unit 1. And the control part 20 is equipped with microcomputer IC2, and the table T1 in which the light emission time etc. of each LED group 3, 4, 5, 6 was matched and memorize | stored for every light emission color in the memory is stored.

When the dimming and toning signal is input to the control unit 20, the table T1 is referred to, the control of the semiconductor element IC1 in the DC voltage conversion circuit 12, and the light source switches Q3, Q4, Q5, and Q6 are sequentially selected. The operation to turn on automatically is repeated periodically.
Thereby, in the light source unit 1, the LED group 3, LED group 4, LED group 5, and LED group 6 repeat the operation of lighting in order at a constant cycle, and emit light for the light emission time specified by the dimming and toning signal. Exit.

2. Specific Configuration of Each Part Hereinafter, specific configuration examples of the light source unit 1, the power unit 10, the light source switches Q3, Q4, Q5, Q6, and the control unit 20 will be described.
(Light source unit 1)
Each LED constituting the LED groups 3, 4, 5 and 6 is mounted on a substrate having a base plate made of a metal material laminated with an insulating layer on one surface in consideration of thermal conductivity. Or you may mount on the board | substrate etc. which used the ceramic material and synthetic resin material which were comparatively favorable in the thermal radiation characteristic and were excellent in durability as a base board.

Each color LED is mounted on a substrate by a surface mounting (SMD) method in which LED bare chips are packaged. However, it is not limited to the surface mounting method, and may be mounted by a chip on board (COB) method in which an LED bare chip is directly mounted on a substrate.
An LED bare chip is, for example, an InGaN-based element in which a light-emitting layer is stacked on a light-transmitting sapphire element substrate, and an n-type nitride semiconductor layer, an InGaN light-emitting layer, and a p-type nitride semiconductor layer are sequentially stacked. Has been formed.

For the white LED, a bare chip of an LED that emits blue light is used, and white light is emitted by converting the wavelength of part of the blue light with a phosphor applied thereto.
The electrode in the bare chip is formed of a plus side electrode formed with a p-type electrode pad on a p-type nitride semiconductor layer and a minus side electrode formed with an n-type electrode pad on an n-type nitride semiconductor layer. . These positive electrode and negative electrode are electrically connected by a bonding wire. The bonding wire is made of a thin wire such as gold, and is connected to the electrode through a bump mainly composed of gold in order to improve mounting strength and reduce damage to the bare chip of the LED.

Since LEDs having different emission colors generally have different layer structures and materials, the forward voltages when the same current flows through the LEDs are different. In general, the forward voltage of an LED when a current of 10 mA flows is about 1.8 V for a red LED, about 2.4 V for a green LED, and about 3.6 V for a blue LED and a white LED.
Therefore, the forward voltages (Vf) when the same current flows through the LED groups 3, 4, 5, and 6 are generally different.

(Power unit 10)
The DC power supply circuit 11 includes a full-wave rectifier circuit 11a and a smoothing circuit 11b.
The full-wave rectifier circuit 11a is a diode bridge circuit. Since the detailed operation of the full-wave rectifier circuit 11a is known, a description thereof will be omitted.
The smoothing circuit 11b is a power factor improving step-up chopper circuit including an inductor L1, a switching element Q1, a diode D1, a capacitor C1, and a resistance element R1 that detects a current flowing through the switching element Q1.

The DC voltage conversion circuit 12 is a step-down chopper circuit including an inductor L2, a switching element Q2, a capacitor C2, a diode D2, and a semiconductor element IC1.
In this step-down chopper circuit, the switching element Q2 functions as a chopping switch for chopping the DC voltage on the input side, and outputs a pulsating current to the inductor L2 by performing a chopping operation that repeats on / off.

Switching elements Q1, Q2 are FETs (Field Effect Transistors).
The operating frequency of the chopping operation in the switching element Q2 is, for example, several tens kHz to several hundreds kHz.
Capacitor C2 smoothes the current output from inductor L2.
Semiconductor element IC1 and burst control circuit 14:
The semiconductor element IC1 includes a pulse oscillation circuit that repeatedly oscillates a pulse signal that turns on and off the switching element Q2, a protection circuit that suppresses an overcurrent from flowing through the switching element Q2, and the like. The semiconductor element IC1 controls the output current I1 with the output control data IA instructed from the control unit 20 as a target value while oscillating a pulse signal to the switching element Q2. In the present embodiment, the target value IA of the output control current is a constant value.

The burst control circuit 14 controls whether or not to drive the semiconductor element IC1. That is, the burst control circuit 14 receives a start signal / end signal instructing the start / end of chopping from the IC 2 of the control unit 20, and causes the semiconductor element IC1 to perform a chopping operation only from the start signal to the end signal.
Further, during a time other than between the chopping start signal and the end signal, the chopping operation of the semiconductor element IC1 is suspended and the switching element Q2 is maintained in the off state.

Thus, during the period from the chopping start signal to the end signal (chopping operation period), the switching element Q2 is PWM controlled while being repeatedly turned on / off, and the output current I1 is adjusted to the target value IA of the output current. Further, during the rest period from the chopping end signal to the start signal, the switching element Q2 is maintained in the off state.
The current control by the semiconductor element IC1 during the chopping operation period is performed by feedback control while monitoring the voltage signal from the current detection circuit 13 with the output control data IA instructed from the control unit 20 as a target value as follows. .

The current detection circuit 13 includes a fixed resistance element R2, and outputs a voltage value appearing at the fixed resistance element R2 to the semiconductor element IC1. Since this voltage value is proportional to the current I1 output from the DC voltage conversion circuit 12, the semiconductor element IC1 can detect the output current value I1 from the voltage value input from the current detection circuit 13.
The semiconductor element IC1 adjusts the pulse width of the oscillating pulse so that the detected output current I1 matches the target value IA of the output control current instructed from the control unit 20, and the ON time of the switching element Q2 Adjust the length. That is, when the detected current value I1 is lower than the target value IA of the output control current, the semiconductor element IC1 increases the oscillating pulse width (ON time of the switching element Q2). On the other hand, when the detected output current value I1 is higher than the target value IA of the output control current, the oscillating pulse width (ON time of the switching element Q2) is decreased. Thereby, the output current I1 is controlled so as to match the target value IA of the output control current.

By controlling the switching element Q2 by the semiconductor element IC1 as described above, constant current (constant power) for supplying a constant current from the power unit 10 to the light source unit 1 can be realized during the period of the chopping operation.
Here, the current control is performed by changing the ON duty ratio of the pulse width (ON time of the switching element Q2) that the semiconductor element IC1 oscillates. However, as described in the fourth embodiment below, the oscillation frequency The current can also be controlled by increasing or decreasing.

(Light source switches Q3, Q4, Q5, Q6 and series load circuits 30, 40, 50, 60)
Each light source switch Q3, Q4, Q5, Q6 shown in FIG. 1 is a MOSFET (Metal Oxide Semiconductor Field Effect Transistor). However, bipolar transistors can also be used.
As described above, the series load circuit 30, the series load circuit 40, the series load circuit 50, and the series load circuit 60 are connected in parallel to the output terminal of the DC voltage conversion circuit 12.

The light source switches Q3, Q4, Q5, and Q6 are alternatively turned on in order according to an instruction from the control unit 20. As a result, the output current output from the power unit 10 is selectively supplied to the series load circuits 30, 40, 50, 60 in which the light source switches Q3, Q4, Q5, Q6 are turned on. .
(Control unit 20)
The control unit 20 is read from a control processing unit IC2, which is a microcomputer that executes various control processes, a table T1, a ROM (Read Only Memory) storing various control programs, and the like, and is used for the control process. Volatile main memory MM such as RAM (Random Access Memory) that temporarily stores data of various control parameter values, and nonvolatile sub memory SM such as EEPROM (Electrically Erasable Programmable Read-Only Memory) It has a timer TM for measuring. In FIG. 1, the ROM is displayed as a table T1, and the main memory MM and the sub memory SM are not shown. The timer TM and the sub memory SM may be part of the function of the control processing unit IC2.

For example, a dimming / toning signal is input to the control unit 20 by a user operating a remote controller (not shown). The dimming toning signal is a signal designating any one of the dimming toning signal data Va (n) (0 to 255) described in the table T1, and the form of the signal is DMX signal, DALI signal, UART signal, etc.
When the control unit 20 acquires the light control and toning signal Va (n), the control unit 20 sends to the burst control circuit 14 a start signal for starting the chopping operation and an end signal for ending the chopping operation. The control unit 20 also performs operations such as sending an on / off signal to the gates of the light source switches Q3, Q4, Q5, and Q6.

The table T1 stored in the memory of the control unit 20 will be described. FIG. 5A shows the same table T1 as described in FIG.
The table T1 includes dimming / toning signal data Va (n), burst control time data TA (n), TB (n), TC (n), TD (n) and output control time data ta (n), tb (n), tc (n), and td (n) are associated with each other and stored in the ROM of the control unit 20.

“N” in the light control toning signal data Va (n) is any one of 0 to 255 indicating any one combination number selected by the user among the 256 types. For example, when the tenth combination is shown, it is expressed as a light adjustment toning signal Va (10). When not collectively representing a specific combination, it is displayed as a dimming / toning signal Va (n).
Burst control time data TA (n), TB (n), TC (n), and TD (n) indicate the length of time for supplying power to the LED groups 3, 4, 5, and 6 in one cycle. It is data. That is, it is data indicating the light emission time length of the LED groups 3, 4, 5 and 6 necessary for emitting light corresponding to each number from the light source unit 1. The output control time data ta (n), tb (n), tc (n), and td (n) are data indicating the length of the ON period of the switching elements Q3, Q4, Q5, and Q6 in one cycle. It is. Also in this case, n is a number indicating the combination number selected by the user.

  The burst control time data TA (n) is set shorter than the output control time data ta (n). Similarly, the burst control time data TB (n), TC (n), and TD (n) are set shorter than the output control time data tb (n), tc (n), and td (n). Although this time difference will be described in detail later, it corresponds to the time length of a pause period in which the chopping operation is paused.

By adjusting the burst control time data TA (n), TB (n), TC (n), and TD (n), the time emitted from the light sources 3, 4, 5 and 6 is adjusted, respectively. Toning can be performed.
Further, the time length of one cycle is changed by adjusting the output control time data ta (n), tb (n), tc (n), td (n) and changing the length of the pause period. Can do light. That is, when the total [ta (n) + tb (n) + tc (n) + td (n)] of the output control time data is increased, the light emission amount per unit time emitted from the lighting apparatus 100 is decreased.

  FIG. 6A shows a specific example of the table T1. In this figure, among 256 dimming / toning signal data Va (n), 8 Nos. Typically, only (n = 0, 1, 10, 11, 20, 21, 30, 31) TA (n), ta (n), TB (n), tb (n), TC (n), The numerical values of tc (n), TD (n), and td (n) are described, and the remaining No. These figures are omitted for.

  In the specific example of the table T1 shown in FIG. 6A, Va (0) and Va (1) are set so that the light emission times of the four color LED groups are equal, and when these are selected, the light source unit. 1 emits white light. However, when Va (1) is selected, since the ratio of light emission time (duty ratio) in one cycle is smaller than Va (0), the amount of light emission per unit time is slightly smaller.

On the other hand, in Va (10) and Va (11), the red light emission time is set longer than the light emission time of other colors, and when these are selected, the light emitted from the light source unit 1 is red to white light. The light is a mixed color light.
In Va (20) and Va (21), the green light emission time is set longer than the light emission times of the other colors. When these are selected, the light emitted from the light source unit 1 is mixed with white light and green light. It becomes the light of the color.

In Va (30) and Va (31), the light emission time of blue is set longer than the light emission time of other colors. When these are selected, the light emitted from the light source unit 1 is mixed with white light and green light. Becomes mixed light.
(Control operation in the control unit 20)
The control operation performed by the control unit 20 with reference to the table T1 will be described with reference to the flowchart shown in FIG.

FIG. 3 shows the gate voltage of the light source switches Q3, Q4, Q5, Q6 formed as a result of this control operation, the gate voltage of the switching element Q2, the current I1 output from the power unit 10, and the voltage Vc1 at the output end of the power unit 10. FIG.
When power is turned on to the luminaire 100, the flow shown in FIG. 2 is started and the initial process is executed (step S1). Here, the initial process will be described below. First, the control processing unit IC2 reads the light adjustment and tonal signal data Va (n) stored in the sub memory SM. Then, burst control time data TA (n), TB (n), TC (n), TD (n) and output control time data ta ( n), tb (n), tc (n), and td (n) are read from the table T1, and these data are stored in the main memory MM. The above processing is the initial processing in the flow of the first embodiment.

Here, the light adjustment toning signal data Va (n) first read from the sub memory SM after the power is turned on is the light adjustment toning signal data stored last in the sub memory SM during the previous use. That is, the data indicates the combination number which is the light adjustment and toning setting last selected by the user when used last time.
Then, the control unit 20 resets and starts the timer TM and instructs the burst control circuit 14 to start the chopping operation. Further, the light source switch Q3 is turned on, and the light source switches Q4, Q5, and Q6 are turned off (step S2, time t1 in FIG. 3). Here, the term “turning off” the light source switch means that the light source switch that is already in the off state is maintained in the off state.
Next, it is monitored whether Tm which is the value of the timer TM has reached TA (n) (step S3). This TA (n) is burst control time data TA (n) corresponding to the light adjustment toning signal data Va (n) stored in the main memory MM. Here, if the light control and tonal signal data read from the sub memory SM in step S1 is specifically Va (10), for example, the burst control time data stored in the main memory MM is TA (10 Therefore, the burst control time data to be judged by TM in step S3 is TA (10). Hereinafter, the same applies to (n) in various control parameters in each step of this flow.

When Tm reaches TA (n), the control unit 20 instructs the burst control circuit 14 to end the chopping operation. As a result, the switching element Q2 is turned off (step S4, time point t2 in FIG. 3).
Subsequently, it is monitored whether or not Tm has reached ta (n) (step S5), and when it reaches ta (n), the control unit 20 resets and starts the timer TM, and sets the burst control circuit 14 to start. Instructs to start chopping operation. Thereby, the semiconductor element IC1 starts the chopping operation of the switching element Q2. The control unit 20 turns on the light source switch Q4 and turns off the light source switches Q3, Q5, and Q6. Accordingly, the light source switch that is turned on is switched from Q3 to Q4 (step S6, time point t3 in FIG. 3).

As a result of the control in steps S2 to S6, the LED group 3 is turned on and red light is emitted during a period from time t1 to time t2 corresponding to the burst control time data TA (n). Further, the switching element Q2 is maintained in the OFF state during the period from the time point t2 to the time point t3.
Next, it is monitored whether or not Tm has reached TB (n) (step S7). When TB (n) is reached, the control unit 20 instructs the burst control circuit 14 to end the chopping operation. Thereby, the switching element Q2 is turned off (step S8, time point t4 in FIG. 3).

  Subsequently, it is monitored whether or not Tm has reached tb (n) (step S9), and when it reaches tb (n), the control unit 20 resets and starts the timer TM, and sends the burst control circuit 14 with it. Instructs to start chopping operation. Thereby, the semiconductor element IC1 starts the chopping operation of the switching element Q2. The control unit 20 turns on the light source switch Q5 and turns off the light source switches Q3, Q4, and Q6. Accordingly, the light source switch that is turned on is switched from Q4 to Q5 (step S10, time point t5 in FIG. 3).

As a result of the control in steps S6 to S10, the LED group 4 is turned on and green light is emitted from time t3 to time t4 corresponding to the burst control time data TB (n). Further, the switching element Q2 is maintained in the OFF state during the period from the time point t4 to the time point t5.
Next, it is monitored whether or not Tm has reached TC (n) (step S11), and when it reaches TC (n), the control unit 20 instructs the burst control circuit 14 to end the chopping operation. The switching element Q2 is maintained in the off state (step S12, time point t6 in FIG. 3).

  Subsequently, it is monitored whether or not Tm has reached tc (n) (step S13). When tm (n) is reached, the control unit 20 resets and starts the timer TM, and at the same time the burst control circuit 14 Instructs to start chopping operation. Thereby, the semiconductor element IC1 starts the chopping operation of the switching element Q2. Further, the control unit 20 turns on the light source switch Q6 and turns off the light source switches Q3, Q4, and Q5. As a result, the light source switch that is turned on is switched from Q5 to Q6 (step S14, time point t7 in FIG. 3).

As a result of the control in steps S10 to S14, the LED group 5 is turned on and blue light is emitted during a period from time t5 to time t6 corresponding to the burst control time data TC (n). Further, the switching element Q2 is maintained in the OFF state during the period from the time point t6 to the time point t7.
Next, it is monitored whether or not Tm has reached TD (n) (step S15), and when it reaches TD (n), the control unit 20 instructs the burst control circuit 14 to end the chopping operation. Thereby, the switching element Q2 is turned off (step S16, time point t8 in FIG. 3).

  Subsequently, it is monitored whether or not Tm has reached td (n) (step S17). When tm (n) is reached (time t1 in FIG. 3), the dimming / toning signal data Va (n) is acquired. If not (No in step S18), the control unit 20 returns to step S2 and repeats the operation from step S2. Thereby, the light source switch to be turned on is switched from Q6 to Q3.

As a result of the control in steps S14 to S18 and S2, the LED group 6 is turned on and white light is emitted during a period from time t7 to time t8 corresponding to the burst control time data TD (n). Further, the switching element Q2 is maintained in the OFF state during the period from the time point t8 to the time point t9.
On the other hand, when the light adjustment toning signal data Va (n) is acquired (Yes in step S18), the control unit 20 stores the acquired light adjustment toning signal data Va (n) in the sub memory SM. Further, the control unit 20 refers to the table T1, and burst control time data TA (n) to TD (n) and output control time data ta (n) to td corresponding to the light adjustment and toning signal data Va (n). (N) is read and stored in the main memory MM (step S19). And it returns to step S1 and repeats the operation | movement from step S1.

  Here, when the light adjustment toning signal data newly acquired in step S18 is specifically Va (20), for example, the light adjustment toning data stored in the sub memory SM in step S19 is Va (20). The main memory MM stores burst control time data TA (20), TB (20), TC (20), TD (20), and output control time data ta (20), tb (20). , Tc (20), td (20). Therefore, when returning from step S19 to step S2, the burst control time data TA (20), TB (20), TC (20), TD (20) are used in the processing from step S2 to step S18. , And output control time data ta (20), tb (20), tc (20), td (20).

The control unit 20 repeats the same operation with the above steps S1 to S19 as one cycle.
Thereby, each LED group 3, 4, 5, 6 of the lighting fixture 100 has burst control time data TA (n) to TD (n) corresponding to the number specified by the dimming / toning signal data Va (n). Light is emitted in a time-sharing manner for each time corresponding to.

  When the lighting fixture 100 is shipped, default dimming / toning signal data Va (n) is stored in the sub memory SM. At the first use, the default dimming / toning signal data Va (n) is read from the sub memory SM in step S1. Then, output control time data TA (n), TB (n), TC (n), TD (n) and output control time data ta corresponding to the read default light adjustment toning signal data Va (n). (N), tb (n), tc (n), and td (n) are read from the table T1 and stored in the main memory MM. The data stored in the main memory MM is used for the control from step S2 to step S18. After that, when the user inputs setting of dimming toning, output control time data TA (n), TB (n), TC (n) corresponding to default dimming toning signal data Va (n) , TD (n) and output control time data ta (n), tb (n), tc (n), and td (n) are newly input settings (newly acquired dimming toning signal data Va The data corresponding to (n)) is overwritten. Hereinafter, the same applies to each embodiment and each modification.

(Time-division drive and its effect in the lighting fixture 100)
The light source switches Q3, Q4, Q5, and Q6 are switched so as to be alternatively turned on by the control operation based on the flowchart described above. In addition, the LED groups 3, 4, 5, and 6 have the time corresponding to [ta (n) + tb (n) + tc (n) + td (n)] as one cycle, and output control time data TA (n), The operation of sequentially emitting light is repeated in a length corresponding to TB (n), TC (n), and TD (n), and red, green, blue, and white light is emitted at this ratio.

Accordingly, the LED groups 3, 4, 5, and 6 are turned on once in a time-division manner in one cycle, and light of the luminescent color specified by the dimming toning signal Va (n) is emitted. Will be.
In this way, by lighting the plurality of LED groups 3, 4, 5, and 6 in a time-sharing manner, it is possible to easily adjust the emission color while changing the brightness of each LED group 3, 4, 5, and 6. I can make a color. In addition, since the output is basically from one DC voltage conversion circuit 12 and each LED group 3, 4, 5 and 6 is not provided with a constant current circuit, the circuit can be reduced in size and cost. it can.

  Since the LED groups 3, 4, 5, and 6 are lit in a time-sharing manner, if the time of one cycle (ta (n) + tb (n) + tc (n) + td (n)) is long, flickering visually. However, flickering by visual observation can be suppressed by setting one period to about 15 ms or less. Further, if one cycle is set to about 10 ms or less, it is possible to further suppress visual flicker.

Here, in the specific example of the table T1 shown in FIG. 6A, the time of one cycle [ta (n) + tb (n) + tc (n) + td (n)] is set to 6 ms to 10 ms. ing.
(Burst control and its effects)
By the control operation by the control unit 20, as shown in the operation waveform of FIG. 3, an operation period for performing the chopping operation of the switching element Q <b> 2 and an idle period for pausing the chopping operation are alternately formed. Switching element Q2 is kept off.

Control in such a manner that the operation period of the chopping operation and the idle period in which the switching element Q2 is kept off in this manner is alternately repeated is referred to as burst control in this specification.
One cycle of operation includes four chopping periods and four rest periods. The length of each pause period is [ta (n) -TA (n)], [tb (n) -TB (n)], [tc (n) -TC (n)], [td (n)- TD (n)].

In the operation waveform of FIG. 3, the timing at which each of the light source switches Q3, Q4, Q5, and Q6 is switched is after the start time of the pause period (end point of the chopping operation) and after the stop period (the next chopping operation). (Start point) is set.
In the present embodiment, the timing at which each of the light source switches Q3, Q4, Q5, and Q6 is switched is the same as the end point of the pause period in the pause period. Therefore, the times Δta, Δtb, Δtc, Δtd from the start of the pause period to the switching of the light source switches Q3, Q4, Q5, Q6 are the same as the length of the pause period. That is, Δta = ta (n) −TA (n), Δtb = tb (n) −TB (n), Δtc = tc (n) −TC (n), Δtd = td (n) −TD (n) is there.

The effects obtained by switching the light source switches Q3, Q4, Q5, and Q6 in this manner during the pause period from the start of the pause period will be described below.
FIG. 4 is a waveform diagram for explaining the effect of the burst control. FIG. 4A shows an example in which burst control is performed, and FIG. 4B shows a comparative example in which burst control is not performed.

In both the example and the comparative example, the light source switches Q3, 4, 5, and 6 are alternately turned on in order in one cycle, and the LED groups 3, 4, 5, and 6 are lit in this order. Is the same.
In FIG. 4, a period in which the light source switch Q6 is turned on and the LED group 6 is turned on, and a period in which the light source switch Q3 is turned on and the LED group 3 is turned on in the next cycle are extracted.

  In the comparative example in which the burst control is not performed, as shown in FIG. 4B, the chopping operation of the switching element Q2 is not provided with a pause period, and the light source switches Q3, Q4, Q5, Q6 are turned on / off during the chopping operation. OFF switching is performed. In this comparative example, the LED groups 3, 4 and 5 are turned on only for the length of time [ta (n), tb (n), tc (n), td (n)] of the light source switches Q3, Q4, Q5 and Q6. , 6 will be lit.

In the case of the comparative example, when the light source switches Q3, Q4, Q5, and Q6 are switched ON / OFF while the current is flowing through the chopping operation of the switching element Q2, the light source switches Q3, Q4, Q5, and Q6 It can be stressed and cause a reduction in life.
On the other hand, in the embodiment, as shown in FIG. 3 and FIG. 4A, a pause period for suspending the chopping operation is provided, and the light source switch Q3 is set after the time Δta, Δtb, Δtc, Δtd from the start of the pause period. , Q4, Q5, and Q6 are switched.

In the rest period of the chopping operation, the electric charge remaining in the capacitor C2 of the DC voltage conversion circuit 12 flows to the light source unit 1, so that the current output from the power unit 10 as shown in FIGS. I1 gradually decreases. Along with this, the voltage VC1 at the output terminal of the DC voltage conversion circuit 12 also gradually decreases.
Therefore, since the light source switches Q3, Q4, Q5, and Q6 are switched when the current I1 and the voltage VC1 are reduced, the stress applied to the light source switches Q3, Q4, Q5, and Q6 is reduced.

As will be described below, when the forward voltages (Vf) of the LED groups 3, 4, 5, and 6 are different, inrush current to the series load circuit is likely to occur. However, in the embodiment in which burst control is performed, There is also an effect to suppress it.
As described above, since the forward voltages (Vf) of the LED groups 3, 4, 5, and 6 are generally different from each other, the direct current depends on which of the light source switches Q3, Q4, Q5, and Q6 is turned on. The magnitude of the voltage Vc1 at the output terminal of the voltage conversion circuit 12 changes.

In FIG. 3, the magnitude of the voltage Vc1 when the light source switches Q3, 4, 5, and 6 are on is indicated by V3, V4, V5, and V6.
In the example of FIG. 3, the forward voltage (Vf) of the LED groups 3, 4, 5 and 6 is increased in this order, so that the voltage Vc1 is also increased in the order of V3, V4, V5 and V6. (V3 <V4 <V5 <V6).

Therefore, the period shown in FIGS. 4A and 4B is a period in which the LED group through which the current flows switches from the LED group 6 having a high forward voltage (Vf) to the LED group 3 having a low forward voltage (Vf). .
Here, as in the comparative example shown in FIG. 4B, when the light source switch that was turned on was switched from Q6 to Q3 during the chopping operation, the LED group 6 having a high forward voltage (Vf) was flowing. Current flows by switching to the LED group 3 having a low forward voltage (Vf). At this time, an excessive inrush current tends to flow through the series load circuit 30 including the light source switch Q3 and the LED group 3.

On the other hand, in the embodiment shown in FIG. 4A, the light source switch that is turned on is switched from Q6 to Q3 when the current I1 and the voltage VC1 from the DC voltage conversion circuit 12 are reduced. Therefore, an excessive inrush current to the series load circuit 30 is suppressed, and stress applied to the light source switch Q3 and the LED group 3 is reduced.
As described above, according to the present embodiment, deterioration due to excessive inrush current to the LED groups 3, 4, 5 and 6 is suppressed, and deterioration due to stress of the LEDs and the light source switches Q3, Q4, Q5 and Q6 is suppressed. Therefore, the life of the device can be extended.

(Time from start of rest period to switching of light source switches Q3, Q4, Q5, Q6)
The length of each time Δta, Δtb, Δtc, Δtd from the start point of the rest period until the light source switches Q3, Q4, Q5, Q6 are switched is set longer than the cycle of turning on / off the switching element Q2 during the chopping operation. I will do it.
The light source switches Q3, Q4, Q5, and Q6 are preferably switched when the output current I1 is as small as possible (when the current is close to 0).

Here, it can be considered that the rate at which the current I1 decreases after entering the rest period is determined by the time constant when the discharge is performed from the capacitor C2 to the series load circuits 30, 40, 50, 60 side.
That is, the current I1 is IA at the start of the rest period, but when a time corresponding to the time constant when discharging from the capacitor C2 to the respective series load circuits 30, 40, 50, 60 passes, Decreases to about 37% of IA. As time further elapses, the current I1 approaches zero.

  From such consideration, the length of each time Δta, Δtb, Δtc, Δtd is set to be equal to or longer than the time constant when discharging from the capacitor C2 to each series load circuit 30, 40, 50, 60 in the idle period. Is desirable. In addition, it can be said that it is preferable to set the length of each time Δta, Δtb, Δtc, Δtd to be equal to or longer than the time when the output current I1 is substantially zero.

On the other hand, if the length of each time Δta, Δtb, Δtc, Δtd is set long, the time of one cycle (ta (n) + tb (n) + tc (n) + td (n)) also becomes long. If the time of one cycle becomes too long, flickering easily occurs.
Therefore, the length of each time Δta, Δtb, Δtc, Δtd may be set to an appropriate length in consideration of the above points.

In the specific example of the table T1 shown in FIG. 6A, the lengths of Δta, Δtb, Δtc, and Δtd are all set to 0.5 ms.
It is considered easy in terms of design to set the four times Δta, Δtb, Δtc, and Δtd included in one cycle uniformly to the same length. However, this length may not be uniform. For example, depending on the length of the period TA (n), TB (n), TC (n), TD (n) of the chopping operation, Δta, You may change the time length of (DELTA) tb, (DELTA) tc, (DELTA) td.

(Application example of lighting apparatus 100)
11A to 11C are external views of lighting devices 100a to 100c to which the lighting fixture 100 having the above-described configuration is applied.
The lighting device 100a shown in FIG. 11A is an example applied to a downlight, and includes a lighting device 2 and a lamp body 7a, both of which are connected by a wiring 8. The light source unit 1 is mounted in the lamp body 7a.

Illumination devices 100b and 100c shown in FIG. 11B are examples applied to spotlights.
The lighting device 100b also has the lighting device 2 and the lamp body 7b, and both are connected by wiring (not shown). The light source unit 1 is mounted in the lamp body 7b.
The lighting device 100 c also includes the lighting device 2 and the lamp body 7 c, and both are connected by the wiring 8. The light source unit 1 is mounted in the lamp body 7c.

In addition to this, the luminaire 100 can also be applied to a product that adjusts the color to match the black body locus and the CIE daylight from a light bulb color to daylight white, for example, a ceiling light.
In this way, by applying the lighting fixture 100 described above to various lighting devices, it is possible to extend the life of the lighting device by preventing the influence of overcurrent and the like while downsizing the device.

(Summary of Embodiment 1)
The luminaire 100 includes a DC power supply circuit 11 and a DC voltage conversion circuit 12 that adjusts an output current by a chopping operation that repeatedly turns on / off a switching element Q2 provided in a power line from the DC power supply circuit 11 to the light source unit 1. And a light source unit 1 having a plurality of LED groups 3, 4, 5, and 6 having different emission colors, and a control unit 20 that controls a current flowing through each of the LED groups 3, 4, 5, and 6. Each of the series load circuits 30, 40, 50, 60 in which the light source switches Q3, Q4, Q5, Q6 are connected in series with each LED group 3, 4, 5, 6 in a one-to-one relationship The output terminal of the circuit 12 is connected in parallel.

  The control unit 20 operates the DC voltage conversion circuit 12 so as to repeat an operation period in which the chopping operation is performed and an idle period in which the chopping operation is suspended and the switching element Q2 is kept off. At the same time, an operation of sequentially switching the plurality of light source switches Q3, Q4, Q5, and Q6 so as to be alternatively turned on is performed. Here, switching of the plurality of light source switches Q3, Q4, Q5, and Q6 is performed at a point in time during the suspension period from the start point of the suspension period.

Therefore, the electric power output from the DC voltage conversion circuit 12 is supplied to the plurality of LED groups 3, 4, 5, and 6 in order, and the LED groups 3, 4, 5, and 6 are timed so that the ON periods do not overlap each other. Lights up in divisions.
In addition, since the switching operation of the plurality of light source switches Q3, Q4, Q5, and Q6 is performed in the pause period at a time from the start point of the pause period, the series load circuits 30, 40, 50, and 60 are performed. The switching operation is performed when there is little current flowing through the.

Thereby, the stress applied to the LED groups 3, 4, 5, 6 and the light source switches Q3, Q4, Q5, Q6 constituting the series load circuits 30, 40, 50, 60 at the time of switching can be reduced.
<Embodiment 2>
The configuration of the lighting fixture according to the present embodiment is the same as that of the lighting fixture 100 of the first embodiment shown in FIG. The control operation of the control unit 20 is also performed based on the flowchart shown in FIG.

However, in the present embodiment, the control unit 20 stores a table T2 shown in FIG. 5B, and performs a control operation with reference to the table T2.
In the lighting fixture of the present embodiment, based on the number indicated by the dimming toning signal Va (n), the output control time data TA (n), TB (n), TC (n), TD ( n) is read out, the LED groups 3, 4, 5 and 6 are lit for that time, and the combined light is emitted, as in the first embodiment.

On the other hand, in the lighting fixture of the present embodiment, the output control time data ta (n), tb (n), tc (n), and td (n) stored in the table T2 are fixed values tas, tbs, and tcs. , Tds, which is different from the first embodiment in that it does not change depending on the light control toning signal Va.
In the table T2, the values of the output control time data TA (n), TB (n), TC (n), TD (n) are smaller than the values of the output control time data tas, tbs, tcs, tds at the maximum. Is set to a value.

FIG. 6B shows a specific example of the table T2. In this figure as well, only eight (No. 0, 1, 10, 11, 20, 21, 30, 31) among 256 dimming / toning signal data Va (n) are representatively TA. (N), TB (n), TC (n), and TD (n) are described, and the remaining No. These figures are omitted for.
In the table T2 of FIG. 6B, the values of TA (n), TB (n), TC (n), and TD (n) are set within a range of 3.0 ms or less, and the output control time data tas, tbs , Tcs, tds are uniformly set at 3.5 ms. Accordingly, the length of the pause period is 0.5 ms or more.

As described above, even when the control unit 20 performs the control operation using the table T2, it is possible to obtain the effect by the time division driving and the effect by the burst control described in the first embodiment.
In other words, an operation period in which the chopping operation of the switching element Q2 is performed and a pause period in which the chopping operation is paused are alternately formed, and the switching element Q2 is kept off in the pause period. The switching timing of the light source switches Q3, Q4, Q5, and Q6 is performed in the rest period with a time from the start time of the rest period.

Accordingly, since the light source switches Q3, Q4, Q5, and Q6 are switched after the current I1 and the voltage VC1 are reduced, the stress applied to each light source switch is reduced, and the series load circuits 30, 40, 50, and 60 are applied. There is also an effect of suppressing the occurrence of inrush current.
On the other hand, in the lighting fixture 100 of the first embodiment, the time of one cycle varies depending on the light control and toning signal Va (n), but in the lighting fixture of the present embodiment, the time of one cycle is constant [tas + tbs + tcs + tds]. . In the specific example shown in FIG. 6B, the time of one cycle is 14 ms.

<Embodiment 3>
The configuration of the lighting fixture according to the present embodiment is also the same as that of the lighting fixture 100 of the first embodiment shown in FIG. The control operation of the control unit 20 is also performed based on the flowchart shown in FIG.
However, in the present embodiment, the control unit 20 includes the table T3 in FIG. 5C, and performs a control operation with reference to the table T3.

  In the lighting fixture of the present embodiment, based on the number indicated by the dimming toning signal Va (n), output control time data ta (n), tb (n), tc (n), td ( n) is read, and the light source switches Q3, Q4, Q5, Q6 are switched based on the output control time data ta (n), tb (n), tc (n), td (n). The point is the same as in the first embodiment.

On the other hand, in the lighting apparatus of the present embodiment, the values of the output control time data TA (n), TB (n), TC (n), TD (n) stored in the table T3 are fixed values TAs, TBs. , TCs, and TDs, which are different from those of the first embodiment in that they are not changed depending on the light adjustment and toning signal Va.
In the table T3, the values of the output control time data ta (n), tb (n), tc (n), td (n) are always larger than the values of the output control time data TAs, TBs, TCs, TDs. Is set to

Thus, the effect by the burst control described in the first embodiment can also be obtained by the control unit 20 performing the control operation using the table T3.
In other words, an operation period in which the chopping operation of the switching element Q2 is performed and a pause period in which the chopping operation is paused are alternately formed, and the switching element Q2 is kept off during the pause period. The switching timing of the light source switches Q3, Q4, Q5, and Q6 is performed in the rest period with a time from the start time of the rest period.

Accordingly, since the light source switches Q3, Q4, Q5, and Q6 are switched when the current I1 and the voltage VC1 are reduced, the stress applied to each light source switch is reduced, and the series load circuits 30, 40, 50, and 60 are applied. There is also an effect of suppressing the occurrence of inrush current.
On the other hand, in the lighting fixture 100 of the first embodiment, the lighting times of the LED groups 3, 4, 5 and 6 are changed by the dimming / adjusting signal Va (n), but in the lighting fixture of the present embodiment, output control time data Since TA (n), TB (n), TC (n), and TD (n) are fixed values, the ratio of the lighting times of the LED groups 3, 4, 5, and 6 does not change.

Therefore, even if the light adjustment toning signal Va (n) changes, the emission color of the emitted light does not basically change. However, the length of the pause period can be changed by the dimming / toning signal Va (n), and the ratio of the light emission time in one cycle is also changed, so that dimming can be performed.
<Embodiment 4>
The circuit configuration of the luminaire 100 according to the fourth embodiment is the same as that of the luminaire 100 according to the first embodiment shown in FIG.

However, the output current data IA is fixed in the lighting fixture 100 of the first embodiment, whereas the output current data IA changes in accordance with the toning signal data Va (n) in the lighting fixture 100 of the present embodiment. The point is different.
In the lighting fixture 100 of the present embodiment, a table T4 shown in FIG. 5D is stored in the memory in the control unit 20 in place of the table T1.

  This table T4 includes the toning signal data Va (n), burst control time data TA (n), TB (n), TC (n), TD (n) and output control time data ta (n), tb ( n), tc (n), and td (n) are stored in association with each other as in the table T1. However, in addition to this, in the table T4, output current data IA (n) (A (0) to (255)) is stored in association with the toning signal data Va (n).

The output current data IA (n) corresponds to a target value of the output current I1 when the DC voltage conversion circuit 12 performs a chopping operation.
The flowchart showing the control operation of the control unit 20 is the same as the flowchart shown in FIG. However, in steps S1 and S19, from the table T4, burst control time data TA (n), TB (n), TC (n), TD (n) and output control time data ta (n), tb (n), In addition to tc (n) and td (n), output control current data IA (n) is read.

The output control current data IA (n) is output to the semiconductor element IC1. During the chopping period, the semiconductor element IC1 uses the output control current data IA (n) as a current target value, performs feedback control while monitoring the voltage signal from the current detection circuit 14, and sets the output current I1 to the current target value IA ( n).
7A and 7B are timing charts showing how the current I1 output to the light source unit 1 is adjusted according to the magnitude of the output control current data IA (n) input to the semiconductor element IC1. .

  (A) shows a case where the value A0 of the output control current data IA (n) is relatively large (for example, 20 mA), and (b) shows a case where the value A1 of the output control current data IA (n) is relatively small ( For example, 10 mA). In each figure of (a), (b), ON / OFF of switching element Q2, pulsating current IL2 flowing through inductor L2, and output current I1 from DC voltage conversion circuit 12 are shown.

The semiconductor element IC1 increases or decreases each pulse ON width (Ton) for turning on / off the switching element Q2 so as to match the output control current data IA (n).
That is, the semiconductor element IC1 monitors the output current I1, and increases the pulse ON width (Ton) when the output current I1 is smaller than the output control current data IA (n). On the other hand, when the output current I1 is larger than the output control current data IA (n), the pulse ON width (Ton) is decreased.

7A and 7B, when the pulse ON width (Ton) of the switching element Q2 is small, the peak of the pulsating current IL2 becomes small, and as a result, the output current I1 Becomes smaller.
As described above, when the semiconductor element IC1 controls the pulse ON width of the switching element Q2, the output current I1 becomes the target value IA (n) as shown in the waveform of I1 in FIGS. A0 and A1 are set.

Further, as can be seen from the waveforms of Q2 and IL2 in FIGS. 7A and 7B, the pulsating current IL2 rises while the pulse of Q2 is ON, and the pulsating current IL2 when Q2 is OFF. Decreases. Here, in the present embodiment, the semiconductor element IC1 performs control to switch the switching element Q2 from OFF to ON when the pulsating current IL2 decreases to near zero.
Accordingly, as can be seen from the fact that the frequency of Q2 is larger in (b) than in (a) in FIG. 7, the chopping frequency increases when the pulse ON width (Ton) of the switching element Q2 is small. become.

Therefore, when the target value IA (n) of the output current I1 is small, the chopping frequency of the switching element Q2 is increased, so that the amount of light emitted from the light source unit 1 can be reduced without causing flickering.
Also in the lighting fixture of this embodiment, the effect by the burst control demonstrated in Embodiment 1 can be acquired similarly.

Furthermore, according to the lighting apparatus of the present embodiment, the lighting times of the LED groups 3, 4, 5, 6 are changed by the burst control time data TA (n), TB (n), TC (n), TD (n). In addition, the color can be adjusted by changing the amount of current by changing the output control current data IA (n).
Therefore, according to the present embodiment, it is possible to simply perform control that achieves both toning and dimming, and to perform dimming with a wider range.

<Embodiment 5>
FIG. 8 is a diagram illustrating a circuit configuration of the lighting apparatus 200 according to the fifth embodiment. In this figure, the same components as those of the lighting apparatus 100 shown in FIG.
The lighting fixture 200 according to the present embodiment has the same configuration as that of the lighting fixture 100 of the first embodiment, except that, in the power unit 10, the discharge circuit 15 is connected to the output terminal of the DC voltage conversion circuit 12. Is different.

The operation of the lighting fixture 200 is basically the same as that of the lighting fixture 100, and the control unit 20 performs the control operation based on the flowchart of FIG.
The discharge circuit 15 provided in the power unit 10 is connected in parallel with the four series load circuits 30, 40, 50, 60.
The discharge circuit 15 has a function of accelerating the discharge of charges accumulated in the capacitor C2 while the switching element Q2 is OFF.

The discharge circuit 15 is composed of an impedance element, and here is composed of a resistor R3. However, it is not limited to the resistor R3, and any function that discharges the electric charge accumulated in the capacitor C2 is sufficient. For example, the discharge circuit 15 may be an inductance circuit.
Thus, in the lighting fixture 200 concerning this Embodiment, since it has the discharge circuit 15 in parallel with a series load circuit in the output terminal of the electric power unit 10, compared with the lighting fixture 100, in the idle period of a burst operation | movement, The charge accumulated in the capacitor C2 is quickly discharged. Accordingly, the current I1 and the voltage VC1 are rapidly decreased during the idle period, and the current I1 approaches 0 in a shorter time.

Therefore, in this lighting fixture 200, the effect of suppressing the inrush current can be obtained in the same manner even when the duration of the pause period is set shorter than that of the lighting fixture 100.
When the time length of the pause period is set to be short, the time of one cycle for sequentially switching the light source switches Q3 to Q6 can be shortened, and flickering hardly occurs.
Note that a current flows through the discharge circuit 15 even during the chopping operation period, but the current flowing through the discharge circuit 15 does not contribute to lighting. Therefore, the discharge circuit 15 uses an impedance element having an impedance about 10 times higher than the highest impedance among the impedances of the series load circuits 30, 40, 50, 60 so that a small current flows. It is preferable.

<Embodiment 6>
The lighting fixture according to the sixth embodiment has a circuit configuration similar to that of the lighting fixture 100 shown in FIG. The table T1 in the microcomputer IC2 is the same, but there is a difference in the operation of the lighting fixture 100.
That is, in the luminaire 100 of the first embodiment, the chopping operation in the semiconductor element IC1 is started simultaneously with the timing of switching the light source switch elements Q3, 4, 5, and 6 (t1, t3, t5, and t7 in FIG. 3). reference). On the other hand, in the lighting fixture 100 of this embodiment, after switching the light source switches Q3, 4, 5, and 6, the chopping operation in the semiconductor element IC1 is started after a minute time ΔT has elapsed.

FIG. 9 is a flowchart showing a control operation of the control unit 20 according to the present embodiment.
This flowchart is the same as the flowchart shown in FIG. 2, but the control operations of steps S2-1 to S2-3 are performed instead of step S2. Accordingly, the light source switch is switched by a time ΔT before the end of the pause period. That is, the chopping operation of the switching element Q2 is started after the time ΔT has elapsed since the light source switch to be turned on is switched from Q3 to Q4.

Further, the control operations of steps S6-1 to S6-3 are performed instead of step S6. Thereby, the chopping operation of the switching element Q2 is started after the time ΔT has elapsed since the light source switch to be turned on is switched from Q4 to Q5.
In the flowchart of FIG. 9, steps S10 to S17 are omitted. Similarly, in step S10 shown in FIG. 2, switching is performed after a time ΔT has elapsed since the light source switch to be turned on is switched from Q5 to Q6. The chopping operation of the element Q2 is started. In step S14 shown in FIG. 2, the chopping operation of the switching element Q2 is started after the time ΔT has elapsed since the light source switch to be turned on is switched from Q6 to Q3.

FIG. 10 is a waveform diagram showing the gate voltage of the light source switches Q3, Q4, Q5, the gate voltage of the switching element Q2, and the current I1 output from the power unit 10 formed as a result of this control operation.
As shown in FIG. 10, the timing at which the light source switches Q3, 4, 5, and 6 are switched is a time ΔT before the end of the pause period (t1 to t2, t4 to t5 in FIG. 10). t7 to t8, t10 to t11).

(Effect of lighting apparatus 100 according to the present embodiment)
In the lighting fixture 100 according to the first embodiment, since the switching timing of the light source switches Q3, 4, 5, and 6 and the start of the chopping operation of the switching element Q2 are set simultaneously, basically the light source switch No current flows when switching between Q3, 4, 5, and 6. However, if the timing is slightly deviated and the chopping operation starts slightly before the light source switches Q3, 4, 5, 6, current flows when the light source switches Q3, 4, 5, 6 are switched. The

  On the other hand, in the lighting fixture 100 of the present embodiment, the switching time point of the light source switches Q3, 4, 5, and 6 is set before the end time of the pause period by the time ΔT. Accordingly, even if the switching timing of the light source switches Q3, 4, 5, and 6 is somewhat delayed or the timing of starting the chopping operation is advanced, if the deviation amount is smaller than the time ΔT, the light source switches Q3, 4, 5 , 6 no current flows when switching.

Therefore, according to the lighting fixture 100 of this embodiment, switching of the light source switches Q3, 4, 5, and 6 can be more reliably performed in a state where the current is small.
Therefore, the life of the light source switches Q3, 4, 5, and 6 and the LED groups 3, 4, 5, and 6 can be extended more reliably.
<Modification>
As described above, the invention has been described based on the embodiment. However, the invention is not limited to the above-described embodiment, and the following modifications may be implemented.

1. Light Source In the above embodiment, four types of LED groups having different emission colors are used in the light source unit, but the present invention is not limited to this. The light emission color of the light source may be three or two, or five or more.
Moreover, as a semiconductor light emitting element which comprises a light source, an organic EL (Electro Luminescence) element, a laser diode (Laser Diode) element, etc. other than LED can also be used.

In the above embodiment, the plurality of light sources have different emission colors, but some of the light sources may have the same emission color.
In the above-described embodiments, the emission colors of the LEDs are R (red), G (green), B (blue), and W (white). For example, a plurality of LEDs that emit white light having different color temperatures are used. May be.
2. DC power supply circuit In the above-described embodiment, the step-up chopper circuit is used as the smoothing circuit. However, for example, a smoothing capacitor may be used alone. Further, although the step-down chopper circuit is used as the DC voltage conversion circuit, for example, another DC-DC converter such as a flyback circuit may be used.

3. Light source switch In the above-described embodiments and the like, MOSFETs are used as light source switches, but switching elements such as bipolar transistors may also be used.
4). Control Circuit In the above embodiment, the control unit 20 stores the time during which the LED groups 3, 4, 5 and 6 emit light and the output control current data IA (n) in the table. However, the present invention is not limited to this. For example, burst control time data TA (n), TB (n), TC (n), TD (n), output control time data ta (n), tb (n), tc (n) , Td (n) and output control current data IA (n) are included, and the control unit 20 can receive the same.

It is also possible to input a signal for color control and a signal for light control to the control unit 20 from two systems, and the control unit 20 performs similar control based on the signals.
5. The provision of the discharge circuit 15 in the power unit 10 as in the fifth embodiment may be combined with any of the driving methods in the second, third, fourth, and sixth embodiments.

DESCRIPTION OF SYMBOLS 1 Light source unit 2 Lighting device 3,4,5,6 LED group 10 Power unit 11 DC power supply circuit 11a Full wave rectifier circuit 11b Smoothing circuit 12 DC voltage conversion circuit 13 Current detection circuit 14 Burst control circuit 15 Discharge circuit 30, 40, 50, 60 Series load circuit 100, 200 Lighting equipment 100a, 100b, 100c Lighting device IC1 Semiconductor element IC2 Microcomputer C1 Capacitor D2 Diode L2 Inductor C2 Capacitor R2 Fixed resistance element T1, T2, T3, T4 Tables Q3, Q4, Q5, Q6 ... Light source switch Q
TA to TD Output control time data ta to td Output control time data IA Output control time data

Claims (7)

A lighting device that has a plurality of light sources having different emission colors, and each light source is a light source unit composed of a semiconductor light emitting element,
A DC power supply circuit;
An output adjustment circuit that adjusts an output current by a chopping operation of a chopping switch provided in a power line from the DC power supply circuit to the light source unit;
A plurality of light source switches connected in series to each of the plurality of light sources in a one-to-one relationship to form a series load circuit;
A control unit for controlling a time for supplying a current to each of the light sources,
Each of the series load circuits is connected in parallel to the output terminal of the output adjustment circuit,
The controller is
While operating the output adjustment circuit to repeat the operation period of performing the chopping operation and the pause period of pausing the chopping operation,
An operation of sequentially switching the plurality of light source switches so as to be selectively turned on,
The switching of the plurality of light source switches is performed at a time from the start point of the pause period in the pause period.
Lighting device. The control unit controls the length of time that each of the plurality of light sources emits light by changing the length of an operation period in which the output adjustment circuit performs a chopping operation.
The lighting device according to claim 1. The output adjustment circuit includes:
It has a capacitor to smooth the chopped pulsating current,
The time from the start point of the pause period to the time of switching the light source switches is
It is set to be equal to or greater than the time constant when discharging from the capacitor to the series load circuit side during the rest period,
The lighting device according to claim 1 or 2. A discharge circuit is provided in parallel with the plurality of series load circuits at the output end of the output adjustment circuit,
The lighting device according to claim 1. The controller is
Switching between the plurality of light source switches before the end of the pause period;
The lighting device according to claim 1. The control unit further includes:
Set the target current value based on external instructions,
The output adjustment circuit includes:
A chopping operation is performed so that the output current matches the set target current value.
The lighting device according to claim 1. A light source unit having a plurality of light sources having different emission colors, each light source comprising a semiconductor light emitting element;
The lighting device according to claim 1,
lighting equipment.

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