JP2013069448A - Lighting device and lighting fixture including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lighting device which can be achieved by simpler control while suppressing the instantaneous change in the quantity of light due to light control, and to provide a lighting fixture including the same.SOLUTION: A light control circuit 6 includes an oscillation unit generating an oscillation output at a constant period, and a signal generation unit generating the control signals PWM1-PWM3, each repeating a H level and a L level at the period of an oscillation output from the oscillation unit, for each lighting circuit 11-13. Each lighting circuit 11-13 lights the light source 21-23 by supplying power (DC) to the light source 21-23 connected respectively, during the period when each control signal PWM1-PWM3 input from the light control circuit 6 has the H level. The light control circuit 6 classifies a plurality of lighting circuits 11-13 into a first group where the control signal is active from the start of one period of oscillation output to the way, and a second group where the control signal is active from the way of one period to the end thereof.

Description

  The present invention relates to a lighting device for lighting a light source and a lighting fixture including the lighting device.

  In recent years, lighting fixtures using LEDs (Light Emitting Diodes) as light sources instead of incandescent bulbs and discharge lamps are rapidly spreading. In connection with this, cost reduction and high functionality are requested | required about the lighting device for supplying electric power to LED and lighting LED.

  Since LEDs are easier to control the light color than incandescent bulbs and discharge lamps, lighting fixtures that use LEDs as light sources have also been developed that can control light control and color control depending on the scene (situation). Yes. For example, in a lighting fixture that emits mixed color light of three colors of RGB (red, green, and blue) LEDs, the lighting device performs dimming control for each color LED individually, so that relatively high color reproducibility ( Color rendering).

  As a dimming control method in this type of LED lighting device, a PWM (Pulse Width Modulation) dimming method that changes a duty ratio, which is a time ratio between turning on and off the LED, is generally used. . The PWM dimming method has an advantage that the linearity is high and the light color is stable as compared with the DC dimming that changes the magnitude of the DC voltage applied to the LED. In addition, in the lighting device using an LED as a light source, control such as starting is unnecessary as in the case where a discharge lamp is used as a light source.

  However, since the lighting device adopting the PWM dimming method intermittently supplies the current supplied to the LED based on the pulse-like control signal (PWM signal), an instantaneous light amount change occurs. If the blinking cycle is below a certain level, flickering due to blinking of the LED should not actually be felt due to human visual characteristics, but some people may feel flickering sensuously. In addition, when the current supplied to the LED by the lighting device changes rapidly, the burden on the power supply also increases.

  On the other hand, there has been proposed a luminaire that reduces the instantaneous change in the amount of light by dimming control while adopting the PWM dimming method (for example, Patent Document 1). In the luminaire described in Patent Document 1, the PWM controller outputs a PWM signal corresponding to each of a plurality of LED groups to which one or more LEDs belong, and the phase angle of the PWM signal between the LED groups is 360 degrees / LED group. It is shifted by a few. Thereby, even if it performs the light control by a PWM light control system, a lighting fixture will always be in the state in which 1 or more LED groups were lighted, and the variation | change_quantity of the light quantity by blinking of LED is disperse | distributed uniformly temporally.

JP 2009-277582 A

  By the way, since cost reduction is requested | required with respect to the lighting device of LED, in the lighting device with a light control function, it is common to control several LED using a microcomputer (microcontroller). . In particular, if a one-chip microcomputer having a PWM timer function is used, the lighting device can easily realize PWM dimming control.

  However, complicated control as described in Patent Document 1 (control for shifting the phase angle of the PWM signal by 360 degrees / the number of LED groups) requires a microcomputer having a dedicated timer function and hinders cost reduction. Therefore, there is a problem that it is difficult to employ the lighting device.

  The present invention has been made in view of the above reasons, and it is an object of the present invention to provide a lighting device that can be realized by simpler control while suppressing a change in instantaneous light amount due to dimming control, and a lighting fixture including the same. And

  The lighting device of the present invention receives a power supply from a single power source and outputs a control signal to each of the plurality of lighting circuits for lighting the light sources connected to each of the plurality of lighting circuits. A dimming control circuit for dimming and controlling the lighting circuit so that the light source is lit with brightness according to the duty ratio of the control signal, and the dimming control circuit generates an oscillation output at a constant cycle And a signal generation unit that generates, for each of the lighting circuits, the control signal that repeats active and inactive at a period of the oscillation output, and the plurality of lighting circuits are connected to one of the oscillation outputs. The control signal is grouped into a first group in which the control signal is active from the beginning to the middle of the cycle and a second group in which the control signal is active from the middle to the end of the cycle.

  In this lighting device, the output value of the oscillating unit changes at the fixed period, and the signal generating unit compares the output value of the oscillating unit with a reference value and determines whether the control signal is active according to the comparison result. It is desirable to have a comparator for switching between inactive and inactive for each lighting circuit.

  In this lighting device, the dimming control circuit is configured to minimize a difference between the maximum power consumed by the lighting circuits in the first group and the maximum power consumed by the lighting circuits in the second group. It is more desirable to group them into groups.

  In this lighting device, it is more preferable that the lighting circuit has a delay circuit that delays the timing of the output change to the light source with respect to the rise and fall times of the control signal.

  In this lighting device, it is more preferable that the lighting circuit has a fade circuit that gradually changes the output to the light source as time elapses from the time when the control signal rises and falls.

  In this lighting device, it is more preferable that the dimming control circuit changes the group configuration of the first group and the second group in accordance with an operation state of the plurality of lighting circuits.

  In this lighting device, the light source is more preferably a light emitting diode.

  The lighting fixture of this invention is equipped with one of the said lighting devices and the said light source, It is characterized by the above-mentioned.

  The present invention has an advantage that it can be realized by simpler control while suppressing an instantaneous change in light quantity due to light control.

It is a schematic circuit diagram which shows the structure of the lighting fixture which concerns on embodiment. It is a schematic circuit diagram which shows the structure of the dimming control circuit which concerns on embodiment. It is explanatory drawing which shows operation | movement of the light control circuit which concerns on embodiment. It is explanatory drawing which shows operation | movement of the lighting device which concerns on embodiment.

  The lighting fixture 10 of this embodiment is provided with the lighting device 1 and the light source 2 as shown in FIG. The luminaire 10 has a dimming function capable of arbitrarily changing the light output of the light source 2, and for example, a dimmer that generates a dimming signal in accordance with an operation of a dimming operation unit such as a wall switch. In response to the dimming signal from 3, the light source 2 is dimmed.

  The light source 2 includes a first light source 21, a second light source 22, and a third light source 23. In the present embodiment, the light source 2 is composed of LEDs (Light Emitting Diodes), and the first light source 21 includes two LEDs 211 and 212 connected in series, and two LEDs 213 and 214 that are also connected in series. It is configured to be connected in parallel. The second light source 22 includes two LEDs 221 and 222 connected in series, and the third LED 23 includes two LEDs 231 and 232 connected in series. Here, the light color of the LEDs 211 to 214 as the first light source 21 is red, the light color of the LEDs 221 and 222 as the second light source 22 is green, and the light color of the LEDs 231 and 232 as the third light source 23 is blue. It is. The light source 2 is configured to emit mixed color light (white light) of these three colors (RGB).

  The lighting device 1 includes a first lighting circuit 11, a second lighting circuit 12, and a third lighting circuit 13 that turn on the light sources 2 connected to the lighting device 1. "). A first light source 21 is connected to the first lighting circuit 11, a second light source 22 is connected to the second lighting circuit 12, and a third light source 23 is connected to the third lighting circuit 13. ing.

  Further, the lighting device 1 includes an AC / DC converter 5 that converts alternating current from an alternating current power source (commercial power source) 4 into direct current and supplies the direct current to the lighting circuit 100, a dimming control circuit 6 that performs dimming control on the lighting circuit 100, A dimming input unit 7 for inputting a dimming signal from the dimmer 3 is provided. Here, the AC / DC converter 5 constitutes a power source that supplies power to the lighting circuit 100 together with the AC power source 4, and supplies DC power to the first to third lighting circuits 11 to 13. That is, the 1st-3rd lighting circuits 11-13 receive electric power supply from one common power supply, and light the light source 2 connected to each.

  The AC / DC converter 5 includes a rectifier 51 composed of a diode bridge connected to the AC power source 4, a power conversion circuit 52 connected to the output of the rectifier 51, and a smoothing capacitor 53 connected to the output of the power conversion circuit 52. And have. The power conversion circuit 52 receives the voltage that has been full-wave rectified by the rectifier 51 and generates a DC voltage having a predetermined magnitude. The smoothing capacitor 53 smoothes the output of the power conversion circuit 52 and generates a DC voltage V0 to be applied to the lighting circuit 100. The power conversion circuit 52 may be a flyback circuit type as long as the output power is low (for example, 25 W or less), and may have an insulating circuit configuration.

  The dimming control circuit 6 individually outputs control signals to the first to third lighting circuits 11 to 13 so that the light sources 21 to 23 are lit with brightness according to the duty ratio of the control signals. Further, the lighting circuits 11 to 13 are dimmed and controlled by a PWM (Pulse Width Modulation) dimming method. That is, the dimming control circuit 6 outputs a rectangular pulse-shaped PWM signal that repeats the H level (active) and the L level (inactive) periodically (for example, 1 kHz) to the lighting circuit 100 as a control signal. The dimming ratio is changed by changing the duty ratio.

  In the present embodiment, the dimming control circuit 6 is composed of a microcomputer (microcontroller) and performs an operation based on a signal from the dimming input unit 7, and the control signal cycle and duty ratio (that is, H level occupying one cycle). The ratio of the period). The dimming control circuit 6 has a plurality of output terminals for control signals, and the lighting circuits 11 to 13 are individually connected to the output terminals. Here, the dimming control circuit 6 outputs the control signal PWM 1 to the first lighting circuit 11, outputs the control signal PWM 2 to the second lighting circuit 12, and the third lighting circuit 13. In response to this, the control signal PWM3 is output. A detailed configuration of the dimming control circuit 6 will be described later.

  The dimming input unit 7 converts the dimming signal from the dimmer 3 into a dimming signal (“DIM” in the figure) suitable for input to the dimming control circuit 6 made of a microcomputer. Thereby, the dimming control circuit 6 can dimm the light sources 21 to 23 with the dimming ratio corresponding to the dimming signal input from the dimmer 3 to the dimming input unit 7. The dimmer 3 outputs, for example, a PWM signal or an asynchronous serial communication signal to the lighting device 1 as a dimming signal.

  Each of the lighting circuits 11 to 13 includes a DC / DC converter, and each of the control signals PWM1 to PWM3 input from the dimming control circuit 6 is supplied with electric power ( The light sources 21 to 23 are turned on by supplying (DC). That is, each of the lighting circuits 11 to 13 has a switching element (not shown) that turns on and off the power supply to the light source 2 in response to the control signals PWM1 to PWM3 from the dimming control circuit 6, and is connected to each of them. An operation of switching on / off (flashing) of the light sources 21 to 23 is performed. The lighting circuit 100 further includes a capacitor (not shown) for smoothing the power output intermittently according to the control signals PWM1 to PWM3, and supplies the smoothed DC power to the light source 2. May be.

  In addition, the first to third lighting circuits 11 to 13 do not have to have a uniform amount of power output during a period in which the control signals PWM1 to PWM3 are at the H level. In the present embodiment, the second and third light sources 22 and 23 are each composed of two LEDs, whereas the first light source 21 connected to the first lighting circuit 11 is composed of four LEDs. Therefore, assuming that the power consumption of each LED is the same, the first lighting circuit 11 supplies the light source 2 with twice the power of the second and third lighting circuits 12 and 13. become.

  Further, in the present embodiment, the lighting circuits 11 to 13 gradually change the output currents to the light sources 21 to 23 with the passage of time from the rising and falling times of the corresponding control signals PWM1 to PWM3. An adjustment circuit 110 (see FIG. 1) is included. That is, the adjustment circuit 110 functions as a fade circuit that gradually changes the supply power instead of changing the change in the supply power to the light source 2 immediately after the control signals PWM1 to PWM3 change. The change in the light output of the light source 2 also becomes gradual. The adjustment circuit 110 is not limited to the fade circuit, and the output change timing to the light source 2 is delayed by a predetermined delay with respect to the rise and fall times of the control signals PWM1 to PWM3 corresponding to the lighting circuits 11 to 13. It may function as a delay circuit that delays by time. The delay time is about several tens of μs, for example.

  Next, a more detailed configuration of the dimming control circuit 6 will be described with reference to FIG.

  The dimming control circuit 6 generates a memory 61 including a ROM and a RAM, a CPU (Central Processing Unit) 62, an A / D conversion unit 63 connected to the dimming input unit 7, and control signals PWM1 to PWM3. It has a PWM timer 8 and a bus 64 that connects each part.

  The memory 61 is composed of a fresh memory (flash ROM), an EEPROM (Electrically Erasable Programmable Read-Only Memory), or the like. The CPU 62 performs various arithmetic processes. The A / D conversion unit 63 converts the dimming signal DIM input from the dimming input unit 7 into a digital value and stores the digital value in the memory 61 via the bus 64.

  The PWM timer 8 is a function originally provided in the dimming control circuit 6 composed of a microcomputer, and here, a PWM timer having a resolution of about 16 bits is adopted in order to realize a wide range of dimming. The PWM timer 8 generates, for each of the lighting circuits 11 to 13, an oscillation unit 81 that generates an oscillation output at a constant period, and control signals PWM 1 to PWM 3 that repeat H level and L level at an oscillation output period from the oscillation unit 81. And a signal generation unit 82 for generation.

  The oscillation unit 81 includes a main counter 811, a main comparator 812, and a main register 813, and outputs the count value of the main counter 811 to the signal generation unit 82 as an oscillation output. Specifically, the main counter 811 counts up with the clock CLK, and resets the count value with a clear signal (“CLEAR” in the figure) from the main comparator 812.

  The main comparator 812 compares the count value of the main counter 811 with the interval value INT stored in the main register 813, and determines the reset timing of the main counter 811. That is, when the count value of the main counter 811 reaches the interval value INT, the main comparator 812 outputs a clear signal and resets the count value of the main counter 811 to “0”. As a result, the main counter 811 repeatedly counts up the count value in the range of “0” to “INT”, and the oscillation output period (constant period) depends on the period when the count value makes a round and the main comparator 812 outputs the clear signal. ) Is determined.

  The signal generation unit 82 compares the output value of the oscillation unit 81 (count value of the main counter 811) with a reference value, and switches the control signal according to the comparison result (first comparator 821, second comparator). Each of the lighting circuits 11 to 13 includes a comparator 822 and a third comparator 823). Here, the first comparator 821 corresponds to the first lighting circuit 11, the second comparator 822 corresponds to the second lighting circuit 12, and the third comparator 823 corresponds to the third lighting circuit 13. Corresponding to Further, the signal generation unit 82 corresponds to the first to third comparators 821 to 823, and first to third polarity setting units 831 to 831 for setting the polarity (H level or L level) of the control signals PWM1 to PWM3. 833 and first to third registers 841 to 843 storing reference values.

  The first comparator 821 compares the output value of the oscillating unit 81 (hereinafter referred to as “oscillation output value”) with the first reference value REF1 stored in the first register 841, and compares the comparison result with the first comparison value. 1 to the polarity setting unit 831. The first polarity setting unit 831 outputs the control signal PWM1 to the first lighting circuit 11 according to the comparison result of the first comparator 821, and the input from the first comparator 821 is the polarity as it is. Decides whether to output in reverse or invert. In the present embodiment, the first polarity setting unit 831 is formed of a buffer, and outputs to the first lighting circuit 11 when the output of the first comparator 821 becomes H level due to the oscillation output value reaching the reference value REF1. The control signal PWM1 is set to H level.

  The second comparator 822 compares the oscillation output value with the second reference value REF 2 stored in the second register 842, and outputs the comparison result to the second polarity setting unit 832. The second polarity setting unit 832 outputs the control signal PWM2 to the second lighting circuit 12 according to the comparison result of the second comparator 822, and the input from the second comparator 822 is used as it is. Decides whether to output in reverse or invert. In the present embodiment, the second polarity setting unit 832 includes an inverter, and when the output of the second comparator 822 becomes H level when the oscillation output value reaches the reference value REF2, the control signal PWM2 is set to L level. .

  The third comparator 823 compares the oscillation output value with the third reference value REF 3 stored in the third register 843, and outputs the comparison result to the third polarity setting unit 833. The third polarity setting unit 833 outputs the control signal PWM3 to the third lighting circuit 13 according to the comparison result of the third comparator 823, and inputs the input from the third comparator 823 as it is. Decides whether to output in reverse or invert. In the present embodiment, the third polarity setting unit 833 includes an inverter, and when the output of the third comparator 823 becomes H level when the oscillation output value reaches the reference value REF3, the control signal PWM3 is set to L level. .

  Here, the first to third reference values REF1 to REF3 stored in the first to third registers 841 to 843 are all smaller than the interval value INT, and determine the duty ratio of the control signals PWM1 to PWM3. The value to be In other words, in the above configuration, the signal generation unit 82 applies the control signal PWM1 to PWM3 every time the oscillation output value of the oscillation unit 81 (the count value of the main counter 811) reaches any of the reference values REF1 to REF3. Switch between H level and L level.

  Specifically, the duty ratio of the control signal PWM1 that the reference value REF1 outputs to the lighting circuit 11 is determined, the duty ratio of the control signal PWM2 that the reference value REF2 outputs to the lighting circuit 12 is determined, and the reference value REF3 is the lighting circuit 13 The duty ratio of the control signal PWM3 to be output is determined. Therefore, the ratio (duty ratio) of the H level period in one cycle (one cycle of oscillation output) in each control signal PWM1 to PWM3 is determined by the values of the first to third reference values REF1 to REF3, respectively. It will be.

  By the way, in this embodiment, the dimming control circuit 6 makes the plurality of lighting circuits 11 to 13 the first group in which the control signal becomes active from the start of one cycle of oscillation output to the middle, and the middle of the same cycle. Group into a second group in which the control signal is active until the end. That is, since the oscillation output is periodic, the start and end of one cycle are equal, and in this embodiment, when the count value of the main counter 811 reaches “INT” and is reset to “0”. To start or end one cycle.

  In the present embodiment, the signal generation unit 82 compares the oscillation output value with the reference values REF1 to REF3 by the first to third comparators 821 to 823 as described above, and performs control corresponding to the comparison result. The polarities of the signals PWM1 to PWM3 are set by the polarity setting units 831 to 833. Therefore, during the period from the start of one cycle of oscillation output until the oscillation output value reaches each of the reference values REF1 to REF3, the outputs of the comparators 821 to 823 are all at the L level. Whether the control signals PWM1 to PWM3 are to be active (H level) or inactive (L level) during this period is determined by the polarity setting units 831 to 833 corresponding to the control signals PW1 to PWM3.

  In short, among the lighting circuits 11 to 13, the lighting circuit corresponding to the polarity setting units 831 to 833 that invert the inputs from the comparators 821 to 823 outputs the control signal from the start of one cycle of the oscillation output to the middle. It belongs to the first group that becomes active. On the other hand, among the lighting circuits 11 to 13, the lighting circuit corresponding to the polarity setting units 831 to 833 that directly output the inputs from the comparators 821 to 823 has the control signal active from the middle to the end of one cycle of the oscillation output. Belongs to the second group. Here, the second and third lighting circuits 12 and 13 corresponding to the second and third polarity setting sections 832 and 833 are the first group, and the first lighting circuit 11 corresponding to the first polarity setting section 831 is the first lighting circuit 11. It belongs to the second group.

  Next, the operation of the dimming control circuit 6 configured as described above will be described with reference to FIG. In FIG. 3, with the horizontal axis as the time axis, (a) is the oscillation output value (count value of the main counter 811), (b) is the control signal PWM1, (c) is the control signal PWM2, and (d) is the control signal PWM3. Respectively. FIG. 3 illustrates a case where the magnitude relationship between the first to third reference values REF1 to REF3 is REF3 <REF2 <REF1. In the following, description will be given focusing on one period of oscillation output (time t0 to t4), but the dimming control circuit 6 repeats the same operation after time t4.

  The oscillation output value is “0” at time t0 and gradually increases (counts up) as time elapses, reaches the interval value INT at time t4, and is reset to “0”. The oscillating unit 81 thus outputs an oscillation output whose value changes at a constant period with the times t0 to t4 as one period. The oscillation output value increases in proportion to the elapsed time, and the oscillation output becomes a sawtooth output (actually a counter value which is a discrete value) as shown in FIG. Here, as an example, it is assumed that the clock CLK cycle is 25 [ns] and the interval value INT is “39999”. In this case, the oscillation output cycle is 1 [ms] and the oscillation output frequency is 1 [ms]. kHz].

  In this example, the first comparator 821 sets the output to the first polarity setting unit 831 to the L level while the oscillation output value is smaller than the first reference value REF1, and the oscillation output value is the first reference value. When the signal reaches REF1, the output to the first polarity setting unit 831 is switched from the L level to the H level. For example, if the first reference value REF1 is “30000”, the output of the first comparator 821 changes from the L level to the H level at time t3 25 [ns] × 30000 = 750 [μs] after time t0. Change. When the oscillation output value is reset to “0” at time t4 thereafter, the output of the first comparator 821 is reset to L level at the same time. Since the first polarity setting unit 831 outputs the same polarity as that of the first comparator 821, the control signal PWM1 output from the first polarity setting unit 831 to the first lighting circuit 11 is the same as that shown in FIG. ) At time t0 to t3, and H level at times t3 to t4.

  Further, the second comparator 822 sets the output to the second polarity setting unit 832 to L level while the oscillation output value is smaller than the second reference value REF2, and the oscillation output value becomes the second reference value REF2. When it reaches, the output to the second polarity setting unit 832 is switched from the L level to the H level. For example, if the second reference value REF2 is “20000”, the output of the second comparator 822 changes from the L level to the H level at time t2 25 [ns] × 20000 = 500 [μs] after time t0. Change. When the oscillation output value is reset to “0” at time t4 thereafter, the output of the second comparator 822 is reset to L level at the same time. Since the second polarity setting unit 832 outputs an output having a polarity opposite to that of the second comparator 822, the control signal PWM2 output from the second polarity setting unit 832 to the second lighting circuit 12 is shown in FIG. ) At time t0 to t2, and becomes L level at times t2 to t4.

  Similarly, the third comparator 823 sets the output to the third polarity setting unit 833 to L level while the oscillation output value is smaller than the third reference value REF3, and the oscillation output value is the third reference value REF3. The output to the third polarity setting unit 833 is switched from L level to H level. For example, if the third reference value REF3 is “12000”, the output of the third comparator 823 changes from the L level to the H level at time t1 25 [ns] × 12000 = 300 [μs] after time t0. Change. When the oscillation output value is reset to “0” at time t4 thereafter, the output of the third comparator 823 is reset to the L level at the same time. Since the third polarity setting unit 833 outputs an output having a polarity opposite to that of the third comparator 823, the control signal PWM3 output from the third polarity setting unit 833 to the third lighting circuit 13 is shown in FIG. ) At time t0 to t1, and at time t1 to t4.

  In short, the control signal PWM1 output from the first polarity setting unit 831 becomes the H level while the oscillation output value is between “REF1” and “INT”, and the oscillation output value is reset to “0” ( At time t0, t4), the signal falls from the H level to the L level. On the other hand, the control signal PWM2 output from the second polarity setting unit 832 becomes H level while the oscillation output value is between “0” and “REF2”, and the control signal output from the third polarity setting unit 833. PWM3 is at the H level while the oscillation output value is between “0” and “REF3”. These control signals PWM2 and PWM3 rise from the L level to the H level at the timing (time t0, t4) when the oscillation output value is reset to “0”.

  Next, the operation of the lighting device 1 when the dimming control circuit 6 outputs the control signals PWM1 to PWM3 as described above will be described with reference to FIG. In FIG. 4, with the horizontal axis as the time axis, (a) is the control signal PWM1, (b) is the output current I1 of the lighting circuit 11, (c) is the control signal PWM2, and (d) is the output current I2 of the lighting circuit 12. , (E) represents the control signal PWM3, and (f) represents the output current I3 of the lighting circuit 13. FIG. 4G shows the total current (total current) I0 input from the AC / DC converter 5 to the first to third lighting circuits 11-13. Note that the following description will focus on one cycle of oscillation output (time t0 to t4), but the lighting device 1 repeats the same operation after time t4.

  Here, the second light source 22 and the third light source 23 have the same power consumption, and the power consumption of the first light source 21 is twice that of the second light source 22. Therefore, during the period when the control signals PWM1 to PWM3 are at the H level, the relationship between the output currents I1, I2, and I3 of the first to third lighting circuits 11 to 13 is I1 = I3 = Id (peak value). = 2Id.

  The first to third lighting circuits 11 to 13 supply the output currents I1 to I3 to the light sources 21 to 23 connected to the light sources 21 to 23 while the control signals PMW1 to PWM3 corresponding thereto are at the H level. Illuminate ~ 23. Here, each lighting circuit 11-13 has the adjustment circuit 110 which functions as a fade circuit.

  In the example of FIG. 4, since the control signal PWM1 falls to the L level at time t0 when one cycle of the oscillation output starts, the first lighting circuit 11 as the second group peaks the output current I1 from time t0 to time t10. From “2Id” to “0”. Since the control signals PWM2 and PWM3 rise to the H level at time t0, the second and third lighting circuits 12 and 13 as the first group change the output currents I2 and I3 from “0” from time t0 to time t10. Gradually increase to the peak “Id”. Thereby, from time t10 to t1, the second and third lighting circuits 12 and 13 as the first group turn on the second and third light sources 22 and 23, and the total current I0 becomes “2Id”.

  Since the control signal PWM3 falls to the L level at time t1 thereafter, the output current I3 of the third lighting circuit 13 gradually decreases from the peak “Id” to “0” from time t1 to time t11, and time t11. Then, the third light source 23 is turned off. Thereby, at the time t11-t2, the 2nd lighting circuit 12 which is a 1st group lights the 2nd light source 22, and the total electric current I0 becomes "Id". Since the control signal PWM2 falls to the L level at time t2 thereafter, the output current I2 of the second lighting circuit 12 gradually decreases from the peak “Id” to “0” from time t2 to time t12, and time t12 Then, the second light source 22 is turned off. As a result, from time t12 to t3, all the first to third lighting circuits 11 to 13 stop outputting, and the total current I0 becomes “0”.

  When the control signal PWM1 rises to H level at time t3 thereafter, the output current I1 of the first lighting circuit 11 as the second group gradually increases from “0” to the peak “2Id” from time t3 to t13. From time t3 to time t13, the first light source 21 is gradually turned on. Thereby, from time t13 to t4, the first lighting circuit 11 which is the second group turns on the first light source 21, and the total current I0 becomes “2Id”.

  Further, since the control signal PWM1 falls to the L level at time t4 thereafter, the first lighting circuit 11 as the second group gradually decreases the output current I1 from “2Id” to “0” from time t4 to t14. Let On the other hand, since the control signals PWM2 and PWM3 rise to H level at time t4, the second and third lighting circuits 12 and 13 as the first group change the output currents I2 and I3 to “0” from time t4 to t14. Gradually increase from “Id” to “Id”. As a result, before and after time t4 when one cycle of the oscillation output ends, the total current I0 becomes “2Id” and does not change, so that the load fluctuation of the AC / DC converter 5 can be suppressed.

  According to the lighting device 1 of the present embodiment described above, the plurality of lighting circuits 11 to 13 include the first group in which the control signal is active from the start to the middle of one cycle of the oscillation output and the middle of the same cycle. Grouped into a second group in which the control signal is active until the end. That is, the lighting circuit 100 of the first group lights the light source 2 from the start of one cycle of the oscillation output to the middle (when the oscillation output value reaches each reference value), and the lighting circuit 100 of the second group The light source 2 is turned on from the middle to the end of one output cycle. Thereby, the lighting device 1 can shift the period during which the light source 2 is lit in one cycle of the oscillation output between the first group and the second group. In other words, the lighting device 1 adopts the PWM dimming method, but the amount of change in the amount of light caused by the blinking of the light source 2 is dispersed in the time axis direction. Can be reduced.

  In addition, the dimming control circuit 6 simply sets the polarity of the control signal for each lighting circuit 100 using the function of a general PWM timer 8 using one oscillation output, and the first group and the second group. And can be divided into Therefore, the lighting device 1 has an advantage that it can be realized by simpler control as compared with the conventional configuration, while suppressing an instantaneous change in light amount due to dimming control.

  Further, since the signal generator 82 includes the comparators 821 to 823 for each of the lighting circuits 11 to 13, the reference values REF1 to REF3 for determining the duty ratios of the control signals PWM1 to PWM3 are individually set for each of the lighting circuits 11 to 13. Can be set to That is, the dimming ratio can be individually set for each of the lighting circuits 11 to 13, and when the light sources 21 to 23 having different light colors are used as in the present embodiment, the light color of the mixed color light can be adjusted. It becomes possible.

  Furthermore, in the present embodiment, the plurality of lighting circuits 11 to 13 have the same maximum power consumed by the first group lighting circuits 12 and 13 and the maximum power consumed by the second group lighting circuit 11. It is divided into groups. Thereby, the lighting device 1 is the sum of the currents (total current) input from the AC / DC converter 5 to the first to third lighting circuits 11 to 13 before and after the end of one cycle of the oscillation output. And the load fluctuation of the AC / DC converter 5 can be efficiently suppressed. However, in the plurality of lighting circuits 11 to 13, the difference between the maximum power consumed by the first group lighting circuits 12 and 13 and the maximum power consumed by the second group lighting circuit 11 is minimized. It only needs to be grouped, and it is not essential that the two match.

  Further, the lighting circuits 11 to 13 function as fade circuits that gradually change the output currents to the light sources 21 to 23 as time elapses from the rising and falling times of the control signals PWM1 to PWM3 corresponding thereto. An adjustment circuit 110 is included. Therefore, the lighting device 1 can reduce the circuit stress by suppressing the abrupt load fluctuation of the AC / DC converter 5 and the lighting circuits 11 to 13. In addition, for example, even if there is some variation in the timing of the control signals PWM1 to PWM3, when one cycle of the oscillation output ends, the control signals PWM2 and PWM3 of the first group and the control signal PWM1 of the second group It is possible to avoid overlapping active periods. That is, the lighting device 1 is configured such that the sum of the currents (total current) input from the AC / DC converter 5 to the first to third lighting circuits 11 to 13 is activated when all of the control signals PWM1 to PWM3 are activated. It can be prevented from becoming abnormally large.

  Furthermore, in the case where the adjustment circuit 110 functions as a delay circuit that delays the timing of the output change to the light source 2 by the delay time, the dimming control circuit 6 uses the A / D converter 63 during the delay time. By performing input processing, dimming control that is less susceptible to noise is possible.

  In the above embodiment, the dimming control circuit 6 is realized by a one-chip microcomputer. However, the dimming control circuit 6 may be configured by an analog circuit. In this case, the dimming control circuit 6 includes an oscillating unit that generates a sawtooth or triangular wave-like oscillation output, and a plurality of comparators that compare the output value of the oscillating unit with a reference value. The same operations and effects can be achieved with the same operation as the embodiment.

  The light source 2 is not limited to the LED, but may be lit by receiving power supply from the lighting device 1, and may be, for example, an organic EL (ElectroLuminescence). Furthermore, the light sources 2 may have the same light color, and the number of light sources 2 and lighting circuits 100 may be two or more.

  By the way, the dimming control circuit 6 may further have a function of changing the group configuration of the first group and the second group in accordance with the operation state of the first to third lighting circuits 11 to 13. The operation state of the lighting circuits 11 to 13 here is the state of operation of the lighting circuits 11 to 13 that varies depending on the dimming level (dimming ratio) and the operation mode (for example, all lighting, dimming lighting, and extinguishing). I mean. In other words, in this configuration, the dimming control circuit 6 does not fix the group configuration of the first group and the second group, but appropriately determines the group according to the operating state of the first to third lighting circuits 11 to 13. Change the configuration automatically.

  For example, as illustrated in the above embodiment, the failure of the first light source 21 occurs when the second and third lighting circuits 12 and 13 are grouped into the first group and the first lighting circuit 11 is grouped into the second group. Thus, the case where the first lighting circuit 11 stops operating will be described as an example. In this case, the dimming control circuit 6 groups the second and third lighting circuits 12 and 13 again so that the remaining second and third light sources 22 and 23 are continuously lit. At this time, if the third lighting circuit 13 is the first group and the second lighting circuit 12 is the second group, the dimming control circuit 6 determines the control signal PWM2 corresponding to the second lighting circuit 12. Change the timing.

  That is, the dimming control circuit 6 performs a process of inverting the output polarity of the second polarity setting unit 832 and setting the difference (INT−REF2) between the interval value INT and the reference value REF2 as a new reference value REF2. Thus, the timing of the control signal PWM2 is changed. Specifically, the dimming control circuit 6 changes the setting of the second polarity setting unit 832 to a setting for outputting the input from the second comparator 822 with the same polarity, and a new second reference. The value REF2 is calculated and the reference value REF2 stored in the second register 842 is updated.

  Thereby, even if the operating state of the 1st-3rd lighting circuits 11-13 changes, the lighting device 1 changes the light quantity change amount by blinking of the light source 2 by reviewing the group structure of the lighting circuits 11-13. A state of being dispersed in the time axis direction can be maintained.

1 lighting device 4 AC power supply
5 AC / DC converter (power supply)
6 dimming control circuit 10 lighting fixture 11-13,100 lighting circuit 21-23,2 light source 81 oscillating unit 82 signal generating unit 110 adjusting circuit (delay circuit, fade circuit)
211 to 214, 221, 222, 231, 232 LED (light emitting diode)
821-823 Comparator PWM1-PWM3 Control signal

Claims (8)

A plurality of lighting circuits for receiving power supply from one power source and lighting the light sources connected to each of the plurality of lighting circuits, individually outputting a control signal to each of the plurality of lighting circuits, and a duty ratio of the control signal A dimming control circuit for dimming and controlling the lighting circuit so that the light source is lit at a brightness according to
The dimming control circuit includes an oscillating unit that generates an oscillation output at a constant cycle, and a signal generation unit that generates the control signal that repeats active and inactive at the cycle of the oscillation output for each lighting circuit. The first group in which the control signal is active from the start to the middle of one cycle of the oscillation output and the second group in which the control signal is active from the middle to the end of the one cycle. A lighting device characterized by being grouped into two groups.   The output value of the oscillating unit changes at the fixed period, and the signal generating unit compares the output value of the oscillating unit with a reference value, and determines whether the control signal is active or inactive according to a comparison result. The lighting device according to claim 1, further comprising a comparator for switching for each of the lighting circuits.   The dimming control circuits are grouped so that the difference between the maximum power consumed by the lighting circuits in the first group and the maximum power consumed by the lighting circuits in the second group is minimized. The lighting device according to claim 1, wherein the lighting device is a lighting device.   4. The lighting circuit according to claim 1, wherein the lighting circuit includes a delay circuit that delays a timing of an output change to the light source with respect to a rise time and a fall time of the control signal. The lighting device according to item.   4. The lighting circuit according to claim 1, further comprising a fade circuit that gradually changes an output to the light source as time elapses from a time when the control signal rises and falls. The lighting device according to claim 1.   6. The dimming control circuit according to claim 1, wherein the dimming control circuit changes a group configuration of the first group and the second group according to an operating state of the plurality of lighting circuits. The lighting device described in 1.   The lighting device according to any one of claims 1 to 6, wherein the light source includes a light emitting diode. A lighting fixture comprising: the lighting device according to any one of claims 1 to 7; and the light source.

Images