JP2020061324A - Led lighting device and lighting equipment - Google Patents

Abstract

To provide an LED lighting device reducing a stress applied to a circuit element by releasing an inrush current at the time when starting a lighting, and a lighting equipment.SOLUTION: An LED lighting device 30 comprises: a plurality of LED loads 21 to 24; a power supply circuit 31; switching elements M3 to M6 serially connected to each of the LED loads 21 to 24; and a control circuit 33 that sequentially turns on each of the LED loads 21 to 24 by sequentially turning on/off the switching elements M3 to M6. Each of the LED loads 21 to 24 includes: one or more LEDs; and smooth capacitors C2 to C5 connected to one or more LEDs in parallel. The control circuit 33 simultaneously turns on at least two of the switching elements M3 to M6 just before the start of lighting of each LED load, and charges each correspondence smooth capacitor to a forward voltage or less of each LED load.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an LED lighting device that lights a plurality of LED (Light Emitting Diode) loads having different emission colors.

  Patent Document 1 discloses a lighting device capable of dimming and toning by sequentially switching and lighting a plurality of LEDs having different emission colors and adjusting the intensity and mixing ratio of each emission color.

JP, 2004-311635, A

  However, according to the above conventional technique, the smoothing capacitor may be connected in parallel to each of the plurality of LED loads. In this case, the problem of inrush current may occur at the start of lighting, that is, immediately after the power is turned on. The inrush current is a current larger than usual mainly flowing to start charging the smoothing capacitor immediately after the power is turned on, which may give a great stress to the circuit element through which the inrush current flows. Such stress can, for example, induce failure of circuit elements, impair life, and reduce reliability.

  Therefore, it is an object of the present invention to provide an LED lighting device and a lighting device that alleviate a rush current at the start of lighting and reduce stress applied to a circuit element.

  In order to solve the above problems, an LED lighting device of the present invention includes a plurality of LED loads having different emission colors, a power supply circuit that supplies power to the plurality of LED loads, and a series connection to each of the plurality of LED loads. And a control circuit for sequentially lighting the plurality of LED loads by sequentially turning on and off the switching elements (M3 to M6), and each of the plurality of LED loads has one The control circuit includes the above LEDs and a smoothing capacitor connected in parallel with the one or more LEDs, and the control circuit simultaneously controls at least two of the switching elements immediately before starting lighting of the LED load. Turn on and charge the corresponding smoothing capacitor below the forward voltage of the LED load.

  According to the LED lighting device and the lighting fixture of the present invention, it is possible to reduce the inrush current at the start of lighting and reduce the stress applied to the circuit element.

FIG. 1 is a diagram showing a circuit configuration example of a lighting fixture having an LED lighting device according to an embodiment. FIG. 2 is a diagram showing a current waveform and a voltage waveform of each part during initial charging and progressive lighting of a lighting fixture having the LED lighting device according to the embodiment. FIG. 3 is a diagram showing an example of a voltage waveform of the smoothing capacitor of the lighting fixture including the LED lighting device according to the embodiment. FIG. 4 is a flowchart showing an example of processing of initial charging by the control circuit (MCU). FIG. 5A is a diagram illustrating an appearance example of a lighting fixture including an LED lighting device. FIG. 5B is a diagram showing another appearance example of a lighting fixture having an LED lighting device. FIG. 5C is a diagram showing still another appearance example of a lighting fixture having an LED lighting device. FIG. 6 is a diagram showing a configuration of a lighting fixture of a comparative example. FIG. 7: is a figure which shows the electric current waveform of the lighting fixture of a comparative example.

(Findings that form the basis of the present invention)
The present inventor has found that the following problems occur in the lighting device described in the “Background Art” section.

  First, a lighting fixture according to the knowledge of the present inventor will be described as a comparative example.

  FIG. 6 is a diagram showing a configuration of a lighting fixture of a comparative example according to the knowledge of the present inventor. The luminaire shown in the figure includes a power supply circuit 90, LED loads 91 to 94, and switching elements SW3 to SW6. The power supply circuit 90 is a so-called step-down chopper type DC-DC converter having switching elements SW1 and SW2 and an inductor L0. The switching elements SW1 and SW2 are controlled to be exclusively turned on. The inductor L0 stores and releases energy supplied from the connection point of the switching elements SW1 and SW2.

  The LED loads 91 to 94 have different emission colors.

  The switching elements SW3 to SW6 are controlled so as to be sequentially turned on within one cycle.

  FIG. 7: is a figure which shows the electric current waveform of the lighting fixture of a comparative example. The vertical axis of the figure shows the inductor current. The inductor current is an output current of the power supply circuit 90 which is supplied to any of the LED loads via the inductor L0. The horizontal axis represents time. The upper part of the figure shows a relatively bright state. The lower part of the figure shows a darkened state due to dimming. Further, the color α, the color β, the color γ, and the color δ indicate the emission colors of the LED loads 91 to 94. The emission colors of the LED loads 91 to 94 are, for example, red, green, blue, and white.

  As shown in FIG. 7, the LED loads 91 to 94 emit light once in a cycle Ts. This operation is called sequential lighting. FIG. 7 shows a case where the cycle Ts is fixed and the switching frequencies of the switching elements SW3 to SW6 are fixed.

  Further, a configuration in which smoothing capacitors are connected in parallel to each of the LED loads 91 to 94 in FIG. 6 can be considered in order to reduce flicker. In this case, a problem of inrush current may occur at the start of lighting. A great deal of stress may be applied to the circuit element through which the inrush current flows. Such stress can, for example, induce failure of circuit elements, impair life, and reduce reliability.

  In order to solve such a problem, an LED lighting device according to an aspect of the present invention includes a plurality of LED loads having different emission colors, a power supply circuit that supplies power to the plurality of LED loads, and a plurality of the plurality of LED loads. The plurality of LEDs are provided with a switching element connected in series to each of the LED loads, and a control circuit for sequentially lighting the plurality of LED loads by sequentially turning on and off the switching elements (M3 to M6). Each of the loads has one or more LEDs and a smoothing capacitor connected in parallel with the one or more LEDs, and the control circuit immediately before starting lighting of the LED loads, the switching element. At least two of them are turned on at the same time and the corresponding smoothing capacitors are charged below the forward voltage of the LED load.

  As a result, the inrush current at the start of lighting can be relaxed and the stress applied to the circuit element can be reduced.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  It should be noted that each of the embodiments described below shows one comprehensive or specific example of the present invention. Numerical values, shapes, materials, constituent elements, arrangement positions and connection forms of constituent elements, steps, order of steps, and the like shown in the following embodiments are examples, and are not intended to limit the present invention. Further, among the constituent elements in the following embodiments, constituent elements that are not described in the independent claims showing the highest concept are described as arbitrary constituent elements.

(Embodiment 1)
[1.1 Configuration of LED Lighting Device and Lighting Fixture]
First, a configuration example of the lighting fixture 100 including the LED lighting device 30 according to the first embodiment will be described.

  FIG. 1 is a diagram illustrating a circuit configuration example of a lighting fixture 100 including the LED lighting device 30 according to the first embodiment. The lighting fixture 100 shown in the figure includes an AC-DC power supply 10, a light source 20, and an LED lighting device 30.

  The AC-DC power supply 10 is connected to, for example, a commercial 100V power supply, inputs AC power, and converts it to DC power.

  The light source 20 includes LED loads 21 to 24. The LED loads 21-24 have different emission colors. The emission colors of the LED loads 21 to 24 are, for example, R (red), G (green), B (blue), W (white).

  The LED load 21 in the light source 20 is connected in series with the switching element M3. When the switching element M3 is on, the LED load 21 is in a selected state in which energization is possible. When the switching element M3 is off, the LED load 21 is in a non-selected state in which it cannot energize.

  As a specific circuit example, the LED load 21 includes LEDs d1 to d3, a smoothing capacitor C2 connected in parallel with the LEDs d1 to d3, and a backflow prevention connected in series with a parallel circuit including the LEDs d1 to d3 and the smoothing capacitor C2. Diode Da and a resistor R2 for discharging when the power is off.

  The LEDs d1 to d3 are LED light emitting elements of the same light emission color that are connected in series, and are connected in series with the switching element M3.

  The smoothing capacitor C2 smoothes the inductor current supplied from the inductor L1 via the diode Da.

  The diode Da prevents reverse current from flowing from the smoothing capacitor C2 to the inductor L1. That is, the diode Da supplies only the LEDs d1 to d3 with the charges charged in the smoothing capacitor C2.

  The resistor R2 has a high resistance value and discharges the electric charge of the smoothing capacitor C2 after the power source is turned on.

  The LED loads 22 to 24 have the same configuration as the LED load 21 except that the emission colors are different. The LED load 21 may be configured without the smoothing capacitor C2 and the backflow preventing diode Da. The same applies to the LED loads 22 to 24.

  The LED lighting device 30 is a device that lights a plurality of LED loads 21 to 24 having different emission colors. Therefore, the LED lighting device 30 includes a power supply circuit 31, a selector circuit 32, and a control circuit 33.

  The power supply circuit 31 is a DC-DC converter that converts DC power from the AC-DC power supply 10 into DC power having different voltages and supplies the converted DC power to the light source 20.

  The power supply circuit 31 in the LED lighting device 30 is an example of a step-down chopper circuit. Specifically, the power supply circuit 31 includes a regulator 34, an HVIC (High Voltage Integrated Circuit) 35, input resistors R6 and R7, switching elements M1 and M2, and an inductor L1.

  The regulator 34 receives the DC power from the AC-DC power supply 10 and supplies a stabilized power supply voltage to the HVIC 35 and the control circuit 33.

  The HVIC 35 supplies a gate signal to the switching elements M1 and M2 via the input resistors R6 and R7 under the control of the control circuit 33. The gate signals of the switching elements M1 and M2 are activated exclusively at high speed and periodically.

  The switching elements M1 and M2 are high-side transistors and low-side transistors for alternately connecting the DC voltage supplied from the AC-DC power supply 10 and the ground level to the inductor L1.

  The inductor L1 stores and releases electric energy according to the switching of the switching elements M1 and M2.

  The selector circuit 32 causes the power supply circuit 31 to supply power to the selected LED load by sequentially cyclically selecting one LED load from the plurality of LED loads 21 to 24. Therefore, the selector circuit 32 includes switching elements M3 to M6. Each of the switching elements M3 to M6 is connected in series with any one of the LED loads 21 to 24. For example, in FIG. 1, the switching element M3 is connected to the LED load 21 in series. The switching element M4 is connected to the LED load 22 in series. The switching element M5 is connected to the LED load 23 in series. The switching element M6 is connected to the LED load 24 in series. For example, these switching elements M3 to M6 are controlled so as to be exclusively turned on. As a result, the LED loads 21 to 24 emit light exclusively, that is, one by one.

  More specifically, the selector circuit 32 includes input resistors R8 to R11 and switching elements M3 to M6.

  The switching element M3 is connected in series with the LED load 21. A gate signal for instructing on and off is input from the control circuit 33 to the gate of the switching element M3 via the input resistor R8. The switching element M3 turns on and off according to the gate signal.

  The switching elements M4 to M6 are similar to the switching element M3.

  The control circuit 33 is configured by, for example, a MCU (Micro Controller Unit or Micro Computer Unit) including a processor, a memory, a timer 36, and an ADC (analog-digital converter) 37. The control circuit 33 broadly divides and controls the sequential lighting and the initial charging. During progressive lighting, the control circuit 33 controls the selector circuit 32 so as to sequentially cyclically select one LED load from the plurality of LED loads 21 to 24. In the control of the initial charge, the control circuit 33 turns on at least two of the switching elements M3 to M6 at the same time immediately before starting the lighting of the LED loads 21 to 24, and sets the corresponding smoothing capacitors to the forward voltage of the LED load. Charge below.

  The timer 36 measures various periodic times. For example, it is used to measure a cycle in which a plurality of LED loads 21 to 24 are selected, a power feeding section, a pause section, and the like.

  The ADC 37 converts the voltage values va to vd of the smoothing capacitors C2 to C5 from analog values to digital values, respectively. That is, the ADC 37 is used to detect the voltages va to vd of the smoothing capacitors C2 to C5 during initial charging, respectively.

[1.2 Operation of LED Lighting Device and Lighting Equipment]
Next, an operation example of the lighting fixture 100 including the LED lighting device 30 according to the first embodiment will be described.

  FIG. 2 is a diagram showing a current waveform and a voltage waveform of each part during initial charging and progressive lighting of a lighting fixture having the LED lighting device according to the embodiment. The horizontal axis of the figure is the time axis. The vertical axis represents the current or voltage of each part.

  The "initial charge" section is a period during which the smoothing capacitors C2 to C5 are initially charged or precharged, and is provided immediately before the progressive lighting. The control circuit 33 simultaneously raises the gate voltages V0, Vr, Vg, Vb, and Vw (sets the active level) at the start of the initial charging. In other words, the control circuit 33 turns on the switching elements M3 to M6 at the same time to bring the LED loads 21 to 24 into a selected state (that is, a state in which electricity can be supplied), and at the same time, turns on the switching element M1 (that is, the high-side transistor). Power supply starts by turning on. As a result, power supply from the power supply circuit 31 via the inductor L1 starts, and the smoothing capacitors C2 to C5 start charging as precharge.

  Further, the control circuit 33 lowers the gate voltage V0 (sets it to the inactive level) before one of the smoothing capacitors C2 to C5 reaches the forward voltage of the corresponding LED load. As a result, power supply from the power supply circuit 31 via the inductor L1 is stopped, and the smoothing capacitors C2 to C5 complete charging as precharge. Further, the control circuit 33 lowers the gate voltages Vr, Vg, Vb, and Vw (that is, makes them inactive levels).

  In this way, the control circuit 33 charges the smoothing capacitor to a voltage equal to or lower than the forward voltage of the LED load in the initial charging.

  Following the initial charging, the control circuit 33 controls the progressive lighting.

  The cycle Ts indicates a one-cycle lighting cycle, which is a cycle in which the LED loads 21 to 24 are lit one cycle during the sequential lighting. Here, it is assumed that the one-turn lighting period Ts is fixed. The colors α, β, γ, and δ indicate the emission colors of the LED loads 21 to 24, and are, for example, R (red), G (green), B (blue), and W (white).

  The section Ta is a power supply section in which power is supplied from the power supply circuit 31 to the LED load 21 of the emission color α. Similarly, the sections Tb, Tc, and Td are power supply sections where power is supplied from the power supply circuit 31 to the LED loads 22, 23, and 24.

  The inductor current IL indicates a current flowing through the inductor L1, that is, a current supplied from the power supply circuit 31 to any of the LED loads. In the figure, the section in which the inductor current IL is flowing is the power supply section. The power feeding section Ta indicates a section where the power is supplied from the power supply circuit 31 to the LED load 21. Similarly, power feeding sections Tb to Td respectively indicate sections in which power is supplied from the power supply circuit 31 to the LED loads 22 to 24. The emission colors of the LED loads 21 to 24 are R, G, B, and W.

  The gate voltage V0 indicates a voltage input from the control circuit 33 to the gate of the switching element M1 via the HVIC 35. When the gate voltage Vo is at high level, the switching element M1 is turned on. The inductor current IL increases while the gate voltage V0 is at the high level. At this time, the inductor L1 stores electric energy as magnetic energy. When the gate voltage V0 is at low level, the switching element M1 is turned off. Immediately after the switching element M1 is switched from the ON state to the OFF state, the inductor L1 releases the accumulated energy, that is, the inductor current IL is reduced to 0 by the back electromotive force of the inductor L1 and is supplied to the LED load 21. . As a result, the power feeding section Ta becomes longer than the high level section of the gate voltage V0. The inductor current IL has a triangular wave in the figure. The power supply section Ta in which the power supply circuit 31 supplies power to the LED load includes one triangular wave section. In other words, the power feeding section Ta may coincide with the triangular wave section, or may include the triangular wave section and the section in which the inductor current IL is zero. The same applies to the power feeding sections Tb to Td.

  The gate voltage Vr represents the voltage input from the control circuit 33 to the gate of the switching element M3. When the gate voltage Vr is at the high level, the switching element M3 is in the ON state, that is, the corresponding LED load 21 is in the selected state. Further, the high level section of the gate voltage Vr is controlled to include a high level section of the gate voltage V0 and a period including the triangular wave of the corresponding inductor current IL. The gate voltages Vg, Vb, and Vw are the same as the gate voltage Vr. It should be noted that there is a dead time in which all four are low level between the high level sections of the gate voltages Vr, Vg, Vb and Vw.

  The LED current Ir indicates the current flowing through the LEDs d1 to d3 in the LED load 21. After the power supply section Ta, that is, after the power supply from the power supply circuit 31 to the LED load 21 is finished, the LED current Ir does not become 0 but the current continues to flow while decreasing. This is due to the smoothing capacitor C2 and the backflow prevention diode Da.

  The LED currents Ig, Ib, and Iw are the same as the LED current Ir.

  Note that the toning for adjusting the color of the illumination light in the lighting fixture 100 is realized by changing the ratio of brightness of a plurality of emission colors. Specifically, in FIG. 2, the control circuit 33 performs color adjustment by changing the ratio of the four pulse widths of the gate voltage V0 in the power feeding sections Ta to Td. Further, the light control for adjusting the brightness of the illumination light in the lighting fixture 100 is realized by changing the brightness while keeping the ratio of the brightness of the plurality of emission colors constant. Specifically, in FIG. 2, the control circuit 33 adjusts by increasing or decreasing the four pulse widths of the gate voltage V0 while keeping the ratio of the four pulse widths of the gate voltage V0 in the power feeding sections Ta to td constant. Glow.

  In the example of sequential lighting shown in FIG. 2, the switching element M1 of the power supply circuit 31 is controlled to be turned on within a period in which any one of the LED loads is selected by the selector circuit 32. That is, the switching operation of the power supply circuit 31, which is a switching power supply, and the selection operation of the selector circuit 32 are synchronized.

  As shown in FIG. 2, the smoothing capacitors C2 to C5 are precharged in the initial charging. That is, the smoothing capacitors C2 to C5 have already been precharged at the time when the lighting of the LED load is started. As a result, the rush current at the start of lighting the LED load can be mitigated, and the stress applied to the circuit element can be reduced.

  It should be noted that the one-cycle lighting cycle Ts may be periodic at a speed that cannot be perceived by humans. For example, the frequency that is the reciprocal of the one-turn lighting period Ts may be 100 Hz or higher.

  Here, "periodic at a speed that cannot be perceived by a person" means "a person does not perceive flicker". Regarding the measures against flicker of LED lighting, for example, "Electrical Appliance and Material Safety Law (PSE) commentary document," Enforcement of revised government ordinance of Electrical Appliance and Material Safety Law (enforced from July 1, 2012) "(METI) Standards are provided in the Business Safety Group, Product Safety Division. In the “Countermeasure against flicker of light output” on page 28 of the same explanatory document, the frequency that brings about an effect equivalent to “the light output does not feel flicker” is interpreted as follows. That is, in the explanation document, "the light output does not flicker" is satisfied (1) the repetition frequency is 100 Hz or more and there is no missing part in the light output, and (2) the repetition frequency is 500 Hz. It is interpreted as one of the above.

  In the luminaire 100 of the present embodiment, it is considered that the optical output is not missing in the example of FIG. 2, so it is considered that the above (1) should be satisfied. In this case, the frequency that is the reciprocal of the one-turn lighting period Ts may be 100 Hz or higher.

  Next, an example of the voltage waveform of the smoothing capacitor in the initial charging will be described.

  FIG. 3 is a diagram showing an example of a voltage waveform of the smoothing capacitor of the lighting fixture including the LED lighting device according to the embodiment. The figure shows a voltage waveform of any one of the smoothing capacitors C2 to C5 as a representative example. The horizontal axis represents the time axis, and the vertical axis represents the voltage of the smoothing capacitor. The voltage Vf indicates the forward voltage value of the LED load corresponding to the smoothing capacitor. The voltage Vic shows a value slightly smaller than the forward voltage Vf. In the initial charge, in the selector circuit 32, switching elements corresponding to two or more smoothing capacitors are selected, so that power supply from the power supply circuit 31 to the smoothing capacitor is started, and as the power supply voltage increases, the smoothing capacitor The voltage rises. The voltage of the smoothing capacitor is analog-digital converted by the ADC 37 and monitored by the control circuit 33. In FIG. 3, the control circuit 33 stops the power supply from the power supply circuit 31 when the digital value reaches the voltage Vic. In this way, the control circuit 33 charges the smoothing capacitor to a voltage value below the forward voltage of the LED load. This prevents the LED load from erroneously emitting light during initial charging.

  In the progressive lighting following the initial charging, as shown in FIG. 3, the capacitance value of the smoothing capacitor and the power supply voltage value of the power supply circuit 31 are designed so that the voltage of the smoothing capacitor does not fall below the forward voltage Vf. Good. Then, it is possible to prevent the lighting state of the LED load during the sequential lighting from being interrupted by the smoothing action of the smoothing capacitor.

  Next, an example of the initial charging process performed by the control circuit 33 will be described.

  FIG. 4 is a flowchart showing an example of initial charging processing by the control circuit 33 (MCU). The initial charging process in the figure is executed by the control circuit 33 immediately before the lighting of the LED load is started, that is, immediately before the sequential lighting is started.

  First, the control circuit 33 turns on the switching elements M3 to M6 in the selector circuit 32 by setting the gate voltages Vr, Vg, Vb, and Vw to the high level (S11). Further, the control circuit 33 turns on the switching element M1 (that is, the high side transistor) in the power supply circuit 31 by setting the gate voltage V0 to the high level. When the switching element M1 is turned on, the power supply circuit 31 starts charging the smoothing capacitors C2 to C5. At this time, the control circuit 33 starts monitoring the voltage values va to vd of the smoothing capacitors C2 to C5 via the ADC 37 (S12). The monitor of the voltage values va to vd may notify the processor in the control circuit 33 of the conversion result of the ADC 37 by, for example, interrupt processing that occurs periodically.

  Subsequently, the control circuit 33 determines whether the voltage value va of the smoothing capacitor C2 obtained from the ADC 37 is equal to or higher than the first threshold value (S13). If the voltage value va is not greater than or equal to the first threshold value tha, the control circuit 33 determines whether the voltage value vb of the smoothing capacitor C3 obtained from the ADC 37 is greater than or equal to the second threshold value thb (S14). . If the voltage value vb is not greater than or equal to the second threshold value thb, the control circuit 33 determines whether the voltage value vc of the smoothing capacitor C4 obtained from the ADC 37 is greater than or equal to the third threshold value thc (S15). . If the voltage value vc is not greater than or equal to the third threshold value thc, the control circuit 33 determines whether the voltage value vd of the smoothing capacitor C5 obtained from the ADC 37 is greater than or equal to the fourth threshold value thd (S15). . Here, the first threshold value tha is a value smaller than the forward voltage of the LED load 21. The second threshold value thb is a value smaller than the forward voltage of the LED load 22. The third threshold value thc is a value smaller than the forward voltage of the LED load 23. The fourth threshold value thd is a value smaller than the forward voltage of the LED load 24.

  When the determination result of any of steps S13 to S16 is affirmative, the control circuit 33 turns off the switching element M1 in the power supply circuit 31 (S17). At the same time, the control circuit 33 turns off the switching elements M3 to M6 in the selector circuit 32 (S18), and finishes monitoring the voltage values va to vd of the smoothing capacitors C2 to C5 (S19).

  As shown in FIG. 4, the control circuit 33 can charge each of the smoothing capacitors C2 to C5 to a voltage value smaller than the corresponding forward voltage.

  The control circuit 33 may perform the following process instead of step S17. That is, the control circuit 33 turns off the corresponding switching element M3 when the determination result of step S13 is affirmative. When the determination result of step S14 is affirmative, the control circuit 33 turns off the corresponding switching element M4. When the determination result of step S15 is affirmative, the control circuit 33 turns off the corresponding switching element M5. When the determination result of step S16 is affirmative, the control circuit 33 turns off the corresponding switching element M6. In this way, the smoothing capacitors C2 to C5 can be charged to the first to fourth threshold values, respectively.

  As described above, the LED lighting device 30 according to the embodiment includes a plurality of LED loads 21 to 24 having different emission colors, a power supply circuit 31 that supplies power to the plurality of LED loads 21 to 24, and a plurality of power supply circuits 31. Switching elements M3 to M6 connected in series to each of the LED loads 21 to 24, and a control circuit 33 that sequentially turns on and off the switching elements M3 to M6 to sequentially light the plurality of LED loads 21 to 24. Each of the plurality of LED loads 21 to 24 has one or more LEDs (d1 or the like) and a smoothing capacitor (C2 or the like) connected in parallel with the one or more LEDs, and the control circuit 33 Immediately before starting the lighting of the LED loads 21 to 24, at least two of the switching elements M3 to M6 are turned on at the same time, and the corresponding smoothing capacitors are turned on. The charges below the forward voltage of the LED load.

  According to this, since all or part of the smoothing capacitor is initially charged, it is possible to reduce the rush current at the start of lighting and reduce the stress applied to the circuit element. As a result, it is possible to suppress the failure of the circuit element, the deterioration of the life, and the deterioration of the reliability due to the stress.

  Here, the at least two switching elements may be the same in number as the plurality of LED loads.

  According to this, since the entire smoothing capacitor is initially charged, the inrush current at the start of lighting can be more relaxed and the stress applied to the circuit element can be further reduced.

  Here, the control circuit 33 may detect the charging voltage of the smoothing capacitor and turn off the switching element when a predetermined voltage level is reached.

  According to this, the voltage value of the initial charge can be closer to the forward voltage. As a result, the inrush current can be further reduced.

  Here, the power supply circuit 31 is a switching power supply including the inductor L1 and may supply power to the plurality of LED loads 21 to 24 via the inductor L1.

  According to this, it is possible to achieve high efficiency, downsizing, and cost reduction of the power supply circuit.

  Here, each of the plurality of LED loads may have a backflow prevention diode in series with the smoothing capacitor.

  According to this, it is possible to prevent malfunction (for example, erroneous light emission) due to backflow.

  Here, each of the plurality of LED loads may have a discharge resistor in parallel with the smoothing capacitor.

  According to this, the smoothing capacitor can be appropriately discharged in the power-off state after the end of lighting.

  Moreover, the lighting fixture which concerns on embodiment is equipped with the said LED lighting device.

  According to this, since all or part of the smoothing capacitor is initially charged, it is possible to reduce the rush current at the start of lighting and reduce the stress applied to the circuit element. As a result, it is possible to suppress the failure of the circuit element, the deterioration of the life, and the deterioration of the reliability due to the stress.

  The combination of the emission colors of the LED loads 91 to 94 is not limited to red, green, blue, and white.

  An example of the lighting fixture 100 including the above LED lighting device 30 will be described with reference to FIGS. 5A to 5C.

  FIG. 5A is a diagram showing an external appearance example of a lighting fixture 100 including the LED lighting device 30 according to the embodiment. FIG. 5A shows the appearance of the downlight 100a as an example of the lighting fixture 100.

  The downlight 100a includes a circuit box 101a, a lamp body 102a, and a wiring 103a. The circuit box 101a is a housing that houses all or part of the LED lighting device 30 according to the embodiment. The lamp body 102a is a lamp body to which the light source 20 is attached. The wiring 103a electrically connects the circuit box 101a and the light source 20 in the lamp body 102a.

  Drawing 5B is a figure showing other examples of appearance of lighting fixture 100 which has LED lighting device 30 concerning an embodiment. FIG. 5B shows an external appearance of the spotlight 100b as an example of the lighting fixture 100. The spotlight 100b includes a circuit box 101b, a lamp body 102b, and a wiring 103b. The circuit box 101b, the lamp body 102b, and the wiring 103b are the same as the circuit box 101a, the lamp body 102a, and the wiring 103a in FIG. 5A.

  FIG. 5C is a diagram showing still another appearance example of the lighting fixture 100 including the LED lighting device 30 according to the embodiment. FIG. 5C shows an external appearance of a spotlight 100c as an example of the lighting fixture 100. The spotlight 100c includes a circuit box 101c and a lamp body 102c. These are also similar to the circuit box 101a and the lamp body 102a in FIG. 5A.

  The LEDs d1 to d12 in the light source 20 are not limited to so-called light emitting diodes, but may be solid state light emitting elements such as organic EL light emitting elements (OLED: Organic Light Emitting Diode) and laser light emitting elements.

  The LED lighting device according to one or more aspects of the present disclosure has been described above based on the embodiment, but the present disclosure is not limited to this embodiment. As long as it does not deviate from the gist of the present disclosure, various modifications that a person skilled in the art can think of in the present embodiment, and configurations constructed by combining components in different embodiments are also included in the scope of the present disclosure. May be.

21, 22, 23, 24 LED load 30 LED lighting device 31 power supply circuit 32 selector circuit 33 control circuit 100 lighting fixtures C2, C3, C4, C5 smoothing capacitors d1 to d12 LED
Da, Db, Dc, Dd Diode L1 Inductors M3, M4, M5, M6 Switching elements R2 to R5 Resistance

Claims (7)

An LED lighting device,
A plurality of LED (Light Emitting Diode) loads having different emission colors,
A power supply circuit 31 for supplying electric power to the plurality of LED loads,
A switching element connected in series to each of the plurality of LED loads;
A control circuit for sequentially lighting the plurality of LED loads by sequentially turning on and off the switching elements,
Each of the plurality of LED loads has one or more LEDs and a smoothing capacitor connected in parallel with the one or more LEDs,
The LED lighting device, wherein the control circuit turns on at least two of the switching elements at the same time immediately before starting lighting of the LED load and charges a corresponding smoothing capacitor to a voltage equal to or lower than the forward voltage of the LED load. The LED lighting device according to claim 1, wherein the number of the at least two switching elements is the same as the number of the LED loads. The LED lighting device according to claim 1, wherein the control circuit detects a charging voltage of the smoothing capacitor and turns off the switching element when a predetermined voltage level is reached. The LED lighting device according to claim 1, wherein the power supply circuit is a switching power supply including an inductor, and supplies power to the plurality of LED loads via the inductor. The LED lighting device according to any one of claims 1 to 4, wherein each of the plurality of LED loads has a diode for preventing backflow in series with the smoothing capacitor. The LED lighting device according to claim 1, wherein each of the plurality of LED loads has a discharge resistor in parallel with the smoothing capacitor. A lighting fixture comprising the LED lighting device according to claim 1.

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