JP7304521B2 - Lighting devices and lighting fixtures - Google Patents

Description

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

In a lighting device, there is known a technique of providing a smoothing capacitor in a power supply path to the control circuit in order to supply power to the control circuit of the lighting device for as long as possible even after the commercial power supply is stopped due to an instantaneous power failure or the like (for example, See Patent Document 1). Also, from the viewpoint of reducing loss, the power supply circuit for the control circuit is preferably composed of a switching circuit (see the same patent document). In particular, when the control circuit includes a circuit that consumes a large amount of power, such as a wireless module, the use of the switching circuit is highly effective in reducing loss.

Japanese Patent No. 5743041

However, when the power supply circuit for the control circuit is composed of a switching circuit as in the prior art disclosed in Patent Document 1, the supply voltage to the power supply circuit is kept high to some extent in order to obtain a stable output from the switching circuit. There is a need. However, the voltage of the smoothing capacitor may fluctuate greatly, such as when the normal mode shifts to the standby mode. In addition, the output voltage of the smoothing capacitor may be controlled to be low, which may cause the output of the power supply circuit to stop or become unstable.

Accordingly, an object of the present disclosure is to supply stable power to the control circuit regardless of the voltage of the smoothing capacitor in a lighting device in which a smoothing capacitor is provided in a power supply path to the control circuit.

In order to solve the above problems, a lighting device according to an embodiment of the present disclosure includes a main circuit including a smoothing capacitor provided between output nodes and supplying power to a light source connected to the output node; a first circuit used to control the main circuit; a first power supply having a switching circuit connected to the output node and outputting power for operating the first circuit; and a first power supply connected to the output node. a second power supply for outputting power for operating the first circuit; and during normal operation, power from the first power supply is supplied to the first circuit while the output and a switching circuit for supplying power from the second power supply to the first circuit when output from the first power supply is stopped due to a voltage between nodes becoming lower than a predetermined threshold.

According to the present disclosure, in a lighting device in which a smoothing capacitor is provided in a power supply path to a control circuit, stable power can be supplied to the control circuit regardless of the voltage of the smoothing capacitor.

The figure which showed the structural example of the lighting fixture which concerns on embodiment Waveform diagram for explaining the operation of the lighting device according to the embodiment Waveform diagram for explaining the operation of the lighting device according to the comparative example Waveform diagram for explaining power distribution control

Hereinafter, embodiments of the present disclosure will be described in detail based on the drawings. The following description of the embodiments is merely illustrative in nature, and is not intended to limit the present invention, its applications, or its uses.

<Lighting device>
FIG. 1 shows the configuration of a lighting fixture LM according to an embodiment. The lighting fixture LM includes a light source 10 and a lighting device 20 for lighting the light source 10 . Although the type of the light source 10 is not particularly limited, for example, it is configured using a light emitting element 11 such as an LED (Light Emitting Diode).

<Lighting device>
The lighting device 20 includes an input filter circuit 21 , a rectifier circuit 22 , a main circuit 23 , a first power supply 50 , a second power supply 60 , a switching circuit 70 and a control circuit 80 . In FIG. 1, P1 is an input terminal pair of the lighting device 20, and P2 is an output terminal pair of the lighting device 20. As shown in FIG. For convenience of explanation, the wiring between one input terminal P11 and one output terminal P21 may be referred to as wiring L11, and the wiring between the other input terminal P12 and the other output terminal P22 may be referred to as wiring L12. .

－Input filter circuit－
The input filter circuit 21 removes unnecessary frequency components such as harmonic noise from AC power input from the commercial power source E via the input terminal pair P1. The configuration of the input filter circuit 21 is not particularly limited. If a power source that does not require filtering is used instead of the commercial power source E, the input filter circuit 21 may be omitted. In that case, the rectifier circuit 22 is directly connected to the input terminal pair P1.

－rectifier circuit－
The rectifier circuit 22 rectifies (full-wave rectification or half-wave rectification) the AC voltage output from the input filter circuit 21 and outputs it as a rectified voltage. Although not shown, the rectifier circuit 22 is composed of, for example, a diode bridge circuit.

-Main circuit-
The main circuit 23 supplies power to the light source 10 connected to the output terminal pair P2. The main circuit 23 includes at least a smoothing capacitor 31 provided between the output terminal pair P2. The main circuit 23 also includes a transistor 32 provided on one wiring L11. In this way, by providing the smoothing capacitor 31 between the output terminal pair P2, the voltage drop in the event of an instantaneous power failure or instantaneous voltage drop in the commercial power source E is moderated, and the voltage between the output terminal pair P2 rises sharply. can be prevented from declining.

In the example of FIG. 1 , the main circuit 23 includes a step-up/step-down circuit 30 that converts the power output of the rectifier circuit 22 and a constant current circuit 40 that supplies a constant current to the light source 10 .

In FIG. 1, the step-up/step-down circuit 30 includes the above-described transistor 32 and diode 33 provided in series on one wiring L11. The transistor 32 has one terminal connected to the output of the rectifier circuit 22 and the other terminal connected to the cathode of the diode 33 . The anode of diode 33 is connected to the input of constant current circuit 40 . The transistor 32 is turned on and off under the control of the control circuit 80 . The step-up/step-down circuit 30 also includes an input capacitor 34 connected in parallel between the wiring L11 and the wiring L12, an inductor 35, and the smoothing capacitor 31 described above. The input capacitor 34 is provided between the rectifying circuit 22 and the transistor 32, the inductor 35 is provided between the transistor 32 and the diode 33, and the smoothing capacitor 31 is provided between the diode 33 and the constant current circuit 40, respectively.

The constant current circuit 40 has a function of receiving a dimming control signal LC from a dimming circuit 82 (to be described later) and adjusting the amount of current flowing from the main circuit 23 to the light source 10 . Although the specific configuration of the constant current circuit 40 is not particularly limited, it is configured by the circuit shown in FIG. 1, for example. The constant current circuit 40 of FIG. 1 includes a resistor 41 and a transistor 43 connected in series between the anode of the diode 33 and the output terminal P21. The constant current circuit 40 also includes an amplifier 42 . One input terminal of amplifier 42 receives dimming control signal LC from dimming circuit 82 , and the other input terminal is connected to wiring L<b>11 between resistor 41 and transistor 43 . Also, the output terminal of the amplifier 42 is connected to the gate of the transistor 43 .

In the present disclosure, providing the smoothing capacitor 31 between the output terminal pair P2 means that a constant current circuit 40, a passive element, or the like is interposed between the output terminal pair P2 and the smoothing capacitor 31, as shown in FIG. It is a concept that includes a configuration in which the smoothing capacitor 31 is directly connected to the output terminal pair P2. Further, in the present disclosure, the term “terminal” indicates an entrance/exit of current. For example, the term "output terminal" is used as a term indicating an entrance/exit of current output from the lighting device 20 to light the light source 10 . Therefore, for example, the "terminal" may be a physical metal fitting such as a terminal block, or the "terminal" may be wiring (for example, an electric wire) for connecting electric circuits.

Further, in FIG. 1, the step-up/step-down circuit 30 may be replaced with another conversion circuit (converter). For example, instead of the step-up/step-down circuit in FIG. 1, a step-down circuit may be used, or a circuit in which the step-up circuit and the step-down circuit are separated from each other may be used. Also, the circuit system of the step-up/step-down circuit 30 is not limited to the configuration of FIG. A converter can be used.

- 1st power supply -
The first power supply 50 is composed of a switching circuit connected to the smoothing capacitor 31, and outputs power for use as a power supply for the control circuit 80 (hereinafter simply referred to as power supply power). Specifically, the voltage Vf of the smoothing capacitor 31 is stepped down to a voltage Vd1 (Vf>Vd1) and output.

In this way, by using a switching circuit in a circuit that outputs power supply power (so-called power supply circuit), loss can be reduced compared to the case of using a dropper circuit, which will be described later. For example, like a wireless module 81 to be described later, there is a particularly remarkable loss reduction effect in a circuit that consumes relatively large power.

A specific configuration of the switching circuit that configures the first power supply 50 is not particularly limited. In the example of FIG. 1, the first power supply 50 comprises an input capacitor 51, a switching transistor 52, a diode 53, an inductor 55 and an output capacitor . The input capacitor 51 is connected between the wiring L11 and the wiring L12. The switching transistor 52 has one end connected to the wiring L<b>12 and the other end connected to the switching circuit 70 via the inductor 55 . That is, the power supply power output from the first power supply 50 is supplied to the switching circuit 70 . Diode 53 has a cathode connected to the wiring between switching transistor 52 and inductor 55, and an anode connected to wiring L11. The output capacitor 54 is connected between the wiring between the inductor 55 and the switching circuit 70 and the wiring L11.

-Second power supply-
The second power supply 60 is composed of a dropper circuit connected to the smoothing capacitor 31 and outputs power for use as a power supply for the control circuit 80 (hereinafter simply referred to as power supply power). Specifically, the voltage Vf of the smoothing capacitor 31 is stepped down to a voltage Vd2 (Vf>Vd2) and output. Also, the output voltage Vd2 of the second power supply 60 is set to be lower than the output voltage Vd1 of the first power supply 50 in the normal mode. The normal mode refers to the entire range that can be set as the light amount of the light source 10 . The normal mode does not include a so-called "standby mode" in which the lighting device 20 is powered on but the light source 10 is off.

In this way, by using the dropper circuit as the power supply circuit, when the voltage Vf of the smoothing capacitor 31 that is the input drops, the output of the power supply power can be maintained even if the voltage is lower than that of the switching circuit. In other words, the voltage Vf2 of the smoothing capacitor 31 when the output of the second power supply 60 stops is smaller than the voltage Vf1 of the smoothing capacitor 31 when the output of the first power supply 50 stops. That is, when the voltage of the smoothing capacitor 31 gradually drops, the output of the second power supply 60 can continue to be output for a longer period than the output of the first power supply 50 .

A specific configuration of the dropper circuit that constitutes the second power supply 60 is not particularly limited. In the example of FIG. 1, the second power supply 60 has a series circuit of a resistor 61 and a Zener diode 62 and a series circuit of a resistor 63, a transistor 64, and a capacitor 65 arranged in parallel between the wiring L11 and the wiring L12. It has a connected configuration. The gate of transistor 64 is connected to the wiring between resistor 61 and the cathode of Zener diode 62 . Also, power supply power is output from the wiring between the transistor 64 and the capacitor 65, and is supplied to the switching circuit 70 and the light control circuit 82, which will be described later.

-Switching circuit-
The switching circuit 70 receives supply of power from each of the first power supply 50 and the second power supply 60, and outputs power from one of the power supplies to a wireless module 81, which will be described later. Specifically, the switching circuit 70 supplies the power supply power output from the first power supply 50 to the wireless module 81 when the voltage of the smoothing capacitor 31 is equal to or higher than a predetermined threshold. On the other hand, the switching circuit 70 supplies the power supply power output from the second power supply 60 to the wireless module 81 when the voltage of the smoothing capacitor 31 becomes lower than a predetermined threshold (hereinafter referred to as first threshold Vt1).

In the example of FIG. 1, the switching circuit 70 includes a first diode 71 provided between the output of the first power supply 50 and the power line L81 of the wireless module 81, the output of the second power supply 60 and the power supply of the wireless module 81. and a second diode 72 provided between the line L81. The power line L81 is an example of a power terminal.

By using the circuit shown in FIG. 1 , the output of the first power supply 50 and the output of the second power supply 60 , whichever has the higher voltage, is supplied to the wireless module 81 . The output of the switching circuit 70 may be passed through a three-terminal regulator to step down to a constant voltage Vd3 (Vd2>Vd3) and supplied to the wireless module 81. FIG.

In the circuit of FIG. 1, in the normal mode, that is, when the voltage of the smoothing capacitor 31 is higher than the first threshold value Vt1, the output voltage Vd1 of the first power supply 50 is higher than the output voltage Vd2 of the second power supply 60. configured to be high. Thereby, in the normal mode, the output power from the first power supply 50 is supplied to the wireless module 81 . As the voltage Vf of the smoothing capacitor 31 drops, the output voltage Vd1 of the first power supply 50 drops, and when it becomes less than the output voltage Vd2 of the second power supply 60, the output from the second power supply 60 is transferred to the wireless module 81. supplied. With such a configuration, the circuit that supplies power to the wireless module 81 can be automatically switched from the first power supply 50 to the second power supply 60 .

Here, the first threshold Vt1 is set, for example, to a value equal to or higher than the voltage Vf of the smoothing capacitor 31 when the output of the first power supply 50 is stopped. The voltage Vf1 when the output of the first power supply 50 stops is determined based on, for example, the configuration of the first power supply 50, the threshold voltage of the switching transistor 52, and the like. For example, the first threshold Vt1 may be set to the voltage Vf of the smoothing capacitor 31 when the output of the first power supply 50 is stopped. Then, since the first power supply 50 is used until the output of the first power supply 50 stops, the first power supply 50 can be utilized to the maximum. In this case, for example, instead of the switching circuit 70, a relay (not shown) for switching between the output of the first power supply 50 and the output of the second power supply 60 is provided, the output of the first power supply 50 is monitored by a sensor or the like, and the result You may make it control a relay based on.

Alternatively, the voltage Vfw of the smoothing capacitor 31 in the standby mode may be used as the first threshold Vt1. The voltage Vfw is set, for example, to a value that is lower than the voltage Vf1 when the output of the first power supply 50 stops and higher than the voltage Vf2 when the output of the second power supply 60 stops. At this time, for example, the voltage Vfn of the smoothing capacitor 31 in the normal mode is set to a value higher than the voltage Vf1. As a result, the wireless module 81 can be driven by the first power source 50 in the normal mode, and the second power source 60 can be used in situations where power consumption is relatively low, such as in the standby mode or power outage. Loss can be reduced.

-Control circuit-
The control circuit 80 receives a dimming instruction signal from an external device (for example, a master unit (not shown)) or an operating means (not shown) that accepts a user's operation, and outputs a dimming control signal LC based on the dimming instruction signal. Output to constant current circuit 40 . The control circuit 80 includes a first circuit 81 that consumes relatively large power and a second circuit 82 that consumes less power than the first circuit 81 .

The first circuit 81 is, for example, a wireless module that receives a wireless dimming instruction signal output from the parent device or operating means. In the following description, the first circuit 81 will be described as being a wireless module. Note that the wireless module will be described with the same reference numeral 81 as that of the first circuit. The wireless module 81 receives a dimming instruction signal from the outside through wireless communication, generates a PWM (Pulse Width Modulation) signal based on the dimming instruction signal, and outputs the PWM (Pulse Width Modulation) signal to a dimming circuit 82 described later. Note that the first circuit 81 is not limited to a wireless module. For example, although not shown, a sensor circuit may be used as the first circuit 81 when dimming is performed using an output from a sensor such as a motion sensor or an illuminance sensor.

The second circuit 82 is, for example, a dimming circuit that receives the PWM signal output from the wireless module 81 , generates a dimming control signal LC based on the PWM signal, and outputs it to the constant current circuit 40 . In the following description, the second circuit 82 will be described as being a dimming circuit. The dimming circuit will also be described with the same reference numeral 82 as that of the second circuit.

<Operation of lighting device>
Next, the operation of the lighting device 20 will be described with reference to FIGS. 2A and 2B (hereinafter collectively referred to simply as FIG. 2). FIG. 2A shows an operation example of the lighting device 20 of this embodiment, and FIG. 2B shows an operation example of the lighting device of the comparative example. 2, Vi is the input voltage from the commercial power supply E to the lighting device 20, If is the output current of the constant current circuit 40, Vf is the voltage of the smoothing capacitor 31, Vd1 is the output voltage of the first power supply 50, and Vd2 is the second voltage. The output voltage of the power supply 60, Vd3 is the output voltage of the switching circuit 70, and PWM is the PWM signal output from the wireless module 81. FIG.

In FIG. 2, the lighting device 20 operates with the light intensity of the light source 10 maximized until time t10, and operates with the light intensity of the light source 10 reduced to a dim state (Dim state) after t10. shall be Further, it is assumed that the commercial power source E fails at time t20 and is restored at time t30. In addition, in order to enlarge and illustrate the characteristic part of the present disclosure, in FIG. 2, the voltage difference/current difference when the maximum light amount is set and when the Dim state is set is shown to be smaller than the actual difference. ing.

Here, the time between time t20 and time t30 is the time during which the voltage Vf of the smoothing capacitor 31 is maintained at a voltage higher than the voltage at which the output of the second power supply 60 stops at time t30. . Also, the on-resistance of each diode is ignored.

During the period up to time t10, the amount of light is maximum, so the PWM signal output from the wireless module 81 is fixed at Low. The dimming circuit 82 controls the constant current circuit 40 so that the amount of light from the light source 10 is maximized. The first power supply 50 and the second power supply 60 each output power according to the voltage Vf of the smoothing capacitor 31 . The switching circuit 70 receives power from both the first power supply 50 and the second power supply 60, and since the output of the first power supply is larger than the output of the second power supply 60 in the normal mode as described above, the first power supply The power supply power output from 50 is supplied to the wireless module 81 .

During the period from time t10 to time t20, the amount of light is reduced, so the PWM signal output from the wireless module 81 becomes a pulse signal with a predetermined duty ratio. The dimming circuit 82 controls the constant current circuit 40 so that the light source 10 has an amount of light corresponding to the PWM signal. The first power supply 50 and the second power supply 60 continuously output power according to the voltage Vf of the smoothing capacitor 31 . Since the switching circuit 70 receives power from both the first power supply 50 and the second power supply 60, the power supplied from the first power supply 50 is supplied to the wireless module 81 as in the period up to time t10. be done.

At time t20, when the commercial power supply E stops supplying power, the output current If of the constant current circuit 40 stops, and the light source 10 goes out. Also, the voltage Vf of the smoothing capacitor 31 gradually decreases. Then, in the first power supply 50, the bias for operating the switching circuit becomes insufficient, and the output voltage Vd1 gradually decreases and eventually stops (see time t21). On the other hand, since the second power supply 60 is composed of a dropper circuit, even if the output of the first power supply 50 stops, the previous output state is maintained for a while (see times t20 to t30). ). Then, between time t20 and time t21, there is a time when the output voltage Vd1 of the first power supply 50 becomes lower than the output voltage Vd2 of the second power supply 60, and at that time, the output of the switching circuit 70 changes from the first power supply 50 to the output of the second power supply 60 . As a result, power can be continuously supplied from the second power supply 60 to the wireless module 81 even when the output of the first power supply 50 is stopped.

At time t30, the voltage Vf of the smoothing capacitor 31 begins to rise after a while after the power supply from the commercial power supply E is resumed (see time t31). At this time, although the first power supply 50 is stopped, since power is being supplied from the second power supply 60 to the wireless module 81, the wireless module 81 maintains the operating state, and the PWM signal indicating the previous light amount (Dim) is displayed. A signal is output.

That is, the wireless module 81 outputs a pulse signal with a predetermined duty ratio in the same manner as in the period from time t10 to time t20 (see time t31). As a result, it is possible to prevent the occurrence of a so-called flashing phenomenon in which the output current If abruptly rises and the illumination lights up brightly for a moment (see the period from time t32 to time t33).

- Comparative example -
FIG. 2B shows an operation example of the lighting device according to the comparative example. Although the specific circuit configuration of the comparative example is not shown, except for the switching circuit 70 from the circuit of FIG. configured to be supplied to Other configurations are the same as those in FIG.

In FIG. 2B, when the output of the first power supply 50 stops at time t21, the power of the wireless module 81 is stopped and the wireless module 81 is reset, which may take time to recover. For example, once the wireless module 81 is reset, it takes time for initialization, time for establishing communication with the parent device, waiting time for the signal of the parent device after communication is established, etc., and normal PWM It may take some time before the signal can be output.

Then, shortly after the power supply from the commercial power supply E is restarted at time t30, the output voltage of the smoothing capacitor 31 rises, and when the output current If starts to flow, the light control circuit 82 is set to the maximum light quantity, The above-mentioned on-pick phenomenon may occur (see the period from time t32 to time 34 in FIG. 2B). On the other hand, as described above, according to the configuration of the embodiment, it is possible to prevent the occurrence of the on-pick phenomenon.

As described above, the lighting device 20 according to this embodiment includes the main circuit 23 , the control circuit 80 , the first power supply 50 , the second power supply 60 , and the switching circuit 70 . Specifically, the main circuit 23 has a smoothing capacitor 31 provided between the output terminal pair P2 and supplies power to the light source 10 connected to the output terminal pair P2. A control circuit 80 controls the main circuit 23 . The first power supply 50 has a switching circuit connected to the smoothing capacitor 31 and outputs power for the wireless module 81 of the control circuit 80 . The second power supply 60 has a dropper circuit connected to the smoothing capacitor 31 and outputs power supply power for the wireless module 81 of the control circuit 80 . The switching circuit 70 supplies the power supply power output from the first power supply 50 to the wireless module 81 when the voltage Vf of the smoothing capacitor 31 is equal to or higher than the predetermined threshold, and the voltage Vf of the smoothing capacitor 31 is lower than the predetermined threshold. Then, the power supply power output from the second power supply 60 is supplied to the wireless module 81 .

With such a configuration, even when the output voltage of the smoothing capacitor 31 is controlled to a low voltage below the operating range of the switching circuit, the second power supply 60 using the dropper circuit can be used. , the power supply to the wireless module 81 can be continued. As a result, in the normal mode in which the power consumption is relatively high, the loss is reduced by supplying power from the first power supply 50 using the switching circuit, and even if the output voltage of the smoothing capacitor 31 is low, the wireless module 81 can be stably supplied with power. That is, stable power can be supplied to the control circuit 80 regardless of the voltage Vf of the smoothing capacitor 31 . In particular, a significant effect can be obtained for a circuit such as the wireless module 81 that consumes a relatively large amount of current.

In the lighting device 20 described above, the control circuit 80 may include a wireless module 81 and a dimming circuit 82 that consumes less power than the wireless module 81 . Then, the switching circuit 70 supplies power to the wireless module 81, and the power is output from the second power supply 60 to the dimming circuit 82 both in the normal mode and when the output of the first power supply 50 is stopped. It may be said that the power supply power is supplied.

As described above, once the power supply to the wireless module 81 is stopped, it tends to take a long time to recover, and the effect of applying the technology of the present disclosure is more pronounced.

<Other embodiments>
Note that power distribution control in the standby state may be performed using the configuration of the above embodiment (see FIG. 1). Specific control will be described with reference to FIG.

In FIG. 3, the lighting device 20 operates with the light amount of the light source 10 set to the maximum until time t50, and operates so that the light source 10 is in the Dim state from time t50 to time t60. and Also, it is assumed that the device enters the standby state from time t60 to time t70 and returns to the Dim state at time t70. In FIG. 3, similarly to FIG. 2, the voltage difference/current difference between when the maximum light amount is set and when the Dim state is set is shown to be smaller than the actual difference. Also, the operation up to time t60 in FIG. 3 is the same as the operation up to time t20 in FIG. 2, and the description is omitted here.

In the example of FIG. 3, when the standby mode is entered at time t60, the voltage Vf of the smoothing capacitor 31 is controlled to form a sawtooth wave. For example, using a square-wave control signal DimVf that turns off Vf when it is high, the voltage Vf is controlled to have a sawtooth wave. Here, the control signal DimVf is set such that the upper limit value Vt2 of the sawtooth wave (voltage Vf) in the standby mode is smaller than the voltage Vf of the smoothing capacitor 31 in the Dim state. Further, the control signal DimVf is set so that the lower limit value of the sawtooth wave (voltage Vf) in the standby mode is smaller than the threshold voltage Vt3 at which the switching circuit of the first power supply 50 stops operating and the output stops. set.

By performing such control, as shown in FIG. 3, the output voltage Vd1 from the first power supply 50 is stopped during the period when the voltage Vf of the smoothing capacitor 31 is less than the threshold voltage Vt3 (between times t61 and t63). do. As a result, including the time until the first power supply 50 recovers, the output of the switching circuit 70 changes from the first power supply 50 (voltage Vd1) to the second power supply 60 (voltage Vd2) between times t61 and t64. switch.

As described above, by using the configuration of the above-described embodiment, in addition to the effect of supplying stable power to the control circuit regardless of the voltage Vf of the smoothing capacitor 31, the power used in the standby mode can be dispersed. can be done.

INDUSTRIAL APPLICABILITY The lighting device according to the present invention can supply stable power to the control circuit regardless of the voltage of the smoothing capacitor.

LM lighting fixture 10 light source 23 main circuit 31 smoothing capacitor 50 first power supply 60 second power supply 70 switching circuit 71 first diode 72 second diode 80 control circuit 81 wireless module (first circuit)
82 dimming circuit (second circuit)
P2 Output terminal pair (output terminal)
Vt1 First threshold

Claims (9)

a main circuit having a smoothing capacitor provided between output terminals and supplying power to a light source connected to the output terminals;
a control circuit that controls the main circuit;
a first power supply having a switching circuit connected to the smoothing capacitor and outputting power supply power for the control circuit;
a second power supply having a dropper circuit connected to the smoothing capacitor and outputting power supply power for the control circuit;
When the voltage of the smoothing capacitor is equal to or higher than a predetermined threshold, power supply power output from the first power supply is supplied to the control circuit, and when the voltage of the smoothing capacitor is lower than the predetermined threshold, the power is output from the second power supply. A lighting device, comprising: a switching circuit for supplying power from a source to the control circuit. The control circuit includes a first circuit and a second circuit that consumes less power than the first circuit,
The switching circuit supplies power to the first circuit,
2. The lighting device according to claim 1, wherein the second circuit is supplied with the power source power output from the second power source both in the normal mode and when the output of the first power source is stopped. . 3. The lighting device according to claim 2, wherein the first circuit includes a wireless communication module for wirelessly communicating with an external device. 4. The lighting device according to claim 2, wherein the second circuit includes a dimming circuit for controlling dimming. 5. The predetermined threshold value according to any one of claims 1 to 4, wherein the predetermined threshold value is a voltage corresponding to the input voltage to the first power supply when the output of the first power supply is stopped. lighting device. The lighting device according to any one of claims 1 to 5, wherein the predetermined threshold is the voltage of the smoothing capacitor in standby mode. The switching circuit includes a first diode provided between the output of the first power supply and the power supply terminal of the first circuit, and provided between the output of the second power supply and the power supply terminal of the first circuit. 5. The lighting device according to any one of claims 2 to 4, further comprising a second diode that is mounted on the second diode. 7. A power conversion circuit according to any one of claims 1 to 6, wherein said main circuit has a power conversion circuit of a method selected from the group of a step-up/step-down method, a step-down method, a flyback method, a SEPIC method, a Cuk method, and a Zeta method. 1. The lighting device according to 1. a lighting device according to any one of claims 1 to 8;
and the light source to which power is supplied from the lighting device.

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