JP7394318B2 - Lighting devices and lighting equipment - Google Patents

Description

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

In lighting devices, a technique is known in which a smoothing capacitor is provided in the 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 a momentary power outage or the like (for example, (See Patent Document 1). Further, from the viewpoint of reducing loss, it is preferable that the power supply circuit for the control circuit is configured with 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 effect of reducing loss by using a switching circuit is large.

Patent No. 5743041

However, when the power supply circuit for the control circuit is configured with a switching circuit as in the prior art shown in Patent Document 1, the voltage supplied to the power supply circuit is kept high to a certain extent in order to obtain a stable output from the switching circuit. There is a need. However, there are cases where the voltage of the smoothing capacitor fluctuates greatly, such as when transitioning from normal mode to 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.

Therefore, 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 that includes a smoothing capacitor provided between output nodes and supplies power to a light source connected to the output node; a first circuit used to control the main circuit, a switching circuit connected to the output node, and a first power supply configured to output power for operating the first circuit; and a first power source connected to the output node. a second power supply that outputs power for operating the first circuit; and a second power supply that supplies power from the first power supply to the first circuit during normal operation; A switching circuit is provided that supplies power from the second power source to the first circuit when output from the first power source 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.

A diagram showing an example of the configuration of a lighting fixture according to the first embodiment Waveform diagram for explaining the operation of the lighting device according to the first embodiment Waveform diagram for explaining the operation of the lighting device according to the comparative example A diagram showing a configuration example of a lighting fixture according to a second embodiment Waveform diagram for explaining the operation of the lighting device according to the second embodiment Waveform diagram to explain power distribution control

Hereinafter, each embodiment of the present disclosure will be described in detail based on the drawings. The following description of each embodiment is essentially only an example, and is not intended to limit the present invention, its applications, or its uses.

≪First embodiment≫
A first embodiment will be described with reference to the drawings.

<Lighting device>
FIG. 1 shows a configuration example of a lighting fixture LM according to the first 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 light source 10 is not particularly limited, it is configured using, for example, 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 power supply circuit 24, a switching circuit 70, and a control circuit 80. In FIG. 1, P1 is a pair of input terminals of the lighting device 20, and P2 is a pair of output terminals of the lighting device 20. For convenience of explanation, the wiring between one input terminal P11 and one output terminal P21 may be called the wiring L11, and the wiring between the other input terminal P12 and the other output terminal P22 may be called the wiring L12. .

-Input filter circuit-
The input filter circuit 21 removes unnecessary frequency components such as harmonic noise from the AC power input from the commercial power source E through the input terminal pair P1. The configuration of the input filter circuit 21 is not particularly limited. Note that 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, rectifier circuit 22 is directly connected to 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 configured 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. Further, the main circuit 23 includes a transistor 32 provided on one wiring L11. In this way, by providing the smoothing capacitor 31 between the output terminal pair P2, when a momentary power outage or instantaneous voltage drop occurs in the commercial power supply E, the voltage drop is moderated, and the voltage between the output terminal pair P2 is reduced suddenly. can be prevented from decreasing.

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

In FIG. 1, the step-up/down circuit 30 includes the above-described transistor 32 and diode 33, which are 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 the diode 33 is connected to the input of the constant current circuit 40. The transistor 32 is turned on and off under the control of the control circuit 80. Further, the step-up/down circuit 30 includes an input capacitor 34, an inductor 35, and the above-mentioned smoothing capacitor 31 connected in parallel between the wiring L11 and the wiring L12. The input capacitor 34 is provided between the rectifier 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.

The constant current circuit 40 has a function of adjusting the amount of current flowing from the main circuit 23 to the light source 10 in response to a dimming control signal LC from a dimming circuit 82 described later. Although the specific configuration of the constant current circuit 40 is not particularly limited, it may be configured as a circuit as shown in FIG. 1, for example. The constant current circuit 40 in 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. Further, the constant current circuit 40 includes an amplifier 42. The amplifier 42 receives the dimming control signal LC from the dimming circuit 82 at one input terminal, and has the other input terminal connected to the wiring L11 between the resistor 41 and the transistor 43. Further, 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, as shown in FIG. This concept includes a configuration in which the smoothing capacitor 31 is directly connected to the output terminal pair P2. Furthermore, in the present disclosure, a "terminal" indicates an inlet/outlet of current. For example, the term "output terminal" is used to indicate an inlet/outlet of a current output from the lighting device 20 in order to light the light source 10. Therefore, for example, a physical metal fitting such as a terminal block may be provided as a "terminal", or a "terminal" may be wiring (for example, an electric wire) for connecting electric circuits.

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

-Power circuit-
The power supply circuit 24 includes a first power supply 50 and a second power supply 60 connected to a smoothing capacitor.

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

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

Note that the specific configuration of the switching circuit that constitutes the first power supply 50 is not particularly limited. In the example of FIG. 1, the first power supply 50 includes an input capacitor 51, a switching transistor 52, a diode 53, an inductor 55, and an output capacitor 54. Input capacitor 51 is connected between wiring L11 and wiring L12. The switching transistor 52 has one end connected to the wiring L12 and the other end connected to the switching circuit 70 via the inductor 55. That is, the power source power output from the first power source 50 is supplied to the switching circuit 70. The diode 53 has a cathode connected to the wiring between the switching transistor 52 and the inductor 55, and an anode connected to the 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 configured with a dropper circuit connected to the smoothing capacitor 31, and outputs power to be used as a power source 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 the voltage Vd2 (Vf>Vd2) and output. Further, 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 turned off.

In this way, by using the dropper circuit as the power supply circuit, when the voltage Vf of the input smoothing capacitor 31 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 decreases, 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.

Note that the 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 connected in parallel between the wiring L11 and the wiring L12. Has a connected configuration. The gate of the transistor 64 is connected to the wiring between the resistor 61 and the cathode of the Zener diode 62. Further, power is output from the wiring between the transistor 64 and the capacitor 65, and is supplied to the switching circuit 70 and the dimming circuit 82, which will be described later.

-Control circuit-
The control circuit 80 receives a dimming instruction signal from an external device (for example, a base unit (not shown)) or an operation means (not shown) that accepts a user's operation, and determines a dimming control signal based on the dimming instruction signal. Output to the current circuit 40. The control circuit 80 includes a first circuit 81 whose power consumption is relatively large, and a second circuit 82 whose power consumption is smaller 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 base device or operating means described above. In the following description, the first circuit 81 will be described as a wireless module. Note that the wireless module will also be described with the same reference numeral 81 as the first circuit. The wireless module 81 receives a dimming instruction signal from the outside via wireless communication, generates a PWM (Pulse Width Modulation) signal based on the dimming instruction signal, and outputs it to a dimming circuit 82, which will be described later. Note that the first circuit 81 is not limited to a wireless module. For example, although not shown in the drawings, a sensor circuit may be used as the first circuit 81 when controlling the light using an output from a sensor such as a human sensor or an illuminance sensor.

The second circuit 82 is, for example, a dimming circuit that receives a 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 a dimming circuit. Note that the dimmer circuit will also be described with the same reference numeral 82 as the second circuit.

Further, the control circuit 80 performs dimming control to cause the dimming circuit 82 to output the signal regardless of the PWM signal output from the wireless module 81 when the voltage Vf of the smoothing capacitor 31 becomes equal to or lower than a predetermined first threshold value Vt1. The signal is controlled so that the amount of light from the light source 10 is maintained below a predetermined level. In the following description, a mode in which the control circuit 80 maintains the dimming control signal so that the amount of light from the light source 10 is below a predetermined level will be referred to as a "Dim mode."

Here, the "first threshold Vt1" can be set arbitrarily and is not particularly limited. For example, the "first threshold value Vt1" is set to a position slightly lower than the voltage Vf of the smoothing capacitor 31 when the light intensity target value of the light source 10 is set to the Dim state (lower limit level in normal mode). be done. Moreover, the "first threshold value Vt1" is set to a voltage higher than the voltage Vf of the smoothing capacitor 31 in the standby mode. In this way, by setting the voltage higher than that in standby mode, even when returning from standby mode, lighting of the light source 10 can be started from the lower limit level in normal mode, reducing stress on the circuit. I can do it.

Moreover, the above-mentioned "predetermined level" is, but is not particularly limited to, the dimming lower limit level (for example, Dim state). More specifically, the control circuit 80 controls the light source by setting the light amount target value of the light source 10 to the dimming lower limit level (for example, Dim state) in the dimming control signal output from the dimming circuit 82, for example. 10 is maintained below a predetermined level. Note that "to hold" here means that the light amount of the light source 10 may be held at a fixed value, or may have some fluctuation in the light amount of the light source 10.

Furthermore, when the voltage Vf of the smoothing capacitor 31 returns to a predetermined second threshold value Vt2 or more after becoming a predetermined first threshold value Vt1 or less, the control circuit 80 cancels the setting of the Dim mode, that is, dimming. It may be configured to release the holding operation of the control signal. Note that the first threshold value Vt1 and the second threshold value Vt2 may be the same setting value or may be different values from each other. For example, the second threshold value Vt2 may be set to a higher value than the first threshold value Vt1. may have been done. FIG. 2A, which will be described later, shows an example in which the first threshold Vt1 and the second threshold Vt2 are set to the same value.

The specific operation of the control circuit 80 will be explained in "Operation of lighting device" below.

<Operation of lighting device>
Next, the operation of the lighting device 20 will be described with reference to FIGS. 2A and 2B (hereinafter also simply referred to as FIG. 2). FIG. 2A is an example of the operation of the lighting device 20 of this embodiment, and FIG. 2B is an example of the operation of the lighting device of the comparative example. In FIG. 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 The output voltage of the power supply 60 and PWM are the PWM signals output from the wireless module 81.

Further, in FIG. 2, the lighting device 20 operates with a setting where the light intensity of the light source 10 is maximized until time t10, and after t10, it operates with a setting where the light intensity of the light source 10 is reduced to a dim state (dim state). shall be taken as a thing. It is also assumed that the commercial power source E experiences a power outage at time t20 and is restored at time t30. Further, as shown in FIG. 2A, the first threshold value Vt1 is set at a position slightly lower than the voltage Vf of the smoothing capacitor 31 when the light intensity target value of the light source 10 is set to the Dim state (at a position higher than in the standby mode). ) is set. Note that in order to enlarge and illustrate the characteristic portions of the present disclosure, in FIG. 2, the voltage difference/current difference between the case where the maximum light amount is set and the case where the Dim state is set are 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. .

During the period up to time t10, the amount of light is at its 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 source 50 and the second power source 60 each output power according to the voltage Vf of the smoothing capacitor 31.

Since the light intensity is reduced during the period from time t10 to time t20, 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 emits light according to the PWM signal.

At time t20, when the power supply from the commercial power supply E is stopped, the output current If of the constant current circuit 40 is stopped, and the light source 10 is turned off. In addition, the voltage Vf of the smoothing capacitor 31 gradually decreases and becomes equal to or lower than the first threshold value Vt1 described above after a while (see time t21). Furthermore, the first power supply 50 runs out of bias for operating the switching circuit, and the output voltage Vd1 gradually decreases and stops after a while (see time t21). When the output of the first power supply 50 stops, the output of the PWM signal from the wireless module 81 also stops. That is, the PWM signal is in a signal state in which the maximum light amount is the target value.

At this time, the control circuit 80 is set to the Dim mode as described above. That is, the control circuit 80 controls the dimming circuit 82 so that the amount of light from the light source 10 is maintained at a predetermined level or less, regardless of the PWM signal output from the wireless module 81. As a result, even if the output of the first power source 50 is stopped, the target value of the amount of light output from the dimming circuit 82 is maintained in the Dim state.

At time t30, after a while after the power supply from the commercial power source E is resumed, the voltage Vf of the smoothing capacitor 31 starts to rise (see time t31). At this time, although the first power source 50 is stopped, the second power source 60 is operating, so the dimming control signal LC that sets the light amount target value to the Dim state is output from the dimming circuit 82 (time t31 to time t32). Then, when the voltage Vf of the smoothing capacitor 31 exceeds the second threshold value Vt2, the Dim mode of the control circuit 80 is canceled and the dimming circuit 82 starts operating based on the PWM signal from the wireless module 81. As described above, according to this aspect, the light intensity of the light source becomes the light intensity in the Dim state, so it is possible to prevent the occurrence of the so-called on-pika phenomenon, in which the output current If suddenly increases and the lighting turns on brightly for a moment ( (See the period from time t32 to time 33).

Note that if the light intensity between time t10 and time t20 is in a state other than the Dim state, the light intensity target value is once set to the Dim state by the dimming circuit 82, and then the light source 10 is changed as the wireless module 81 returns. It operates in such a way that the amount of light gradually increases.

-Comparative example-
FIG. 2B shows an example of the operation of the lighting device according to the comparative example. Although the specific circuit configuration of the comparative example is not shown, the switching circuit 70 is removed from the circuit in FIG. It is configured so that it is supplied to The other configurations are the same as in FIG. 1.

In FIG. 2B, when the output of the first power source 50 stops at time t21, the power of the wireless module 81 is stopped, the wireless module 81 is reset, and it may take time to recover. For example, once the wireless module 81 is reset, there will be time for initialization, time for establishing communication with the base unit, time for waiting for a signal from the base unit after communication is established, etc., and normal PWM It may take some time to reach a state where a signal can be output.

Then, some time after the power supply from the commercial power source E resumes at time t30, and after the output voltage of the smoothing capacitor 31 rises, when the output current If starts flowing, the dimmer circuit 82 is set to the maximum light amount, There is a possibility that the above-mentioned on-picture 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, the occurrence of the on-picture phenomenon can be prevented.

As described above, the lighting device 20 according to the present embodiment includes the smoothing capacitor 31 provided between the output terminal pair P2, and the main circuit 23 that supplies power to the light source 10 connected to the output terminal pair P2. , a dimming circuit 82 that outputs a dimming control signal LC for controlling the light amount of the light source 10 to the main circuit 23, and a power supply circuit 24 connected to the smoothing capacitor 31 and supplying power to the dimming circuit 82. . Then, when the voltage of the smoothing capacitor 31 becomes equal to or less than a predetermined first threshold value Vt1, the dimming circuit 82 operates to maintain the dimming control signal LC so that the amount of light from the light source becomes equal to or less than a predetermined level. . For example, the control circuit 80 performs control to maintain the dimming control signal output from the dimming circuit 82 so that the amount of light from the light source is below a predetermined level, regardless of the PWM signal output from the wireless module 81. .

With such a configuration, even if the circuit operation for outputting the PWM signal (for example, the wireless module 81) stops due to power supply to the circuit (for example, the wireless module 81) being stopped, the dimming is still possible. Since the target light amount value of the light source installed from the circuit 82 is set to a predetermined level or less, it is possible to prevent the so-called on-pika phenomenon from occurring.

≪Second embodiment≫
FIG. 3 is a configuration example of the lighting fixture LM of the second embodiment. In FIG. 3, the same components as those in FIG. 1 may be given the same reference numerals and their descriptions will be omitted. 3 differs from the configuration in FIG. 1 in that a switching circuit 70 is added to the power supply circuit 24.

-Switching circuit-
The switching circuit 70 is supplied with power from each of the first power source 50 and the second power source 60 and outputs one of the power sources to the wireless module 81 . Specifically, the switching circuit 70 supplies the power output from the first power source 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 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 third threshold Vt3).

In the example of FIG. 3, the switching circuit 70 includes a first diode 71 provided between the output of the first power source 50 and the power line L81 of the wireless module 81, and a first diode 71 provided between the output of the second power source 60 and the power source line L81 of the wireless module 81. and a second diode 72 provided between the line L81 and the line L81. The power line L81 is an example of a power terminal.

By using a circuit as shown in FIG. 3, the higher voltage output of the output of the first power supply 50 and the output of the second power supply 60 is supplied to the wireless module 81. Note that the output of the switching circuit 70 may be passed through a three-terminal regulator to be stepped down to a constant voltage Vd3 (Vd2>Vd3), and then supplied to the wireless module 81.

In the circuit of FIG. 3, in the normal mode, that is, in a state where the voltage of the smoothing capacitor 31 is higher than the third threshold value Vt3, the output voltage Vd1 of the first power supply 50 is higher than the output voltage Vd2 of the second power supply 60. It is configured to be high. As a result, in the normal mode, the output power from the first power source 50 is supplied to the wireless module 81. Then, as the voltage Vf of the smoothing capacitor 31 decreases, the output voltage Vd1 of the first power source 50 decreases, and when it becomes less than the output voltage Vd2 of the second power source 60, the output from the second power source 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 source 50 to the second power source 60.

Here, the third threshold value Vt3 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 at which the output of the first power supply 50 is stopped 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 third threshold value Vt3 may be set to the voltage Vf of the smoothing capacitor 31 when the output of the first power supply 50 is stopped. In this case, the first power source 50 will be used until the output of the first power source 50 stops, so the first power source 50 can be utilized to the fullest. In this case, for example, a relay (not shown) that switches between the output of the first power source 50 and the output of the second power source 60 is provided in place of the switching circuit 70, and the output of the first power source 50 is monitored with a sensor or the like, and the result is The relay may be controlled based on.

Further, the third threshold value Vt3 may be set to the voltage Vfw of the smoothing capacitor 31 in the standby mode. The voltage Vfw is set, for example, to a value smaller than the voltage Vf1 when the output of the first power supply 50 is stopped and larger than the voltage Vf2 when the output of the second power supply 60 is stopped. At this time, for example, the voltage Vfn of the smoothing capacitor 31 in the normal mode is set to a value larger than the above voltage Vf1. This allows the first power source 50 to drive the wireless module 81 in the normal mode, while the second power source 60 can be used in situations where power consumption is relatively low, such as in standby mode or during a power outage. Loss can be reduced.

<Operation of lighting device>
Next, the operation of the lighting device 20 will be described with reference to FIG. 4. In FIG. 4, Vi, If, Vf, Vd1, and Vd2 are the same as in FIG. 2. Further, Vd3 is the output voltage of the switching circuit 70. 4, similarly to FIG. 2, the lighting device 20 operates at a setting where the light intensity of the light source 10 is maximized until time t10, and after t10, the lighting device 20 is set to reduce the light intensity of the light source 10 to a dim state (Dim state). Assume that it is running. It is also assumed that the commercial power source E experiences a power outage at time t20 and is restored at time t30.

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. . Furthermore, the on-resistance of each diode is ignored.

During the period up to time t10, the amount of light is at its 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 source 50 and the second power source 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 source 50 and the second power source 60, and as described above, in the normal mode, the output of the first power source is larger than the output of the second power source 60, so the switching circuit 70 receives power from both the first power source 50 and the second power source 60. Power source power output from 50 is supplied to wireless module 81 .

Since the light intensity is reduced during the period from time t10 to time t20, 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 emits light according 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, respectively. Since the switching circuit 70 receives power from both the first power source 50 and the second power source 60, the power output from the first power source 50 is supplied to the wireless module 81 as in the period up to time t10. be done.

At time t20, when the power supply from the commercial power supply E is stopped, the output current If of the constant current circuit 40 is stopped, and the light source 10 is turned off. Further, the voltage Vf of the smoothing capacitor 31 gradually decreases. Then, the first power supply 50 lacks the bias for operating the switching circuit, and the output voltage Vd1 gradually decreases and eventually stops (see time t21). When the output of the first power supply 50 stops, the output of the PWM signal from the wireless module 81 also stops. That is, the PWM signal is in a signal state in which the maximum light amount is the target value.

On the other hand, since the second power supply 60 is configured with a dropper circuit, even if the output of the first power supply 50 stops, it maintains the previous output state for a while (see time 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 smaller than the output voltage Vd2 of the second power supply 60, and at that time, the output of the switching circuit 70 becomes lower than the output voltage Vd1 of the first power supply 50. The output is switched from the output of the second power supply 60 to the output of the second power supply 60. Thereby, even if the output of the first power source 50 stops, power can be continuously supplied to the wireless module 81 from the second power source 60.

Further, similarly to the first embodiment described above, the voltage Vf of the smoothing capacitor 31 gradually decreases and becomes equal to or lower than the first threshold value Vt1 described above after a while (see time t21). Then, similarly to the first embodiment, the control circuit 80 is set to Dim mode. That is, the control circuit 80 controls the dimming circuit 82 so that the amount of light from the light source 10 is maintained at a predetermined level or less, regardless of the PWM signal output from the wireless module 81. As a result, the light amount target value output from the dimming circuit 82 is maintained in the Dim state.

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

That is, the wireless module 81 outputs a pulse signal with a predetermined duty ratio similarly to the period from time t10 to time t20 (see time t31). Thereby, it is possible to prevent the occurrence of the so-called on-pika phenomenon, in which the output current If suddenly increases and the illumination lights up brightly for a moment (see the period from time t32 to time 33).

Further, similarly to the first embodiment, when the voltage Vf of the smoothing capacitor 31 exceeds the second threshold value Vt2, the Dim mode of the control circuit 80 is canceled. In other words, since the control circuit 80 is set to the Dim mode until the voltage Vf of the smoothing capacitor 31 exceeds the second threshold value Vt2, the occurrence of the on-picture phenomenon can be more reliably prevented.

As described above, the lighting device 20 according to the present embodiment has the switching circuit 70 added to the configuration of the first embodiment. That is, in this embodiment, the power supply circuit 24 has a switching circuit connected to the smoothing capacitor 31, and supplies power to the wireless module 81 when the voltage of the smoothing capacitor 31 is equal to or higher than the predetermined third threshold Vt3. It has a first power supply 50 and a dropper circuit connected to the smoothing capacitor 31, and supplies power to the wireless module 81 when the voltage Vf of the dimming circuit 82 and the smoothing capacitor 31 is less than a predetermined third threshold Vt3. A second power source 60 is provided.

With this configuration, even when the output voltage of the smoothing capacitor 31 is controlled to a low voltage that is 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 where power consumption is relatively high, power is supplied from the first power supply 50 using a switching circuit to reduce loss, and even if the output voltage of the smoothing capacitor 31 becomes 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, remarkable effects can be obtained for circuits with relatively large current consumption, such as the wireless module 81. Furthermore, as described above, since the control circuit 80 is set to the Dim mode until the voltage Vf of the smoothing capacitor 31 exceeds the second threshold value Vt2, the occurrence of the on-peek phenomenon can be more reliably prevented.

<Other embodiments>
Note that the configuration of the second embodiment described above (see FIG. 3) may be used to perform power distribution control in the standby state. Specific control will be explained with reference to FIG. 5.

In FIG. 5, the lighting device 20 operates at a setting that maximizes the light intensity of the light source 10 until time t50, and operates so that the light source 10 is in the dim state from time t50 to time t60. shall be. Further, 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. Note that in FIG. 5 as well, as in FIG. 4, the voltage difference/current difference between the case where the maximum light amount is set and the case where the Dim state is set is shown to be smaller than the actual difference. Further, the operation up to time t60 in FIG. 5 is the same as the operation up to time t20 in FIG. 4, and the explanation will be omitted here.

In the example of FIG. 5, when the standby mode is entered at time t60, the voltage Vf of the smoothing capacitor 31 is controlled to have a sawtooth waveform. For example, the voltage Vf is controlled to have a sawtooth wave using a square wave control signal DimVf that turns off Vf when it is high. Here, the control signal DimVf is set so 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. The control signal DimVf is set such 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. 5, 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 (from time t61 to t63). do. As a result, including the time until the first power supply 50 is restored, 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 time t61 and t64. Switch.

As described above, by using the configuration of the above embodiment, in addition to the effect of supplying stable power to the control circuit regardless of the voltage Vf of the smoothing capacitor 31, it is possible to distribute the power used in standby mode. I can do it.

Since the lighting device according to the present invention can supply stable power to a control circuit regardless of the voltage of the smoothing capacitor, it is extremely useful as a lighting device for lighting a light source such as an LED, for example.

LM lighting fixture 10 light source 20 lighting device 23 main circuit 24 power supply circuit 31 smoothing capacitor 50 first power supply 60 second power supply 80 control circuit 81 wireless module (first circuit)
82 Dimmer circuit P2 Output terminal pair (output terminal)
Vt1 First threshold Vt2 Second threshold Vt3 Third threshold

Claims (12)

a main circuit having a smoothing capacitor provided between the output terminals and supplying power to a light source connected to the output terminals;
a control circuit that receives a dimming instruction signal from the outside, generates a dimming control signal for controlling the light amount of the light source based on the dimming instruction signal, and outputs it to the main circuit;
a power supply circuit connected to the smoothing capacitor and supplying power to the control circuit ;
The control circuit maintains the dimming control signal so that when the voltage of the smoothing capacitor becomes equal to or less than a first predetermined threshold, the amount of light from the light source becomes equal to or less than a predetermined level regardless of the dimming instruction signal. A lighting device characterized by: 2. The control circuit according to claim 1, wherein the holding operation of the dimming control signal of the control circuit is canceled when the voltage of the smoothing capacitor exceeds a second threshold set to be equal to or higher than the first threshold. The lighting device described. The control circuit includes a first circuit that receives the dimming instruction signal from the outside, and a circuit that consumes less power than the first circuit, generates the dimming control signal based on the dimming instruction signal, and controls the main circuit. Equipped with a dimming circuit that outputs to the circuit ,
The power supply circuit is
a first power supply having a switching circuit connected to the smoothing capacitor and supplying power to the first circuit when the voltage of the smoothing capacitor is equal to or higher than a predetermined third threshold;
a dropper circuit connected to the smoothing capacitor, and a second power supply supplying power to the first circuit when the voltage of the dimming circuit and the smoothing capacitor is less than the predetermined third threshold. The lighting device according to claim 1 or 2, characterized in that: . The lighting device according to claim 3, wherein the first circuit includes a wireless communication module for wirelessly communicating with an external device. The lighting device according to any one of claims 1 to 4, wherein the first threshold is set to a voltage higher than a voltage of the smoothing capacitor in standby mode. 6. The main circuit has a power conversion circuit of a method selected from the group of buck-boost method, step-down method, flyback method, SEPIC method, Cuk method, and Zeta method. The lighting device according to item 1. a main circuit having a smoothing capacitor provided between the output terminals and supplying power to a light source connected to the output terminals;
a dimmer circuit that outputs a dimmer control signal to the main circuit to control the amount of light from the light source;
a power supply circuit connected to the smoothing capacitor and supplying power to the dimming circuit;
The dimming circuit maintains the dimming control signal so that the amount of light from the light source becomes equal to or less than a predetermined level when the voltage of the smoothing capacitor becomes equal to or less than a predetermined first threshold;
A control circuit including the dimmer circuit and a first circuit that consumes more power than the dimmer circuit,
The power supply circuit is
a first power supply having a switching circuit connected to the smoothing capacitor and supplying power to the first circuit when the voltage of the smoothing capacitor is equal to or higher than a predetermined third threshold;
a dropper circuit connected to the smoothing capacitor, and a second power supply supplying power to the first circuit when the voltage of the dimming circuit and the smoothing capacitor is less than the predetermined third threshold. A lighting device characterized by: The lighting device according to claim 7, wherein the first circuit includes a wireless communication module for wirelessly communicating with an external device. 9. The lighting device according to claim 7, wherein the first threshold is set to a voltage higher than the voltage of the smoothing capacitor in standby mode. a main circuit having a smoothing capacitor provided between the output terminals and supplying power to a light source connected to the output terminals;
a dimmer circuit that outputs a dimmer control signal to the main circuit to control the amount of light from the light source;
a power supply circuit connected to the smoothing capacitor and supplying power to the dimming circuit;
The dimming circuit maintains the dimming control signal so that the amount of light from the light source becomes equal to or less than a predetermined level when the voltage of the smoothing capacitor becomes equal to or less than a predetermined first threshold;
The lighting device, wherein the first threshold value is set to a voltage higher than a voltage of the smoothing capacitor in standby mode. The lighting device according to any one of claims 1 to 10,
A lighting device characterized in that the dimming control signal is a PWM (Pulse Width Modulation) signal. The lighting device according to any one of claims 1 to 11 ,
A lighting fixture comprising: the light source to which power is supplied from the lighting device.

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