JP7040382B2 - Lighting device and lighting equipment - Google Patents

Description

Embodiments of the present invention relate to lighting devices and luminaires.

A lighting fixture including a light source such as an LED (Light Emitting Diode) and a lighting device that supplies a direct current to the light source to light the light source is known (for example, Patent Document 1). The lighting device detects the current flowing through the light source, compares the detected value of the current with the target value of the current, and feedback-controls the current flowing through the light source according to the comparison result, so that the current flowing through the light source is substantially constant. Is being made to flow.

Further, in the lighting device, the light source is turned on with the brightness corresponding to the dimming signal by changing the magnitude of the current flowing through the light source according to the dimming signal. At this time, on the lower limit side of dimming, the detected value and the target value may become small, and the error of the comparison result may become large, making it difficult to perform proper dimming.

For example, it has been proposed to adjust the brightness while suppressing a decrease in the current value by intermittently supplying a current to the light source on the lower limit side of the dimming. However, in the configuration in which the detected value and the target value are compared, if the current is intermittently supplied to the light source, the difference between the detected value and the target value becomes large in the section where the current is not supplied. Therefore, when switching from the non-supplying section to the supplying section, a current larger than the current value corresponding to the dimming signal may flow to the light source. As described above, even in a configuration in which a current is intermittently supplied to the light source, it is still difficult to perform proper dimming.

It is also considered to provide a switching element for dimming separately from the switching element for current control so that the brightness can be appropriately controlled down to the lower limit side of dimming. However, in this case, the circuit configuration of the lighting device becomes complicated, for example, a switching element for dimming must be separately provided.

Therefore, in the lighting device and the luminaire, it is desired that the current flowing through the light source is controlled to be substantially constant, and the dimming can be appropriately performed up to the dimming lower limit side with a simple configuration.

Japanese Unexamined Patent Publication No. 2016-66433

An embodiment of the present invention provides a lighting device and a lighting fixture capable of appropriately dimming to the dimming lower limit side with a simple configuration while controlling the current flowing through the light source substantially to be constant.

According to the embodiment of the present invention, a constant DC current flows through the light source, a constant current circuit capable of varying the current value of the DC current, and a current value of the DC current flowing through the light source are detected. The target value of the comparison circuit is set based on the detection unit, the comparison circuit that compares the detection value of the detection unit with the target value, and the dimming signal input from the outside, and the dimming signal and the comparison. By controlling the operation of the constant current circuit based on the comparison result of the circuits and supplying the DC current having the current value corresponding to the dimming signal to the light source, the brightness corresponding to the dimming degree of the dimming signal is supplied. A control unit for lighting the light source is provided, and the control unit intermittently supplies the DC current to the light source when the dimming degree of the dimming signal is equal to or less than a predetermined value, and the DC current is provided. The period of supply of the DC current and the period of suspension of the supply of the DC current are changed according to the dimming degree, and the target value is changed in synchronization with the period of the supply of the DC current and the period of the suspension. A lighting device is provided.

According to the embodiment of the present invention, it is possible to provide a lighting device and a lighting fixture capable of appropriately dimming to the dimming lower limit side with a simple configuration while controlling the current flowing through the light source substantially to be constant.

It is a block diagram schematically showing a lighting device and a lighting fixture which concerns on 1st Embodiment. 2 (a) and 2 (d) are graphs schematically showing an example of the operation of the lighting device according to the first embodiment. It is a block diagram schematically showing a lighting device and a lighting fixture which concerns on 2nd Embodiment. 4 (a) to 4 (d) are graphs schematically showing an example of the operation of the lighting device according to the second embodiment.

Hereinafter, each embodiment will be described with reference to the drawings.
It should be noted that the drawings are schematic or conceptual, and the relationship between the thickness and width of each part, the ratio of the sizes between the parts, and the like are not necessarily the same as the actual ones. Further, even when the same part is represented, the dimensions and ratios may be different from each other depending on the drawing.
In the specification of the present application and each figure, the same elements as those described above with respect to the above-mentioned figures are designated by the same reference numerals, and detailed description thereof will be omitted as appropriate.

(First Embodiment)
FIG. 1 is a block diagram schematically showing a lighting device and a lighting fixture according to the first embodiment.
As shown in FIG. 1, the luminaire 10 includes a lighting device 12 and a light source module 14.

The light source module 14 has a light source 16. The light source module 14 includes, for example, a plurality of light sources 16. Each light source 16 is connected in series, for example. Each light source 16 may be a combination of, for example, a series connection and a parallel connection. The number of light sources 16 may be arbitrary. The number of light sources 16 may be, for example, one.

For the light source 16, for example, a light emitting diode (LED) is used. The light source 16 may be, for example, an organic light emission diode (OLED), an inorganic electroluminescence light emitting element, an organic electroluminescence light emitting element, or another electroluminescent light emitting element. good. The light source 16 may be, for example, a light bulb. Hereinafter, the light source 16 will be described as an LED.

The lighting device 12 includes a constant current circuit 20, a detection unit 22, a comparison circuit 24, and a control unit 26.

The lighting device 12 is electrically connected to, for example, the AC power supply 2. AC power is supplied to the lighting device 12 from the AC power source 2. The AC power supply 2 is, for example, a commercial power supply. The AC power source 2 may be, for example, a private power generator. The electric power supplied to the lighting device 12 is not limited to AC power, but may be DC power or the like. Further, in the specification of the present application, "electrically connected" includes not only the case of being directly contacted and connected, but also the case of being connected via another conductive member or the like.

The lighting device 12 is electrically connected to the light source module 14. The lighting device 12 converts the AC power supplied from the AC power supply 2 into DC power corresponding to the light source module 14, and supplies the DC current to the light source module 14. As a result, the lighting device 12 lights the light source 16 of the light source module 14.

The lighting device 12 includes an output unit 28. The output unit 28 is used for electrical connection with the light source module 14. The output unit 28 has a first terminal 28a connected to the high-voltage side terminal 14a of the light source module 14, and a second terminal 28b connected to the low-voltage side terminal 14b of the light source module 14. The terminal 14a on the high voltage side of the light source module 14 is, in other words, the anode of the light source 16 which is an LED. The terminal 14b on the low pressure side of the light source module 14 is, in other words, the cathode of the light source 16 which is an LED. The light source module 14 is detachably connected to the lighting device 12 via the output unit 28. The lighting device 12 is not limited to this, and may be directly connected to the light source module 14 by wiring or the like. The configuration of the lighting device 12 may be any configuration capable of lighting the light source 16.

Further, the lighting device 12 further includes, for example, a filter circuit 30, a rectifier circuit 32, a power factor improving circuit 34, and the like.

The filter circuit 30 is electrically connected to the AC power supply 2. The filter circuit 30 suppresses noise included in the AC power supplied from the AC power supply 2, for example.

The rectifier circuit 32 is electrically connected to the filter circuit 30. The rectifier circuit 32 rectifies the AC voltage input via the filter circuit 30 and converts it into a rectified voltage. For the rectifier circuit 32, for example, a diode bridge in which four rectifier elements are combined is used. That is, the rectifier circuit 32 is a full-wave rectifier. The rectified voltage is, for example, a pulsating current voltage.

The rectifier circuit 32 has a pair of input terminals 32a and 32b, a high potential output terminal 32c, and a low potential output terminal 32d. The input terminals 32a and 32b are electrically connected to the filter circuit 30. The rectifier circuit 32 converts the AC voltage input via the input terminals 32a and 32b into a rectifier voltage, and outputs the AC voltage from the high potential output terminal 32c and the low potential output terminal 32d. The potential of the low potential output terminal 32d is set to a reference potential (for example, a ground potential). The potential of the high potential output terminal 32c is set to a higher potential than the potential of the low potential output terminal 32d.

The rectifier circuit 32 may be a half-wave rectifier or the like. The rectified voltage may be a full-wave rectified pulsating current or a half-wave rectified pulsating current. For the rectifier circuit 32, for example, a Schottky barrier diode is used. Thereby, for example, good responsiveness can be obtained.

The power factor improving circuit 34 is electrically connected to the output side of the rectifier circuit 32. The power factor improving circuit 34 suppresses the generation of harmonics that are integral multiples of the power supply frequency in the rectified voltage. As a result, the power factor improving circuit 34 improves the power factor of the rectified voltage.

The power factor improving circuit 34 includes, for example, a switching element 40, an inductor 41, a diode 42, and a smoothing capacitor 43. The switching element 40 has electrodes 40a to 40c. One end of the inductor 41 is electrically connected to the high potential output terminal 32c. The other end of the inductor 41 is electrically connected to the electrode 40a. The electrode 40b is electrically connected to the low potential output terminal 32d. The anode of the diode 42 is electrically connected to the electrode 40a. The cathode of the diode 42 is electrically connected to one end of the smoothing capacitor 43. The other end of the smoothing capacitor 43 is electrically connected to the low potential output terminal 32d. That is, in this example, the power factor improving circuit 34 is a step-up chopper circuit. The power factor improving circuit 34 is not limited to this, and may be any circuit capable of improving the power factor of the rectified voltage.

The electrode 40c is electrically connected to the control unit 26. The electrode 40c is a so-called control electrode. The switching element 40 switches according to the signal from the control unit 26. The power factor improving circuit 34 improves the power factor by, for example, switching the switching element 40 and bringing the input current closer to a sine wave.

The switching element 40 is, for example, an n-channel type FET. For example, the electrode 40a is a drain, the electrode 40b is a source, and the electrode 40c is a gate. The switching element 40 may be, for example, a p-channel type FET, a bipolar transistor, or the like.

The smoothing capacitor 43 converts the pulsating current voltage into a DC voltage by smoothing the pulsating current voltage after the power factor is improved.

For example, when the electric power supplied to the lighting device 12 is DC electric power, the filter circuit 30, the rectifier circuit 32, and the power factor improving circuit 34 may be omitted. As described above, the filter circuit 30, the rectifier circuit 32, and the power factor improving circuit 34 are provided as necessary and can be omitted.

The constant current circuit 20 controls the output current so that the direct current supplied to the light source module 14 connected to the output unit 28 becomes constant. The constant current circuit 20 has a pair of input terminals 20a and 20b and a pair of output terminals 20c and 20d. The input terminal 20a on the high potential side is electrically connected to one end on the high potential side of the smoothing capacitor 43. The input terminal 20b on the low potential side is electrically connected to the low potential output terminal 32d. That is, in the constant current circuit 20, DC power is supplied to the pair of input terminals 20a and 20b. The output terminal 20c is electrically connected to the first terminal 28a of the output unit 28. The output terminal 20d is electrically connected to the second terminal 28b of the output unit 28. As a result, the current output from the constant current circuit 20 is supplied to the light source module 14.

The constant current circuit 20 includes, for example, a switching element 50, an inductor 51, and a diode 52. The switching element 50 has electrodes 50a to 50c. The electrode 50a is electrically connected to the input terminal 20a. The electrode 50b is connected to one end of the inductor 51. The other end of the inductor 51 is electrically connected to the output terminal 20c on the high potential side. The cathode of the diode 52 is electrically connected to the electrode 50b of the switching element 50. The anode of the diode 52 is electrically connected to the input terminal 20b and the output terminal 20d on the low potential side.

The electrode 50c is electrically connected to the control unit 26. The switching element 50 switches according to the signal from the control unit 26. The switching element 50 controls the current flowing through the inductor 51. The constant current circuit 20 controls the DC current supplied to the light source module 14 to be constant by switching the switching element 50.

Further, in this example, the constant current circuit 20 is a so-called step-down chopper circuit. The constant current circuit 20 steps down the voltage value of the DC voltage boosted by the power factor improving circuit 34 to a voltage value corresponding to the light source module 14. Further, the constant current circuit 20 makes it possible to change the current value of the direct current supplied to the light source module 14. The constant current circuit 20 allows a constant DC current to flow through the light source 16 of the light source module 14, and makes it possible to change the current value of the DC current.

The configuration of the constant current circuit 20 is not limited to the above, and may be any configuration capable of supplying a substantially constant direct current to the light source module 14. The constant current circuit 20 may be a current type converter having at least a switching element 50 and an inductor 51.

As the switching element 50 of the constant current circuit 20, for example, a semiconductor element (semiconductor switching element) containing at least one of silicon, gallium nitride, and gallium oxide is used. More specifically, a transistor using silicon, a MOSFET, an IGBT, a GaN-HEMT using gallium nitride, or the like is used.

The detection unit 22 is provided on the downstream side of the light source module 14 and detects the current value of the direct current flowing through the light source module 14 (light source 16). The detection unit 22 is electrically connected to the comparison circuit 24 and inputs a detection value to the comparison circuit 24.

The detection unit 22 is, for example, a detection resistor for detecting the current value of a direct current. The detection unit 22 may be, for example, a clamp-type ammeter that measures changes in magnetic flux or the like. The detection unit 22 may be configured to detect the voltage of the light source module 14 (light source 16). The detection unit 22 may be configured to detect both current and voltage.

The comparison circuit 24 has, for example, a pair of input terminals 24a and 24b and an output terminal 24c. As described above, the detection value of the detection unit 22 is input to one input terminal 24a of the comparison circuit 24. The other input terminal 24b of the comparison circuit 24 is electrically connected to the target value setting unit 36. The target value setting unit 36 inputs the target value of the current flowing through the light source 16 of the light source module 14 to the other input terminal 24b of the comparison circuit 24.

The comparison circuit 24 compares the detected value of the detection unit 22 with the target value, and outputs the comparison result from the output terminal 24c. The comparison circuit 24 takes, for example, a difference between the detected value and the target value, and outputs a signal corresponding to the difference from the output terminal 24c. The comparison circuit 24 is, for example, a differential amplifier circuit.

The control unit 26 is electrically connected to the communication control device 4. The communication control device 4 is communicably connected to the external device 6 via a network or the like. The communication control device 4 is capable of mutual communication with, for example, an external device 6. The communication control device 4 receives a dimming signal from the external device 6. The communication control device 4 may be configured to enable only reception of a dimming signal from, for example, an external device 6.

The control unit 26 can communicate with the communication control device 4, for example. The control unit 26 receives a dimming signal from the communication control device 4. The control unit 26 may be configured to only receive a dimming signal from the communication control device 4. Further, the dimming signal may be input to the control unit 26 from an operation unit such as a dial or a slide switch provided on the lighting device 12 itself, for example.

The control unit 26 includes a control circuit 60 and drive units 62 and 64. The control circuit 60 includes, for example, at least one of a microcomputer, a dedicated control IC (Integrated Circuit), and an FPGA (Field-Programmable Gate Array). The control circuit 60 may be configured by one element or may be configured by combining a plurality of elements.

The drive unit 64 controls the operation of the power factor improving circuit 34. The drive unit 64 is electrically connected to the electrode 40c of the switching element 40, and controls the operation of the power factor improving circuit 34 by switching the switching element 40.

The drive unit 62 controls the operation of the constant current circuit 20. The drive unit 62 is electrically connected to the electrode 50c of the switching element 50 and controls the operation of the constant current circuit 20 by switching the switching element 50.

The control circuit 60 is electrically connected to the communication control device 4. As a result, the dimming signal is input to the control circuit 60 via the communication control device 4. Further, the control circuit 60 is electrically connected to the target value setting unit 36 and the drive unit 62. The control circuit 60 inputs the input dimming signal to the target value setting unit 36 and the drive unit 62.

The target value setting unit 36 sets the target value of the comparison circuit 24 based on the dimming signal by changing the DC voltage applied to the input terminal 24b of the comparison circuit 24 based on the input dimming signal.

The drive unit 62 controls the operation of the constant current circuit 20 based on the input dimming signal and the comparison result of the comparison circuit 24, and transfers the direct current of the current value corresponding to the dimming signal to the light source 16 of the light source module 14. Supply to. As a result, the drive unit 62 turns on the light source 16 with a brightness corresponding to the dimming degree of the dimming signal. That is, the drive unit 62 controls the dimming of the light source 16 according to the dimming signal.

The drive unit 62 inputs, for example, a pulsed control signal to the electrode 50c of the switching element 50. Then, the drive unit 62 changes the current value of the direct current according to the dimming signal by controlling the control signal by PWM (pulse width modulation) according to the dimming signal and the comparison result. The drive unit 62 reduces the duty ratio of the PWM control when the dimming degree is low, and increases the duty ratio of the PWM control when the dimming degree is high. Further, the drive unit 62 reduces the duty ratio of the PWM control when the detected value is higher than the target value, and increases the duty ratio of the PWM control when the detected value is lower than the target value. As a result, a direct current having a current value corresponding to the dimming signal can be supplied to the light source 16 of the light source module 14, and the light source 16 can be turned on with a brightness corresponding to the dimming degree of the dimming signal.

The dimming control by the drive unit 62 is not limited to the pulse width modulation method, and may be, for example, a pulse density modulation method or an amplitude modulation method. In the pulse density modulation method, for example, the larger the dimming degree, the higher the density of the switching element 50 during the on state, thereby dimming the brightness of the light emitted from the light source 16. In the amplitude modulation method, for example, the larger the luminous intensity, the higher the DC voltage boosted by the power factor improving circuit 34, thereby dimming the brightness of the light emitted from the light source 16.

2 (a) and 2 (d) are graphs schematically showing an example of the operation of the lighting device according to the first embodiment.
FIG. 2A schematically shows an example of the dimming degree set by the dimming signal.
FIG. 2B schematically shows an example of a control signal input from the drive unit 62 to the electrode 50c of the switching element 50 of the constant current circuit 20.
FIG. 2C schematically shows an example of a direct current flowing through the light source 16 of the light source module 14.
FIG. 2D schematically shows an example of a target value set in the comparison circuit 24.

As shown in FIGS. 2 (a) and 2 (d), when the dimming degree of the dimming signal is larger than a predetermined value (period T1 in FIG. 2), the control unit 26 is described as described above. By controlling the operation of the constant current circuit 20 based on the input dimming signal and the comparison result of the comparison circuit 24, and supplying the DC current of the current value corresponding to the dimming signal to the light source 16 of the light source module 14. , The light source 16 is turned on with a brightness corresponding to the dimming degree of the dimming signal.

On the other hand, when the dimming degree of the dimming signal is equal to or less than a predetermined value (periods T2 and T3 in FIG. 2), the control unit 26 intermittently supplies a direct current to the light source 16. The predetermined value or less is, for example, a dimming intensity of 10% or less.

Then, when the dimming degree is equal to or less than a predetermined value, the control unit 26 changes the DC current supply period T _ON and the DC current supply stop period T _OFF according to the dimming degree. For example, the period T2 in FIG. 2 shows a state in which the supply period is turned _ON every four cycles. In the period T3, which has a lower dimming intensity than the period T2, the supply period is set to _ON every 8 cycles.

As described above, when the dimming degree is equal to or less than the predetermined value, the control unit 26 makes the stop period T _OFF longer as the dimming degree becomes lower. The stop period T _OFF does not represent an off period in PWM control or the like, but represents a period in which the PWM control itself is stopped.

When the dimming degree is equal to or less than a predetermined value, the control unit 26 changes the length of the stop period T _OFF while keeping the duty ratio of the control signal input to the electrode 50c of the switching element 50 constant, for example. As a result, the duty ratio becomes excessively small, the DC current flowing through the light source 16 becomes small, the detection value and the target value of the detection unit 22 become small, and the error of the comparison result in the comparison circuit 24 becomes large, which is appropriate. It is possible to prevent the dimming from being stopped. However, while changing the length of the stop period T _OFF , the duty ratio may be further changed within a range in which the error of the comparison result does not become large.

In other words, the control unit 26 may perform PWM control when the luminous intensity is larger than the predetermined value, and perform PFM control when the luminous intensity is equal to or less than the predetermined value. When the dimming degree is equal to or less than a predetermined value, the control unit 26 lengthens the cycle between the supply periods _TON as the dimming degree becomes lower.

Further, when the dimming intensity is equal to or less than a predetermined value, the control unit 26 changes the target value in synchronization with the DC current supply period T _ON and the stop period T _OFF . For example, the control unit 26 sets a target value of a value according to the dimming degree of the dimming signal during the DC current supply period _{TON, and sets a dimming lower limit (for example, 0%) during the stop period T OFF .} Set the target value. In other words, the control unit 26 sets a target value corresponding to a state in which no direct current is flowing through the light source 16 during the stop period T _OFF .

As described above, in the lighting fixture 10 and the lighting device 12 according to the present embodiment, the control unit 26 intermittently supplies a direct current to the light source 16 when the dimming degree of the dimming signal is equal to or less than a predetermined value. , The DC current supply period T _ON and the DC current supply stop period T _OFF are changed according to the dimming degree, and the DC current supply period T _ON and the stop period T _OFF are synchronized. Change the target value.

As a result, in the lighting fixture 10 and the lighting device 12, the difference between the detected value and the target value becomes large during the DC current supply stop period T _OFF , and the switching from the stop period T _OFF to the supply period T _ON is performed. At that time, it is possible to prevent a DC current larger than the current value corresponding to the dimming signal from flowing to the light source 16.

Further, in the lighting fixture 10 and the lighting device 12, it is not necessary to separately provide a switching element for dimming or the like in addition to the switching element 50 for current control. As a result, it is possible to suppress an increase in the number of parts and a complicated circuit configuration in the lighting device 12. Therefore, the lighting fixture 10 and the lighting device 12 can appropriately perform dimming to the dimming lower limit side with a simple configuration while controlling the direct current flowing through the light source 16 to be substantially constant.

(Second embodiment)
FIG. 3 is a block diagram schematically showing a lighting device and a lighting fixture according to the second embodiment.
Those having substantially the same function and configuration as those described with respect to the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.
As shown in FIG. 3, in the lighting device 12a of the lighting fixture 10a, the control circuit 60 of the control unit 26 is configured so that the output of the comparison result of the comparison circuit 24 can be set. In this example, the comparison circuit 24 compares, for example, the detection value of the detection unit 22 with the target value, outputs the comparison result from the output terminal 24c, and outputs the output corresponding to the input signal from the control circuit 60 to the output terminal 24c. Output from.

4 (a) to 4 (d) are graphs schematically showing an example of the operation of the lighting device according to the second embodiment.
4 (a) to 4 (c) are the same as those of FIGS. 3 (a) to 3 (c).
FIG. 4D schematically shows an example of the output of the comparison result of the comparison circuit 24.

As shown in FIGS. 4A to 4D, when the dimming degree of the dimming signal is larger than a predetermined value (period T1 in FIG. 4), the control unit 26 performs the first operation. Similar to the embodiment, the operation of the constant current circuit 20 is controlled based on the input dimming signal and the comparison result of the comparison circuit 24, and the DC current of the current value corresponding to the dimming signal is transmitted to the light source 16 of the light source module 14. Light source 16 is turned on with a brightness corresponding to the dimming degree of the dimming signal. At this time, the comparison circuit 24 outputs the comparison result between the detected value and the target value.

On the other hand, when the dimming degree of the dimming signal is equal to or less than a predetermined value (periods T2 and T3 in FIG. 4), the control unit 26 intermittently supplies a direct current to the light source 16 and turns _on the direct current supply period. And the DC current supply stop period T _OFF are changed according to the dimming degree, and the output of the comparison result of the comparison circuit 24 is made constant at a predetermined value during the stop period T _OFF .

The comparison circuit 24 uses, for example, the output when the detected value and the target value match as the reference value, makes the output smaller than the reference value when the detected value is larger than the target value, and conversely, the detected value. When is smaller than the target value, the output is made larger than the reference value. For example, when the output of the comparison circuit 24 is larger than the reference value, the drive unit 62 increases the duty ratio of the control signal input to the electrode 50c of the switching element 50, and the output of the comparison circuit 24 is smaller than the reference value. In this case, the duty ratio of the control signal input to the electrode 50c of the switching element 50 is reduced.

The control unit 26 sets the output of the comparison result of the comparison circuit 24 in a state (reference value) in which the detected value and the reference value match, for example, during the stop period T _OFF .

As a result, as in the first embodiment, the difference between the detected value and the target value becomes large during the DC current supply stop period T _OFF , and the stop period T _OFF is switched to the supply period T _ON . At this time, it is possible to prevent a DC current larger than the current value corresponding to the dimming signal from flowing to the light source 16. It is not necessary to separately provide a switching element for dimming, and it is possible to suppress an increase in the number of parts and a complicated circuit configuration. Therefore, it is possible to appropriately perform dimming up to the dimming lower limit side with a simple configuration while controlling the direct current flowing through the light source 16 to be substantially constant.

The output of the comparison result of the comparison circuit 24, which is kept constant during the stop period T _OFF , is not limited to the reference value. For example, the output of the comparison result of the comparison circuit 24 when switching from the supply period T _ON to the stop period T _OFF may be maintained as it is.

Further, when the output of the comparison circuit 24 is made constant, the target value may or may not be changed as described in the first embodiment. That is, the fact that the difference between the detected value and the target value becomes large during the period T _OFF during which the supply of DC current is stopped may be suppressed on the input side or the output side of the comparison circuit 24. good.

Although some embodiments and examples of the present invention have been described, these embodiments or examples are presented as examples and are not intended to limit the scope of the invention. These novel embodiments or examples can be implemented in various other embodiments, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments or examples and variations thereof are included in the scope and gist of the invention, and are included in the scope of the invention described in the claims and the equivalent scope thereof.

2 ... AC power supply, 4 ... Communication control device, 6 ... External device, 10, 10a ... Lighting equipment, 12, 12a ... Lighting device, 14 ... Light source module, 16 ... Light source, 20 ... Constant current circuit, 22 ... Detector, 24 ... comparison circuit, 26 ... control unit, 28 ... output unit, 30 ... filter circuit, 32 ... rectifier circuit, 34 ... power factor improvement circuit, 36 ... target value setting unit, 40 ... switching element, 41 ... inductor, 42 ... Diode, 43 ... smoothing capacitor, 50 ... switching element, 51 ... inductor, 52 ... diode, 60 ... control circuit, 62 ... drive unit, 64 ... drive unit

Claims (5)

A constant current circuit that allows a constant DC current to flow through the light source and that can change the current value of the DC current.
A detector that detects the current value of the direct current flowing through the light source,
A comparison circuit that compares the detected value of the detection unit with the target value,
The target value of the comparison circuit is set based on the dimming signal input from the outside, and the operation of the constant current circuit is controlled based on the comparison result of the dimming signal and the comparison circuit to control the dimming. A control unit that lights the light source with a brightness corresponding to the dimming degree of the dimming signal by supplying the DC current having a current value corresponding to the signal to the light source.
Equipped with
When the dimming degree of the dimming signal is equal to or less than a predetermined value, the control unit intermittently supplies the direct current to the light source, and the period of supplying the direct current and the period of stopping the supply of the direct current. A lighting device that changes the target value according to the dimming degree and changes the target value in synchronization with the supply period and the stop period of the direct current. The control unit sets the target value of a value corresponding to the dimming degree of the dimming signal during the supply period, and sets the target value of the dimming lower limit during the stop period. The lighting device described. A constant current circuit that allows a constant DC current to flow through the light source and that can change the current value of the DC current.
A detector that detects the current value of the direct current flowing through the light source,
A comparison circuit that compares the detected value of the detection unit with the target value,
The target value of the comparison circuit is set based on the dimming signal input from the outside, and the operation of the constant current circuit is controlled based on the comparison result of the dimming signal and the comparison circuit to control the dimming. A control unit that lights the light source with a brightness corresponding to the dimming degree of the dimming signal by supplying the DC current having a current value corresponding to the signal to the light source.
Equipped with
When the dimming intensity of the dimming signal is equal to or less than a predetermined value, the control unit intermittently supplies the direct current to the light source, and the period of supplying the direct current and the period of stopping the supply of the direct current. A lighting device that changes the current according to the dimming intensity and keeps the output of the comparison result of the comparison circuit constant at a predetermined value during the stop period. The lighting device according to claim 3, wherein the control unit sets an output of the comparison result of the comparison circuit in a state where the detected value and the target value match during the stop period. Light source and
The lighting device according to any one of claims 1 to 4,
Lighting equipment equipped with.

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