JP6601769B2 - LED lighting circuit and lighting apparatus provided with the same - Google Patents

Description

  The present invention relates to an LED lighting circuit and a lighting fixture including the same.

  Conventionally, an LED lighting circuit capable of dimming an LED (light emitting diode) light source has been used.

  As an LED lighting device using this type of LED lighting circuit, a structure including a power supply circuit, a current detection unit, and a control circuit is known (for example, Patent Document 1).

  In the LED lighting device of Patent Document 1, the power supply circuit supplies a load current to the light emitting diode. The current detection unit is connected to the power supply circuit in series with the light emitting diode. The current detection unit outputs a detection voltage proportional to the load current flowing through the light emitting diode. The control circuit compares the detection voltage of the current detection unit with the reference voltage, and adjusts the output of the power supply circuit so that the detection voltage matches the reference voltage.

  The current detection unit includes a first fixed resistor connected in series to the light emitting diode, and a series circuit of one or more fixed resistors and a variable resistor connected in parallel to the first fixed resistor. In the LED lighting device of Patent Document 1, the luminous flux of the light emitting diode can be increased or decreased according to the resistance value of the operated variable resistor.

JP 2012-182189 A

  By the way, the LED lighting circuit is required to have a structure that allows dimming control to be performed relatively easily, and the above-described configuration of Patent Document 1 that operates the variable resistor is not sufficient, and further improvement is required.

  An object of the present invention is to provide an LED lighting circuit capable of dimming control relatively easily and a lighting fixture including the LED lighting circuit.

  The LED lighting circuit of the present invention includes a power supply circuit, a current detection unit, a control circuit, and a dimming unit. The power supply circuit includes a first switch element. The power supply circuit converts direct-current input power into predetermined power by switching the first switch element on and off. The power supply circuit outputs the converted predetermined power to the LED light source. The current detection unit includes a first resistor. The first resistor is electrically connected in series with the first switch element. The current detection unit outputs a detection voltage value proportional to the current flowing through the LED light source. The control circuit controls the first switch element so that the detected voltage value matches a predetermined reference value. The said light control part adjusts the light output of the said LED light source. The said light control part is comprised so that the said detection voltage value may be changed in steps with respect to the same electric current value based on the light control signal.

  The lighting fixture of the present invention includes the above LED lighting circuit and the LED light source. The LED light source is lit based on an output from the LED lighting circuit.

  The LED lighting circuit of the present invention has an effect that dimming control can be performed relatively easily.

  The lighting fixture of the present invention has an effect that it can be configured to include an LED lighting circuit that can perform dimming control relatively easily.

FIG. 1 is a circuit diagram showing an LED lighting circuit according to Embodiment 1 of the present invention. FIG. 2 is a perspective view showing the lighting apparatus according to Embodiment 1 of the present invention. FIG. 3 is a timing chart for explaining lighting control of the lighting apparatus. FIG. 4 is a timing diagram for explaining dimming control of the above-described lighting fixture. FIG. 5 is a circuit diagram showing an LED lighting circuit according to Embodiment 2 of the present invention. FIG. 6 is a timing diagram illustrating lighting control of the lighting fixture according to the second embodiment of the present invention. FIG. 7 is a timing chart for explaining dimming control of the above-described lighting fixture. FIG. 8 is a schematic cross-sectional view showing the same lighting fixture.

(Embodiment 1)
Below, the lighting fixture 20 provided with the LED lighting circuit 10 of this embodiment is demonstrated with reference to FIG. In the figure, the same reference numerals are assigned to the same members, and duplicate descriptions are omitted. The size and positional relationship of the members shown in each drawing may be exaggerated for clarity of explanation. In the following description, each element constituting the present embodiment may be configured such that a plurality of elements are constituted by one member and the plurality of elements are shared by one member, and the function of one member is plural. You may implement | achieve by sharing with a member.

  As shown in FIG. 1, the LED lighting circuit 10 of the present embodiment includes a power supply circuit 1, a current detection unit 2 a, a control circuit 2, and a dimming unit 3. The power supply circuit 1 includes a first switch element Q1. The power supply circuit 1 converts the DC input power into predetermined power by switching the first switch element Q1 on and off. The power supply circuit 1 outputs the converted predetermined power to the LED light source 21. The current detection unit 2a includes a first resistor R1. The first resistor R1 is electrically connected in series with the first switch element Q1. The current detection unit 2 a outputs a detection voltage value proportional to the current flowing through the LED light source 21. The control circuit 2 controls the first switch element Q1 so that the detected voltage value matches a predetermined reference value. The dimmer 3 adjusts the light output of the LED light source 21. The dimming unit 3 is configured to change the detection voltage value stepwise with respect to the same current value based on the dimming signal.

  The LED lighting circuit 10 according to the present embodiment can perform dimming control relatively easily with a configuration in which the dimming unit 3 changes the detection voltage value stepwise with respect to the same current value based on the dimming signal.

  Below, the lighting fixture 20 provided with the LED lighting circuit 10 of this embodiment is demonstrated more concretely. The lighting fixture 20 includes an LED lighting circuit 10 and an LED light source 21. The LED light source 21 is lit based on the output from the LED lighting circuit 10.

  As shown in FIG. 1, the lighting fixture 20 according to the present embodiment includes a power supply device 24 and a sensor unit 25 in addition to the LED lighting circuit 10 and the LED light source 21. The LED lighting circuit 10 of the present embodiment includes a lighting control unit 4, a fourth switch element Q4, and a power supply unit 5 in addition to the power supply circuit 1, the current detection unit 2a, the control circuit 2, and the dimming unit 3. I have. In the lighting fixture 20, an external power supply 40 and a power supply device 24 are electrically connected. As the external power source 40, for example, a commercial AC power source is used.

  The power supply device 24 includes a filter circuit 24a, a full-wave rectifier 24b, and a booster circuit 24c. The filter circuit 24 a is configured to prevent noise from being transmitted from the power supply device 24 to the external power supply 40. The filter circuit 24a can be configured using, for example, a common mode choke coil and an across-the-line capacitor. The full-wave rectifier 24b is configured by a diode bridge. The full-wave rectifier 24b is electrically connected to the external power source 40 through the filter circuit 24a. The full-wave rectifier 24b is configured so as to be able to full-wave rectify and output an AC voltage / AC current supplied from the external power supply 40. The step-up circuit 24c constitutes a step-up chopper circuit including, for example, a choke coil, a switch element, a rectifier element, and a smoothing capacitor. The booster circuit 24c is configured to boost the pulsating voltage output from the full-wave rectifier 24b.

  The DC voltage output from the booster circuit 24 c of the power supply device 24 is applied to the power supply circuit 1. The power supply circuit 1 constitutes a DC-DC converter. The power supply circuit 1 converts the DC input voltage supplied from the power supply device 24 into a lower predetermined DC output voltage and outputs the converted voltage. The power supply circuit 1 is configured to output the converted output voltage to the LED light source 21. The power supply circuit 1 includes a rectifying element D1, an inductor L1, and a smoothing capacitor C1 in addition to the first switch element Q1. In the power supply circuit 1, the first switch element Q1, the rectifier element D1, the inductor L1, and the smoothing capacitor C1 constitute a step-down chopper circuit.

  The first switch element Q1 is composed of a field effect transistor. The drain of the first switch element Q1 is electrically connected to the anode of the rectifier element D1. One end of the inductor L1 is electrically connected to a connection point between the drain of the first switch element Q1 and the anode of the rectifier element D1. A smoothing capacitor C1 is electrically connected between the other end of the inductor L1 and the cathode of the rectifying element D1. The LED light source 21 is electrically connected to both ends of the smoothing capacitor C1.

  The source of the first switch element Q1 is connected to the negative electrode of the power supply device 24 and the ground via the first resistor R1 of the current detector 2a. In other words, in the lighting fixture 20, the series circuit of the first switch element Q 1 and the first resistor R 1 is electrically connected in series to the series circuit of the power supply device 24 and the LED light source 21. In the power supply circuit 1, a drive signal is given from the control circuit 2 to the gate of the field effect transistor that constitutes the first switch element Q1.

  The control circuit 2 controls on and off of the first switch element Q1. In the LED lighting circuit 10, when the first switch element Q1 is on, a current flows through the inductor L1. When the first switch element Q1 is on, the control circuit 2 controls the first switch element Q1 to be off when the current flowing through the inductor L1 reaches a predetermined value. In the LED lighting circuit 10, when the first switch element Q1 is controlled to be turned off, a current flows from the inductor L1 to the LED light source 21 via the rectifier element D1.

  The control circuit 2 is electrically connected to the power supply unit 5. The power supply unit 5 is configured to generate drive power for the control circuit 2 from the output voltage of the booster circuit 24 c of the power supply device 24. The power supply unit 5 is not limited to the configuration that generates the drive power of the control circuit 2 with the output voltage from the power supply device 24. The power supply unit 5 may be a battery provided separately from the power supply device 24 as long as the drive power of the control circuit 2 can be output. The control circuit 2 is configured to be driven by electric power from the power supply unit 5. The control circuit 2 is electrically connected between both ends of the first resistor R1 of the current detection unit 2a. One end of the first resistor R1 is electrically connected to the source of the first switch element Q1 in the power supply circuit 1. The other end opposite to one end of the first resistor R1 is electrically connected to the ground. As the first resistor R1, a fixed resistor is used, but a variable resistor may be used. The control circuit 2 is configured such that a detection voltage value proportional to the current flowing through the LED light source 21 is input. The control circuit 2 can be configured using, for example, a driver IC.

  For example, the control circuit 2 amplifies the difference between the detected voltage value and the voltage of a predetermined reference value with an error amplifier, and outputs a drive signal composed of square pulses adjusted so as to reduce the error. The control circuit 2 gives a drive signal to the gate of the first switch element Q1 to control the on / off of the first switch element Q1. The control circuit 2 raises the drive signal to a high level at a predetermined switching cycle to turn on the first switch element Q1, and lowers the drive signal to a low level when the peak value of the inductor current reaches a target value. Turn off. The control circuit 2 controls on and off of the first switch element Q1, and performs constant current control of the power supply circuit 1 so that the current flowing through the LED light source 21 is constant. The control circuit 2 is not limited to the configuration that controls the first switch element Q1 based on the peak value of the inductor current. The control circuit 2 detects the current flowing from the inductor L1 to the LED light source 21 via the rectifier element D1 when the first switch element Q1 is off, and turns on the first switch element Q1 when the current becomes zero. You may make it comprise.

  The dimmer 3 includes a second resistor R2, a third resistor R3, and a second switch element Q2. The light control unit 3 includes a third switch element Q3 and a fourth resistor R4 in addition to the second resistor R2, the third resistor R3, and the second switch element Q2. The second switch element Q2 is composed of a field effect transistor.

  The second resistor R2 and the third resistor R3 are electrically connected in series. A series circuit of the second resistor R2 and the third resistor R3 is electrically connected in parallel with the first resistor R1. The connection point between the second resistor R2 and the third resistor R3 is electrically connected to the drain of the field effect transistor constituting the second switch element Q2. The third resistor R3 is electrically connected to the source of the second switch element Q2 on the side opposite to the connection point with the second resistor R2. The gate of the second switch element Q2 is electrically connected to the collector of the transistor constituting the third switch element Q3 and one end of the fourth resistor R4. The other end opposite to the one end of the fourth resistor R4 is electrically connected to the power supply unit 5 via the fourth switch Q4. The emitter of the third switch element Q3 is electrically connected to the ground. The base of the third switch element Q3 is electrically connected to the lighting control unit 4 so that a dimming signal can be input.

  Based on the dimming signal input from the lighting control unit 4, the dimming unit 3 controls the on / off of the second switch element Q2 via the third switch element Q3. The dimming unit 3 is configured such that the first switch R1 and the second resistor R2 are connected in parallel, the first resistor R1, and the second resistor by switching the second switch element Q2. The state is switched to a state in which R2 and the series circuit of the third resistor R3 are connected in parallel. In the light control part 3, when the 2nd switch element Q2 is an ON state, 3rd resistance R3 will be in a short circuit state. The dimmer 3 can detect a voltage proportional to the current flowing through the LED light source 21 by the parallel circuit of the first resistor R1 and the second resistor R2 when the second switch element Q2 is in the ON state. it can. In other words, when the second switch element Q2 is in the ON state, the parallel circuit of the first resistor R1 and the second resistor R2 constitutes a voltage dividing circuit that detects a detection voltage value proportional to the current flowing through the LED 21. To do. That is, it can be said that a part of the light control unit 3 constitutes a part of the current detection unit 2a.

  In the dimming unit 3, when the second switch element Q2 is in the OFF state, the first resistor R1, and the series circuit of the second resistor R2 and the third resistor R3 are electrically connected in parallel. When the second switch element Q2 is in the OFF state, the parallel circuit in which the first resistor R1 and the series circuit of the second resistor R2 and the third resistor R3 are electrically connected in parallel is connected to the current flowing through the LED 21. A voltage dividing circuit for detecting a proportional detection voltage value is configured. The control circuit 2 is proportional to the current flowing through the LED light source 21 based on a voltage dividing circuit in which a first resistor R1 and a series circuit of a second resistor R2 and a third resistor R3 are electrically connected in parallel. Detect voltage. As the second resistor R2, a fixed resistor is used, but a variable resistor may be used. As the third resistor R3, a fixed resistor is used, but a variable resistor may be used.

  The dimming unit 3 changes the voltage dividing ratio of the voltage dividing circuit stepwise depending on whether the third resistor R3 is short-circuited by switching the second switch element Q2 on and off. The detected voltage value proportional to the current flowing through can be changed stepwise. The control circuit 2 increases or decreases the current flowing through the LED light source 21 because the input detection voltage value changes stepwise in accordance with the switching of the second switch element Q2 by the dimmer 3. Dimming control.

  That is, in the LED lighting circuit 10 of the present embodiment, the dimming unit 3 includes the second resistor R2, the third resistor R3, and the second switch element Q2. The second resistor R2 and the third resistor R3 are electrically connected in series. A series circuit of the second resistor R2 and the third resistor R3 is electrically connected in parallel with the first resistor R1. The second switch element Q2 is electrically connected in parallel with the third resistor R3. It is preferable that the dimming unit 3 is configured to control the on / off of the second switch element Q2 based on the dimming signal.

  The LED lighting circuit 10 of the present embodiment is relatively easy to change the electrical connection state between the second resistor R2 and the third resistor R3 by controlling the second switch element Q2 on and off. With this configuration, the LED light source 21 can perform step dimming that performs dimming step by step.

  The lighting control unit 4 is configured to output a lighting signal to the fourth switch element Q4. The lighting control unit 4 controls driving of the power supply circuit 1 by a lighting signal. The lighting signal is a binary signal of high level and low level. The lighting control unit 4 is configured to output a dimming signal to the dimming unit 3. The lighting control unit 4 controls the dimming unit 3 with the dimming signal. The dimming signal is a binary signal of high level and low level. The lighting control unit 4 can be configured using, for example, a microcomputer. The microcomputer has a built-in memory 4a. The microcomputer is driven by an appropriate program stored in the memory 4a. The lighting control unit 4 is electrically connected to the sensor unit 25. The lighting control unit 4 is configured to store the sensor signal received from the sensor unit 25 in the memory 4a. The microcomputer may be provided with a timer function that measures the time elapsed since the sensor signal was received from the sensor unit 25. When the sensor signal from the sensor unit 25 is input, the lighting control unit 4 outputs a lighting signal to the fourth switch element Q4. The fourth switch element Q4 is configured to be able to supply drive power from the power supply unit 5 to the control circuit 2 when a lighting signal is input and in an on state. The fourth switch element Q4 is configured so that drive power is not supplied from the power supply unit 5 to the control circuit 2 when a lighting signal is input and in the off state. The lighting control unit 4 controls the turning on and off of the fourth switch element Q4 by the lighting signal to drive and stop the power supply circuit 1. The lighting control unit 4 is configured to output a dimming signal to the third switch element Q3 of the dimming unit 3 based on the sensor signal from the sensor unit 25.

  The LED light source 21 is composed of a series circuit of a plurality of LEDs 21a. The LED light source 21 is not limited to the configuration of the series circuit of the plurality of LEDs 21a, and may be configured of a parallel circuit of the plurality of LEDs 21a, or may be configured of a series-parallel circuit of the plurality of LEDs 21a. .

  The sensor unit 25 includes an illuminance sensor 25a and a human detection sensor 25b. The human detection sensor 25b can be configured using, for example, an infrared sensor such as a pyroelectric element. The infrared sensor detects, for example, heat rays emitted from the human body. The heat rays are infrared rays that are electromagnetic waves in the infrared region. The human detection sensor 25b may be configured to detect infrared rays at any time, or may be configured to detect infrared rays at preset time intervals. In other words, the human detection sensor 25b is configured to detect the presence or absence of a human body. The illuminance sensor 25a can be configured using, for example, a photodiode or a phototransistor. The illuminance sensor 25a is configured to detect ambient brightness. For example, the sensor unit 25 can be configured to output a sensor signal when the surroundings of the illuminance sensor 25a are below a predetermined brightness and the human detection sensor 25b detects the presence of a person. The sensor unit 25 is not limited to the configuration including both the illuminance sensor 25a and the human detection sensor 25b. The sensor unit 25 may have only a configuration including the illuminance sensor 25a or only a configuration including the human detection sensor 25b.

  The lighting fixture 20 according to the present embodiment forms a downlight as shown in FIG. For example, the downlight is installed and used in a toilet, a hallway, a front door, and the like. In addition to the LED lighting circuit 10, the LED light source 21, the power supply device 24, and the sensor unit 25, the lighting fixture 20 includes a main body unit 22, a frame body 23, a power supply unit 26, a feeder line 27, an attachment spring 28, And a signal line 29.

  For example, the LED light source 21 may have a configuration in which a plurality of LEDs 21a are mounted on a mounting board. The LED 21a has, for example, an LED chip and a sealing portion that covers the LED chip. As the LED chip, a blue LED chip capable of emitting blue light is used. The sealing portion is made of a light transmissive material. A phosphor is mixed in the material of the sealing portion. As the phosphor, a yellow phosphor that emits yellow light when excited by blue light emitted from a blue LED chip is used. The LED 21a can emit white light by mixing the blue light emitted from the blue LED chip and the yellow light emitted from the yellow phosphor. LED21a does not need to mix the fluorescent substance with the material of the sealing part. A printed wiring board is used as the mounting board. The mounting substrate is not limited to a printed wiring board, and for example, a ceramic substrate, a metal base printed wiring board, or the like may be used. The LED light source 21 is mounted on the main body 22 such that the side of the mounting substrate opposite to the LED chip mounting surface is in contact with the main body 22.

  The main body portion 22 includes a base body 22a, a lens 22f, and a plurality of fins 22j. The base 22a has a bottomed cylindrical outer shape. The base 22a is configured so that the LED light source 21 can be accommodated therein. The fins 22j are provided so as to protrude outward from the base body 22a. The fin 22j has a flat outer shape. The plurality of fins 22j are provided at a predetermined interval. The base 22a can radiate the heat generated by the LED light source 21 to the outside through the fins 22j. The base 22a is made of aluminum die cast. The substrate 22a is not limited to a configuration using aluminum. The base body 22a may be formed of a metal material such as copper or stainless steel, for example, as a material having higher thermal conductivity than the resin.

  The lens 22f has a disk-like outer shape. The lens 22f has a plurality of lens portions 22fc arranged in a front view. The lens part 22fc is formed so that the light from the LED light source 21 can be condensed or diffused. The lens portion 22fc is formed to constitute a convex lens, a concave lens, a Fresnel lens, or the like. The lens 22f is disposed so as to cover the LED light source 21. The lens 22f can emit light from the LED light source 21 so as to obtain a predetermined orientation characteristic. The entire lens 22f has translucency. Examples of the material of the lens 22f include resin materials such as polycarbonate resin, acrylic resin, and polybutylene terephthalate resin, and glass. The lens 22f can be formed by injection molding or the like when formed using a resin material.

  The frame body 23 includes a reflector 23a, a flange portion 23b, a frame body 23c, and a holding portion 23d. The reflector 23 a is formed so that the opening diameter increases as the distance from the main body 22 increases along the optical axis of the LED light source 21 attached to the main body 22. The reflector 23a includes an exposure hole 23aa that exposes the lens 22f. The reflector 23 a can control the light distribution of the light emitted from the LED light source 21. The reflector 23a is configured to reflect light emitted from the LED light source 21 to obtain a predetermined light distribution. The reflector 23a can cut a part of the light emitted from the LED light source 21 so that the spread angle of the light from the LED light source 21 is within a predetermined range.

  The flange 23b has an outer shape of an annular flat plate when viewed from the front. The flange 23b is provided so as to spread outward from the tip edge of the reflector 23a. The collar portion 23b has a protruding piece 23e that protrudes toward the exposure hole 23aa in a front view. The sensor unit 25 is placed on the protruding piece 23e. The protruding piece 23e has a transmission hole 23ea penetrating in the thickness direction. The transmission hole 23ea is provided corresponding to the sensor unit 25. An illuminance sensor 25a and a human detection sensor 25b are arranged on the protruding piece 23e so as to block the transmission hole 23ea. The projecting piece 23e is provided with a cover body 25f that protects the sensor unit 25. The cover body 25f is configured to transmit visible light and infrared light. As a material of the cover body 25f, for example, a polyethylene resin or an acrylic resin can be used.

  The frame main body 23c is attached to the main body 22 on the side opposite to the reflector 23a by screws. The holding portion 23d is provided so as to straddle the flange portion 23b and the reflector 23a along the outer periphery of the reflector 23a. The holding portion 23d is formed so as to hold the attachment spring 28. The holding portion 23d is configured so that the one end portion 28a of the attachment spring 28 can be inserted.

  In the frame body 23, a reflector 23a, a flange portion 23b, a frame body 23c, and a holding portion 23d are integrally formed. As a material of the frame 23, for example, a metal material such as aluminum or stainless steel can be used. The material of the frame body 23 is not limited to a metal material, and various resin materials may be used.

  The power supply unit 26 includes a terminal block 26a and a housing portion 26b. In the power supply unit 26, the LED lighting circuit 10 that controls the lighting of the LED light source 21 is accommodated in the housing portion 26b. In the power supply unit 26, a power supply device 24 that supplies power to the LED lighting circuit 10 is accommodated in a housing portion 26b. The LED lighting circuit 10 is configured to be able to supply appropriate power to the LED light source 21 via the feeder line 27. The LED lighting circuit 10 is electrically connected to the sensor unit 25 through the signal line 29 so that the sensor signal can be received. The terminal block 26 a is configured to supply power from the external power supply 40 to the power supply device 24. The terminal block 26 a is electrically connected to the external power supply 40 via the power cable 41.

  The housing part 26b is formed in a long box shape. In the housing part 26b, a terminal block 26a is arranged on one end side in the longitudinal direction. The power supply unit 26 is configured separately from the main body portion 22 so that the housing portion 26b that houses the LED lighting circuit 10 and the power supply device 24 can be arranged away from the main body portion 22. The housing part 26b is formed by punching and bending a metal plate material.

  The attachment spring 28 has a long plate-like outer shape. The attachment spring 28 is formed in an L shape in a side view. The attachment spring 28 is configured such that one end portion 28a in the longitudinal direction is held by the holding portion 23d. The attachment spring 28 is formed by punching and bending a metal plate.

  Below, the construction work of the lighting fixture 20 is demonstrated easily.

  In the construction work, first, the power cable 41 from the external power supply 40 and the terminal block 26a are electrically connected. In the construction work, the power supply unit 26 is inserted from the mounting hole 50aa provided in the ceiling material 50 so that the power supply unit 26 electrically connected to the power cable 41 is placed on the ceiling material 50 as a construction material.

  Next, in the construction work, in the state where the other end portion 28b opposite to the one end portion 28a of the mounting spring 28 with the one end portion 28a held by the frame body 23 is pushed down so as to approach the frame body 23c, the mounting hole 50aa The main body 22 is inserted into the body. In the lighting fixture 20, when the flange portion 23b of the frame body 23 is pushed into the attachment hole 50aa until it hits the peripheral portion of the attachment hole 50aa of the ceiling member 50, the other end portion 28b of the attachment spring 28 opens in a direction away from the frame body 23c. . In the lighting fixture 20, the other end portion 28 b of the attachment spring 28 gives the elastic force of the attachment spring 28 to the peripheral portion of the attachment hole 50 aa, and the other end portion 28 b of the attachment spring 28 and the flange portion 23 b of the frame body 23. The ceiling material 50 is attached to the ceiling material 50 by sandwiching it.

  That is, in the lighting fixture 20 according to the present embodiment, the main body portion 22 is embedded in the mounting hole 50aa provided in the ceiling material 50, and the back surface of the flange portion 23b is applied to the edge of the mounting hole 50aa in the ceiling material 50. Is attached to the ceiling material 50.

  Below, operation | movement of the lighting fixture 20 which concerns on this embodiment is demonstrated, referring FIG.3 and FIG.4.

  In the luminaire 20, the sensor unit 25 outputs a sensor signal to the lighting control unit 4 when the surroundings of the illuminance sensor 25 a are below a predetermined brightness and the human detection sensor 25 b detects the presence of a person. When receiving the sensor signal from the sensor unit 25, the lighting control unit 4 outputs a lighting signal to the fourth switch element Q4 at time t1, as shown in FIG. In the lighting fixture 20, when the fourth switch element Q <b> 4 is turned on, driving power is supplied to the control circuit 2, and predetermined DC power is output from the power supply device 24 to the LED light source 21. When the lighting control unit 4 receives a sensor signal from the sensor unit 25, the lighting control unit 4 does not output a dimming signal.

  In the lighting fixture 20, since the lighting control unit 4 does not output a dimming signal to the dimming unit 3, the third switch element Q3 is turned off, and the second switch element Q2 is connected via the fourth switch element Q4. The voltage of the power supply unit 5 is applied to the gates of these. In the lighting fixture 20, when the voltage of the power supply unit 5 is applied to the gate of the second switch element Q2, a parallel circuit of the first resistor R1 and the second resistor R2 is configured. In the lighting fixture 20, the parallel circuit of the first resistor R <b> 1 and the second resistor R <b> 2 can be regarded as a current detection unit 2 a that detects a detection voltage value proportional to the current flowing through the LED light source 21. The lighting fixture 20 detects a detection voltage value based on a voltage dividing circuit configured by a parallel circuit of a first resistor R1 and a second resistor R2. The lighting fixture 20 sets the LED light source 21 to a constant current so that the detected voltage value detected using the parallel circuit of the first resistor R1 and the second resistor R2 matches a predetermined reference value set in advance. To drive. In the lighting fixture 20, as shown in FIG. 3, when the lighting signal is turned on, the LED light source 21 is turned on from a light-off state.

  Next, in the lighting fixture 20, when the LED light source 21 is in the lighting state by the lighting signal from the lighting control unit 4, the sensor unit 25 detects the heat rays when the surroundings of the lighting fixture 20 are below a predetermined brightness. If it stops, the lighting control part 4 will output a light control signal after predetermined time progress. For example, as illustrated in FIG. 4, in the lighting fixture 20, when the lighting control unit 4 outputs a dimming signal to the dimming unit 3 at time t <b> 2, the third switch element Q <b> 3 is turned on, and the second switch element The voltage at the gate of Q2 decreases. When the voltage of the gate of the second switch element Q2 is lowered and the second switch element Q2 is turned off, the lighting fixture 20 has the first resistor R1, the second resistor R2, and the third resistor R3. A parallel circuit is formed with the series circuit. When the parallel circuit of the 1st resistance R1 and the series circuit of 2nd resistance R2 and 3rd resistance R3 is formed, the lighting fixture 20 will be parallel of 1st resistance R1 and 2nd resistance R2. Compared to the voltage dividing circuit configured by the circuit, the detected voltage value is increased with the same current. Since the luminaire 20 has a high detection voltage value, the current flowing through the LED light source 21 can be reduced, and the light control of the LED light source 21 can be performed.

  Next, when the lighting light source 20 detects the sensor signal from the sensor unit 25 again within a predetermined time when the LED light source 21 is in the lighting state by the lighting signal from the lighting control unit 4, the lighting control unit 4 Does not output dimming signal. As shown in FIG. 4, in the lighting fixture 20, when the lighting control unit 4 stops outputting the dimming signal to the dimming unit 3 at time t3, the third switch element Q3 is turned off, and the second switch element The voltage at the gate of Q2 rises. In the lighting fixture 20, when the voltage of the gate of the second switch element Q2 rises and the second switch element Q2 is turned on, a parallel circuit of the first resistor R1 and the second resistor R2 is formed. The When the parallel circuit of the first resistor R1 and the second resistor R2 is formed, the lighting fixture 20 includes the first resistor R1, the series circuit of the second resistor R2, and the third resistor R3. The detection voltage value is reduced by a voltage dividing circuit formed by a parallel circuit. Since the detected voltage value of the lighting fixture 20 becomes small, the current flowing through the LED light source 21 can be increased and the lighting device 20 can be turned on.

  In the dimming unit 3, the voltage dividing ratio of the voltage dividing circuit connected in series with the LED light source 21 is determined depending on whether or not the third resistor R3 is short-circuited by switching the second switch element Q2 on and off. Can be changed. The luminaire 20 can perform dimming control by changing the detection voltage value to be driven by constant current by feedback by the dimmer 3 changing the voltage dividing ratio of the voltage dividing circuit. In the lighting fixture 20 according to the present embodiment, the lighting control unit 4 is configured to turn off the lighting signal after a predetermined time has elapsed without outputting the sensor signal after outputting the dimming signal. ing.

  In other words, the LED lighting circuit 10 of the present embodiment includes the power supply unit 5. The control circuit 2 is configured to be driven by power from the power supply unit 5. Between the power supply unit 5 and the control circuit 2, a fourth switch element Q4 is provided. The fourth switch element Q4 is switched on and off by a lighting signal. The fourth switch element Q4 is preferably configured to switch the LED light source 21 between the lighting state and the extinguishing state by switching between on and off.

  In the LED lighting circuit 10 of the present embodiment, the LED light source 21 is switched between a lighting state and a light-off state with a relatively simple configuration including a fourth switch element Q4 that switches on and off according to a lighting signal. Can do.

  The LED lighting circuit 10 of this embodiment includes a lighting control unit 4 to which a control signal is input from the outside. The lighting control unit 4 is configured to switch the LED light source 21 to one of a lighting state, a dimming state, and a light-off state by outputting a lighting signal and a dimming signal separately based on the control signal. It is preferable that

  In the LED lighting circuit 10 of the present embodiment, the LED light source 21 is configured with a relatively simple configuration in which the lighting control unit 4 outputs a lighting signal and a dimming signal separately based on a control signal input from the outside. It can be switched to any of a lighting state, a dimming state, and a light-off state.

  In the LED lighting circuit 10 of the present embodiment, the lighting control unit 4 is electrically connected to the illuminance sensor 25a so that an illuminance signal from the illuminance sensor 25a that senses brightness can be input as a control signal. preferable.

  The LED lighting circuit 10 of the present embodiment can perform dimming control based on the illuminance signal from the illuminance sensor 25a.

  In the LED lighting circuit 10 of the present embodiment, the lighting control unit 4 is electrically connected to the human detection sensor 25b so that a sensor signal from the human detection sensor 25b that senses the presence or absence of a person can be input as a control signal. Preferably it is.

  The LED lighting circuit 10 of the present embodiment can perform dimming control based on the sensor signal from the human detection sensor 25b.

(Embodiment 2)
The circuit configuration of the LED lighting circuit 10 of the present embodiment shown in FIG. 5 is the same as that of the first embodiment shown in FIG. 1, and the capacitor C2 is connected to the gate of the field effect transistor that constitutes the second switch element Q2. This is mainly different. In the LED lighting circuit 10 of the present embodiment, the same components as those of the first embodiment are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

  As shown in FIG. 5, the LED lighting circuit 10 of the present embodiment includes a power supply unit 5. The light control unit 3 includes a fourth resistor R4 and a capacitor C2. The fourth resistor R4 and the capacitor C2 are electrically connected in series. The series circuit of the fourth resistor R4 and the capacitor C2 is electrically connected to the power supply unit 5 in series. The second switch element Q2 is composed of a field effect transistor. The gate of the second switch element Q2 is electrically connected to the connection point between the fourth resistor R4 and the capacitor C2.

  As in the first embodiment, the LED lighting circuit 10 according to the present embodiment has a configuration in which the dimming unit 3 changes the detection voltage value stepwise with respect to the same current based on the dimming signal. Dimming control is possible. In the LED lighting circuit 10 of the present embodiment, the gate of the second switch element Q2 is electrically connected to the connection point between the fourth resistor R4 and the capacitor C2, and the LED light source 21 is slightly changed from a dark state. It is possible to perform a fade operation that becomes brighter one by one.

  In the LED lighting circuit 10 of the present embodiment, the dimming unit 3 includes a third switch element Q3. The third switch element Q3 is electrically connected in parallel with the capacitor C2. The third switch element Q3 is preferably switched by a dimming signal.

  In the LED lighting circuit 10 of the present embodiment, the lighting of the LED light source 21 can be dimmed and controlled by a fade operation by the third switch element Q3 that is switched by the dimming signal.

  Below, operation | movement of the lighting fixture 20 which concerns on this embodiment is demonstrated, referring FIG.6 and FIG.7.

  When the illumination sensor 20 detects that the illuminance sensor 25a of the sensor unit 25 has a predetermined brightness or less and the human detection sensor 25b detects the presence of a person, the sensor unit 25 outputs a sensor signal. Output to. As illustrated in FIG. 6, when the lighting control unit 4 receives a sensor signal from the sensor unit 25 at time t4, the lighting control unit 4 outputs a lighting signal to the fourth switch element Q4. In the lighting fixture 20, the driving power is supplied from the power supply unit 5 to the control circuit 2 by turning on the fourth switch element Q <b> 4. In the lighting fixture 20, when the fourth switch element Q <b> 4 is turned on, predetermined DC power is output from the power supply device 24 to the LED light source 21.

  In the lighting fixture 20, when the lighting control unit 4 receives a sensor signal from the sensor unit 25, the lighting control unit 4 does not output a dimming signal to the dimming unit 3. In the luminaire 20, when the dimming signal is not output to the dimming unit 3, the third switch element Q <b> 3 is in an off state.

  When the lighting control unit 4 outputs a lighting signal and no light control signal is output to the light control unit 3, the lighting fixture 20 charges the capacitor C2 via the fourth switch element Q4 and the fourth resistor R4. Accumulated. In the lighting fixture 20, when the third switch element Q3 is in the OFF state, the terminal voltage of the capacitor C2 is applied to the gate of the second switch element Q2. In the lighting fixture 20, when the charge accumulation in the capacitor C2 is small, the second switch element Q2 is turned off until the voltage applied to the gate of the second switch element Q2 reaches a predetermined voltage value. When the second switch element Q2 is in the OFF state, the lighting fixture 20 is a parallel circuit in which the first resistor R1, and the series circuit of the second resistor R2 and the third resistor R3 are electrically connected in parallel. Configure. In the lighting fixture 20, the detected voltage value detected by the voltage dividing circuit in which the first resistor R1, the series circuit of the second resistor R2, and the third resistor R3 are electrically connected in parallel is a predetermined reference. The control circuit 2 controls the power supply circuit 1 so as to match the value. The lighting fixture 20 lights the LED light source 21 in a dimming state immediately after the lighting signal is output.

  In the light control unit 3, the second switch element Q2 is charged until the capacitor C2 is completely charged with the power supplied from the power supply unit 5 to the capacitor C2 via the fourth switch element Q4 and the fourth resistor R4. Does not turn on completely. In the second switch element Q2, charge accumulation in the capacitor C2 increases until charging of the capacitor C2 is completed. The second switch element Q2 is in the off state until time t5 when the voltage applied to the gate of the second switch element Q2 exceeds a predetermined voltage value. In the lighting fixture 20, the LED light source 21 is lit in a dimming state from time t4 to time t5 when the second switch element Q2 starts to be driven. When the voltage applied to the gate of the second switch element Q2 exceeds a predetermined voltage value after time t5, the second switch element Q2 increases with the increase in the terminal voltage of the capacitor C2. The current flowing between the source and drain of Q2 rises.

  The lighting fixture 20 can perform a fade operation by gradually changing the dimming state to the lighting state as the LED light source 21 is charged to the capacitor C2. The lighting fixture 20 is based on the resistance value of the parallel circuit of the first resistor R1 and the second resistor R2 when the charging of the capacitor C2 is completed at time t6 and the second switch element Q2 is completely turned on. Thus, the detection voltage value is detected. The luminaire 20 sets the LED light source 21 to a constant current so that the detected voltage value matches a predetermined reference value based on the resistance value of the parallel circuit of the first resistor R1 and the second resistor R2. To drive.

  Next, in the lighting fixture 20, when the LED light source 21 is in the lighting state by the lighting signal from the lighting control unit 4, when the sensor signal from the sensor unit 25 is not input, the lighting control unit 4 performs the dimming signal after a predetermined time has elapsed. Is output. As shown in FIG. 7, when the lighting control unit 4 outputs a dimming signal to the dimming unit 3 at time t7, the lighting device 20 turns on the third switch element Q3 and turns on the second switch element Q2. The gate voltage drops. When the voltage of the gate of the second switch element Q2 decreases and the second switch element Q2 is turned off, the lighting fixture 20 includes the first resistor R1, the second resistor R2, and the third resistor R3. A parallel circuit with the series circuit is formed. The luminaire 20 has a detection voltage value detected by a voltage dividing circuit formed by a parallel circuit of a first resistor R1, a series circuit of a second resistor R2, and a third resistor R3 for the same current value. Therefore, the current flowing through the LED light source 21 can be reduced, and dimming control of the LED light source 21 can be performed.

  Next, when the LED light source 21 is in the lighting state by the lighting signal from the lighting control unit 4, the lighting fixture 20 adjusts the lighting control unit 4 to the light control unit 3 when the sensor signal is input again from the sensor unit 25. The optical signal is not output. As shown in FIG. 7, in the lighting fixture 20, when the lighting control unit 4 stops outputting the dimming signal to the dimming unit 3 at time t8, the second switch element Q2 is turned off, and the second switch The voltage at the gate of the element Q2 gradually rises from time t9 according to the accumulation of electric charge in the capacitor C2. When the voltage of the gate of the second switch element Q2 rises and the second switch element Q2 is completely turned on, the lighting fixture 20 has a parallel circuit of the first resistor R1 and the second resistor R2. It is formed. When the parallel circuit of the first resistor R1 and the second resistor R2 is formed, the lighting fixture 20 includes the first resistor R1, the series circuit of the second resistor R2, and the third resistor R3. Compared with the case where a parallel circuit is formed, the detected voltage value is smaller for the same current value. When the detection voltage value decreases, the lighting fixture 20 increases the current flowing through the LED light source 21 and can be in a fully lit state.

  The dimmer 3 can adjust the timing of short-circuiting the third resistor R3 using the capacitor C2 by switching the second switch element Q2 on and off. In the lighting fixture 20, the dimming unit 3 gradually changes the voltage dividing ratio of the voltage dividing circuit, thereby gradually changing the detection voltage value to be driven by constant current by feedback and performing dimming control with a fade operation. it can.

  Next, the lighting fixture 20 which concerns on this embodiment is demonstrated based on FIG. The lighting fixture 20 comprises the ceiling light installed directly in the ceiling material 50, for example.

  The lighting fixture 20 according to the present embodiment is different from the lighting fixture 20 according to the first embodiment shown in FIG. 2 in that the LED lighting circuit 10, the power supply device 24, and the sensor unit 25 are integrally provided in the housing 26s. ing.

  In the lighting fixture 20, the LED lighting circuit 10 and the power supply device 24 are formed using a circuit board 26e on which a plurality of electronic components 26d are mounted. The power supply device 24 is electrically connected to the power cable 41 led out from the ceiling material 50. In the lighting fixture 20, a plurality of LEDs 21 a are mounted on a wiring board 26 f on which the sensor unit 25 is mounted. In the lighting fixture 20, the LED light source 21 is comprised by LED21a and the wiring board 26f in which LED21a was mounted. In the luminaire 20, the LED lighting circuit 10, the LED light source 21, and the power supply device 24 are housed in a bottomed cylindrical casing 26 s. The circuit board 26e and the wiring board 26f are electrically connected by a wiring cord 29c. The lighting fixture 20 is provided with a lens 22f so as to close the opening of the housing 26s and cover the LED light source 21. The LED lighting circuit 10 of the present embodiment may be applied to the configuration of the lighting fixture 20 according to the first embodiment.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the technical idea of the present invention.

C2 capacitor C2
Q1 1st switch element Q2 2nd switch element Q3 3rd switch element Q4 4th switch element R1 1st resistance R2 2nd resistance R3 3rd resistance 1 Power supply circuit 2 Control circuit 2a Current detection part 3 Light control unit 4 Lighting control unit 5 Power supply unit 10 LED lighting circuit 20 Lighting fixture 21 LED light source 25 Sensor unit 25a Illuminance sensor 25b Human detection sensor

Claims (9)

A power supply circuit comprising a first switch element, which converts DC input power into predetermined power by switching on and off of the first switch element and outputs the predetermined power to the LED light source;
A current detection unit that includes a first resistor electrically connected in series with the first switch element and outputs a detection voltage value proportional to a current flowing through the LED light source;
A control circuit for controlling the first switch element so that the detected voltage value matches a predetermined reference value;
A light control unit for adjusting the light output of the LED light source,
The said light control part is comprised so that the said detection voltage value may be changed in steps with respect to the same electric current value based on the light control signal, The LED lighting circuit characterized by the above-mentioned. The dimming unit includes a second resistor, a third resistor, and a second switch element,
The second resistor and the third resistor are electrically connected in series, and a series circuit of the second resistor and the third resistor is electrically in parallel with the first resistor. Connected,
The second switch element is electrically connected in parallel with the third resistor,
2. The LED lighting circuit according to claim 1, wherein the dimming unit is configured to control on and off of the second switch element based on the dimming signal. With power supply,
The dimming unit includes a fourth resistor and a capacitor,
The fourth resistor and the capacitor are electrically connected in series, and a series circuit of the fourth resistor and the capacitor is electrically connected in series to the power supply unit,
The second switch element is composed of a field effect transistor,
The LED lighting circuit according to claim 2, wherein a gate of the second switch element is electrically connected to a connection point between the fourth resistor and the capacitor. The dimming unit includes a third switch element electrically connected in parallel with the capacitor,
The LED lighting circuit according to claim 3, wherein the third switch element is switched by the dimming signal. With power supply,
The control circuit is configured to be driven by power from the power supply unit,
A fourth switch element is provided between the power supply unit and the control circuit,
5. The fourth switching element is configured to switch the LED light source between a lighting state and a light-off state by switching on and off by a lighting signal. The LED lighting circuit according to any one of the above. With a lighting control unit that receives control signals from the outside,
The lighting control unit outputs the lighting signal and the dimming signal separately based on a control signal so as to switch the LED light source to any one of a lighting state, a dimming state, and a light-off state. The LED lighting circuit according to claim 5, wherein the LED lighting circuit is configured as follows.   The LED according to claim 6, wherein the lighting control unit is electrically connected to the illuminance sensor so that an illuminance signal from an illuminance sensor that senses brightness can be input as the control signal. Lighting circuit.   The said lighting control part is electrically connected with the said human detection sensor so that the sensor signal from the human detection sensor which detects the presence or absence of a person can be input as said control signal. LED lighting circuit of description.   An illumination fixture comprising: the LED lighting circuit according to any one of claims 1 to 8; and the LED light source that is lit based on an output from the LED lighting circuit.

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