JP2010040182A - Lighting device for dimming and illuminating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lighting device for illumination control capable of restraining damages of a base board and electronic parts caused by an incorrect wiring with an input terminal of a light control circuit without enlarging the size of the base board. <P>SOLUTION: The lighting device for illumination control 1 comprises: an illumination control circuit 2 equipped with a current correcting element 9 composed of a first and a second resistive elements 8a, 8b connected in series between a rectifying circuit 7 and one of the two input terminals 6a, with the first resistive element 8a having a lower resistance value than the second resistive element 8b and with the former 8a connected further toward an input terminal 6a side than the latter 8b, and an overvoltage protecting element 10 connected between a middle point a1 of the first and the second resistive elements 8a, 8b and the other input terminal 6b; a main circuit 3 converting and outputting an input power from an alternating-current power source Vs in accordance with the direct-current voltage outputted from the illumination control circuit 2; and a light source 4 which illuminates light in accordance with the power output from the main circuit 3. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a light control lighting device and a lighting device in which a light source performs light control lighting according to a light control signal.

  There is a discharge lamp lighting device that can suppress the occurrence of a failure against a human error in which a commercial power supply is connected to the output terminal by mistake between the input terminal and output terminal of the discharge lamp lighting device and the power is turned on as it is. It has been proposed (see Patent Document 1). In this prior art discharge lamp lighting device, when a power supply voltage is applied to a terminal block for supplying a periodic voltage generated by an inverter circuit to an external discharge lamp, the power supply voltage is supplied to a control power supply unit. It is equipped with a diode that prevents this. As a result, the short-circuit current caused by the commercial power supply is suppressed, and the switching element and other diodes are prevented from being damaged or destroyed by the short-circuit current in the polarity inversion circuit. It can be done.

  By the way, there is a discharge lamp lighting device in which a fluorescent lamp as a discharge lamp is dimmed in accordance with a PWM dimming signal (see, for example, Patent Document 2). That is, the PWM dimming signal output from the dimming device is input to the input terminal of the dimming circuit. And at the time of construction, as in the case of the discharge lamp lighting device of Patent Document 1, the power supply line connected to the commercial AC power supply may be mistakenly connected to the input terminal of the dimming circuit. For example, a discharge lamp lighting device is often disposed inside a lighting fixture. In this case, a transmission line connected to an input terminal of a dimming circuit and a lead wire connected to a commercial AC power source are respectively connected from the lighting fixture. Pull out. The transmission line may be mistakenly connected to a power line wired to a commercial AC power source, and there is a concern about the erroneous connection in the future.

  When a commercial AC power supply is input to the input terminal of the dimming circuit, a rectifier that rectifies the PWM dimming signal, a resistance element for current adjustment, and the like generate heat, thereby damaging the substrate and other electronic components. For this reason, as with the discharge lamp lighting device of Patent Document 1, a countermeasure against the occurrence of the erroneous wiring (erroneous connection) is required.

  And as the said countermeasure, the structure shown in the power supply circuit of patent document 3 can be used, for example. That is, in the power supply circuit, an overvoltage protection element is connected between a positive electrode terminal and a negative electrode terminal via a fuse. It becomes conductive and the fuse is blown by overcurrent. Thereby, an electronic device (load) is protected.

As the countermeasure, the configuration shown in the overvoltage / reverse connection protection circuit of Patent Document 4 can be used. That is, the overvoltage / reverse connection protection circuit connects a series circuit of a constant voltage diode and a relay in parallel to a load via a normally closed contact of the relay, and connects a DC power source to the series circuit to operate the series circuit. The voltage is set as the upper limit voltage of the allowable range of the load. When the charging voltage of the DC power supply rises to an overvoltage state, the relay is turned on, the normally closed contact is opened, and the load is protected from the overvoltage.
JP 2006-134732 A (page 9, FIG. 2) Japanese Patent Laying-Open No. 2006-107784 (pages 4, 7 and 1) Japanese Unexamined Patent Publication No. 2000-188826 (second page, FIG. 1) No. 2-136439 (page 6-8, FIG. 1)

  However, when a fuse is used in the dimming circuit as in the power supply circuit of Patent Document 3, since the area occupied by the fuse on the board on which the electronic component is mounted is large, there is a disadvantage that the board becomes large. Further, when a relay is used as in the voltage / reverse connection protection circuit of Patent Document 4, there are disadvantages that the board becomes large and the number of parts increases, which increases the cost of the discharge lamp lighting device.

  It is an object of the present invention to provide a dimming lighting device and an illumination device that can suppress damage to a substrate and electronic components without increasing the size of the substrate against erroneous wiring to an input terminal of a dimming circuit And

  In the invention of the lighting device for dimming according to claim 1, a dimming signal is inputted to the input terminal, and a DC voltage converting unit that outputs a DC voltage corresponding to the dimming signal, and the DC voltage converting unit flows. A current adjusting element including a first and a second resistance element for adjusting current, the first resistance element being blown by the overcurrent when the overcurrent is input to the input terminal; A light control circuit in which the resistance value is set to be smaller than the resistance value of the second resistance element; and a pair of power input terminals connected to the AC power source via lead wires, and input to the power input terminal A main circuit that converts electric power from an AC power source into electric power corresponding to the DC voltage output from the dimming circuit and outputs the electric power; and a light source that lights up according to the electric power output from the main circuit. It is characterized by that.

  In the present invention and each of the following inventions, each configuration is as follows unless otherwise specified.

  The structure of the input terminal and the power input terminal is not particularly limited, such as a screw terminal, a screwless terminal, or a pin terminal.

  The resistance values of the first and second resistance elements are set values when the dimming signal is input to the input terminal, and the combined resistance values are set so that the set current flows through the DC voltage conversion unit. Has been.

  The resistance value of the first resistance element is set to be smaller than the resistance value of the second resistance element when the overcurrent flows through the first resistance element (input terminal). This is for instantly (immediately) melting.

  According to the present invention, when an overcurrent is input to the input terminal of the dimming circuit to which the dimming signal is input, the resistance value of the first resistance element is smaller than the resistance value of the second resistance element. It has a relatively small resistance value, and melts instantaneously due to the overcurrent. Thereby, the thermal damage to the board | substrate which mounts another electronic component and an electronic component is suppressed.

  The dimming lighting device according to claim 2 is the dimming lighting device according to claim 1, wherein the dimming circuit includes a pair of input terminals to which a dimming signal is input and an input to the input terminal. And a first rectifier connected in series between the rectifier circuit and one of the input terminals, and an output side of the rectifier circuit. The combined resistance value of the first and second resistance elements is set so that a predetermined current flows through the first resistance element, and the resistance value of the first resistance element is set smaller than the resistance value of the second resistance element. A current adjusting element in which the first resistance element is connected to one input terminal side of the second resistance element, a midpoint of the first and second resistance elements, and the other input terminal Is connected between the overvoltage protection element and the non-conductive overvoltage protection element when the dimming signal is applied. A, characterized in that it is configured to output a DC voltage corresponding to the dimming signal.

  The resistance values of the first and second resistance elements are set values when a dimming signal is input to the input terminal, and the combined resistance values so that a predetermined current flows on the output side of the rectifier circuit. Is set.

  The “midpoint of the first and second resistance elements” is not limited to the connection point between the first resistance element and the second resistance element, but between the first and second resistance elements connected in series. Indicates the position.

  The overvoltage protection element is conductive at an AC voltage of a commercial AC power supply, and is, for example, a varistor.

  According to the present invention, when an AC power supply input to the pair of power supply input terminals of the main circuit is erroneously connected to the pair of input terminals of the dimming circuit, the overvoltage protection element becomes conductive, Overcurrent flows in the closed circuit of the one resistance element, the overvoltage protection element, and the other input terminal. Since the resistance value of the first resistance element is smaller than the resistance value of the second resistance element, the first resistance element has a relatively small resistance value and is blown instantaneously when the overcurrent flows. Thereby, the thermal damage to the board | substrate which mounts another electronic component and an electronic component is suppressed.

  The dimming lighting device according to claim 3 is the dimming lighting device according to claim 1, wherein the dimming circuit includes a pair of input terminals to which a dimming signal is input and an input to the input terminal. A rectifier circuit for rectifying a dimming signal, a first resistor element connected between the rectifier circuit and one of the input terminals, and a second resistor connected between the outputs of the rectifier circuit The combined resistance value of the first and second resistance elements is set so that a predetermined current flows to the output side of the rectifier circuit, and the resistance value of the first resistance element is equal to that of the second resistance element. And a current adjustment element set smaller than the resistance value, and is configured to output a DC voltage corresponding to the dimming signal.

  According to the present invention, when an AC power supply that is erroneously input to the pair of power input terminals of the main circuit is connected to the pair of input terminals of the dimming circuit, the one input terminal, the first resistance element, and the rectifier circuit And an overcurrent flows in the closed circuit of the other input terminal. Since the resistance value of the first resistance element is smaller than that of the second resistance element, the first resistance element has a relatively small resistance value. When the overcurrent flows, the first resistance element instantaneously melts and does not generate heat. Alternatively, the rectifier circuit is destroyed due to the overcurrent, the current does not flow in the closed circuit, and the first resistance element does not generate heat. Thereby, the thermal damage to the board | substrate which mounts another electronic component and an electronic component is suppressed.

  A lighting device according to a fourth aspect of the present invention is the lighting control device according to any one of the first to third aspects; and is connected to an input terminal of a light control circuit of the lighting control device via a transmission line. A dimming device for outputting a dimming signal to the input terminal; and a lighting fixture provided with a light source.

  According to the present invention, when the power supply line incorrectly connected to the AC power supply is connected to the input terminal of the light control circuit of the light control lighting device instead of the transmission line connected to the light control device, Provided is a lighting device including a dimming lighting device capable of instantaneously fusing a first resistance element of a dimming circuit.

  According to the first aspect of the present invention, when an overcurrent flows through the input terminal of the dimming circuit, the first resistance element is instantaneously blown off, resulting in thermal damage to another electronic component or a substrate on which the electronic component is mounted. Therefore, it is possible to reduce the size of the substrate by using the current adjusting elements including the first and second resistance elements that occupy a smaller area on the substrate than current protection elements such as fuses and relays. Therefore, it is possible to suppress an increase in size and cost of the dimming lighting device.

  According to the second aspect of the present invention, when the AC power source that is erroneously input to the pair of power source input terminals of the main circuit is connected to the pair of input terminals of the dimming circuit, the first resistance element is blown instantaneously. Therefore, it is possible to suppress thermal damage to other electronic components and the substrate on which the electronic component is mounted, so that the first and second resistors occupy a smaller area on the substrate than current protection elements such as fuses and relays. By using the element, an increase in size of the substrate can be suppressed, and an increase in size and cost of the dimming lighting device can be suppressed.

  According to the invention of claim 3, when the AC power source that is erroneously input to the pair of power input terminals of the main circuit is connected to the pair of input terminals of the dimming circuit, the first resistance element is instantaneously blown out. In addition, since the rectifier circuit is broken and thermal damage to other electronic components and the substrate can be suppressed, the first and second occupying areas on the substrate are smaller than the current protection elements such as fuses and relays. By using the resistance element, the increase in size of the substrate can be suppressed, and the increase in size and cost of the dimming lighting device can be suppressed.

  According to the invention of claim 4, when the AC power supply is mistakenly connected to the input terminal of the dimming circuit of the dimming lighting device, the first resistance element of the dimming circuit is instantaneously melted and dimming is performed. It is possible to provide a lighting device in which thermal damage to the lighting device is suppressed.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. First, a first embodiment of the present invention will be described.

  FIG. 1 is a schematic circuit diagram of a lighting control lighting device showing a first embodiment of the present invention.

  The dimming lighting device 1 includes a dimming circuit 2, a main circuit 3, a light source 4, and a control circuit 5, and the light source 4 is dimmed and lit by a dimming signal transmitted from a dimming device (not shown). Is. That is, the dimming signal is input to the dimming circuit 2. The dimming circuit 2 converts the dimming signal into a DC voltage and outputs it to the control circuit 5. The control circuit 5 controls the main circuit 2 according to the DC voltage, and causes the main circuit 2 to output electric power according to the DC voltage. The light source 4 is dimmed by energizing the power output from the main circuit 2.

  The dimmer circuit 2 includes a pair of input terminals 6a and 6b, a rectifier 7 as a rectifier circuit, a current adjusting element 9 and an overvoltage protection element 10 including a first resistance element 8a and a second resistance element 8b. It is configured. Lead wires 11 and 11 are connected to the pair of input terminals 6a and 6b, respectively. The lead wires 11 are connected to a transmission line (not shown) connected to a light control device (not shown) by, for example, a crimp terminal. A PWM dimming signal as a dimming signal output from the dimming device is input to the pair of input terminals 6a and 6b. The positive side of the PWM signal is input to the input terminal 6a, and the negative side of the PWM signal is input to the input terminal 6b.

  The input side of the rectifier 7 is connected to the input terminals 6a and 6b via the first and second resistance elements 8a and 8b. Further, a photodiode PD1 of the photocoupler PC1 is connected between the outputs. The rectifier 7 rectifies the PWM dimming signal input to the input terminals 6a and 6b, and causes the photodiode PD1 to emit light by the rectified current.

  The current adjusting element 9 adjusts the current flowing to the output side of the rectifier 7 and includes a first resistance element 8a and a second resistance element 8b. The first resistance element 8a and the second resistance element 8b are connected in series between one input side of the rectifier 7 and one input terminal 6a. The combined resistance value of the first and second resistance elements 8a and 8b is such that a predetermined current (for example, 1 to 2 mA) flows through the photodiode PD1 of the photocoupler PC1 connected between the outputs of the rectifier 7. Is set.

  The first resistance element 8a is set to have a resistance value smaller than that of the second resistance element 8b, and is connected to the one input terminal 6a side of the second resistance element 8b. It is what. The voltage value of the PWM dimming signal input to the pair of input terminals 6a and 6b is, for example, DC12V, and the combined resistance value of the first and second resistance elements 8a and 8b is about 10 kΩ. That is, the resistance values of the first and second resistance elements 8a and 8b are relatively small compared to the resistance values of the other resistance elements of the lighting control lighting device 1. And since the resistance value is relatively small, the outer shapes of the first and second resistance elements 8a and 8b are also relatively small, and the first and second resistance elements 8a and 8b on the mounted substrate are reduced. Occupied area is also small.

  The overvoltage protection element 10 is, for example, a varistor, and is connected between the midpoint a1 of the first and second resistance elements 8a and 8b and the other input terminal 6b. The overvoltage protection element 10 is selected so that it does not conduct even when the voltage value (DC12V) of the PWM dimming signal is applied. However, when the voltage value (AC100V) of the AC power supply Vs is applied, it becomes conductive.

  The cathode and emitter of the photodiode PTr1 of the photocoupler PC1 are connected to the dimming main circuit unit 12. The dimming main circuit unit 12 is connected to the control circuit 5.

  The photodiode PD1 emits light when a predetermined current (for example, 1 to 2 mA) rectified by the rectifier 7 flows during the on-duty period of the PWM dimming signal. The phototransistor PTr1 becomes conductive when the photodiode PD1 emits light. The dimming main circuit unit 12 is formed to output a constant DC voltage corresponding to a period during which the phototransistor PTr1 is conductive.

  The photocoupler PC1 and the dimming main circuit unit 12 form a DC voltage conversion unit that generates and outputs a DC voltage corresponding to the PWM dimming signal. The current adjusting element 9 including the first and second resistance elements 8a and 8b adjusts the current flowing through the photodiode PD1 of the DC voltage conversion unit. In this way, the dimming circuit 2 is configured to output a constant DC voltage corresponding to the PWM dimming signal input to the pair of input terminals 6 a and 6 b to the control circuit 5.

  The control circuit 5 is formed to control the main circuit 3 according to the DC voltage output from the dimming circuit 2.

  The main circuit 3 has power input terminals 13a and 13b. Lead wires 14 and 14 are connected to the power input terminals 13a and 13b. The lead wires 14, 14 are connected to power supply lines WD1, WD2 wired to the commercial AC power supply Vs. The main circuit 3 is supplied with AC power from a commercial AC power supply Vs via lead wires 14 and 14 and power supply lines WD1 and WD2. The main circuit 3 converts the AC power from the commercial AC power supply Vs input to the power input terminals 13a and 13b into power corresponding to the DC voltage output from the dimming circuit 2 under the control of the control circuit 5. And output. That is, the main circuit 3 is configured to output power corresponding to the PWM dimming signal input to the input terminals 6 a and 6 b of the dimming circuit 2.

  For example, when the light source 4 is a fluorescent lamp, the main circuit 2 has a DC power supply circuit that converts an AC voltage of the commercial AC power supply Vs into a DC voltage, an inverter circuit that converts the DC voltage into an AC high frequency voltage, and a resonance voltage to the fluorescent lamp. It is formed with a resonance circuit or the like for applying. When the light source 4 is a light emitting diode, it is formed with a constant current circuit for supplying a current corresponding to the PWM dimming signal to the light emitting diode in addition to the DC power supply circuit.

  The light source 4 is connected between the outputs of the main circuit 3 and is dimmed according to the power output from the main circuit 3. The light source 4 may be a discharge lamp such as a fluorescent lamp, a light emitting diode (LED), an electroluminescent (EL) element, or a light bulb that emits illumination light and can use the illumination light.

  Next, the operation of the first embodiment of the present invention will be described.

  The power supply lines WD1 and WD2 wired to the commercial AC power supply Vs are not connected to the lead wires 14 and 14 connected to the power supply input terminals 13a and 13b of the main circuit 3, and are input to the dimming circuit 2 by mistake. When connected to the lead wires 11 and 11 connected to the terminals 6a and 6b, the dimming circuit 2 is connected to the commercial AC power supply Vs via the lead wires 11 and 11 and the power supply lines WD1 and WD2. When the commercial AC power supply Vs is turned on, an AC voltage (for example, AC100V) is applied to the overvoltage protection element 10, and the overvoltage protection element 10 is turned on, so that the commercial AC power supply Vs, one input terminal 6a, the first Overcurrent flows in the closed circuit of the resistance element 8a, the overvoltage protection element 10, and the other input terminal 6b.

  Since the resistance value of the first resistance element 8a is relatively small, when an overcurrent flows, the first resistance element 8a is instantaneously blown. That is, the first resistance element 8a has a resistance value smaller than the resistance value of the second resistance element 9 by reducing the resistance ratio in the combined resistance value of the first and second resistance elements 8a and 8b. The resistance value is relatively small and can be blown instantaneously by an overcurrent.

  When the first resistance element 8a is melted, no current flows in the closed circuit, and the first resistance element 8a does not generate heat. Thereby, the thermal damage to the board | substrate which mounts other electronic components, such as the rectifier 7, and the electronic component of the lighting device 1 for light control, is suppressed. Then, the dimming lighting device 1 can be reused by replacing the first resistive element 8a with respect to the dimming lighting device 1 having the erroneous wiring (incorrect connection).

  The first and second resistance elements 8a and 8b have a small outer shape and have a smaller occupied area and occupied space on the substrate than current protection elements such as fuses and relays, so that an increase in the size of the substrate is suppressed. be able to. As a result, an increase in the size and cost of the dimming lighting device 1 can be suppressed.

  Next, a second embodiment of the present invention will be described.

  FIG. 2 is a schematic circuit diagram of a lighting control lighting device showing a second embodiment of the present invention. The same parts as those in FIG. 1 are denoted by the same reference numerals, and description thereof is omitted.

  The dimming lighting device 15 shown in FIG. 2 is the same as the dimming lighting device 1 shown in FIG. 1 except that the overvoltage protection element 10 is removed and the first rectifier 7 is connected between one input side and one input terminal 6a. Are connected to each other, and the second resistor element 8b is connected in series with the photodiode PD1 of the photocoupler PC1 between the outputs of the rectifier 7 to form a dimming circuit 2A.

  The power supply lines WD1 and WD2 wired to the commercial AC power supply Vs are erroneously connected to the lead wires 11 and 11 connected to the input terminals 6a and 6b of the dimming circuit 2, and in this state, the commercial AC power supply Vs Is turned on, an overcurrent flows in the closed circuit of the commercial AC power supply Vs, one input terminal 6a, the rectifier 7 and the other input terminal 6b.

  Since the resistance value of the first resistance element 8a is set to be smaller than the resistance value of the second resistance element 8b, the first resistance element 8a has a relatively small resistance value and instantaneously blows due to overcurrent. Alternatively, when an overcurrent flows through the rectifier 7, the rectifier 7 may be instantaneously destroyed. As a result, no current flows in the closed circuit, and the first resistance element 8a does not generate heat. As a result, thermal damage to other electronic components such as the photocoupler PC1 and the substrate is suppressed. Then, the dimming lighting device 15 can be reused by replacing the first resistive element 8a and the rectifier 7 with respect to the dimming lighting device 15 having the erroneous wiring (incorrect connection).

  The first and second resistance elements 8a and 8b have a small outer shape, and occupy less area and space on the substrate than current protection elements such as fuses and relays. In addition, the overvoltage protection element 10 is used. Therefore, the increase in size of the substrate can be further suppressed. As a result, an increase in size and cost of the dimming lighting device 15 can be suppressed.

  Next, a third embodiment of the present invention will be described.

  It is a schematic block diagram of the illuminating device which shows the 3rd Embodiment of this invention. The same parts as those in FIG. 1 are denoted by the same reference numerals, and description thereof is omitted.

  The illuminating device 16 shown in FIG. 3 includes a luminaire 17, a discharge lamp lighting device 18, and a light control device 19.

  The lighting fixture 17 is a direct-attached lighting fixture that is directly attached to the ceiling surface 20, and a pair of lamp sockets 22, 22 are provided at both ends of a substantially frame-shaped fixture main body 21. Then, a straight tube fluorescent lamp 23 as a light source is mounted on the lamp sockets 22 and 22. In addition, the fixture body 21 is attached with a reflecting plate 24 having a substantially dish-shaped cross section so as to face the fluorescent lamp 23. The surface of the reflecting plate 24 is formed on the reflecting surface 24a.

  Moreover, the fixture main body 21 is fixing the lighting device 18 for discharge lamps with the screw which is not illustrated inside the reflecting plate 24. FIG. The discharge lamp lighting device 18 is configured by removing the light source 4 from the dimming lighting device 1 shown in FIG.

  The discharge lamp lighting device 18 leads out lead wires 14 and 14 connected to the power input terminals 13a and 13b of the main circuit 3. The lead wires 14 and 14 are connected to power supply lines WD1 and WD2 which are drawn out to the back of the ceiling via the lighting fixture 17 and wired to the commercial AC power supply Vs. The discharge lamp lighting device 18 leads out lead wires 11 and 11 connected to the input terminals 6 a and 6 b of the dimming circuit 2. The lead wires 11 and 11 are drawn out to the back of the ceiling through the lighting fixture 17 and are connected to transmission lines 25 and 25 connected to the light control device 19 by crimping terminals (ring sleeves) 26 and 26.

  The light control device 19 has a manual operation unit 27, and is configured to output a PWM light control signal as a light control signal by moving the manual operation unit 27. The PWM dimming signal is input to the input terminals 6 a and 6 b of the dimming circuit 2 of the discharge lamp lighting device 18 via the transmission lines 25 and 25 and the lead wires 11 and 11. The light control device 19 is installed on, for example, a wall surface (not shown).

  The illuminating device 16 outputs a PWM dimming signal corresponding to the manual operation from the dimming device 19 by moving the manual operation unit 27 of the dimming device 19. The discharge lamp lighting device 18 performs a control operation according to the PWM dimming signal, so that the fluorescent lamp 23 is dimmed.

  Then, the power wires WD1 and WD2 wired to the commercial AC power source Vs and the lead wires 11 and 11 connected to the input terminals 6a and 6b of the dimming circuit 2 of the discharge lamp lighting device 18 are miswired (incorrect). When the commercial AC power source Vs is connected (turned on) to the input terminals 6a and 6b, the first resistance element 8a of the dimming circuit 2 is instantaneously blown, whereby the discharge lamp lighting device 18 is connected. Thermal damage can be suppressed.

The schematic circuit diagram of the lighting device for light control which shows the 1st Embodiment of this invention. The schematic circuit diagram of the lighting device for light control which shows the 2nd Embodiment of this invention. The schematic block diagram of the illuminating device which shows the 3rd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,15 ... Lighting device 2 for light control 2, 2A ... Light control circuit 3 ... Main circuit 4 ... Light source 6a, 6b ... Input terminal 7 ... Rectifier 8a as a rectifier circuit ... 1st resistance element 8b ... 2nd resistance element DESCRIPTION OF SYMBOLS 9 ... Current adjustment element 10 ... Overvoltage protection element 13a, 13b ... Power supply input terminal 16 ... Illuminating device 17 ... Lighting fixture 19 ... Dimming device 23 ... Straight tube type fluorescent lamp as a light source

Claims (4)

A current composed of a dimming signal input to the input terminal and outputting a DC voltage corresponding to the dimming signal, and a first and second resistance elements for adjusting the current flowing through the DC voltage conversion unit An adjustment element is provided, and the first resistance element is set to have a resistance value smaller than the resistance value of the second resistance element so that when the overcurrent is input to the input terminal, the first resistance element is blown by the overcurrent. Dimming circuit,
It has a pair of power input terminals connected to the AC power supply via lead wires, and converts the power from the AC power input to this power input terminal into power corresponding to the DC voltage output from the dimming circuit And output main circuit;
A light source that lights in response to the power output from the main circuit;
A lighting control device for dimming, comprising:   The dimming circuit includes a pair of input terminals to which a dimming signal is input, an input side connected to the input terminal, and a rectifier circuit that rectifies the dimming signal, and between the rectifier circuit and one of the input terminals. The combined resistance value of the first and second resistance elements is set such that a predetermined current flows to the output side of the rectifier circuit, and the first and second resistance elements are connected in series. The resistance value of the first resistance element is set to be smaller than the resistance value of the second resistance element, and the first resistance element is connected to the one input terminal side of the second resistance element. And an overvoltage protection element that is connected between a midpoint of the first and second resistance elements and the other input terminal, and is non-conductive when a dimming signal is applied, and the dimming signal It is configured to output DC voltage according to Lighting device for dimming according to claim 1, wherein that.   The dimming circuit includes a pair of input terminals to which a dimming signal is input, an input side connected to the input terminal, and a rectifier circuit that rectifies the dimming signal, and between the rectifier circuit and one of the input terminals. The first resistor element and the second resistor element connected between the outputs of the rectifier circuit, the first resistor element and the second resistor element so that a predetermined current flows to the output side of the rectifier circuit. A current adjusting element in which a combined resistance value is set and a resistance value of the first resistance element is set to be smaller than a resistance value of the second resistance element, and a DC voltage corresponding to the dimming signal The light control lighting device according to claim 1, wherein the lighting control device is configured to output the light. A dimming lighting device according to any one of claims 1 to 3;
A light control device connected to an input terminal of the light control circuit of the lighting device for light control via a transmission line and outputting a light control signal to the input terminal;
A luminaire provided with a light source;
An illumination device comprising:

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