JP2018098104A - Lighting device and luminaire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lighting device achieving both suppression of a flicker in illumination light from a light emitting element and good responsiveness in a dimming control.SOLUTION: A lighting device 10 supplying power to a light emitting element 5 includes: a constant current circuit (transistor Q2) connected to the light emitting element 5 in series and controlling a current flowing through the light emitting element 5; a variable voltage source 15 supplying a variable DC voltage to the light emitting element 5 and the constant current circuit; and a control circuit 16 which receives an instruction for a dimming level of the light emitting element 5, controls the constant current circuit such that a current corresponding to the received instruction flows through the light emitting element 5, and controls the variable voltage source 15 so that the DC voltage such as a voltage drop in the light emitting element 5 reaches a predetermined voltage is output from the variable voltage source 15, on the basis of an integral value of information on a voltage drop in the light emitting element 5. The control circuit 16 changes an integration time of the integral value in accordance with a dimming level indicated by the instruction.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a lighting device capable of controlling a dimming level and a lighting fixture including the lighting device.

  2. Description of the Related Art Conventionally, a lighting fixture that can change the brightness of illumination light, that is, a lighting fixture capable of dimming is known (see, for example, Patent Document 1).

  The luminaire described in Patent Document 1 detects a state of a semiconductor light emitting element and adjusts an operating point of voltage-current characteristics of the semiconductor light emitting element in accordance with an output of the dimming unit. An attempt is made to suppress variations in illumination light intensity between elements.

JP 2009-231147 A

  However, in the luminaire described in Patent Document 1, the voltage detected to adjust the operating point can be affected by noise. For this reason, flickering of illumination light may occur when control is performed based on a detection voltage affected by noise. In order to suppress the influence of such noise, it is also conceivable to suppress fluctuation of the detection voltage due to noise by integrating the detection voltage. However, in this case, the control response for changing the dimming level is delayed.

  Then, an object of this invention is to provide the lighting device provided with the lighting device which can satisfy | fill the flicker suppression of the illumination light from a light emitting element, and the favorable responsiveness of dimming control.

  In order to achieve the above object, a lighting device according to one embodiment of the present invention is a lighting device that supplies power to a light-emitting element, is connected in series with the light-emitting element, and controls a current flowing through the light-emitting element. A current circuit; a variable voltage source that supplies a variable DC voltage to the light emitting element and the constant current circuit; and an instruction about a dimming level of the light emitting element; and a current corresponding to the received instruction is the light emitting element The constant current circuit is controlled so as to flow, and based on the integrated value of the information regarding the voltage drop at the light emitting element, the DC voltage is such that the voltage drop at the light emitting element becomes a predetermined voltage. And a control circuit that controls the variable voltage source so that the variable voltage source is output from the light source. The control circuit changes the integration time of the integral value according to the dimming level indicated by the instruction.

  In order to achieve the above object, a lighting fixture according to one embodiment of the present invention includes the lighting device and a light-emitting element.

  According to the present invention, it is possible to provide a lighting device that can achieve both suppression of flickering of illumination light from a light emitting element and good responsiveness of dimming control, and a lighting fixture including the same.

FIG. 1 is a circuit diagram illustrating an example of a circuit configuration of the lighting device and the lighting fixture according to the embodiment. FIG. 2A is a flowchart showing control on transistor Q2 by the control circuit of the lighting device according to the present embodiment. FIG. 2B is a flowchart illustrating control of the variable voltage source by the control circuit of the lighting device according to the embodiment. FIG. 3 is a graph illustrating an operation example of the lighting fixture according to the embodiment. FIG. 4 is a graph illustrating an operation example of the lighting fixture according to the comparative example. FIG. 5A is an external view of a lighting fixture according to the embodiment. FIG. 5B is an external view of another lighting apparatus according to the embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Each of the embodiments described below shows a specific example of the present invention. Therefore, the numerical values, shapes, materials, components, component arrangements, connection forms, and the like shown in the following embodiments are merely examples, and are not intended to limit the present invention. Therefore, among the constituent elements in the following embodiments, constituent elements that are not described in the independent claims showing the highest concept of the present invention are described as optional constituent elements.

  Each figure is a mimetic diagram and is not necessarily illustrated strictly. Moreover, in each figure, the same code | symbol is attached | subjected about the same structural member.

(Embodiment)
A lighting device according to an embodiment and a lighting fixture including the lighting device will be described.

[1. Configuration of lighting equipment]
Configurations of the lighting device and the lighting fixture according to this embodiment will be described with reference to the drawings.

  FIG. 1 is a circuit diagram illustrating an example of a circuit configuration of the lighting device 10 and the lighting fixture 20 according to the present embodiment.

  The lighting fixture 20 is a fixture that emits illumination light and has a dimming function. As shown in FIG. 1, the lighting fixture 20 includes a lighting device 10 and a light emitting element 5.

  The light emitting element 5 is an element that emits illumination light when supplied with current, and is, for example, an LED.

  The lighting device 10 is a device that supplies power to the light emitting element 5. The lighting device 10 controls the dimming level of the light emitting element 5 based on the dimming signal. The lighting device 10 includes an input circuit 11, a rectifier circuit 12, a variable voltage source 15, a transistor Q 2, a resistor R 1, and a control circuit 16. In FIG. 1, a dimmer 6 connected to the lighting device 10 is also shown.

  The dimmer 6 is a device that outputs a dimming signal that instructs the dimming level to the lighting device 10 (more specifically, the control circuit 16). The dimmer 6 is, for example, an input device such as a dial, a slider, an operation button, a touch panel, a detection circuit that reads an instruction from the input device, a signal generation / output / communication circuit that outputs the instruction as a dimming signal in a wired or wireless manner, and the like Consists of.

  The input circuit 11 is a circuit that receives AC power, and includes, for example, a connector connected to a system power supply such as a commercial power supply, a power filter, and the like.

  The rectifier circuit 12 is a circuit that converts AC power into DC power, and includes a bridge diode or the like.

  The variable voltage source 15 is a power source that supplies a variable DC voltage to the light emitting element 5 and the transistor Q2. The variable voltage source 15 raises or lowers the DC voltage output from the rectifier circuit 12 to a DC voltage corresponding to the control signal input from the first control terminal 16a of the control circuit 16, and outputs the voltage. The SEPIC (Single Ended Primary) Inductor Converter).

  More specifically, the variable voltage source 15 is a switching power supply including a diode D1, inductors L1 and L2, capacitors C1, C2 and C3, and a transistor Q1.

  The capacitor C1 is connected to the two output terminals of the rectifier circuit 12. Inductor L1 has one terminal connected to the output terminal on the high potential side of rectifier circuit 12, and the other terminal connected to the drain electrode of transistor Q1. Capacitor C2 has one terminal connected to the drain electrode of transistor Q1, and the other terminal connected to one terminal of inductor L2. The inductor L2 has one terminal connected to the other terminal of the capacitor C2, and the other terminal grounded. The diode D1 has an anode electrode connected to the one terminal of the inductor L2 and a cathode electrode connected to the output terminal on the high potential side of the lighting device 10. The capacitor C3 is an electrolytic capacitor, the positive electrode of the capacitor C3 is connected to the output terminal on the high potential side of the lighting device 10, and the negative electrode is grounded. The transistor Q1 is an element that switches based on a signal output from the first control terminal 16a of the control circuit 16 (that is, repeats ON and OFF). In the present embodiment, the transistor Q1 is formed of an N-channel MOS (Metal-Oxide Semiconductor) FET (Field-Effect Transistor).

  The transistor Q2 is an example of a constant current circuit that is connected in series with the light emitting element 5 and controls the current flowing through the light emitting element 5, and is, for example, an N-channel MOS FET. The transistor Q2 also functions as a dropper circuit that drops the voltage applied from the variable voltage source 15 to the load (light emitting element 5) by the voltage drop (drain-source voltage Vds) generated here.

  The resistor R1 is a protective resistance element. The resistance value of the resistor R1 is sufficiently smaller than the resistance value between the drain and source of the transistor Q2.

  The control circuit 16 is a circuit that controls the variable voltage source 15 and the transistor Q2 based on the dimming signal from the dimmer 6, and is realized by, for example, a microcomputer. The microcomputer is a one-chip semiconductor integrated circuit having a ROM, a RAM storing a program, a processor (CPU) for executing the program, a timer, an input / output circuit including an A / D converter and a D / A converter, and the like. .

  More specifically, when receiving an instruction (a dimming signal) about the dimming level of the light emitting element 5 from the dimmer 6, the control circuit 16 performs the following two controls. That is, one controls the transistor Q <b> 2 so that a current corresponding to the received instruction flows through the light emitting element 5. The other is variable based on the integrated value of the information related to the voltage drop at the light emitting element 5 so that a DC voltage that causes the voltage drop at the light emitting element 5 to be a predetermined voltage is output from the variable voltage source 15. The voltage source 15 is controlled. Further, the control circuit 16 changes the integration time of the integrated value of the information relating to the voltage drop in the light emitting element 5 according to the dimming level indicated by the instruction.

  Here, the control circuit 16 includes a first control terminal 16a connected to the control terminal (gate) of the transistor Q1 of the variable voltage source 15, and a second control terminal 16b connected to the control terminal (gate) of the transistor Q2. Have The control circuit 16 controls the variable voltage source 15 via the first control terminal 16a so that the voltage drop at the transistor Q2 becomes a predetermined voltage. On the other hand, the control circuit 16 controls the transistor Q2 through the second control terminal 16b so that a current corresponding to an instruction (dimming signal) from the dimmer 6 flows through the light emitting element 5.

[2. Operation]
Next, the operation of the lighting device 10 according to the present embodiment configured as described above will be described. Here, the operation of the control circuit 16 that has received an instruction (dimming signal) from the dimmer 6 will be mainly described.

  When receiving an instruction (a dimming signal) about the dimming level of the light emitting element 5 from the dimmer 6, the control circuit 16 performs the following two controls in parallel (or sequentially). That is, one controls the transistor Q <b> 2 so that a current corresponding to the received instruction flows through the light emitting element 5. The other is to control the variable voltage source 15 so that a DC voltage is output from the variable voltage source 15 so that the voltage drop at the transistor Q2 becomes a predetermined voltage.

  FIG. 2A is a flowchart showing control on the transistor Q2 by the control circuit 16 of the lighting device 10 according to the present embodiment.

  When the control circuit 16 receives an instruction (dimming signal) about the dimming level from the dimmer 6 (S10), a current corresponding to the instruction (dimming signal) from the dimmer 6 flows through the light emitting element 5. Thus, the transistor Q2 is controlled through the second control terminal 16b (S11).

  Specifically, the control circuit 16 stores a correspondence table between an instruction from the dimmer 6 and a voltage to be applied to the control terminal (gate) of the transistor Q2, and from the dimmer 6 according to the correspondence table. Is applied to the control terminal (gate) of the transistor Q2.

  With the control shown in FIG. 2A, a current corresponding to an instruction from the dimmer 6 flows to the light emitting element 5, and dimming control is performed.

  FIG. 2B is a flowchart showing control on the variable voltage source 15 by the control circuit 16 of the lighting device 10 according to the present embodiment.

  When receiving an instruction (dimming signal) about the dimming level from the dimmer 6 (S20), the control circuit 16 determines whether the instruction is equal to or higher than a predetermined dimming level (S21).

  As a result, when the instruction from the dimmer 6 is equal to or higher than the predetermined dimming level (Yes in S21), the control circuit 16 displays the information regarding the voltage drop in the light emitting element 5 in the first integration time. Integrate (S22).

  More specifically, the control circuit 16 monitors the voltage Vds at the connection point between the light emitting element 5 and the transistor Q2 as information relating to the voltage drop in the light emitting element 5. When the instruction from the dimmer 6 is equal to or higher than the predetermined dimming level, the control circuit 16 acquires an integrated value obtained by integrating the voltage Vds with the first integration time.

  On the other hand, when the instruction from the dimmer 6 is less than the predetermined dimming level (No in S21), the control circuit 16 sets the information related to the voltage drop in the light emitting element 5 longer than the first integration time. Integration is performed in the second integration time (S23). That is, the integration time is longer when the dimming level indicated by the instruction from the dimmer 6 is less than the predetermined dimming level than when the dimming level is equal to or higher than the predetermined dimming level.

  More specifically, when the instruction from the dimmer 6 is less than a predetermined dimming level, the control circuit 16 calculates an integration value obtained by integrating the voltage Vds with a second integration time longer than the first integration time. Have acquired.

  The above-mentioned predetermined dimming level may be a dimming level that does not make the flicker caused by the noise of the light emitting element 5 inconspicuous, and is about 20%, for example. Here, the value (%) of the dimming level is a value corresponding to the brightness, with 100% being fully lit (maximum brightness) and 0% being unlit.

  Further, the first integration time and the second integration time may be any time that can suppress the flickering of the light emitting element 5.

  Subsequently, the control circuit 16 controls the variable voltage source 15 so that the integrated value of the information related to the voltage drop in the light emitting element 5 becomes a predetermined voltage (S24). In the present embodiment, the control circuit 16 monitors the voltage Vds as information relating to the voltage drop in the light emitting element 5, and performs feedback control on the transistor Q1 so that the voltage Vds becomes a predetermined voltage. To do.

  For example, the transistor Q1 is controlled by changing the on-duty of the PWM signal applied to the gate terminal of the transistor Q1, that is, by changing the ON time in one ON / OFF cycle in the ON / OFF repetition of the transistor Q1. Done.

  Strictly speaking, the voltage Vds is the sum of the voltage drop at the transistor Q2 and the voltage drop at the resistor R1. However, since the resistance value of the resistor R1 is sufficiently smaller than the resistance value between the drain and source of the transistor Q2, in this embodiment, the control circuit 16 sets the voltage at the connection point between the light emitting element 5 and the transistor Q2 at the transistor Q2. Control is considered as a voltage drop.

  The method for setting the on-duty of the transistor Q1 in the control circuit 16 is not particularly limited. For example, the on-time Y of the transistor Q1 can be set by calculation as follows.

Y = Y _n-1 + α ₁ × E _n + α ₂ × E _n-1 (Formula 1)

_{Here, Y n-1} is the previous on-time applied to the transistor Q1, _{E n} is the current (or latest) the voltage _{Vds, E n-1} is the previous voltage Vds, alpha ₁ the coefficient for the current voltage Vds, alpha ₂ is a coefficient for past voltage Vds, representing respectively. By using the calculation shown in Expression 1, for example, when α ₁ is large and α ₂ is small, the influence of the current voltage Vds becomes relatively large in the on-time Y. Therefore, this example corresponds to the case where a relatively short integration time is used. On the other hand, when α ₁ is small and α ₂ is large, the influence of the past voltage Vds becomes relatively large in the on-time Y. Therefore, this example corresponds to the case where a long integration time is used.

  By using an arithmetic expression for the on-time Y as shown in Expression 1, it is possible to easily calculate the on-time Y corresponding to different integration times.

  Then, the operation example of the lighting fixture 20 provided with the lighting device 10 which concerns on this Embodiment is demonstrated using drawing.

  FIG. 3 is a graph illustrating an operation example of the lighting fixture 20 according to the present embodiment. A graph (a) in FIG. 3 shows an example of a voltage drop in the light emitting element 5, that is, a waveform of a forward voltage. The graph (b) and the graph (c) in FIG. 3 respectively show the waveform of the gate voltage applied to the transistor Q1 and the waveform of the output voltage Vdc of the variable voltage source 15 corresponding to the graph (a). Has been.

  FIG. 4 is a graph illustrating an operation example of the lighting fixture according to the comparative example. The graph (a) in FIG. 4 shows an example of the waveform of the forward voltage of the same light emitting element 5 as the graph (a) in FIG. 3. The graph (b1) and the graph (c1) in FIG. 4 respectively show the waveform of the gate voltage applied to the transistor Q1 and the waveform of the output voltage Vdc of the variable voltage source 15 corresponding to the graph (a). Has been. Each waveform shown in the graph (b1) and the graph (c1) is a waveform when only the first integration time is used as the integration time of the voltage Vds used in the control circuit 16, respectively. The graph (b2) and the graph (c2) in FIG. 4 show the waveform of the gate voltage applied to the transistor Q1 and the waveform of the output voltage Vdc of the variable voltage source 15 corresponding to the graph (a), respectively. Has been. Each waveform shown in the graph (b2) and the graph (c2) is a waveform when only the second integration time is used as the integration time of the voltage Vds used in the control circuit 16, respectively.

  In the example shown in the graph (b1) and the graph (c1) in FIG. 4, since the first integration time that is relatively short is used as the integration time of the voltage Vds, the response of the output voltage Vdc is fast. However, in this example, when the dimming level is less than 20%, the output voltage Vdc shown in the graph (c1) of FIG. 4 is caused by a minute fluctuation in the forward voltage shown in the graph (a) of FIG. Follow. For this reason, in the comparative example shown in the graph (c1), flickering occurs in the illumination light. Note that the minute fluctuations in the forward voltage shown in the graph (a) of FIG. 4 are caused by ripples and noise included in the output voltage Vdc.

  Further, in the example shown in the graph (b2) and the graph (c2) in FIG. 4, since the relatively long second integration time is used as the integration time of the voltage Vds, the output is output as shown in the graph (c2). There is no slight variation in the voltage Vdc. However, in this example, the response of the output voltage Vdc to the forward voltage is slow.

  On the other hand, in the lighting fixture 20 according to the present embodiment, as shown in the graph (c) of FIG. 3, when the dimming level is less than 20%, minute fluctuations in the output voltage Vdc are suppressed. . That is, even at a light control level where flickering is conspicuous, minute fluctuations in the output voltage Vdc are suppressed to such an extent that flickering cannot be confirmed. Moreover, in the lighting fixture 20 according to the present embodiment, when the dimming level is 20% or more, the integration time of the voltage Vds is relatively short, so that the response to the forward voltage is relatively fast.

[3. Summary]
As described above, the lighting device 10 according to the present embodiment is a lighting device 10 that supplies power to the light-emitting element 5, and is connected in series with the light-emitting element 5, and controls a current flowing through the light-emitting element 5. A current circuit; and a variable voltage source 15 that supplies a variable DC voltage to the light emitting element 5 and the constant current circuit. The lighting device 10 further receives an instruction about the dimming level of the light emitting element 5, controls the constant current circuit so that a current corresponding to the received instruction flows through the light emitting element 5, and reduces the voltage drop at the light emitting element 5. A control circuit 16 is provided for controlling the variable voltage source 15 so that a DC voltage that causes a voltage drop at the light emitting element 5 to be a predetermined voltage is output from the variable voltage source 15 based on the integral value of the information. The control circuit 16 changes the integration time of the integration value according to the dimming level indicated by the instruction.

  In such a lighting device 10, for example, when the dimming level indicated by the instruction is 20% or more in the control circuit 16, the integration time is short and the dimming level is less than 20%. Can increase the integration time. Therefore, in the lighting device 10, it is possible to achieve both suppression of flickering of illumination light from the light emitting element 5 and good responsiveness of dimming control.

  In the lighting device 10, the integration time may be longer when the dimming level indicated by the instruction is less than the predetermined value than when the dimming level is greater than or equal to the predetermined value.

  Thereby, in the lighting device 10, it is possible to achieve both suppression of flickering of illumination light from the light emitting element 5 and good responsiveness of dimming control.

  In the lighting device 10, the constant current circuit may include a transistor Q2.

  Thereby, the structure of the lighting device 10 can be simplified.

  Moreover, the lighting fixture 20 according to the present embodiment includes the lighting device 10 and the light emitting element 5.

  Thereby, the lighting fixture 20 can have the same effect as the lighting device 10.

(Other)
Hereinafter, specific examples and modifications of the lighting device 10 and the lighting fixture 20 according to the present embodiment will be described.

  5A and 5B are external views of lighting fixtures 20a and 20b according to the present embodiment, respectively.

  A lighting fixture 20a shown in FIG. 5A is a downlight used for stage effects and the like, and includes a circuit box 21a, a lamp body 22a, and a wiring 23. The circuit box 21a is a metal box that houses the lighting device 10 (not shown) according to the above embodiment. The lamp body 22a is an instrument in which an LED (not shown) as the light emitting element 5 is mounted and is embedded and fixed in a ceiling or the like. The wiring 23 is a cable that electrically connects the lighting device 10 in the circuit box 21a and the LEDs in the lamp body 22a.

  A lighting fixture 20b shown in FIG. 5B is a spotlight used for stage effects and the like, and includes a circuit box 21b and a lamp body 22b. The circuit box 21b is a metal box that houses the lighting device 10 (not shown) according to the above-described embodiment, and is attached to a dedicated rail or the like. The lamp body 22b is an instrument on which an LED (not shown) as the light emitting element 5 is mounted.

  Such lighting fixtures 20a and 20b each include the light emitting element 5 and the lighting device 10 according to the above-described embodiment that supplies power to the light emitting element 5.

  Thereby, in the lighting device 10 with which the lighting fixtures 20a and 20b are equipped, there exists an effect similar to the above-mentioned lighting device 10. FIG. Therefore, flicker can be suppressed when using illumination light at an extremely low dimming level of 20% or less as required for stage effects. In addition, a quick response required for stage production can be realized.

  As mentioned above, although the lighting device 10 and lighting fixture 20a, 20b which concern on this invention were demonstrated based on embodiment, this invention is not limited to this embodiment. Without departing from the gist of the present invention, various modifications conceived by those skilled in the art have been made in the present embodiment, and other forms constructed by combining some components in the embodiment are also within the scope of the present invention. Contained within.

  For example, in the above-described embodiment, the light emitting element 5 is an LED, but is not limited thereto, and may be another light emitting element such as an organic EL.

  Moreover, in the said embodiment, although the transistor Q2 was used as a constant current circuit in the lighting device 10, a constant current circuit is not limited to this. For example, a variable resistor may be used as the constant current circuit.

  Moreover, in the said embodiment, although the lighting device 10 had the input circuit 11 and the rectifier circuit 12, these are not necessarily required. The lighting device 10 may be a power supply circuit that does not require these circuits, for example, a DC voltage from a battery as an input.

  In the above embodiment, the variable voltage source 15 is a SEPIC. However, the variable voltage source 15 is not limited to this, and a linear regulator can be used as long as it is a DC voltage source capable of changing an output voltage in accordance with a control signal from the outside. Other voltage sources may be used.

  In the above embodiment, the protective resistor R1 is used for the lighting device 10, but the resistor R1 is not always necessary and may not be mounted according to the required specifications.

  Moreover, in the said embodiment, the control circuit 16 was implement | achieved like software with the microcomputer which has a program. However, it is not limited to such an implementation method, and may be realized in hardware by a dedicated electronic circuit configured with an A / D converter, a logic circuit, a gate array, a D / A converter, and the like.

  In the above embodiment, the control circuit 16 uses only the first integration time and the second integration time. However, different integration times may be used together. For example, an integration time inversely proportional to the dimming level may be used.

  Moreover, in the said embodiment, although the lighting fixtures 20a and 20b were a downlight and a spotlight, it is not restricted to such a kind, Other types of illumination, such as a ceiling light, a chandelier, a pendant light, and a footlight It may be an instrument.

  In addition, it is realized by arbitrarily combining the components and functions in each embodiment without departing from the scope of the present invention, and forms obtained by making various modifications conceived by those skilled in the art to each embodiment. Forms are also included in the present invention.

5 Light-Emitting Element 10 Lighting Device 15 Variable Voltage Source 16 Control Circuit Q2 Transistor (Constant Current Circuit)

Claims (4)

A lighting device for supplying power to a light emitting element,
A constant current circuit connected in series with the light emitting element and controlling a current flowing through the light emitting element;
A variable voltage source for supplying a variable DC voltage to the light emitting element and the constant current circuit;
An integrated value of information relating to a voltage drop in the light emitting element is received by receiving an instruction about the dimming level of the light emitting element, controlling the constant current circuit so that a current corresponding to the received instruction flows through the light emitting element. And a control circuit for controlling the variable voltage source so that the DC voltage is outputted from the variable voltage source so that a voltage drop at the light emitting element becomes a predetermined voltage.
The control circuit changes an integration time of the integral value according to a dimming level indicated by the instruction. The lighting device according to claim 1, wherein the integration time is longer when the dimming level indicated by the instruction is less than a predetermined value than when the dimming level is greater than or equal to the predetermined value. The lighting device according to claim 1, wherein the constant current circuit includes a transistor. The lighting device according to any one of claims 1 to 3,
A lighting fixture comprising the light emitting element.

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