JP5828107B2 - Lighting device and lighting apparatus provided with the same - Google Patents

Description

  The present invention relates to a lighting device for lighting a light emitting element and a lighting fixture including the same.

  For example, as a lighting fixture used in stores, etc., dimming that can light up light emitting elements such as LEDs (Light Emitting Diodes) and organic EL (Electro Luminescence) by the output of the lighting device, and arbitrarily change the light output of the light emitting elements Devices having a function are known. In this type of lighting fixture, a lighting device receives a control signal from a control device that generates a control signal in accordance with an operation of a dimming operation unit such as a wall switch, and dims and lights a light emitting element. In such lighting fixtures, generally, when a user operates a wall switch or the like, the lighting device is turned on, and at the same time, the control device that generates a control signal is also turned on (for example, Patent Documents). 1).

  By the way, there is no problem if the control signal is input immediately after the lighting apparatus is turned on, but the control signal may be input after the start of the lighting device. In a general discharge lamp lighting device having a filament, since the filament is pre-heated immediately after the power is turned on, a certain period of time is required for start-up, and the discharge lamp is set not to light during that time. Even if the signal input is delayed, it does not matter much. However, in a lighting device for light emitting elements such as LEDs, the circuit is started immediately after the power is turned on without performing pre-heating, so that if the input of the control signal is delayed, the light emitting element is dimmed to a desired light output. There is a possibility of shifting to dimming lighting after all lighting for a moment before being controlled.

  Therefore, in the luminaire described in Patent Document 1, the control signal (dimming signal) is canceled only for a predetermined time immediately after the lighting device (power supply device) is turned on, so that the entire lighting state (all light) To avoid the phenomenon of becoming a state. Patent Document 1 also describes that the lighting device turns off the light emitting element by controlling the DC output with a reference signal for a predetermined time during which the lighting device cancels the control signal.

JP 2009-232625 A

  However, in the lighting device described in Patent Document 1, since the control signal is canceled for a predetermined time immediately after the power is turned on, if the control signal is not input even after the predetermined time has passed since the power is turned on, the light emitting element outputs the desired light output. There is a possibility that all lights will be turned on for a moment before the dimming control is performed. In addition, when the predetermined time is set longer than the maximum delay time from power-on until the control signal is output, if the delay time varies for each control device, the predetermined time is unnecessarily long. The starting of the lighting device will be delayed.

  The present invention has been made in view of the above reasons, and can reliably prevent the light emitting element from being fully turned on for a moment before dimming control is performed to a desired light output, and can be controlled from power-on for each control device. It is an object of the present invention to provide a lighting device that does not delay starting even if there is a variation in the delay time until a signal is output, and a lighting fixture including the lighting device.

The lighting device of the present invention adjusts the light emitting element at a desired dimming ratio by controlling the power supply unit according to a control signal input from the outside and a power supply unit that supplies power to the light emitting element. A dimming control unit for turning on the light, and the dimming control unit stops power supply from the power supply unit to the light emitting element until the control signal is input, and as soon as the control signal is input The power supply unit is controlled so that the light emitting element is dimmed and lit at a dimming ratio according to the control signal, and the dimming control unit is a dimming whose size is determined according to the control signal. A control voltage is compared with a detection voltage representing the magnitude of power supplied from the power supply unit to the light emitting element, and when the detection voltage falls below the dimming control voltage, the power supply unit transfers the light emitting element. The power is supplied and the control signal is input. The so detected voltage is not lower than the said dimming control voltage, the the detection voltage is characterized in that bias constantly being applied in the absence.

  In this lighting device, the control signal may be a signal whose duty ratio changes according to a target value of the dimming ratio, and the dimming control voltage may change in magnitude depending on the duty ratio of the control signal. desirable.

  The lighting fixture of this invention is equipped with said lighting device and the light emission unit which has the said light emitting element, It is characterized by the above-mentioned.

  According to the present invention, it is possible to reliably avoid that the light emitting element is completely turned on for a moment before dimming control is performed to a desired light output, and a delay time from power-on to output of a control signal for each control device. There is an advantage that the start-up is not delayed even if there is a variation.

It is a circuit diagram which shows the structure of the principal part of the lighting fixture which concerns on embodiment. It is a circuit diagram which shows the whole structure of the lighting fixture which concerns on embodiment. It is explanatory drawing of operation | movement of the flyback circuit of the lighting fixture which concerns on embodiment. It is explanatory drawing of operation | movement of the light control circuit of the lighting fixture which concerns on embodiment.

  The lighting fixture 10 of this embodiment is provided with the light emitting unit 1 and the lighting device 2 as shown in FIG. This luminaire 10 has a dimming function that can arbitrarily change the light output of the light emitting unit 1. For example, a control device that generates a control signal in accordance with an operation of a dimming operation unit such as a wall switch ( In response to a control signal from (not shown), the light emitting unit 1 is dimmed. In such a luminaire 10, generally, when the user operates a wall switch or the like, the lighting device 2 is turned on, and at the same time, the control device that generates a control signal is also turned on.

The lighting device 2 includes a flyback circuit 20 as a power supply unit, and lights the light emitting unit 1 by supplying power from the flyback circuit 20 to the light emitting element 11 in the light emitting unit 1. The light emitting unit 1 includes a series circuit of a plurality of light emitting elements 11. The light emitting element here is LED (Light Emitting Diode) and organic EL (Electro Luminescence) means an element that emits light upon receiving power supply. In this embodiment, an LED is used as the light emitting element 11.

  The lighting device 2 is connected to a filter circuit 21 connected to an AC power supply (commercial power supply) 3, a rectifier 22 including a diode bridge that rectifies the output of the filter circuit 21, and an output of the rectifier 22 via an inrush prevention circuit 23. The boost chopper circuit 24 is provided. The flyback circuit 20 is provided at the subsequent stage of the boost chopper circuit 24 and generates a DC voltage to be applied to the light emitting unit 1 with the DC voltage boosted by the boost chopper circuit 24 as an input.

  Further, the lighting device 2 includes a control power supply unit 25 that generates power for a chopper control unit 240 and a flyback control unit 200, which will be described later, a dimming control circuit 26 that enables dimming lighting of the light emitting unit 1, and an output. And a feedback circuit 27 for feeding back. As will be described in detail later, the dimming control circuit 26 controls the flyback circuit 20 in accordance with a control signal input from the outside (control device), thereby dimming the light emitting unit 1 with a desired dimming ratio. Light up.

In addition to the chopper controller 240, the boost chopper circuit 24 includes a capacitor 241 connected between the input terminals, and a series circuit of the chopper choke 242 and the first switching element 243 connected between both ends of the capacitor 241. Have. Here, the first switching element 243 is an N-channel MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor). Further, the step-up chopper circuit 24 includes a series circuit of a diode 244 and an electrolytic capacitor 245 connected between both ends (drain-source) of the first switching element 243. One end of the chopper choke 242 is connected to the connection point between the inrush prevention circuit 23 and the capacitor 241, and the other end is connected to the anode of the diode 244. A chopper controller 240 is connected to the gate of the first switching element 243.

  Here, the chopper controller 240 performs switching control for turning on and off the first switching element 243 according to the secondary output of the chopper choke 242. As a result, the boost chopper circuit 24 accumulates energy in the chopper choke 242 while the first switching element 243 is on, and the electrolytic capacitor 245 via the diode 244 with the energy of the chopper choke 242 during the off period. To charge. As a result, a desired DC voltage boosted from the peak value of the AC voltage is generated at the output terminal of the boost chopper circuit 24 (both ends of the electrolytic capacitor 245).

  The flyback circuit 20 includes a flyback transformer 201, a second switching element 202 made of an N-channel MOSFET, a diode 203, an electrolytic capacitor 204, and a resistor 205 in addition to the flyback control unit 200. ing. The primary winding of the flyback transformer 201 and the second switching element 202 are connected in series between the output terminals of the step-up chopper circuit 24. A diode 203, an electrolytic capacitor 204, and a resistor 205 are connected in series to the secondary winding of the flyback transformer 201. The light emitting unit 1 is connected to both ends of the electrolytic capacitor 204, and the connection point between the resistor 205 and the secondary winding of the flyback transformer 201 is connected to circuit ground. A flyback control unit 200 is connected to the gate of the second switching element 202.

  Here, the flyback control unit 200 detects the current flowing through the primary side of the flyback transformer 201 and performs switching control to turn on and off the second switching element 202 according to the detected current. Accordingly, the flyback circuit 20 stores energy in the flyback transformer 201 when the second switching element 202 is turned on, and charges the electrolytic capacitor 204 via the diode 203 with the energy of the flyback transformer 201 when the second switching element 202 is turned off. As a result, a smoothed DC voltage is generated at the output terminals of the flyback circuit 20 (both ends of the electrolytic capacitor 204), and the light emitting unit 1 is turned on when this DC voltage is applied to the light emitting unit 1.

  Next, the operation of the flyback circuit 20 will be described with reference to FIG. 3, (a) is the drain-source voltage Vds of the second switching element 202, (b) is the drain current Id of the second switching element 202, and (c) is the output voltage Vout of the flyback control unit 200. Represents.

  As shown in FIG. 3, when the output voltage Vout is switched from the L level to the H level at time T1, the second switching element 202 is turned on, and the drain current Id flowing through the primary side of the flyback transformer 201 is gradually increased. Become. Thereafter, when the drain current Id reaches a predetermined threshold value at time T2, the output voltage Vout of the flyback control unit 200 changes from H level to L level, and the second switching element 202 is turned off. As a result, the drain current Id is cut off, the drain-source voltage Vds of the second switching element 202 rises, and the current flows to the secondary side of the flyback transformer 201.

  Thereafter, the current flowing through the secondary side of the flyback transformer 201 becomes zero, and the drain-source voltage Vds of the second switching element 202 starts to decrease. At this time, since a delay time due to the oscillation frequency or the like occurs, at time T3 after the delay time elapses after the drain-source voltage Vds starts to decrease, the output voltage Vout changes from the L level to the H level, and the second switching. Element 202 is turned on.

  In this manner, the flyback circuit 20 generates a DC voltage at the output terminals (both ends of the electrolytic capacitor 204) when the second switching element 202 is turned on and off, and applies the generated DC voltage to the light emitting unit 1.

  The light output of the light emitting unit 1 increases as the current flowing through the light emitting element 11 increases. The magnitude of the current flowing through the light emitting element 11 is reflected in the voltage across the resistor 205 between the secondary winding of the flyback transformer 201 and the electrolytic capacitor 204 shown in FIG. 2, and the resistance increases as the current of the light emitting element 11 increases. The voltage at both ends of 205 increases. Therefore, the feedback circuit 27 is connected to a connection point between the electrolytic capacitor 204 and the resistor 205, and detects a voltage across the resistor 205 to send a feedback signal reflecting the light output of the light emitting unit 1 to the flyback control unit 200. give feedback.

  That is, the feedback circuit 27 receives the output of the dimming control circuit 26, and adjusts the voltage across the resistor 205 so that the light output of the light emitting unit 1 matches the desired dimming ratio determined by the dimming control circuit 26. The output of the dimming control circuit 26 is compared to generate a feedback signal. The flyback control unit 200 controls the switching of the second switching element 202 according to the feedback signal, thereby adjusting the output of the flyback circuit 20 and dimming the light emitting unit 1 with a desired dimming ratio.

  Hereinafter, specific circuit configurations of the dimming control circuit 26 and the feedback circuit 27 for realizing such dimming lighting will be described with reference to FIG. The dimming control circuit 26 and the feedback circuit 27 constitute a dimming control unit.

The dimming control circuit 26 includes a diode bridge 261 provided in the input stage and a photocoupler 262 connected to the output of the diode bridge 261. The diode bridge 261 has a PWM (Pulse Width) in which the duty ratio changes according to the target value of the dimming ratio. A control signal including a modulation signal is input from an external control device (not shown). The control device changes the duty ratio of the control signal in accordance with the target value of the dimming ratio determined by the operation of the dimming operation unit (not shown), and the target value of the dimming ratio becomes large (that is, full lighting The duty ratio of the control signal is increased as the value approaches. The control device has a power circuit different from that of the lighting device 2, but the power is turned on simultaneously with the lighting device 2 when the lighting fixture 10 is activated.

  A control voltage Vcc1 output from the control power supply unit 25 is applied to the secondary side of the photocoupler 262 via the resistor 263. An npn transistor 264 is connected to a connection point between the resistor 263 and the photocoupler 262. The base of is connected. Further, the dimming control circuit 26 has a control IC (integrated circuit) 265. The collector of the transistor 264 is connected to the input terminal of the control IC 265, and the emitter is connected to the circuit ground. The control voltage Vcc1 is applied to the power supply terminal of the control IC 265.

  The output terminal of the control IC 265 is connected to the circuit ground via a series circuit of a pair of resistors 266 and 267, and the connection point of the resistors 266 and 267 is connected to the gate of the third switching element 268. A series circuit of a pair of resistors 270 and 271 is connected between the output terminals of a reference power supply unit (not shown) that generates the reference voltage Vcc2, and the third switching element 268 is connected to a connection point between the resistors 270 and 271 and a circuit ground. Is inserted between. Further, a series circuit of a resistor 272 and a capacitor 273 is connected in parallel with the third switching element 268, and a series circuit of a resistor 274 and a capacitor 275 is connected in parallel with the capacitor 273.

  Thereby, the dimming control circuit 26 rectifies the control signal input from the control device by the diode bridge 261, insulates and inverts it by the photocoupler 262, further inverts it by the transistor 264, and inputs it to the control IC 265. To do. The control IC 265 shapes and inverts the signal waveform input in this way, and performs on / off control of the third switching element 268 as a gate signal. That is, the third switching element 268 is turned off when the control signal is at the H level and turned on when the control signal is at the L level.

  When the third switching element 268 is turned on / off according to the control signal, a pulse wave as shown in FIG. 4A is generated at the connection point P1 of the resistors 270 and 271. The pulse wave generated at the connection point P1 has the same duty ratio and the same polarity as the control signal. That is, the pulse wave generated at the connection point P1 is L level when the control signal is L level, and is H level when the control signal is H level.

  When such a pulse wave is generated at the connection point P1, as shown in FIG. 4B, a waveform smoothed by an integration circuit including the resistance 272 and the capacitor 273 at the connection point P2 between the resistor 272 and the capacitor 273. Occurs. Further, a waveform smoothed by an integrating circuit including the resistor 274 and the capacitor 275 is generated at the connection point P3 between the resistor 274 and the capacitor 275, as shown in FIG.

  In short, a pulse wave composed of a PWM signal is converted into a DC voltage having a relatively small ripple component by a two-stage low-pass filter (integration circuit), and is fed back as a dimming control voltage from a connection point P3 between the resistor 274 and the capacitor 275. It is output to the circuit 27. In other words, the dimming control circuit 26 outputs a DC voltage whose magnitude is determined according to the duty ratio of the control signal to the feedback circuit 27 as a dimming control voltage, and the dimming control circuit 26 adjusts as the duty ratio of the control signal decreases. Reduce the light control voltage.

  The feedback circuit 27 includes an operational amplifier 276 that receives a dimming control voltage at its inverting input terminal, resistors 277 and 278 connected to the non-inverting input terminal of the operational amplifier 276, and a transistor whose base is connected to the output terminal of the operational amplifier 276. 279. A non-inverting input terminal of the operational amplifier 276 is connected to the control power supply unit 25 through a resistor 277 and is connected to a connection point between the electrolytic capacitor 204 and the resistor 205 through a resistor 278. In FIG. 1, the electrolytic capacitor 204 is not shown.

  That is, the control voltage Vcc1 output from the control power supply unit 25 is divided by a series circuit of three resistors 277, 278, 205, and the voltage across the resistors 278, 205 is input to the non-inverting input terminal of the operational amplifier 276. . Here, the voltage across the resistor 205 changes according to the light output of the light emitting unit 1 as described above, and the dimming control voltage is determined according to the duty ratio of the control signal. Therefore, the operational amplifier 276 has a magnitude according to the voltage across the resistors 278 and 205 (hereinafter referred to as “detection voltage”) indicating the magnitude of the power supplied from the flyback circuit 20 to the light emitting element 11 and the control signal. The determined dimming control voltage is compared. Accordingly, the operational amplifier 276 turns on the transistor 279 if the detected voltage is larger than the dimming control voltage, and turns off the transistor 279 if the detected voltage is smaller than the dimming control voltage.

  The transistor 279 is connected to the flyback control unit 200, and the flyback control unit 200 performs switching control of the second switching element 202 in accordance with on / off of the transistor 279. Here, the flyback control unit 200 performs the switching control of the second switching element 202 only when the transistor 279 is off, and stops the switching control of the second switching element 202 when the transistor 279 is on. Therefore, when the transistor 279 is on, the operation of the flyback circuit 20 is stopped and the light emitting unit 1 is turned off.

  In short, the feedback circuit 27 operates the flyback circuit 20 from the flyback circuit 20 to the light emitting element when the detected voltage is lower than the dimming control voltage as a result of comparing the detected voltage and the dimming control voltage. Supply. On the other hand, when the detected voltage exceeds the dimming control voltage, the operation of the flyback circuit 20 is stopped, and the power supply from the flyback circuit 20 to the light emitting element is stopped.

  With the configuration described above, the lighting device 2 maintains the light emitting unit 1 in the extinguished state if the dimming control voltage output from the dimming control circuit 26 is zero, while if the dimming control voltage is maximum, The light emitting unit 1 is fully lit (rated lighting). Further, when the dimming control voltage changes according to the duty ratio of the control signal, the lighting device 2 changes the light output of the light emitting unit 1 along with the change of the dimming control voltage. As a result, the lighting device 2 can dimm and light the light emitting unit 1 with a desired dimming ratio including turning off and full lighting in accordance with a control signal from the control device.

  By the way, in this embodiment, since the dimming control circuit 26 controls the flyback circuit 20 according to the control signal input from the outside (control device), the control signal is input after the start of the lighting device 2. Sometimes. Moreover, in the lighting device 2 for the light emitting element 11, since the circuit is generally started immediately after the power is turned on, the state of the light emitting unit 1 until the control signal is input when the input of the control signal is delayed. It may be unstable.

  Therefore, in the present embodiment, the dimming control unit including the dimming control circuit 26 and the feedback circuit 27 supplies power from the flyback circuit 20 serving as the power supply unit to the light emitting unit 1 when no control signal is input. The flyback circuit 20 is controlled so as to be stopped. That is, if the dimming control voltage output from the dimming control circuit 26 is zero as described above, the lighting device 2 turns on the transistor 279 and stops the operation of the flyback circuit 20, thereby causing the light emitting unit 1. The power supply to is stopped and the light emitting unit 1 is kept in the extinguished state.

  Here, since the feedback circuit 27 operates the flyback circuit 20 when the detected voltage falls below the dimming control voltage, the detected voltage does not fall below the dimming control voltage when no control signal is input. The detection voltage is always biased. Specifically, as described above, the control voltage Vcc1 output from the control power supply unit 25 is divided by a series circuit of three resistors 277, 278, 205, and the operational amplifier 276 uses the voltage across the resistors 278, 205 as the detection voltage. Has been entered. As a result, the detection voltage is constantly biased by the control voltage Vcc1, so that the detection voltage does not become zero even when power is not supplied to the light emitting element 11, and the adjustment is performed when no control signal is input. It will definitely exceed the light control voltage.

  According to the lighting device 2 of the present embodiment described above, the light emitting element 11 maintains the extinguished state when no control signal is input. Therefore, the light emitting element 11 is momentarily controlled to be dimmed to a desired light output. It is possible to reliably avoid the occurrence of flash due to only full lighting. Moreover, since the control signal is not canceled for a predetermined time immediately after the power is turned on as in the configuration described in Patent Document 1, the lighting device 2 immediately responds to the control signal when the control signal is input. The light emitting unit 1 can be dimmed with the dimming ratio. That is, the lighting device 2 is not delayed in starting even if there is a variation in the delay time from when the power is turned on until the control signal is output for each control device.

  As a result, the lighting device 2 turns off the light emitting unit 1 until the control signal is input, even if a control signal is input after the power is turned on, and as soon as the control signal is input, the light emitting unit 1 The light can be dimmed to achieve a gentle rise. By providing the lighting device 10 with such a lighting device 2, it is possible to provide a high-quality lighting device 10 that rises smoothly.

  In addition, since the detection voltage is always biased, the detection voltage is lower than the dimming control voltage even if the dimming control voltage may not be zero due to noise or the like when no control signal is input. The operation of the flyback circuit 20 can be stopped reliably. Therefore, the lighting device 2 can reliably maintain the light emitting element 11 in the extinguished state even when there is an influence of noise or the like when no control signal is input.

  Furthermore, in this embodiment, the control signal is a PWM signal whose duty ratio changes according to the target value of the dimming ratio, and the dimming control voltage changes in magnitude depending on the duty ratio of the control signal. Therefore, the lighting device 2 can be used in combination with a general control device that outputs a PWM signal as a control signal, and fine dimming control is possible by finely setting the magnitude of the dimming control voltage. Become.

  Furthermore, according to the lighting device 2 of the present embodiment, the light emitting unit 1 is always turned off when no control signal is input, regardless of the elapsed time from the time of turning on the power. Even when the control signal is interrupted due to the occurrence, the light-off state can be maintained. A plurality of lighting fixtures 10 having different starting operations are simultaneously turned on, such as a lighting fixture 10 that shifts from a dimming state to a fully lit state after power-on, and a lighting fixture 10 that starts in a fully lit state from the beginning. Even if it does, there exists an advantage by applying the lighting device 2 of this embodiment. In other words, in the state where no control signal is input to the lighting device 2, any lighting fixture 10 maintains the extinguished state, so even if the predetermined time is not set individually for each lighting fixture 10 using a microcomputer or the like, There are advantages such as easy control with desired light output and lighting timing.

DESCRIPTION OF SYMBOLS 1 Light emission unit 2 Lighting device 10 Lighting fixture 11 Light emitting element 20 Flyback circuit (electric power supply part)
26 Dimming control circuit (dimming control unit)
27 Feedback circuit (dimming controller)

Claims (3)

A power supply unit that supplies power to the light emitting element, and a dimming control unit that dimms and lights the light emitting element at a desired dimming ratio by controlling the power supply unit according to a control signal input from outside And
The dimming control unit stops power supply from the power supply unit to the light emitting element until the control signal is input, and immediately after the control signal is input, the dimming control unit adjusts the dimming ratio according to the control signal. And controlling the power supply unit so that the light emitting element is dimmed and lit ,
The dimming control unit compares the dimming control voltage, the magnitude of which is determined according to the control signal, with a detection voltage representing the magnitude of power supplied from the power supply unit to the light emitting element, and performs the detection. When the voltage falls below the dimming control voltage, power is supplied from the power supply unit to the light emitting element,
The lighting device , wherein the detection voltage is always biased so that the detection voltage does not fall below the dimming control voltage when the control signal is not input .   2. The control signal is a signal whose duty ratio changes according to a target value of a dimming ratio, and the dimming control voltage changes in magnitude according to the duty ratio of the control signal. The lighting device described in 1.   A lighting apparatus comprising: the lighting device according to claim 1 or 2; and a light emitting unit having the light emitting element.

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