JP5810380B2 - LED lighting device - Google Patents

Description

  The present invention relates to an LED lighting device corresponding to a dimming function by a phase control dimmer.

  The market for this type of LED lighting device is rapidly expanding for the purpose of energy saving. This LED lighting device is generally provided with a dimmer to change the brightness. This dimmer adjusts the phase in which a thyristor such as a triac is turned on so that the current from the AC power source is supplied to the LED lighting device only during the period in which the thyristor is turned on. Usually, an optical device is used (see, for example, Patent Document 1).

  In the LED lighting device using the phase control type dimmer, in order to change the brightness of the LED for illumination, the LED for illumination is changed according to the phase-controlled AC voltage waveform output from the dimmer. It is necessary to control the LED current to.

  As a control parameter, a method using an effective value and a conduction width of an AC voltage waveform is conventionally known.

JP 2007-35403 A

  However, when the AC voltage fluctuates, the phase control type dimmer changes not only the peak value of the AC voltage waveform subjected to phase control but also the conduction width. There were fluctuations. If this AC voltage fluctuation is large, the LED current fluctuation also increases, and this fluctuation is felt uncomfortable for the user.

  Accordingly, an object of the present invention is to provide a more comfortable LED lighting device by suppressing fluctuations in LED current due to fluctuations in AC voltage.

  In order to achieve this object, the present invention provides a phase control type dimmer capable of adjusting a phase supplied with alternating current from a power source and conducted by an operating means, and a rectifier circuit for rectifying the alternating current from the dimmer. And an input smoothing unit that smoothes the rectified current and voltage of the rectifier circuit to direct current, and converts the direct current from the input smoothing unit to alternating current and smoothes it to direct current, and supplies the output current to the LED for illumination. In an LED lighting device including an LED lighting circuit, a reference voltage is generated based on a charging current detection circuit that detects a charging current of the input smoothing unit, and a time during which the charging current detected by the charging current detection circuit flows, It has a lighting control circuit which controls the LED lighting circuit so that the output current of the LED lighting circuit becomes a current value corresponding to a reference voltage.

  According to this structure, the fluctuation | variation of the LED current by an alternating voltage fluctuation | variation can be suppressed.

It is explanatory drawing of the LED lighting device which concerns on this invention. It is a control circuit diagram of the LED lighting device of FIG. (Example 1) It is explanatory drawing at the time of making the parameter for control of a LED lighting device into the effective value of a voltage waveform. It is an output voltage waveform of the phase control dimmer when the AC input voltage is 90V and 110V. 6 is a waveform of a charging current to the input smoothing unit according to the first embodiment. It is a control circuit diagram which shows the other example of the LED lighting device of FIG. (Example 2) It is explanatory drawing at the time of making the parameter for control of a LED lighting device into the conduction | electrical_connection width of a voltage waveform. 6 is a waveform of a charging current to the input smoothing unit in Examples 2 and 3. FIG. It is a control circuit diagram which shows the other example of the LED lighting device of FIG. (Example 3) It is explanatory drawing at the time of setting the parameter for control of a LED lighting device as the time when the charging current to an input smoothing part flows.

  Hereinafter, an LED lighting device according to an embodiment of the present invention will be described with reference to the drawings.

[Constitution]
In FIG. 1, AC is a commercial power source, 1 is an LED lighting device, and 2 is a phase control type dimmer. The LED lighting device 1 includes an input filter circuit 3, a rectifier circuit 4, an input smoothing circuit 5, an LED lighting circuit 6, a charging current detection circuit 7, and a lighting control circuit 8.

  The phase control type dimmer 2 has a known configuration, but the phase control of the dimmer 2 will be outlined for the convenience of the following description. The dimmer 2 is provided so that an AC voltage from a commercial power source AC can be supplied to the LED lighting device 1 via a thyristor such as a triac. Moreover, the alternating current / voltage from the commercial power supply AC is supplied to the rectifier circuit 4 via the thyristor when the thyristor is ON (conducting). Further, the dimmer 2 controls the supply period of the alternating current / voltage to the LED lighting device 1 by controlling the phase of the alternating current / voltage at which the thyristor is turned on by operating means (not shown), and the LED lighting device. The amount of current supplied from the one lighting control circuit 8 to the illumination LED 80 is controlled as described later, and the amount of illumination light of the illumination LED 80 is adjusted.

Next, specific examples of the input filter circuit 3, the rectifier circuit 4, the input smoothing circuit 5, the LED lighting circuit 6, the charging current detection circuit 7, the lighting control circuit 8, and the like will be described with reference to FIG.
<Input filter circuit 3>
The input filter circuit 3 includes a resistor R1, a capacitor C1, a line filter L1, and the like, and prevents a voltage / current attenuation vibration generated in the power supply loop of the LED lighting device 1 and prevents noise. is there.
<Rectifier circuit 4>
The rectifier circuit 4 is phase-controlled by the dimmer 2 and rectifies the current / voltage (output voltage / current) output from the input filter circuit 3 to be rectified rectified current / voltage (output current / voltage). Are output from the rectified output terminal b on the + side and the rectified output terminal a on the − side. Wirings SL2 and SL1 are connected to the rectified output terminals a and b, respectively. C2 is a noise prevention capacitor connected to the wirings SL1 and SL2.
<Input smoothing circuit 5>
The input smoothing circuit 5 has a smoothing capacitor C3.
<Charging current detection circuit 7>
The charging current detection circuit 7 includes a resistor R2, a light emitting diode LED1, a resistor R3, a diode D1, and the like of a photocoupler PH1 used for detecting a charging current charged in the capacitor C3.

One end of the resistor R2 is connected to the wiring SL1, and the other end is connected to the wiring SL2 via the capacitor C3. Thus, the resistor R2 and the capacitor C3 are connected in series between the wirings SL1 and SL2, and are provided in parallel with the capacitor C2. The light emitting diode LED1, the resistor R3, and the diode D1 are connected in series in this order. Moreover, the anode side of the light emitting diode LED1 is connected to the wiring SL1, and the cathode side of the diode D1 is connected between the resistor R2 and the capacitor C3. As a result, the light emitting diode LED1 and the diode D1 are provided so as to allow a current flow to the connection side from the wiring SL1 to the capacitor C3 and the resistor R2. The light emitting diode LED1 detects the charging current of the capacitor C3 by emitting light when charging the capacitor C3.
<LED lighting circuit 6>
The LED lighting circuit 6 includes an inverter circuit 40 and an output smoothing circuit 50. An output side of the LED lighting circuit 6 is connected to an illumination LED 80 (load) via a connector 70.
(Inverter circuit 40)
The inverter circuit 40 includes a transformer T, a switching element Q1, a drive circuit IC1, and the like. The transformer T includes a primary winding TL1 and a secondary winding TL2 having one end connected to the wiring SL1. Further, a MOS FET is used for the switching element Q1, the drain side of the switching element Q1 is connected to the primary winding TL1, and the source side of the switching element Q1 is connected to the wiring SL2. A transistor other than a MOS FET can be used as the switching element Q1.

  The drive circuit IC1 has an output side connected to the gate of the switching element Q1, and turns on / off the switching element Q1 at a predetermined cycle (at a predetermined frequency).

Note that OL1 is a + side output wiring (+ side wiring) connected to one end of the secondary winding TL2, and OL2 is a − side output wiring (− side wiring) connected to the other end of the secondary winding TL2. It is. An output terminal Ota of the connector 70 is connected to the output wiring OL1, and an output terminal Otb of the connector 70 is connected to the output wiring OL2.
(Output smoothing circuit 50)
In the output smoothing circuit 50, a diode D2 provided in the middle of the output wiring OL1 and having an anode connected to the secondary winding TL2 of the transformer T is connected between the cathode of the diode D2 and the output wiring OL2. A smoothing capacitor C4 is provided. The diode D2 and the capacitor C4 rectify and smooth the AC voltage output from the inverter circuit 40.
<Lighting control circuit 8>
The lighting control circuit 8 includes a constant current control unit 60 and a phototransistor PTr2 of the photocoupler PH2. The phototransistor PTr2 has a collector side connected to the input terminal It of the drive circuit IC1 and an emitter side connected to the wiring SL2. The drive circuit IC1 controls the on-time of the switching element Q1 according to the voltage of the input terminal It controlled by the phototransistor PTr2.

  The constant current control unit 60 includes a comparison circuit (comparator) IC2, a phototransistor PTr1 of the photocoupler PH1, a light emitting diode LED2 of the photocoupler PH2, resistors R4, R5, R6, and R7.

  The phototransistor PTr1 of the photocoupler PH1 has a collector side connected to a power supply and an emitter side connected to the + input terminal of the comparison circuit IC2 via a resistor R4.

  In addition, a resistor R5 and a capacitor C5 are connected in parallel to the + input terminal of the comparison circuit IC2 and the output wiring OL2. Further, one end of the wiring SL3 is connected to the negative input terminal of the comparison circuit IC2, and the other end of the wiring SL3 is connected to the output wiring OL2. Further, the anode side of the light emitting diode LED2 of the photocoupler PH2 is connected to the output side of the comparison circuit IC2, and the cathode side of the light emitting diode LED2 of the photocoupler PH2 is connected to the output wiring OL2 via the resistor R6.

Here, when the connection portion of the capacitor C5 to the output wiring OL2 is P1, the connection portion of the resistor R6 to the output wiring OL2 is P2, and the connection portion of the wiring SL3 to the output wiring OL2 is P3, the connection portion P2 is It is located between the connection parts P1, P3. In addition, the resistor R7 is located between the connecting portions P2 and P3 and is interposed in the middle of the output wiring OL2.
[Action]
Next, the operation of the LED lighting device having such a configuration will be described.

  The AC current / voltage from the commercial power supply AC is input to the LED lighting device 1 and the conduction period of the dimmer 2 is adjusted by a light amount operation means (not shown) such as a volume or push button (not shown) of the dimmer 2. Thus, by controlling the phase of the voltage from the dimmer 2, the dimmer 2 outputs a dimming current / voltage (output voltage / current). The dimming current / voltage (output current / voltage) is input to the rectifier circuit 4 via the input filter circuit 3. At this time, the input filter circuit 3 prevents the damped vibration generated in the power supply loop of the LED lighting device 1 and also prevents the generation of noise.

  The rectifier circuit 4 rectifies the current / voltage (output voltage / current) that is phase-controlled by the dimmer 1 and is output from the input filter circuit 3, and outputs the rectified rectified current / voltage (output current / voltage). Output from the rectified output terminal b on the + side and the rectified output terminal a on the − side.

  The rectified current / voltage (output current / voltage) rectified by the rectifier circuit 4 flows or is applied to the capacitor C3 of the input smoothing circuit 5 to be smoothed. When the charging current is charged in the capacitor C3, the current flows through the capacitor C3 from the wiring SL1 in the order of the light emitting diode LED1, the resistor R3, and the diode D1 of the current detection circuit 7, and the light emitting diode LED1 is turned on. While the light emitting diode LED1 is lit, the time during which the charging current flows to the capacitor C3 is detected.

  The direct current / voltage from the capacitor C3 of the input smoothing circuit 5 is input to the primary winding TL1 of the transformer T in the inverter circuit 40. On the other hand, the drive circuit IC1 of the inverter circuit 40 turns on / off the gate voltage of the switching element Q1 at a predetermined cycle (predetermined frequency) and controls the switching element Q1 on / off at a predetermined cycle (predetermined frequency). With this switching element Q1 on / off control, a direct current from the capacitor C3 flows in the primary winding TL1 of the inverter circuit 40, and an alternating current of a predetermined cycle (predetermined frequency) flows in the secondary winding TL2 of the transformer T in the inverter circuit 40. Flowing. The alternating current having a predetermined period (predetermined frequency) flowing through the secondary winding TL2 is half-wave rectified by the diode D2 of the output smoothing circuit 50, and is smoothed by the capacitor C4 to be DC. The output current of the output smoothing circuit 50 flows to the lighting LED 80 via the connector 70, and the lighting LED 80 is turned on.

  Here, when the AC current / voltage supplied from the commercial power supply AC to the dimmer 2 is 100 V, the dimming output current supplied from the output terminals Ota and Otb to the illumination LED 80 is 100_Ib, and the dimming output voltage is 100_Vb.

  By the way, in such lighting control, the AC voltage input to the dimmer 2 from the AC power supply AC is normally 100V. However, the AC voltage input to the dimmer 2 may fluctuate to 90 V or 110 V, for example. For example, when it fluctuates from 90V to 110V or 110V to 90V as shown in FIG. 3 or this fluctuation is repeated, the effective value of the voltage waveform as shown in FIG. 3 is used as the dimming parameter. The filled portion has a fluctuation difference between 90V and 110V, and this fluctuation difference causes flickering.

  Further, when the conduction width of the voltage waveform is also used as shown in FIG. 7, similarly, the blacked-out portion becomes a fluctuation difference between 90V and 110V, which causes flickering.

  Here, as the parameters for obtaining the dimming conduction periods T1 and T2 of the thyristor of the dimmer 2, the conduction widths of the thyristor of the dimmer 2 can be the conduction widths T3 and T4 as shown in FIG. . That is, a threshold voltage Ve for detecting the conduction width of the thyristor 2 of the dimmer 2 is set, and this threshold value Ve is used to detect the conduction width of the thyristor 2 of the dimmer 2 for obtaining the dimming conduction periods T1 and T2. Use. In the AC voltage 110V, the dimming conduction width (dimming conduction period) of the dimmer 2 is set to the dimming conduction width detection value during the period T4 from time t1 to t22, and the above-described dimming conduction period T2 is obtained. ing. Further, at AC voltage 90V, the dimming conduction width (dimming conduction period) of the dimmer 2 is set to the period T3 from the time t2 (t1 <t2) to t21 (t2 <t22 <t3) as the dimming conduction width detection value. Then, the above-described dimming conduction period T1 is obtained.

  Therefore, it is necessary to control so that the brightness of the illumination LED 80 does not fluctuate even if the AC voltage input to the dimmer 2 fluctuates greatly.

  For this control, in this embodiment, the switching element Q1 by the drive circuit IC1 is determined from the difference in AC voltage fluctuation using the charging current flowing time from the AC power supply AC to the input smoothing unit 2 input to the dimmer 2 as a parameter. The period (frequency) of the voltage is changed.

  Here, the AC voltage input from the AC power source AC to the dimmer 2 is normally 100 V if there is no fluctuation. Therefore, when the AC current / voltage supplied from the commercial power source AC to the dimmer 2 is 100 V, the AC voltage is adjusted to 100 V. The light emission amount (brightness) of the illumination LED 80 when the thyristor of the optical device 2 is conducted during the dimming conduction period is Lx1. Further, even when the AC voltage input to the dimmer 2 greatly fluctuates to 90 V or 110 V as shown in FIG. 3, the light emission amount (brightness) of the illumination LED 80 is set to Lx1, so that It is necessary to control the output current supplied from the LED lighting circuit 6 to the illumination LED 80 so that the illumination light from the LED 80 does not flicker.

  Here, when the AC voltage is 90V, the input voltage waveform having the peak value H1 and the conduction width W1 shown in FIG. 4A is obtained, and when the AC voltage is 110V, the input voltage waveform is shown in FIG. An input voltage waveform having the peak value H2 and the conduction width W2 shown in FIG. 4C is obtained. At this time, the peak value H2 at the AC voltage 110V is larger than the peak value H1 by Δh, and the input voltage waveform of the conduction width W2 at the AC voltage 110V is wider by ΔW than the input voltage waveform of the conduction width W1.

  That is, when the waveform of the AC voltage input to the dimmer 2 greatly fluctuates to 90 V or 110 V as shown in FIG. 4, the voltage fluctuation difference between the peak value Δh and the conduction width Δw in FIG. Even if it exists, it is necessary to enable the drive circuit IC1 of the inverter circuit 40 to execute the same control as when the 100V AC voltage input from the commercial power supply AC to the dimmer 2 is not changed.

  At this time, the time during which the charging current flows through the capacitor C3, which is the input smoothing unit in FIG. 2, that is, the time during which the charging voltage is accumulated, is gradually increased from time t2 to time t2b as shown in FIG. The current waveform decreases to Further, when the charging current accumulated in the capacitor C3, which is the input smoothing unit in FIG. 2, is 110 V, as shown in FIG. 5B, the time ta1 (t1 <t2) to the time ta2 (ta2 <tb2) ) Until the current waveform gradually decreases.

  The charging current flow time at this time is t1 to ta2≈t2 to tb2, and the difference due to the fluctuation of the AC input voltage hardly occurs.

  While this time is detected by the current detection circuit 7, the light emitting diode LED1 of the photocoupler PH1 is lit while it is detected. When the illumination LED 80 is turned on, the light from the light emitting diode LED1 is received by the phototransistor PTr1 of the photocoupler PH1 while the light emitting diode LED1 of the photocoupler PH1 is turned on.

  A current flows through the phototransistor PTr1 while receiving light from the light emitting diode LED1. The time of the current flowing through the phototransistor PTr1 varies depending on the light emission time of the light emitting diode LED1. Then, the current flowing through the phototransistor PTr1 flows into the capacitor C5 through the resistor R4, is charged, and is integrated by the capacitor C5. By this integration, the voltage of the capacitor C5 is input to the + input terminal of the comparison circuit IC2 as a reference voltage that increases or decreases according to the light emission time of the light emitting diode LED1.

  On the other hand, a signal obtained by changing the output current of the output terminal Otb to a voltage is input to the negative input terminal of the comparison circuit IC2 via the resistor R7 and the wiring SL3.

  The comparison circuit IC2 compares the reference voltage input to the + input terminal and the voltage generated by the output current of the output terminal Otb input to the-input terminal, thereby comparing the time of the current flowing through the light emitting diode LED1 and the output terminal Otb. Compare the output current.

  At this time, since the reference voltage hardly changes even if there is a sudden change in the AC voltage supplied to the dimmer 2, the comparison circuit IC <b> 2 has a sudden change and amount of change in the AC voltage supplied to the dimmer 2. Is not detected.

  Then, when the AC voltage supplied to the dimmer 2 fluctuates rapidly with respect to the reference voltage, the comparison circuit IC2 outputs a substantially constant output current from the output side regardless of this fluctuation. This output current flows to the output wiring OL2 via the light emitting diode LED2 of the photocoupler PH2 and the resistor R6. At this time, the light from the light emitting diode LED2 is received by the phototransistor PTr2 of the photocoupler PH2 in the inverter circuit 40.

  A current corresponding to the amount of light from the light emitting diode LED2 flows through the phototransistor PTr2, and a change in the current is input to the drive circuit IC1 of the inverter circuit 40. Then, the drive circuit IC1 cycles the voltage applied to the gate of the switching element Q1 so that the output current output from the output terminals Ota and Otb becomes constant according to the change in the current input from the phototransistor PTr2. Change (frequency). At this time, the drive circuit IC1 has a dimming output current 100_Ib and a dimming output voltage 100_Vb at 100V, and the light emission amount (brightness) of the lighting LED 80 at the time of dimming is Lx1. The period (frequency) of the voltage applied to the gate of Q1 is changed.

  Therefore, there is a large variation in the AC voltage input to the dimmer 2, and even when not only the peak value of the phase-controlled AC voltage waveform but also the conduction width varies, the variation in the current flowing through the lighting LED 80 is prevented. Thus, the fluctuation can be prevented from causing unpleasant flickering to the user.

  FIG. 6 shows Embodiment 2 of the present invention. The second embodiment shows an example in which the input smoothing circuit 5 and the charging current detection circuit 7 of the first embodiment are changed.

  The input smoothing circuit 5 according to the second embodiment includes an input smoothing unit 20. The input smoothing unit 20 includes capacitors C6 and C7 connected in series between the wirings SL1 and SL2, a diode D3 interposed between the capacitors C6 and C7 so that a current flows from the capacitor C6 to the capacitor C7 side, A diode D4 connected to the wiring SL2 and the anode side of the diode D3 so that current flows from the wiring SL2 to the anode side of the diode D3, and a cathode of the diode D3 so that current flows from the cathode side of the diode D3 to the wiring SL1 side. And a wiring D1 interposed between the wiring SL1.

  Further, the charging current detection circuit 7 includes resistors R8 and R9 connected in series to the anode side of the diode D3, the cathode side of the diode D4, and the wiring SL2, and a comparison in which the + input terminal is connected between the resistors R8 and R9. A circuit (comparator) IC3, a reference power supply Eb interposed between the input terminal and the wiring SL2 so as to apply a reference voltage to the −input terminal of the comparison circuit IC3, and an anode on the output side of the comparison circuit IC3 A light-emitting diode LED1 connected on the side, and a resistor R10 connected to the cathode side of the light-emitting diode LED1 and the wiring SL2.

  In this configuration, the current (rectified current) half-wave rectified by the rectifier circuit 4 flows to the capacitors C6 and C7 of the input smoothing unit 20, and is charged in the capacitors C6 and C7. When charging to the capacitors C6 and C7 stops flowing, the capacitors C6 and C7 are discharged, and a discharge current flows to the switching element Q1. In this way, the current half-wave rectified by the rectifier circuit 4 is smoothed by the capacitors C6 and C7 and flows to the switching element Q1.

  On the other hand, the voltage between the capacitor C6 and the diode D3 is input to the + input terminal of the comparison circuit IC3, and the comparison circuit IC3 compares the voltage input to the + input terminal with the voltage of the reference power supply Eb. .

  When the charging current flows through the capacitors C6 and C7 of the input smoothing unit 20, the comparison circuit IC3 compares the voltage input to the + input terminal with the voltage of the reference power supply Eb, and the current flows through the capacitors C6 and C7. Current is output from the output side. This output current turns on the light emitting diode LED1 of the photocoupler PH1. The light from the light emitting diode LED1 is received by the phototransistor PTr1 of the photocoupler PH1 in the lighting control circuit 8, and the operation of the drive circuit IC1 is controlled by the lighting control circuit 8 as in the first embodiment.

  On the other hand, when the charging current does not flow through the input smoothing unit 20 capacitors C6 and C7, the negative side voltage V1 of the capacitor C6 is substantially 0 V (actually, the cathode side voltage VF_d4 [V] of the diode D4). Detection is performed by the comparison circuit IC3.

  The time during which the charging current flows through the capacitors C6 and C7 of the input smoothing unit 20 in FIG. 6, that is, the time during which the charging current is accumulated, is 90 V, from time t2 to the middle of time tb2, as shown in FIG. After gradually decreasing, the current waveform rises slightly until time tb2 and drops. Further, the charging current is accumulated in the capacitor C6, which is the input smoothing unit in FIG. 6, at time 110V, as shown in FIG. 8B, from time t1 (t1 <t2) to time ta2 (ta2 <tb2). ) And then gradually decreases until a time ta2 (ta2 <tb2).

  While this time is detected by the current detection circuit 7, the light emitting diode LED1 of the photocoupler PH1 is lit while it is detected. When the lighting LED 80 is turned on, the light from the light emitting diode LED1 is received by the phototransistor PTr1 of the photocoupler PH1 while the light emitting diode LED1 of the photocoupler PH1 is turned on. The operation is controlled in the same manner as in the first embodiment. As a result, even if there is a large fluctuation in the AC voltage input to the dimmer 2 and not only the peak value of the phase-controlled AC voltage waveform but also the conduction width fluctuates, the current flowing through the LED 80 for illumination The fluctuation can be kept constant, and the fluctuation can be prevented from being unpleasant for the user.

  Further, in the second embodiment, an example in which the charging current of the capacitors C6 and C7 of the input smoothing unit 20 is detected by the charging current detection circuit 7 provided with the comparison circuit IC3 is shown, but the configuration is not necessarily limited to this configuration. It is not a thing. For example, the configuration of the third embodiment using the diode D6 as shown in FIG. 9 may be used.

  In the third embodiment, the comparison circuit IC3 of the charging current detection circuit 7 in the second embodiment is omitted, and as shown in FIG. 9, the cathode side of the light emitting diode LED1 in the photocoupler PH1 is connected to the wiring SL2. . Further, the anode side of the light emitting diode LED1 is connected to the power source E1 through the resistor R11, the anode side of the diode D6 is connected to the connection portion between the anode side of the light emitting diode LED1 and the resistor R11, and the cathode side of the diode D6 is connected to the cathode side. The capacitor C6 is connected to the connection portion between the anode side of the diode D3.

  In this configuration, the current (rectified current) half-wave rectified by the rectifier circuit 4 flows to the capacitors C6 and C7 of the input smoothing unit 20, and is charged in the capacitors C6 and C7.

  When charging to the capacitors C6 and C7 stops flowing, the capacitors C6 and C7 are discharged, and a discharge current flows to the switching element Q1. Thus, the current half-wave rectified by the rectifier circuit 4 is smoothed by the capacitors C6 and C7 and supplied to the switching element Q1.

  In the third embodiment, as in the second embodiment, the time during which the charging current flows through the capacitors C6 and C7 of the input smoothing unit 20 in FIG. 9, that is, the time during which the charging current is accumulated is shown in FIG. As shown, the current waveform gradually decreases from the time t2 to the middle of the time tb2 and then slightly rises and falls to the time tb2. Further, the charging current is accumulated in the capacitors C6 and C7, which are the input smoothing units in FIG. 9, at time 110V, from time t1 (t1 <t2) to time ta2 (ta2) as shown in FIG. After gradually decreasing to the middle of <tb2), it gradually increases and decreases slightly until time ta2 (ta2 <tb2).

  While the rectified current half-wave rectified by the rectifier circuit 4 flows as the charging current to the capacitors C6 and C7 of the input smoothing unit 20, the potential between the capacitor C6 and the diode D3 is high. For this reason, the current from the power source E1 does not flow to the capacitors C6 and C7, but flows to the light emitting diode LED1 via the resistor R11. As a result, while the charging current flows through the capacitors C6 and C7 of the input smoothing unit 20, the light emitting diode LED1 of the charging current detection circuit 7 is turned on, and the charging of the capacitors C6 and C7 is detected.

  In addition, when the charging current does not flow through the capacitors C6 and C7 of the input smoothing unit 20 and the capacitors C6 and C7 are discharged, the potential between the capacitor C6 and the diode D3 is low. As a result, the current from the power source E1 flows to the switching element Q1 side via the resistor R11 and the capacitor C6 and does not flow to the light emitting diode LED1 of the charging current detection circuit 7, so the light emitting diode LED1 is turned off.

  When no charging current flows through the capacitors C6 and C7 of the input smoothing unit 20, the voltage V1 between the diode D3 and the capacitor C6 is the voltage VF_D4 of the diode D4, but the light emitting diode in the photocoupler PH1. The anode of the LED 1 is offset through the diode D6 to cancel the voltage VF_D6 of the diode D6 and becomes 0V, so that the time during which the charging current does not flow can be detected more reliably. Also in this embodiment, the operation of the drive circuit IC1 is controlled by the lighting control circuit 8 in the same manner as in the first embodiment.

  Here, as a parameter for obtaining the dimming conduction periods T1 and T2 of the first embodiment described above, the time during which the charging current flows to the capacitors C6 and C7 of the input smoothing unit 20 can be used. That is, as shown in FIG. 10, when the AC voltage is 110V, the period from time t1 to t21 is the time T5 during which the charging current flows to the capacitors C6 and C7, and when the AC voltage is 90V, the time t2 (t1 <t2) to t22 ( By using the period up to t2 <t22 <t3) as the time T6 during which the charging current flows to the capacitors C6 and C7, it is possible to obtain T5≈T6 regardless of the fluctuation of the dimming conduction periods T1 and T2.

  Therefore, by providing the current detection circuit 7 for supply control, the time during which the charging current flows through the capacitors C6 and C7 of the input smoothing unit 20 in FIG. As shown in (a), the current waveform gradually decreases from time t2 to the middle of time tb2 and then rises and falls slightly to time tb2. Further, the charging current is accumulated in the capacitors C6 and C7, which are the input smoothing units in FIG. 9, at time 110V, from time t1 (t1 <t2) to time ta2 (ta2) as shown in FIG. After gradually decreasing to the middle of <tb2), it gradually increases and decreases slightly until time ta2 (ta2 <tb2).

  While this time is detected by the current detection circuit 7, the light emitting diode LED1 of the photocoupler PH1 is lit while it is detected. When the lighting LED 80 is turned on, the light from the light emitting diode LED1 is received by the phototransistor PTr1 of the photocoupler PH1 while the light emitting diode LED1 of the photocoupler PH1 is turned on. The operation is controlled in the same manner as in the first embodiment. As a result, even if there is a large fluctuation in the AC voltage input to the dimmer 2 and not only the peak value of the phase-controlled AC voltage waveform but also the conduction width fluctuates, the current flowing through the LED 80 for illumination The fluctuation can be kept constant, and the fluctuation can be prevented from being unpleasant for the user.

  As described above, the LED lighting device according to the embodiment of the present invention includes the phase control type dimmer 2 capable of adjusting the phase supplied with alternating current from the power source (commercial power source AC) and conducted by the operating means. The rectifier circuit 4 for rectifying the alternating current from the dimmer 2, the input smoothing unit (capacitors C3 and 20) for smoothing the rectified current and voltage of the rectifier circuit 4 to direct current, and the input smoothing unit (capacitor) The LED lighting circuit 6 is provided which converts direct current from C3, 20) into alternating current and smoothes it to direct current to supply an output current to an illumination LED (illumination LED 80). In addition, the LED lighting device includes a charging current detection circuit 7 that detects a charging current of the input smoothing unit (capacitors C3 and 20), and a reference voltage based on a time during which the charging current detected by the charging current detection circuit 7 flows. And a lighting control circuit 8 for controlling the LED lighting circuit 6 so that the output current of the LED lighting circuit 6 becomes a current value corresponding to the reference voltage.

  According to this structure, the fluctuation | variation of the LED current by an alternating voltage fluctuation | variation can be suppressed.

DESCRIPTION OF SYMBOLS 1 ... LED lighting device 2 ... Dimmer 4 ... Rectifier circuit 5 ... Input smoothing circuit C3 ... Capacitor (input smoothing part)
6 ... LED lighting circuit 7 ... charging current detection circuit 8 ... lighting control circuit 20 ... input smoothing unit 80 ... LED for illumination

Claims (1)

A phase control type dimmer capable of adjusting a phase to which an alternating current from a power source is supplied and is conducted by an operation means;
A rectifying circuit for rectifying alternating current from the dimmer;
An input smoothing unit that smoothes the rectified current and voltage of the rectifier circuit to make a direct current; and
In an LED lighting device including an LED lighting circuit that converts direct current from the input smoothing unit into alternating current and smoothes the direct current to direct current to an LED for illumination.
A charging current detection circuit for detecting a charging current of the input smoothing unit;
A reference voltage is generated based on a charging current flow time detected by the charging current detection circuit, and the LED lighting circuit is controlled so that the output current of the LED lighting circuit becomes a current value corresponding to the reference voltage. An LED lighting device comprising a lighting control circuit.