JP6191940B2 - Light emitting element lighting device and lighting apparatus - Google Patents

Description

  The present invention relates to a light emitting element lighting device and a lighting fixture.

  As a conventional light emitting element lighting device, there is a light emitting element lighting device in which a series circuit of a lighting fixture 111 and a dimmer 112 is connected between both ends of a commercial power source 100 as shown in FIG. reference).

  The luminaire 111 includes a light source unit 111a such as an LED (Light Emitting Diode) element or an organic EL (Electroluminescence) element, and a lighting circuit 111b for dimming and lighting the light source unit 111a. The dimmer 112 includes a triac Q112 that is a bidirectional switching element having a self-holding function, and a dimming control unit 112a that controls the triac Q112.

  The triac Q112 is connected in series between the commercial power supply 100 and the lighting fixture 111. The dimming control unit 112a controls the phase angle at which the triac Q112 is turned on, and performs phase control that makes the conduction angle of the power supply voltage of the commercial power supply 100 variable. Then, the lighting circuit 111b of the lighting fixture 111 controls the load current supplied to the light source unit 111a so as to adjust the dimming level according to the conduction angle of the phase-controlled power supply voltage.

  The triac Q112 is turned on by applying a trigger signal to the gate. When the anode current flowing through the triac Q112 becomes equal to or lower than the holding current, the triac Q112 is turned off.

  Generally, only when the triac Q112 is switched from the off state to the on state (only when the triac Q112 is turned on), a so-called pulse trigger method is adopted in which a pulse-like trigger signal is input to the gate of the triac Q112. However, in this pulse trigger method, when noise is superimposed on the power supply line of the commercial power supply 100, the triac Q112 may unexpectedly switch to the off state because the anode current flowing through the triac Q112 is lower than the holding current due to the noise.

  Therefore, the dimming control unit 112a uses a so-called DC trigger method in which a trigger signal for turning on the triac Q112 is continuously supplied for a predetermined period in a period in which the triac Q112 is turned on and conducted (see, for example, Patent Document 1). ). As shown in FIG. 12, the trigger signal in the DC trigger method continues to be on until the duration T <b> 51 elapses after rising at the phase angle β. The triac Q112 maintains the conductive state until the anode current becomes equal to or lower than the holding current even after the trigger signal duration T51 ends after the trigger signal rises. In this case, the triac conduction period T52 is from when the trigger signal rises until the anode current becomes equal to or lower than the holding current. Therefore, the power supply voltage is applied to the lighting fixture 111 until the power supply voltage reaches the vicinity of the zero cross. In FIG. 12, the broken line indicates the power supply voltage of the commercial power supply 100, and the solid line indicates the applied voltage of the lighting fixture 111.

JP 2012-185998 A

  In the light emitting element lighting device using the DC trigger method described above, the lighting circuit 111b of the lighting fixture 111 supplies the light source control unit 112a to the light source unit 111a in accordance with the phase angle β (see FIG. 12) for turning on the triac Q112. To control the load current. At this time, the lighting circuit 111b stores a dimming curve indicating the relationship between the phase angle and the load current, and controls the load current supplied to the light source unit 111a with reference to the dimming curve.

  However, in the light emitting element lighting device using the DC trigger method, the specific setting of the dimming curve needs to maintain high noise resistance (particularly when the dimming level is low) by the trigger signal. That is, there is a demand for a light-emitting element lighting device that can maintain the effect of suppressing flickering of the light source unit and unexpected turn-off by the DC trigger method even during light control.

  In addition, in a light emitting element lighting device using a DC trigger method, dimming control that does not cause discomfort to the human eye is also required in consideration of the sensitivity of the human eye.

  The present invention has been made in view of the above-described reasons, and an object of the present invention is to perform dimming control that can maintain high noise resistance due to a trigger signal during dimming and that does not cause discomfort to the human eye. It is an object to provide a light emitting element lighting device using a DC trigger method and a lighting fixture.

The light-emitting element lighting device of the present invention has an electric power supplied from an AC power supply as an input, a power conversion circuit that supplies a load current to a light source unit composed of the light-emitting elements, and a series of the power conversion circuit and the AC power supply. A bidirectional switching element connected in series with the circuit and having a self-holding function, and a phase control for varying the conduction angle of the AC voltage of the AC power supply by controlling the phase angle at which the bidirectional switching element is turned on. With reference to a light control section and a dimming curve indicating a relationship between a phase angle at which the bidirectional switching element is turned on and the load current, the power conversion circuit is configured according to the phase angle at which the bidirectional switching element is turned on. The bidirectional switching element is turned on by comparing the dimming circuit for controlling the supplied load current and the AC voltage subjected to the phase control with a predetermined threshold value. A phase detection circuit that generates a binary duty signal set to a duty ratio corresponding to the phase angle to be supplied, and the dimming circuit supplies the power conversion circuit according to the duty ratio of the duty signal The load current is controlled, and the dimming control unit continuously supplies a trigger signal for turning on the bi-directional switching element for a predetermined period in a period for energizing the bi-directional switching element, and the dimming curve is In a region where the phase angle at which the bidirectional switching element is turned on is greater than or equal to the first phase angle and less than or equal to the second phase angle, a curve expressed by a second-order polynomial in which the slope decreases as the phase angle increases. And the load current is reduced to a constant maximum value in a region where the phase angle at which the bidirectional switching element is turned on is less than the first phase angle. In a region where the phase angle at which the bidirectional switching element is turned on exceeds the second phase angle, the load current is set to a certain minimum value existing within a range of 5% ± 3% of the maximum value, The first phase angle is set within a range of 40 ° ± 20 °, the second phase angle is set within a range of 120 ° ± 10 °, and the threshold value is greater than the second phase angle. The dimming curve corresponds to a voltage value of the AC voltage at a phase angle of 3, and the load current is set to the minimum value at least in a region not less than the second phase angle and not more than the third phase angle. And the third phase angle is set within a range of 155 ° ± 10 °, the trigger signal is turned off at a fourth phase angle, and the fourth phase angle is 150 ° ± 10 °. It is characterized by being set within the range.

  In this invention, a bleeder circuit that is connected in parallel to the input side of the power conversion circuit and generates a bypass current using the AC power supply as a supply source, and a parallel angle connected to the bidirectional switching element, the phase angle of the AC voltage Is preferably provided with a power supply unit that generates a control power supply for the dimming control unit using the bypass current generated by the bleeder circuit in a region less than the first phase angle.

  In the present invention, the load current supplied by the power conversion circuit preferably falls within a fluctuation range of 2% or less of the maximum value when controlled to the minimum value by the dimming circuit.

The lighting apparatus of the present invention is connected in series to an AC power supply and a bidirectional switching element having a self-holding function, and the dimming control unit controls the phase angle at which the bidirectional switching element is turned on, whereby the AC of the AC power supply A luminaire that is dimmed by phase control with variable voltage conduction angle, and supplies a load current to the light source unit using a light source unit composed of light emitting elements and power supplied from the AC power supply as inputs. The load that is supplied by the power conversion circuit in accordance with the phase angle controlled by the dimming control unit with reference to a power conversion circuit that performs control and a dimming curve that indicates a relationship between the phase angle and the load current. By comparing the dimming circuit for controlling the current and the AC voltage on which the phase control has been performed with a predetermined threshold, the duty ratio is set according to the phase angle at which the bidirectional switching element is turned on. A phase detection circuit that generates a predetermined binary duty signal, wherein the dimming circuit controls the load current supplied by the power conversion circuit according to the duty ratio of the duty signal, and The optical curve includes the load along a curve expressed by a second-order polynomial in which the slope decreases as the phase angle increases in a region where the phase angle is greater than or equal to the first phase angle and less than or equal to the second phase angle. In a region where the current decreases and the phase angle is less than the first phase angle, the load current is set to a constant maximum value, and in the region where the phase angle exceeds the second phase angle, the load current is The first phase angle is set within a range of 40 ° ± 20 °, and the second phase angle is set to 120 ° ±± with a certain minimum value existing within a range of 5% ± 3% of the maximum value. Set within the range of 10 °, the threshold is , Corresponding to a voltage value of the AC voltage at a third phase angle larger than the second phase angle, and the dimming curve is at least a region not less than the second phase angle and not more than the third phase angle. The load current is set to the minimum value, and the third phase angle is set within a range of 155 ° ± 10 °.

  As described above, in the present invention, by specifically setting the dimming curve referred to by the dimming circuit, in the light-emitting element lighting device using the DC trigger system and the lighting fixture, the trigger signal is used during dimming. There is an effect that it is possible to maintain high noise resistance and to perform dimming control without any sense of incongruity to human eyes.

It is a block diagram which shows the structure of the light emitting element lighting device of embodiment. It is a block diagram which shows the structure of a lighting fixture same as the above. It is a circuit diagram which shows a part of structure of a lighting fixture same as the above. It is a circuit diagram which shows a part of structure of a lighting fixture same as the above. It is a circuit diagram which shows a part of structure of a lighting fixture same as the above. It is a circuit diagram which shows a part of structure of a lighting fixture same as the above. (A)-(d) It is a wave form diagram which shows operation | movement of each part same as the above. It is a wave form diagram which shows operation | movement of a phase detection circuit same as the above. (A)-(d) It is a wave form diagram of each part explaining a bypass current same as the above. It is a characteristic view which shows the light control curve same as the above. It is a block diagram which shows the structure of the conventional light emitting element lighting device. It is a wave form diagram which shows operation | movement of the conventional light emitting element lighting device.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment)
FIG. 1 shows a configuration of a light emitting element lighting device of the present embodiment. The light emitting element lighting device is configured by connecting a series circuit of a lighting fixture 1 and a dimmer 2 between both ends of a commercial power source 10 (AC power source). The dimmer 2 adjusts the power supplied from the commercial power supply 10 to the lighting fixture 1 by phase-controlling the power supply voltage (AC voltage) of the commercial power supply 10.

  As shown in FIG. 2, the luminaire 1 includes an input filter circuit 1a, a power conversion circuit 1b, a phase detection circuit 1c, a dimming circuit 1d, an output feedback circuit 1e, a bleeder circuit 1f, and a light source unit 1h. With.

  The input filter circuit 1a includes a capacitor, an inductor, and the like, and has a function of suppressing noise propagating to the power supply line and noise radiating to the space.

  As shown in FIG. 3, the power conversion circuit 1b includes a rectifier circuit DB1, capacitors C1 and C2, a transformer T1, a switching element Q1, a control circuit K1, and a diode D1, and includes a non-insulating flywheel. Configure the buck converter. The power conversion circuit 1b constitutes a quasi-resonant circuit for reducing loss and noise, and further has a power factor improving function for improving the power factor of the commercial power source 10.

  First, the rectifier circuit DB1 is configured by full-bridge connection of diodes, and full-wave rectifies the power supply voltage of the commercial power supply 10.

  The capacitor C1 is a film capacitor connected between the output terminals of the rectifier circuit DB1, and suppresses a voltage / current spike generated when the switching element Q1 is turned on. The capacitor C1 has a smaller capacity than the smoothing capacitor and does not take into account the smoothing action. That is, the power conversion circuit 1b does not include a smoothing capacitor having a large capacity such as an electrolytic capacitor in the input means, and does not constitute a capacitor input type power supply circuit.

  The transformer T1 includes a primary winding N1, a secondary winding N2, and a tertiary winding N3, and the windings are magnetically coupled to each other. A series circuit of the primary winding N1 and the switching element Q1 is connected between the output ends of the rectifier circuit DB1, and a diode D1 is interposed at one end of the secondary winding N2, and the secondary winding A smoothing capacitor C2 is connected in parallel to the series circuit of N2 and the diode D1.

  The control circuit K1 conducts / cuts off the current flowing from the commercial power supply 10 to the primary winding N1 by driving the switching element Q1 on and off. When the switching element Q1 is on, a current flows through the series circuit of the primary winding N1 and the switching element Q1, and magnetic energy is accumulated in the primary winding N1. Next, when the switching element Q1 is turned off, an induced voltage is generated in the secondary winding N2 due to the magnetic energy of the primary winding N1, and a voltage is generated across the capacitor C2.

  The control circuit K1 performs switching control of the switching element Q1, thereby controlling the output of the power conversion circuit 1b to a predetermined value and further improving the power factor of the commercial power supply 10. Note that the power factor correction operation by the flyback converter is a well-known technique and will not be described in detail.

  The light source unit 1h includes a plurality of LED elements or organic EL elements connected in series or in parallel, and is connected between both ends of the capacitor C2.

  The phase detection circuit 1c is connected to the cathodes of the diodes Da and Db whose anodes are connected to the respective input terminals of the rectifier circuit DB1, and is a voltage Vd (full-wave rectified from the power supply voltage phase-controlled by the dimmer 2). A full-wave rectified voltage Vd) is input. Then, the phase detection circuit 1c detects the conduction angle of the power supply voltage input to the lighting fixture 1 (conduction angle of the full-wave rectified voltage Vd), and is a binary value set to a duty ratio corresponding to the detected conduction angle. The signal (duty signal S1) is output to the dimming circuit 1d.

  The dimming circuit 1d sets a target value of the load current corresponding to the duty ratio of the duty signal S1, and outputs a voltage signal (target signal S2) corresponding to the target value of the load current to the output feedback circuit 1e.

The output feedback circuit 1e detects a load current flowing through the light source unit 1h by a resistor or the like connected in series with the light source unit 1h. The output feedback circuit 1e acquires the target value of the load current based on the target signal S2 input from the dimming circuit 1d. Then, the output feedback circuit 1e outputs a feedback signal S3 (for example, an error between the detected value of the load current and the target value) based on the detected value of the load current and the target value to the control circuit K1 (see FIG. 3).

  The control circuit K1 performs constant current control so that the load current matches the target value by setting the conduction period (ON period) of the switching element Q1 according to the feedback signal S3.

  Next, as shown in FIG. 1, the dimmer 2 includes a capacitor C81 and an inductor L81 that form a noise prevention filter, and a triac Q81 that is a bidirectional switching element having a self-holding function. The capacitor C81 is connected between the input ends of the dimmer 2, and a series circuit of a triac Q81 and an inductor L81 is connected in parallel to the capacitor C81. Then, when the triac Q81 is in a conducting state, AC power is supplied from the commercial power supply 10 to the power conversion circuit 1b.

  The dimmer 2 includes a power supply unit 4. The power source unit 4 generates a control power source for operating each unit (a dimming control unit 3 described later) of the dimmer 2 and is connected in parallel to the triac Q81.

  The power supply unit 4 includes a diode D81, a capacitor C82, a power supply circuit K81, and a capacitor C83.

  The diode D81 is connected to the power supply line from the lighting fixture 1, and the capacitor C82 is connected in parallel to the triac Q81 via the diode D81. The power supply circuit K81 converts the voltage across the capacitor C82 into a control voltage Vs and outputs it. The capacitor C83 is a smoothing capacitor connected between the output terminals of the power supply circuit K81. Here, the low voltage terminal of the capacitor C83 is connected to the circuit ground.

Furthermore, the dimmer 2 includes a dimming control unit 3. The dimming control unit 3 includes a synchronization signal generation unit K82, a control circuit K83, and an operation unit K84, and performs phase control to change the conduction angle of the power supply voltage of the commercial power supply 10 by turning on the triac Q81. Do.

  First, the synchronization signal generation unit K82 is connected to the power supply line (the anode side of the diode D81) from the luminaire 1 via the diode D82. The synchronization signal generator K82 has a ground terminal connected to the circuit ground, generates a synchronization signal shown in FIG. 7A based on the phase of the power supply voltage supplied from the commercial power supply 10, and supplies the synchronization signal to the control circuit K83. Output. Specifically, the synchronization signal generation unit K82 compares the power supply voltage of the commercial power supply 10 with a predetermined threshold Vt1 by detecting the power supply voltage of the commercial power supply 10 via the diode D82, and the power supply voltage sets the threshold Vt1. A synchronization signal is generated with the period exceeding the H level. That is, the synchronization signal rises when the power supply voltage exceeds the threshold value Vt1, and falls when the power supply voltage falls below the threshold value Vt1. 7A to 7C, the broken line indicates the waveform of the power supply voltage of the commercial power supply 10.

  The control circuit K83 generates a trigger signal for turning on the triac Q81 based on the synchronization signal provided from the synchronization signal generation unit K82 and the dimming signal provided from the operation unit K84 (see FIG. 7B). The rise and fall of the trigger signal are both determined with reference to the rise of the synchronization signal. The control circuit K83 outputs a trigger signal to the gate of the triac Q81, whereby a drive current flows through the gate of the triac Q81 and the triac Q81 becomes conductive. Here, the control circuit K83 employs a so-called DC trigger method in which a trigger signal for turning on the triac Q81 is continuously supplied for a predetermined period of time during which the triac Q81 is turned on to be conducted.

  That is, the dimming control unit 3 controls the phase of the power supply voltage applied to the lighting fixture 1 by turning on the triac Q81 using the DC trigger method.

  Hereinafter, the dimming operation of the present embodiment will be described. First, the synchronization signal generation unit K82 generates a synchronization signal and outputs it to the control circuit K83. In addition, the operation unit K84 outputs a dimming signal corresponding to the user operation to the control circuit K83. The control circuit K83 generates a trigger signal based on the synchronization signal and the dimming signal, and outputs it to the gate of the triac Q81. The triac Q81 is turned on when the trigger signal rises and becomes conductive. Therefore, as illustrated in FIG. 7C, the power supply voltage of the commercial power supply 10 is applied to the lighting fixture 1 with phase control. The rising edge of the trigger signal changes in phase angle depending on the voltage signal output from the operation unit K84 operated by the user. Thereby, since the conduction angle of the power supply voltage applied to the lighting fixture 1 changes, light control can be performed.

  Thereafter, when the trigger signal falls, the driving current does not flow to the gate of the triac Q81. Since the triac Q81 maintains a conductive state while the anode current exceeds the holding current, the power supply voltage of the commercial power supply 10 is continuously applied to the lighting fixture 1 for a while after the trigger signal falls (FIG. 7C). )reference). When the anode current of the triac Q81 becomes equal to or lower than the holding current, the triac Q81 is switched to a non-conduction state (off state). Thereby, application of the power supply voltage of the commercial power supply 10 to the lighting fixture 1 stops.

  In the lighting fixture 1, the phase detection circuit 1c detects the conduction angle of the power supply voltage input to the lighting fixture 1, and outputs a duty signal S1 corresponding to the detected conduction angle to the dimming circuit 1d. The dimming circuit 1d sets a target value of the load current according to the duty ratio of the duty signal S1, and outputs a target signal S2 corresponding to the target value. The output feedback circuit 1e outputs a feedback signal S3 based on the detected value of the load current and the target value to the control circuit K1. The control circuit K1 sets the conduction period (ON period) of the switching element Q1 according to the feedback signal S3, thereby performing constant current control so that the load current matches the target value, and dimming the light source unit 1h. To do.

  Here, as shown in FIG. 7B, unlike the pulse trigger, the trigger signal is continuously at the H level for a certain period of time during which the lighting fixture 1 is supplied with power for lighting. As a result, the drive current continues to flow through the gate of the triac Q81 until the trigger signal falls. That is, the drive current is continuously applied to the triac Q81 for a certain period (the H level period of the trigger signal) of the period in which the triac Q81 is turned on.

Moreover, the lighting fixture 1 uses the power converter circuit 1b which has a power factor improvement function, and as shown in FIG.7 (d), the input current of the lighting fixture 1 becomes a sine wave shape, and the power factor of the commercial power source 10 is the same. It has been improved. That is, the anode current of the triac Q81 can be secured even when the voltage value of the power supply voltage of the commercial power supply 10 decreases past the peak and reaches the vicinity of the zero cross. Therefore, even when noise is superimposed on the power supply line of the commercial power supply 10 near the zero cross of the power supply voltage of the commercial power supply 10, fluctuations in the conduction period of the triac Q81 can be suppressed, and the lighting of the light source unit 1h may be flickering or unexpected. The possibility of turning off the light can be reduced.

  Thus, the light emitting element lighting device of the present embodiment performs stable dimming without unexpectedly turning off the triac Q81 even if noise is superimposed on the power supply line of the commercial power supply 10 near the zero cross of the power supply voltage. It can be carried out.

  Furthermore, in this embodiment, a bleeder circuit 1f is provided in parallel on the input side of the power conversion circuit 1b so that a sufficient anode current exceeding the holding current continuously flows in the triac Q81 even in the off period of the trigger signal. (See FIG. 2). The bleeder circuit 1f also has a function of supplying power to the power supply unit 4 of the dimmer 2 when the triac Q81 is turned off.

  First, as shown in FIG. 4, the bleeder circuit 1f includes diodes Da and Db each having an anode connected to each input terminal of the rectifier circuit DB1, cathodes of the diodes Da and Db, and a low-voltage side of the rectified output of the rectifier circuit DB1. And a current drawing portion 1g connected between the two. That is, the bleeder circuit 1 f can be considered equivalent to a bleeder circuit 1 f connected in parallel between the input ends of the lighting fixture 1.

  In a current drawing unit 1g shown in FIG. 4, a series circuit of an FET element Q71, a resistor R71, and a resistor R72 is connected between the cathodes of the diodes Da and Db and the low-voltage side of the rectified output of the rectifier circuit DB1. The drain of the FET element Q71 is connected to the cathodes of the diodes Da and Db, and the source of the FET element Q71 is connected to a series circuit of resistors R71 and R72. Furthermore, the gate of the FET element Q71 is connected to the phase detection circuit 1c. A Zener diode ZD71 is connected between the gate of the FET element Q71 and the low-voltage side of the rectified output of the rectifier circuit DB1.

The phase detection circuit 1 c detects the conduction angle of the power supply voltage input to the lighting fixture 1. Specifically, the full-wave rectified voltage Vd (see FIG. 8A) obtained by full-wave rectifying the power supply voltage is input to the phase detection circuit 1c via the diodes Da and Db. The full-wave rectified voltage Vd Is compared with the threshold value Vt2 to generate a binary duty signal S1 set to a duty ratio corresponding to the conduction angle. The duty signal S1 is L level when the voltage value of the power supply voltage is greater than or equal to the threshold value Vt2, and is H level when the voltage value of the power supply voltage is less than the threshold value Vt2 (see FIG. 8B). The phase detection circuit 1c applies this duty signal S1 to the gate of the FET element Q71 of the current drawing unit 1g.

The FET element Q71 is turned on when the duty signal S1 is at the H level, that is, when the voltage value of the full-wave rectified voltage Vd is less than the threshold value Vt2, via the diode Da or Db, the FET element Q71, and the resistors R71 and R72. Bypass current Ib flows. The bypass current Ib flows through a closed circuit including the commercial power supply 10, the bleeder circuit 1 f, and the dimmer 2 using the commercial power supply 10 as a supply source.

  Hereinafter, the operation of the bleeder circuit 1f will be described with reference to FIGS. In the following description, reference numerals of the bypass currents Ib1 and Ib2 are given depending on the generation period of the bypass current Ib. 9A and 9B, the broken line indicates the waveform of the power supply voltage of the commercial power supply 10.

First, when the power supply voltage passes through the zero cross, the voltage value of the full-wave rectified voltage Vd is less than the threshold value Vt2 (see FIG. 9B), and the duty signal S1 becomes H level (FIG. 9C). The FET element Q71 is turned on and a bypass current Ib1 is generated (see FIG. 9D). At this time, the triac Q81 of the dimmer 2 is off, and the bypass current Ib1 charges the capacitor C82 via the diode D81 of the dimmer 2. That is, the power supply unit 4 generates the control voltage Vs using the bypass current Ib1, and can secure the control power supply with a simple configuration.

  Then, when the trigger signal rises (see FIG. 9A) and the triac Q81 becomes conductive, the power supply voltage of the commercial power supply 10 is applied to the lighting fixture 1. When the full-wave rectified voltage Vd becomes equal to or higher than the threshold value Vt2 (see FIG. 9B), the duty signal S1 becomes L level (see FIG. 9C), the FET element Q71 is turned off, and the bypass current Ib1 becomes zero (see FIG. 9D).

When the voltage value of the power supply voltage decreases to the peak value and then decreases and the trigger signal falls (see FIG. 9A), the drive current does not flow to the gate of the triac Q81, but the triac Q81 The conduction state is maintained while the current exceeds the holding current.

  In this embodiment, when the full-wave rectified voltage Vd becomes less than the threshold value Vt2 (see FIG. 9B), the duty signal S1 becomes H level (see FIG. 9C), and the FET element Q71. Is turned on, and a bypass current Ib2 is generated (see FIG. 9D). The bypass current Ib2 flows through the triac Q81 that maintains the conductive state after the trigger signal falls, so that the anode current is maintained at or above the holding current.

  Therefore, even if noise is superimposed on the power supply line of the commercial power supply 10 near the zero cross of the power supply voltage, stable dimming can be performed without the triac Q81 turning off unexpectedly.

  In the embodiment shown in FIG. 9, by setting the threshold value Vt2 to be relatively high, the duty signal S1 is switched to the H level and the bypass current Ib2 starts to flow before the trigger signal falls, so that noise resistance is improved. Is further improved.

  Note that after the trigger signal falls, the duty signal S1 may be switched to the H level and the bypass current Ib2 may start to flow. In this case, the circuit loss can be further reduced by shortening the period during which the bypass current Ib2 flows.

  Furthermore, in the present embodiment, by using the power conversion circuit 1b having the power factor improvement function, the required bypass current Ib can be suppressed and the circuit loss can be reduced as compared with the case where the capacitor input type power conversion circuit is used. Can be planned.

  Further, the power factor improvement by the power conversion circuit 1b eliminates the need for the bypass current Ib to flow in the phase angle region where the load current is high (the region where the power supply voltage is high), thereby further reducing the circuit loss. Can do.

  In addition, the current drawing unit 1g includes the FET element Q71 so that the sum of the gate-source voltage of the FET element Q71 and the voltage across the series circuit of the resistors R71 and R72 matches the Zener voltage of the Zener diode ZD71. The drain current is constant current controlled. That is, the bypass current Ib is controlled at a constant current by the current drawing unit 1g, and the bypass current Ib does not greatly exceed a necessary holding current, and contributes to a reduction in circuit loss.

  Next, the luminaire 1 includes first to fourth control power supply circuits PS1 to PS4 in order to supply a control voltage to each unit.

  As shown in FIG. 3, the first control power supply circuit PS1 includes a series circuit of a tertiary winding N3 of a transformer T1 and a diode D2. A capacitor Ca is connected in parallel to the series circuit of the tertiary winding N3 and the diode D2. The voltage Vcc across the capacitor Ca becomes the first control voltage Vcc1 by the power supplied from the tertiary winding N3. Further, a discharging resistor Ra is connected between both ends of the capacitor Ca.

  Specifically, when the power conversion circuit 1b is in operation and the switching element Q1 is on, magnetic energy is accumulated in the primary winding N1, and then when the switching element Q1 is turned off, the magnetism of the primary winding N1 Due to the energy, an induced voltage is generated in the tertiary winding N3. Due to this induced voltage, the capacitor Ca is charged via the diode D2, and the first control voltage Vcc1 is generated across the capacitor Ca. That is, the voltage Vcc across the capacitor Ca becomes the first control voltage Vcc1 by the power supplied from the first control power supply circuit PS1.

  As shown in FIG. 5, the second control power supply circuit PS2 includes a resistor R21, a Zener diode ZD21, a transistor Q21, a capacitor C21, and a diode D21. The full-wave rectified voltage Vd is applied to the series circuit of the resistor R21 and the Zener diode ZD21. The base of the transistor Q21 is connected to the midpoint of connection between the resistor R21 and the Zener diode ZD21, and the full-wave rectified voltage Vd is applied to the collector of the transistor Q21. Further, the emitter of the transistor Q21 is connected to the low voltage side of the rectified output of the rectifier circuit DB1 via the capacitor C21, and further connected to the positive electrode of the capacitor Ca via the diode D21.

  In the second control power supply circuit PS2, the sum of the base-emitter voltage of the transistor Q21 and the voltage across the capacitor C21 matches the Zener voltage of the Zener diode ZD21. The voltage across the capacitor C21 is controlled at a constant voltage, and charges the capacitor Ca via the diode D21. That is, the voltage Vcc across the capacitor Ca becomes the second control voltage Vcc2 by the power supplied from the second control power supply circuit PS2. The second control voltage Vcc2 is lower than the first control voltage Vcc1.

  As shown in FIG. 3, the third control power supply circuit PS3 includes resistors R11 and R12, a Zener diode ZD11, a transistor Q11, and a capacitor C11. A series circuit of the resistor R11 and the Zener diode ZD11 is connected in parallel to the secondary-side capacitor C2 of the power conversion circuit 1b. The base of the transistor Q11 is connected to the midpoint of connection between the resistor R11 and the Zener diode ZD11, and the collector of the transistor Q11 is connected to the positive electrode of the capacitor C2. Further, the emitter of the transistor Q11 is connected to the negative electrode of the capacitor C2 via the capacitor C11, and the resistor R12 is connected in parallel to the capacitor C11.

  In the third control power supply circuit PS3, the sum of the base-emitter voltage of the transistor Q11 and the voltage across the capacitor C11 matches the Zener voltage of the Zener diode ZD11. The voltage across the capacitor C11 is constant voltage controlled and becomes the third control voltage Vcc3. That is, the third control power supply circuit PS3 converts the voltage across the capacitor C2 into the third control voltage Vcc3 and outputs it.

  As shown in FIG. 5, the fourth control power supply circuit PS4 includes capacitors C31 and C32 and a three-terminal regulator REG31. A capacitor C31 is connected in parallel to the input side of the three-terminal regulator REG31, and a capacitor C32 is connected in parallel to the output side of the three-terminal regulator REG31. A voltage Vcc across the capacitor Ca is applied to the capacitor C31, and a voltage controlled to a constant voltage is generated in the capacitor C32. The voltage across the capacitor C32 becomes the fourth control voltage Vcc4. That is, the fourth control power supply circuit PS4 converts the voltage Vcc across the capacitor Ca into the fourth control voltage Vcc4 and outputs it.

  Here, the first control voltage Vcc1> the second control voltage Vcc2> the fourth control voltage Vcc4> the third control voltage Vcc3 is set. For example, the first control voltage Vcc1 = 24V, the second control voltage Vcc2 = 18.6V, the fourth control voltage Vcc4 = 7V, and the third control voltage Vcc3 = 4.5V.

  Next, the operations by the control voltages Vcc1 to Vcc4 generated by the first to fourth control power supply circuits PS1 to PS4 are classified into (1) a rising period of the light emitting element lighting device and (2) a period of steady operation of the light emitting element lighting device. (3) Each case when the light emitting element lighting device is stopped will be described.

(1) Rise period of light-emitting element lighting device (period from when power supply from commercial power supply 10 is started to when first control voltage Vcc1 exceeds second control voltage Vcc2)
First, when power supply from the commercial power supply 10 to the lighting fixture 1 and the dimmer 2 is started, the second control power supply circuit PS2 is supplied with the full-wave rectified voltage Vd via the diodes Da and Db, 2 control voltage Vcc2. At this time, the switching element Q1 of the power conversion circuit 1b is in an off state, and the first control power supply circuit PS1 does not generate the first control voltage Vcc1. Thus, the voltage Vcc across the capacitor Ca becomes the second control voltage Vcc2.

  The second control voltage Vcc2 generated at both ends of the capacitor Ca serves as a control power source for the phase detection circuit 1c via the diode Dc.

  As shown in FIG. 6, the phase detection circuit 1c includes a series circuit of a resistor R41 to which a full-wave rectified voltage Vd is applied, a Zener diode ZD41, and a resistor R42, and a capacitor C42 is connected in parallel to the resistor R42. Further, the gate of the transistor Q41 is connected to the midpoint of connection between the Zener diode ZD41 and the resistor R42. The collector of the transistor Q41 is connected to the voltage Vcc across the capacitor Ca (Vcc = Vcc2 in the rising period) via the resistor R43 and the diode Dc, and the emitter of the transistor Q41 is connected to circuit ground. A resistor R44 is connected between the collector and emitter of the transistor Q41. Then, the collector voltage of the transistor Q41 becomes the duty signal S1.

  In the phase detection circuit 1c, when the full-wave rectified voltage Vd is less than the threshold value Vt2 (see FIG. 8), the transistor Q41 is turned off, the collector voltage of the transistor Q41 becomes the second control voltage Vcc2, and the duty signal S1 Becomes H level. When the full-wave rectified voltage Vd is equal to or higher than the threshold value Vt2 (see FIG. 8), the transistor Q41 is turned on, the collector voltage of the transistor Q41 becomes approximately 0V, and the duty signal S1 becomes L level.

  That is, the phase detection circuit 1c generates the duty signal S1 using the second control voltage Vcc2 generated by the second control power supply circuit PS2 during the rising period. The bleeder circuit 1f, to which the duty signal S1 is input, causes the bypass current Ib to flow. The power supply unit 4 of the dimmer 2 generates a control voltage Vs using the bypass current Ib and controls the triac Q81 to start phase control that makes the conduction angle of the power supply voltage of the commercial power supply 10 variable.

  The bleeder circuit 1f originally has a function of causing the triac Q81 to stably operate with the bypass current Ib. And by making this bleeder circuit 1f share the function of generating the control power source of the dimmer 2 at the time of starting, the control power source of the dimmer 2 at the time of starting can be generated with a simple configuration. In addition, the time of starting the dimmer 2 in the present embodiment is a period from when the power supply from the commercial power supply 10 is started until the turn-on operation of the triac Q81 is started.

  Further, the second control voltage Vcc2 is input to the fourth control power supply circuit PS4, and the fourth control power supply circuit PS4 generates the fourth control voltage Vcc4 and supplies it to the dimming circuit 1d.

  The light control circuit 1d has a circuit configuration shown in FIG. First, the FET element Q51 is provided in the input stage, and the duty signal S1 is input to the gate of the FET element Q51. The fourth control voltage Vcc4 is applied to the drain of the FET element Q51 via the resistor R51. Further, a series circuit of resistors R52 and R53 is connected between the drain and source of the FET element Q51, and a capacitor C51 is connected in parallel to the resistor R53. This FET element Q51, resistors R51, R52, R53, and capacitor C51 constitute a first stage RC charge / discharge circuit.

  The dimming circuit 1d also includes an FET element Q52 in the input stage, and the duty signal S1 is input to the gate of the FET element Q52. The voltage across the capacitor C51 is applied to the drain of the FET element Q52 via the resistor R54. Further, a series circuit of resistors R55 and R56 is connected between the drain and source of the FET element Q52, and a capacitor C52 is connected in parallel to the resistor R56. The FET element Q52, resistors R54, R55, R56, and capacitor C52 constitute a second stage RC charge / discharge circuit. Note that the fourth control voltage is also supplied to the power supplies of the operational amplifiers OP51 and OP52.

  Then, as the conduction angle of the power supply voltage decreases and the on-duty ratio of the duty signal S1 increases (as the dimming level decreases), the voltage across the capacitors C51 and C52 decreases. The change in the voltage across the capacitor C52 with respect to the conduction angle of the power supply voltage becomes a curve represented by a second-order polynomial by the first-stage and second-stage RC charge / discharge circuits described above. In FIG. 6, the RC charge / discharge circuit has a two-stage configuration, but by increasing the number of stages of the RC charge / discharge circuit, the change in the voltage across the capacitor C52 with respect to the conduction angle of the power supply voltage is higher order polynomial. It is represented by

  Next, the voltage between both ends of the capacitor C52 is amplified by an amplifier circuit including an operational amplifier OP51 and resistors R57 to R60. In the operational amplifier OP51, the voltage across the capacitor C52 is connected to the non-inverting input via the resistor R57. Further, in the operational amplifier OP51, a resistor R59 is connected between the inverting input and the circuit ground, and a resistor R58 is connected between the inverting input and the output. That is, the operational amplifier OP51 functions as a non-inverting amplifier, and outputs an amplified signal obtained by amplifying the voltage across the capacitor C52 through the resistor R60. The upper limit of the output voltage of the operational amplifier OP51 is limited by the Zener diode ZD51 provided to the output of the operational amplifier OP51 via the resistor R60. That is, the dimming upper limit is determined by setting the upper limit of the output voltage of the operational amplifier OP51 using the Zener diode ZD51.

  Next, the output voltage of the operational amplifier OP51 is input to a subtraction circuit composed of an operational amplifier OP52 and resistors R61 to R66. The output voltage of the operational amplifier OP51 is divided by a series circuit of resistors R61 and R62 and connected to the non-inverting input of the operational amplifier OP52. The fourth control voltage Vcc4 is applied between both ends of the series circuit of the resistors R63 and R64, and the connection midpoint of the resistors R63 and R64 is connected to the inverting input of the operational amplifier OP52 via the resistor R65. Further, a resistor R66 is connected between the inverting input and the output of the operational amplifier OP52. The lower limit of the output voltage of the operational amplifier OP52 is limited by the operational amplifier OP52 functioning as a subtracting circuit. That is, the light control lower limit is determined by setting the lower limit of the output voltage of the operational amplifier OP52.

  The output of the operational amplifier OP52 is divided by a series circuit of resistors R67 and R68, and the voltage at the connection midpoint of the resistors R67 and R68 becomes the target signal S2.

  Here, the frequency of the duty signal S1 is 100 Hz / 120 Hz, which is twice the commercial frequency 50 Hz / 60 Hz of the commercial power supply 10. Therefore, the capacitors C51 and C52 used in the RC charging / discharging circuit of the dimming circuit 1d are required to have a relatively large capacity of about several μF to several tens of μF.

  However, in the present embodiment, as described above, the capacitor C51 of the first stage RC charge / discharge circuit and the capacitor C52 of the second stage RC charge / discharge circuit are generated from the second control voltage Vcc2 during the rising period. It is charged by the fourth control voltage Vcc4. That is, the second control voltage Vcc2 is converted to the fourth control voltage Vcc4 by the fourth control power supply circuit PS4, and is also used for charging the capacitors C51 and C52 during the rising period. Therefore, in the rising period, the time until the target signal S2 is generated can be shortened, and the time required for starting the power conversion circuit 1b can be shortened. In particular, even when the dimming level is low and the conduction angle of the power supply voltage is short, the time required for charging the capacitors C51 and C52 can be shortened, which is effective.

  The fourth control voltage Vcc4 is also supplied to the output feedback circuit 1e via the diode Df, and the output feedback circuit 1e uses the fourth control voltage Vcc4 to output the feedback signal S3 corresponding to the target signal S2. Output.

  The voltage Vcc across the capacitor Ca (Vcc = Vcc2 in the rising period) serves as an operation power supply for the control circuit K1, and the control circuit K1 starts to turn on / off the switching element Q1. When the switching element Q1 starts a switching operation, an induced voltage is generated in the tertiary winding N3, and the first control power supply circuit PS1 generates the first control voltage Vcc1. When the switching element Q1 starts a switching operation, an induced voltage is generated in the secondary winding N2, and the third control power supply circuit PS3 generates the third control voltage Vcc3.

  That is, in the rising period, the second control power supply circuit PS2 generates the second control voltage Vcc2 before the first control power supply circuit PS1 generates the first control voltage Vcc1. Therefore, charging of the capacitor Ca during the rising period of the light emitting element lighting device uses the second control voltage Vcc2 of the second control power supply circuit PS2 (Vcc = Vcc2). When the switching operation of the power conversion circuit 1b is started and the first control voltage Vcc1 exceeds the second control voltage Vcc2, the capacitor Ca is charged by the first control voltage Vcc1 (Vcc = Vcc1). Therefore, in the rising period, the charging time of the capacitor Ca can be shortened, and the time required for starting can be shortened.

  Further, the phase detection circuit 1c generates the duty signal S1 from the second control voltage Vcc2 supplied during the rising period, and this configuration can also shorten the time required for starting.

  Further, the dimming circuit 1d is operated by the duty signal S1 generated from the second control voltage Vcc2 supplied during the rising period, and this configuration can also shorten the time required for starting.

(2) Steady operation period of light-emitting element lighting device (period after power supply from commercial power supply 10 is started and first control voltage Vcc1 exceeds second control voltage Vcc2)
The lighting fixture 1 in the steady operation period is operated by the first control voltage Vcc1 generated by the first control power supply circuit PS1. The timing at which the rising period is switched to the steady operation period (the timing at which the first control voltage Vcc1 exceeds the second control voltage Vcc2) may be before or after the light source unit 1h is turned on.

  The first control voltage Vcc1 is generated at a higher voltage value than the second control voltage Vcc2. Therefore, when the switching element Q1 starts the switching operation and the first control voltage Vcc1 exceeds the second control voltage Vcc2, the charging of the capacitor Ca by the second control power supply circuit PS2 is stopped, and the first control power supply The capacitor Ca is charged by the circuit PS1. Thus, the voltage Vcc of the capacitor Ca is Vcc = Vcc1.

  Then, the fourth control power supply circuit PS4 generates the fourth control voltage Vcc4 using the first control voltage Vcc1 supplied via the diode Dc, and the phase detection circuit 1c receives the first control voltage Vcc1. A duty signal S1 is generated using Vcc1. The first control voltage Vcc1 serves as an operation power supply for the control circuit K1, and the control circuit K1 continues to turn on / off the switching element Q1.

  Thus, during the steady operation of the light-emitting element lighting device, the lighting fixture 1 uses the first control voltage Vcc1 higher than the second control voltage Vcc2 as the control power supply. Since the input / output voltage difference (input voltage-output voltage) of the first control power supply circuit PS1 is smaller than the input / output voltage difference of the second control power supply circuit PS2, the first control voltage Vcc1 is used as the control power supply. As a result, the loss at the time of generating the control voltage can be reduced.

  The operations of the other parts are the same as (1) the operation during the rising period of the light-emitting element lighting device, and a description thereof will be omitted.

(3) When the light emitting element lighting device is stopped (when power supply from the commercial power supply 10 is cut off)
When power supply from the commercial power source 10 to the lighting fixture 1 and the dimmer 2 is interrupted, the capacitor Ca is discharged by the resistor Ra, and the control voltage Vcc is instantaneously reduced. Therefore, the discharge time of the control voltage Vcc is short. Further, since the full-wave rectified voltage Vd becomes zero, the transistor Q41 of the phase detection circuit 1c is turned off.

  On the other hand, the third control power supply circuit PS3 generates the third control voltage Vcc3 by the residual charge of the capacitor C2 on the secondary side of the power conversion circuit 1b. The third control voltage Vcc3 is applied to the gates of the FET elements Q51 and Q52 of the dimming circuit 1d via the diode Dd, and the FET elements Q51 and Q52 are turned on. Therefore, the electric charge of the capacitor C51 of the dimming circuit 1d is discharged through the resistor R52 and the FET element Q51. Furthermore, the electric charge of the capacitor C52 of the dimming circuit 1d is discharged through the resistor R55 and the FET element Q52.

  Thus, after the power supply is cut off, the electric charges of the capacitors C51 and C52 are discharged within a short time. Therefore, even when the time interval from turn-off to restart is short, the residual charge of the capacitors C51 and C52 is small, so that the dimming level at the time of restart becomes higher than necessary, and the light output is temporarily reduced. The phenomenon of starting light jumping out is suppressed.

  Note that the charge of the capacitor C51 is also discharged through the resistor R53, and the charge of the capacitor C52 is discharged through the resistor R56. However, since the resistance value of the resistor R53 is larger than the resistance value of the resistor R52, and the resistance value of the resistor R56 is larger than the resistance value of the resistor R55, each discharge amount through the resistors R53 and R56 is a resistance value. It is smaller than each discharge amount via R52 and R55. That is, the generation of the discharge path through the FET elements Q51 and Q52 when the light emitting element lighting device is stopped is an effective configuration for shortening the discharge time of the capacitors C51 and C52. The greater the number of stages of the charge / discharge circuit, the more effective.

  Further, the third control voltage Vcc3 is also supplied to the output feedback circuit 1e via the diode De.

  As described above, the light emitting element lighting device is started, operated, and stopped by the control voltages Vcc1 to Vcc4 generated by the first to fourth control power supply circuits PS1 to PS4.

  Next, FIG. 10 is a dimming curve showing the dimming characteristics of the dimming circuit 1d, and shows the relationship between the conduction angle of the power supply voltage and the load current. In FIG. 10, the load current corresponds to the phase angle α (see FIG. 9) when the trigger signal rises.

  In the region where the phase angle is α1 or more and the phase angle α2 or less of the dimming curve, the load current decreases in a curved shape as the phase angle α increases, and this curve is represented by a second-order polynomial. That is, as the phase angle α increases (as the conduction angle decreases), the slope at which the dimming curve decreases decreases. Therefore, instead of using linear dimming control, the light output changes suddenly in areas where the dimming level is high, and in areas where the dimming level is low, flickering caused by noise cannot be recognized by human eyes. By reducing the change in light output, natural dimming characteristics are realized. In particular, when the dimming level is low (when the phase angle is small), fine dimming control is possible, and the natural dimming change is suppressed by suppressing the discomfort of the human eye against the change in dimming level. Can be realized.

  In FIG. 10, in the region where the phase angle is α1 or more and the phase angle α2 or less, the load current changes along a curve represented by a quadratic polynomial. This curve shows the sensitivity of the human eye. It may be a curve represented by a LOG scale adapted to the above or a curve showing characteristics close to this.

  In addition, the dimming circuit 1d uses the Zener diode ZD51 to set the upper limit of the output voltage of the operational amplifier OP51. The upper limit of the current is set to a certain maximum value Imax.

  Further, the dimming circuit 1d sets the lower limit of the output voltage of the operational amplifier OP52, thereby making the lower limit of the load current constant in a region that exceeds the phase angle α2 and is less than 180 ° (region where the conduction angle is small). The minimum value Imin is set. The minimum value Imin of the load current is set within a range of 5% ± 3% of the maximum value Imax, and the load current is secured to the extent that the flickering of the light source unit 1h can be suppressed at the lower limit of dimming. .

  In the present embodiment, the phase angle α1 (first phase angle) is set within a range of 40 ° ± 20 °, and the phase angle α2 (second phase angle) is within a range of 120 ° ± 10 °. Set in.

On the other hand, the threshold value Vt2 (see FIG. 9B ) used to generate the duty signal corresponds to the voltage value of the power supply voltage at the phase angle α3, and this phase angle α3 (third phase angle) is 155 °. It is set within a range of ± 10 °. Further, the load current in the region of the phase angle α2 or more and the phase angle α3 or less is set to a certain minimum value Imin. Therefore, dimming control along the dimming curve is possible over the entire range of the duty ratio that can be taken by the duty signal. In FIG. 10, the load current is set to the minimum value Imin in the region of the phase angle α2 to 180 °, but the load current is set to the minimum value Imin in at least the region of the phase angle α2 and the phase angle α3. Should be set.

  The trigger signal is turned off at the phase angle α4 (see FIG. 9), and the phase angle α4 (fourth phase angle) is set within a range of 150 ° ± 10 °. That is, since the phase angle α4> the phase angle α2, the trigger signal is continuously generated up to the phase angle α4 even at the light control lower limit, and the high noise resistance due to the trigger signal can be maintained. Further, the turn-off operation at the start of the next cycle of phase control can be stabilized by turning off the trigger signal at the phase angle α4 smaller than the phase angle 180 °.

  In the region where the phase angle is less than α1, the power supply unit 4 generates the control voltage Vs using the bypass current Ib1 (see FIG. 9D). Then, the generation period of the control voltage Vs (charging period of the capacitor C82) is secured by setting the phase angle α1 within a range of 40 ° ± 20 °.

  Further, when the load current output from the power conversion circuit 1b is controlled to the minimum value Imin by the dimming circuit 1d, the fluctuation range is controlled to be within 2% of the maximum value Imax of the load current. This is realized by appropriately selecting and designing each configuration and each component of the power conversion circuit 1b, the phase detection circuit 1c, the dimming circuit 1d, and the output feedback circuit 1e. Then, by controlling the fluctuation range of the minimum value Imin of the load current to be 2% or less of the maximum value Imax, it is possible to further suppress the flickering of the light source unit 1h at the dimming lower limit.

Thus, in the light emitting element lighting device using the DC trigger method, the dimming circuit 1d performs dimming control along the dimming curve shown in FIG. 10, thereby maintaining high noise resistance due to the trigger signal during dimming. can do. In addition, it is possible to perform dimming control without any sense of incongruity to human eyes.

  In the dimming method of the lighting fixture 1 of the present embodiment, the light source unit 1h is dimmed by turning on and off the switching element Q1, but a circuit that performs dimming by varying the current flowing through the light source unit 1h. It goes without saying that the same effect can be achieved with the configuration.

  The LED element and the organic EL element used for the light source unit 1h are different from the conventional discharge lamp, and particularly require startability and restartability, and shorten the time required for start-up and restart as described above. The configuration is an effective means.

  Moreover, in this embodiment, although the LED element or the organic EL element is used as the light source part 1h, it does not need to be limited to this and you may use another solid light emitting element for the light source part 1h.

DESCRIPTION OF SYMBOLS 1 Lighting fixture 2 Dimmer 3 Dimming control part 4 Power supply part 10 Commercial power supply (AC power supply)
1b Power conversion circuit 1f Bleeder circuit 1h Light source part Q81 Triac (bidirectional switching element)

Claims (4)

A power conversion circuit for supplying a load current to a light source unit composed of light emitting elements, using as an input power supplied from an AC power source;
A bidirectional switching element connected in series to a series circuit of the power conversion circuit and the AC power supply and having a self-holding function;
A dimming control unit that performs phase control to vary the conduction angle of the AC voltage of the AC power supply by controlling the phase angle at which the bidirectional switching element is turned on;
The load current supplied by the power conversion circuit according to the dimming curve showing the relationship between the phase angle at which the bidirectional switching element is turned on and the load current, according to the phase angle at which the bidirectional switching element is turned on A dimming circuit for controlling
A phase detection circuit that generates a binary duty signal set to a duty ratio according to a phase angle at which the bidirectional switching element is turned on by comparing the AC voltage subjected to the phase control with a predetermined threshold; With
The dimming circuit controls the load current supplied by the power conversion circuit according to the duty ratio of the duty signal,
The dimming control unit continuously supplies a trigger signal for turning on the bidirectional switching element for a predetermined period of time during which the bidirectional switching element is conducted,
The dimming curve is a second-order polynomial whose slope decreases as the phase angle increases in a region where the phase angle at which the bidirectional switching element is turned on is greater than or equal to the first phase angle and less than or equal to the second phase angle. In the region where the load current decreases along the represented curve and the phase angle at which the bidirectional switching element is turned on is less than the first phase angle, the load current is set to a certain maximum value, and the bidirectional switching is performed. In the region where the phase angle at which the element is turned on exceeds the second phase angle, the load current is set to a certain minimum value existing within a range of 5% ± 3% of the maximum value,
The first phase angle is set within a range of 40 ° ± 20 °, and the second phase angle is set within a range of 120 ° ± 10 °;
The threshold value corresponds to a voltage value of the AC voltage at a third phase angle larger than the second phase angle,
The dimming curve sets the load current to the minimum value at least in a region not less than the second phase angle and not more than the third phase angle,
The third phase angle is set within a range of 155 ° ± 10 °;
The trigger signal is turned off at a fourth phase angle, and the fourth phase angle is set within a range of 150 ° ± 10 °. A bleeder circuit that is connected in parallel to the input side of the power conversion circuit and generates a bypass current using the AC power source as a supply source;
A control power supply for the dimming control unit is generated using the bypass current generated in parallel with the bidirectional switching element and generated by the bleeder circuit in a region where the phase angle of the AC voltage is less than the first phase angle. The light emitting element lighting device according to claim 1, further comprising:   The load current supplied by the power conversion circuit falls within a fluctuation range of 2% or less of the maximum value when controlled to the minimum value by the dimming circuit. Light emitting element lighting device. The AC power supply and the bidirectional switching element having a self-holding function are connected in series, and the dimming control unit controls the phase angle at which the bidirectional switching element is turned on, thereby changing the conduction angle of the AC voltage of the AC power supply. A lighting fixture that is dimmed by phase control,
A light source unit composed of light emitting elements;
A power conversion circuit for supplying a load current to the light source unit with power supplied from the AC power supply as an input;
Dimming for controlling the load current supplied by the power conversion circuit according to the phase angle controlled by the dimming control unit with reference to a dimming curve indicating the relationship between the phase angle and the load current Circuit,
A phase detection circuit that generates a binary duty signal set to a duty ratio according to a phase angle at which the bidirectional switching element is turned on by comparing the AC voltage subjected to the phase control with a predetermined threshold; With
The dimming circuit controls the load current supplied by the power conversion circuit according to the duty ratio of the duty signal,
The dimming curve follows a curve represented by a second-order polynomial in which the slope decreases as the phase angle increases in a region where the phase angle is greater than or equal to the first phase angle and less than or equal to the second phase angle. In the region where the load current decreases and the phase angle is less than the first phase angle, the load current is set to a certain maximum value, and in the region where the phase angle exceeds the second phase angle, the load current Is a certain minimum value existing within a range of 5% ± 3% of the maximum value,
The first phase angle is set within a range of 40 ° ± 20 °, and the second phase angle is set within a range of 120 ° ± 10 °;
The threshold value corresponds to a voltage value of the AC voltage at a third phase angle larger than the second phase angle,
The dimming curve sets the load current to the minimum value at least in a region not less than the second phase angle and not more than the third phase angle,
The third phase angle is set within a range of 155 ° ± 10 °.

Images