WO2018123115A1 - Lighting device and illumination apparatus - Google Patents

Lighting device and illumination apparatus Download PDF

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Publication number
WO2018123115A1
WO2018123115A1 PCT/JP2017/025307 JP2017025307W WO2018123115A1 WO 2018123115 A1 WO2018123115 A1 WO 2018123115A1 JP 2017025307 W JP2017025307 W JP 2017025307W WO 2018123115 A1 WO2018123115 A1 WO 2018123115A1
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WO
WIPO (PCT)
Prior art keywords
delay time
control unit
mosfet
lighting device
light source
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Application number
PCT/JP2017/025307
Other languages
French (fr)
Japanese (ja)
Inventor
岳秋 飯田
雄一郎 伊藤
Original Assignee
三菱電機株式会社
三菱電機照明株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Application filed by 三菱電機株式会社, 三菱電機照明株式会社 filed Critical 三菱電機株式会社
Priority to JP2018558794A priority Critical patent/JP6694078B2/en
Publication of WO2018123115A1 publication Critical patent/WO2018123115A1/en

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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B47/00—Circuit arrangements for operating light sources in general, i.e. where the type of light source is not relevant
    • H05B47/10—Controlling the light source
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/02—Conversion of ac power input into dc power output without possibility of reversal
    • H02M7/04—Conversion of ac power input into dc power output without possibility of reversal by static converters
    • H02M7/06—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes without control electrode or semiconductor devices without control electrode
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B47/00—Circuit arrangements for operating light sources in general, i.e. where the type of light source is not relevant
    • H05B47/10—Controlling the light source
    • H05B47/17—Operational modes, e.g. switching from manual to automatic mode or prohibiting specific operations

Definitions

  • the present invention relates to a lighting device and a lighting fixture for lighting a light source.
  • the lighting device has a PFC (Power Factor Correction) circuit that is a power factor correction circuit for suppressing harmonics of the input current and improving the power factor.
  • PFC Power Factor Correction
  • Patent Document 1 discloses a method of suppressing an increase in switching frequency at light load and suppressing decrease in on-time by switching the operation mode of the PFC circuit to current discontinuous mode control at light load. Yes.
  • Patent Document 1 has a high harmonic suppression effect because the PFC circuit operates by current critical mode control at high output.
  • the current critical mode control has a problem that the switching loss is large because the switching frequency is higher than that in the case of performing the current discontinuous mode control.
  • the present invention has been made in view of the above, and an object thereof is to obtain a lighting device capable of reducing switching loss while suppressing harmonics of input current.
  • a lighting device includes a rectifier circuit that rectifies AC power, and power that is output from the rectifier circuit while suppressing harmonics to improve the power factor.
  • a DC conversion circuit that converts DC power into DC power and supplies it to the light source, and a control unit that controls the DC conversion circuit, the DC conversion circuit comprising a smoothing capacitor and a switching element disposed between the smoothing capacitor and the rectifier circuit And the coil through which the current output from the rectifier circuit flows, and the control unit turns off the switching element from when the current flowing through the coil becomes zero until the delay time set in the control unit elapses.
  • the switching element is turned on when the delay time has elapsed.
  • the lighting device according to the present invention has an effect of reducing switching loss while suppressing harmonics of the input current.
  • FIG. 1 shows the structure of the electric current control part shown in FIG. Timing chart showing the relationship between the current flowing through the light source, the current flowing through the coil, and the control signal of the MOSFET (Metal Oxide Semiconductor Field Effect Transistor) 1 is a timing chart showing the relationship between the current flowing through the coil constituting the PFC circuit shown in FIG. 1, the drain voltage of the MOSFET, and the gate voltage of the MOSFET.
  • MOSFET Metal Oxide Semiconductor Field Effect Transistor
  • Diagram showing the waveform when dimming with current critical mode control without delay time Diagram showing waveform when dimming with delay time
  • Configuration diagram of lighting device and lighting apparatus shows relationship between current flowing through light source, current flowing through coil and control signal of MOSFET
  • 2nd figure which shows operation
  • Configuration diagram of lighting device and lighting apparatus according to Embodiment 4 In the fourth embodiment, the first timing chart showing the timing for measuring the zero current detection cycle Tzcd during the period from when the light source is turned off to when the light source starts to turn on.
  • the second timing chart showing the timing for measuring the zero current detection period Tzcd during the period from when the light source is turned off to when the light source starts to turn on.
  • the flowchart which shows operation
  • FIG. 1 is a configuration diagram of a lighting device and a lighting fixture according to the first embodiment.
  • the luminaire 200 is connected to the AC power source 1 and converts the power supplied from the AC power source 1 through the input filter 2 that smoothes the AC current output from the AC power source 1 into a DC current that can be input to the light source 8.
  • the lighting device 100 that outputs the light
  • the light source 8 that is turned on by the power supplied from the lighting device 100
  • the dimmer 10 that outputs a dimming signal for turning on, turning off, or dimming the light source 8.
  • the light source 8 is composed of an LED group in which a plurality of LEDs are directly connected. One end of the LED group is connected to the positive side DC bus P, and the other end of the LED group is connected to the negative side DC bus N.
  • the lighting device 100 includes an input filter 2, a rectifier circuit 3 connected to the input filter 2, a capacitor 4 connected in parallel to the rectifier circuit 3, a DC conversion circuit 30, and a current detection that detects a current flowing through the light source 8. And a control unit 9 for controlling the PFC circuit 5 and the current control unit 7.
  • the DC conversion circuit 30 has a function of improving the power factor by suppressing harmonics of the current input from the AC power supply 1 and converting the power output from the rectifier circuit 3 into DC power and supplying it to the light source 8.
  • the DC conversion circuit 30 includes a PFC circuit 5 for improving the power factor by suppressing harmonics of the current input from the AC power supply 1, a smoothing capacitor 6 for smoothing the output voltage of the PFC circuit 5, and a light source 8. And a current control unit 7 for controlling the magnitude of the output current.
  • the input filter 2 disposed between the AC power supply 1 and the rectifier circuit 3 includes a coil 21 and a capacitor 22 and reduces high-frequency noise superimposed on the current output from the AC power supply 1.
  • the coil 21 is connected in series to the AC power source 1.
  • One end of the coil 21 is connected to one end of the AC power supply 1, and the other end of the coil 21 is connected to the capacitor 22 and the rectifier circuit 3.
  • the other end of the capacitor 22 is connected to the AC power source 1 and the rectifier circuit 3.
  • the rectifier circuit 3 is disposed between the input filter 2 and the PFC circuit 5 and converts AC power supplied from the AC power source 1 into DC power.
  • the rectifier circuit 3 is composed of a diode bridge in which four diodes are combined.
  • the configuration of the rectifier circuit 3 is not limited to this, and may be configured by combining MOSFETs that are unidirectional conducting elements.
  • the capacitor 4 is connected in parallel to the output of the rectifier circuit 3, and smoothes the output voltage of the rectifier circuit 3.
  • One end of the capacitor 4 is connected to the positive side DC bus P, and the other end of the capacitor 4 is connected to the negative side DC bus N.
  • the PFC circuit 5 is disposed between the rectifier circuit 3 and the current control unit 7.
  • the PFC circuit 5 includes a MOSFET 51 that is a switching element, a coil 52, and a diode 53.
  • the PFC circuit 5 boosts the output voltage of the rectifier circuit 3 by turning on and off the MOSFET 51 by the control unit 9, and outputs the boosted voltage to the smoothing capacitor 6. Further, the PFC circuit 5 has a function of suppressing the harmonics of the input current and improving the power factor by the control described later.
  • the PFC circuit 5 is configured by a boost chopper circuit will be described.
  • the PFC circuit 5 may be configured by a circuit such as a step-up / step-down chopper circuit, a flyback circuit, a flyforward circuit, a SEPIC (Single Ended Primary Inverter Converter), a Zeta converter, or a Cuk converter.
  • a circuit such as a step-up / step-down chopper circuit, a flyback circuit, a flyforward circuit, a SEPIC (Single Ended Primary Inverter Converter), a Zeta converter, or a Cuk converter.
  • the coil 52 is disposed between the capacitor 4 and the MOSFET 51 on the positive side DC bus P.
  • a primary winding 52 a and a secondary winding 52 b are formed in the coil 52 by winding an insulating wire around a core (not shown).
  • One end of the primary winding 52 a is connected to one end of the capacitor 4.
  • the other end of the primary winding 52 a is connected to the anode of the diode 53.
  • One end of the secondary winding 52b is connected to the control unit 9, and the other end of the secondary winding 52b is connected to the negative-side DC bus N.
  • a voltage having a different polarity is applied to the primary winding 52a as the MOSFET 51 is turned on / off.
  • the voltage generated in the secondary winding 52b is equal to the voltage corresponding to the applied voltage of the primary winding 52a and the turns ratio n.
  • the drain of the MOSFET 51 is connected to the primary winding 52 a and the anode of the diode 53 in the positive side DC bus P.
  • the source of the MOSFET 51 is connected to the other end of the capacitor 4, the other end of the secondary winding 52 b, and the other end of the smoothing capacitor 6 on the negative DC bus N.
  • the gate of the MOSFET 51 is connected to the control unit 9. A control signal output from the control unit 9 is input to the gate of the MOSFET 51. On / off control of the MOSFET 51 is performed by inputting the control signal.
  • the diode 53 is disposed between the MOSFET 51 and the smoothing capacitor 6 in the positive side DC bus P.
  • the anode of the diode 53 is connected to the coil 52 and the MOSFET 51, and the cathode of the diode 53 is connected to the smoothing capacitor 6.
  • the smoothing capacitor 6 is disposed between the PFC circuit 5 and the current control unit 7. One end of the smoothing capacitor 6 is connected to the positive side DC bus P, and the other end of the smoothing capacitor 6 is connected to the negative side DC bus N.
  • the current detector 11 detects a current flowing through the light source 8 and outputs current information corresponding to the detected current value to the controller 9.
  • a configuration in which a current is detected using a shunt resistor or a hall sensor can be exemplified.
  • the control unit 9 includes a target value output unit 91, a zero current detection unit 92, a switching control unit 93, a current input unit 94, and a voltage detection unit 95.
  • the target value output unit 91 is connected to the dimmer 10, and the target value output unit 91 determines an output current target value corresponding to the type of the dimming signal output from the dimmer 10, and the determined output current The target value is output to the switching control unit 93.
  • the output current target value is a signal that specifies a current target value that the lighting device 100 outputs to the light source 8.
  • the voltage detector 95 detects the voltage of the smoothing capacitor 6 and outputs voltage information corresponding to the detected voltage value to the switching controller 93.
  • An example of the voltage detector 95 is a voltage dividing circuit. In the voltage dividing circuit, one end of a series resistor in which two resistors are connected in series is connected to the positive side DC bus P, and the other end of the series resistor is connected to the negative side DC bus N. This circuit divides the voltage applied to the smoothing capacitor 6.
  • the switching control unit 93 outputs a control signal for controlling the current control unit 7 based on the output current target value output from the target value output unit 91 and the current information input to the current input unit 94.
  • the switching control unit 93 stores the output voltage target value of the PFC circuit 5 in advance, and based on at least the voltage information output from the voltage detection unit 95 and the stored output voltage target value. A control signal for controlling the signal is output.
  • the current control unit 7 converts the DC voltage output from the PFC circuit 5 into a DC current that can be input to the light source 8 based on the control signal output from the switching control unit 93.
  • FIG. 2 is a diagram showing a configuration of the current control unit shown in FIG.
  • the current control unit 7 shown in FIG. 2 includes a step-down chopper circuit.
  • a circuit such as a step-up / step-down chopper circuit, a flyback circuit, a fly-forward circuit, a SEPIC, a Zeta converter, or a Cuk converter is used. It may be composed of
  • the current control unit 7 includes a MOSFET 71, a coil 72, a diode 73, and a capacitor 74.
  • MOSFET 71 is arranged on positive side DC bus P.
  • the drain of the MOSFET 71 is connected to one end of the smoothing capacitor 6 and the cathode of the diode 53 shown in FIG.
  • the source of the MOSFET 71 is connected to the cathode of the diode 73 and one end of the coil 72.
  • the gate of the MOSFET 71 is connected to the switching control unit 93.
  • a control signal output from the switching control unit 93 is input to the gate of the MOSFET 71.
  • the control signal is a signal for controlling on / off of the MOSFET 71.
  • One end of the coil 72 is connected to the source of the MOSFET 71 and the cathode of the diode 73.
  • the other end of the coil 72 is connected to one end of the capacitor 74 and one end of the light source 8 shown in FIG.
  • the cathode of the diode 73 is connected to the source of the MOSFET 71 and one end of the coil 72.
  • the anode of the diode 73 is connected to the other end of the smoothing capacitor 6 shown in FIG. 1, the other end of the capacitor 74, and the other end of the light source 8 shown in FIG.
  • FIG. 3 is a timing chart showing the relationship between the current flowing through the light source, the current flowing through the coil, and the control signal of the MOSFET.
  • FIG. 3 shows the current flowing through the light source 8, the current flowing through the coil 72, and the control signal of the MOSFET 71 in order from the top.
  • the horizontal axis represents time.
  • the switching cycle Tsw is equal to the time from when the control signal of the MOSFET 71 changes from OFF to ON until the control signal of the MOSFET 71 changes from OFF to ON again.
  • the switching period Tsw is set in the switching control unit 93 in advance.
  • the on time Ton is equal to the time from when the control signal of the MOSFET 71 changes from off to on until it changes from on to off.
  • the current flowing through the coil 72 has a triangular waveform, but the current output to the light source 8 is smoothed by the capacitor 74, and the average value of the current flowing through the coil 72 is output from the current control unit 7.
  • the switching control unit 93 makes the switching period Tsw for turning on the MOSFET 71 constant, and changes the on-time Ton according to the target value of the output current.
  • the control method for obtaining a specific output by adjusting the on-time Ton in this way is called duty control because the ratio of the on-time Ton to the switching period Tsw is called duty.
  • the MOSFETs 51 and 71 that are switching elements are made of a silicon-based material.
  • the material of the MOSFETs 51 and 71 is not limited to a silicon-based material, and the MOSFETs 51 and 71 may be formed of a wide band gap semiconductor such as silicon carbide, a gallium nitride-based material, or diamond.
  • the conduction loss of the switching element can be reduced.
  • the switching element comprised with a wide band gap semiconductor has high heat resistance.
  • a switching element made of a wide band gap semiconductor has a higher switching speed and a smaller loss at the time of switching than a switching element made of a silicon-based material. Therefore, by increasing the switching frequency, that is, the driving frequency, even if the switching element is switched at high speed, the heat dissipation component for radiating the heat generated by the switching element can be reduced in size. For this reason, the heat dissipation component provided in the PFC circuit 5 and the current control unit 7 can be reduced in size, or the heat dissipation component can be omitted. As a result, the lighting device 100 can be reduced in size and cost.
  • FIG. 4 is a timing chart showing the relationship between the current flowing through the coil constituting the PFC circuit shown in FIG. 1, the drain voltage of the MOSFET, and the gate voltage of the MOSFET.
  • FIG. 4 shows, in order from the top, the current of the AC power source 1 input to the lighting device 100, the current flowing through the coil 52, the drain voltage of the MOSFET 51, and the gate voltage of the MOSFET 51.
  • the horizontal axis represents time.
  • the current of the AC power supply 1 input to the lighting device 100 is indicated as “input current”.
  • the cycle in which the gate voltage of the MOSFET 51 is turned on and off is shown longer than the actual period.
  • the period when the gate voltage of the MOSFET 51 is turned on and off is equal to the time from when the gate voltage of the MOSFET 51 changes from off to on until when the gate voltage of the MOSFET 51 changes from off to on again.
  • the MOSFET 51 When the ON time set in the switching control unit 93 has elapsed, the MOSFET 51 is turned off, thereby forming a closed circuit of the coil 52, the diode 53, and the smoothing capacitor 6. In this closed circuit, the energy accumulated in the coil 52 is released, and the smoothing capacitor 6 is charged.
  • the OFF state of the MOSFET 51 is maintained from when the current flowing through the coil 52 becomes zero until the delay time Tdelay elapses, and when the delay time Tdelay elapses, the MOSFET 51 is turned on again. That is, the control signal of the MOSFET 51 remains off until the delay time Tdelay elapses from the time when the current flowing through the coil 52 becomes zero, and the control signal of the MOSFET 51 is turned on when the delay time Tdelay elapses. Change.
  • the current flowing through the coil 52 has a triangular waveform, and the apex thereof becomes a sine wave envelope as indicated by a dotted line.
  • the current input from the AC power source 1 is smoothed by the input filter 2, and the average value of the coil current flowing through the coil 21 is input to form a sine wave current waveform.
  • the control unit 9 detects the voltage applied to the smoothing capacitor 6 and performs feedback control so that the detected voltage follows the target value, whereby the on-time of the MOSFET 51 is controlled.
  • the response time of the feedback control is set so that the loop gain of the feedback control becomes 1 time (0 dB) or less after being 1/2 of 1 cycle of the AC power supply 1. In other words, the response time of the feedback control is set to be 1 (0 dB) or less at a frequency that is 2 times or less of the frequency of the AC power supply 1.
  • the feedback control loop gain is set to 1 (0 dB) or less at a frequency of 100 Hz or less of the half cycle (half wave) of the power supply frequency, that is, a cycle of 10 msec or more.
  • the feedback control is set so as not to respond in a cycle shorter than 1 ⁇ 2 of the power cycle.
  • the same effect can be obtained by setting the on-time update cycle to a cycle corresponding to half the cycle of the AC power supply 1 or a cycle longer than the cycle corresponding to half the cycle of the AC power supply 1.
  • the MOSFET 51 is switching-controlled by current critical mode control without providing the delay time Tdelay. Therefore, the average value of the current flowing through the coil 52 becomes a complete sine wave, and high power A rate improvement effect can be expected.
  • the lighting device 100 provides the delay time Tdelay and performs switching control of the MOSFET 51 by current discontinuous mode control, thereby lowering the switching frequency compared to the case of current critical mode control. Therefore, the switching loss generated in the MOSFET 51 can be reduced.
  • the delay time Tdelay is set within a range in which an increase in harmonics can be allowed.
  • An example of a range in which an increase in harmonics is allowable is within a current harmonic limit value defined by Japanese Industrial Standards.
  • the voltage oscillation represents the drain voltage oscillation, and the bottom represents the valley portion of the drain voltage oscillation.
  • the control unit 9 turns on the MOSFET 51 at least at the second and subsequent bottoms of the bottom of the voltage oscillation of the MOSFET 51, so that a delay time can be provided with certainty.
  • the switching control unit 93 performs control so as to shorten the ON time of the MOSFET 51 in order to reduce the input current of the AC power supply 1.
  • FIG. 5 is a diagram showing a waveform when dimming with current critical mode control without providing a delay time
  • FIG. 6 is a diagram showing a waveform when dimming with a delay time. 5 and 6 are for explaining an outline of the switching operation of the PFC circuit 5 when the light source 8 is dimmed.
  • FIGS. 5 and 6 shows the input current of the AC power supply 1, the current flowing through the coil 52, the drain voltage of the MOSFET 51, and the gate voltage of the MOSFET 51, as in FIG. 4.
  • the horizontal axis represents time.
  • FIG. 7 is a graph showing the on-time and switching frequency characteristics of the MOSFET, which change according to the dimming rate.
  • FIG. 7 shows, in order from the top, the delay time Tdelay, the ON time of the MOSFET 51, the switching frequency of the control signal for controlling the MOSFET 51, and the dimming rate of the light source 8.
  • the dotted line represents the delay time Tdelay, the ON time of the MOSFET 51, and the switching frequency when the dimming rate is changed when the current critical mode control is performed.
  • a solid line represents the delay time Tdelay, the ON time of the MOSFET 51, and the switching frequency when the dimming rate is changed when the current discontinuous mode control in which the delay time is set is performed.
  • the delay time Tdelay By providing the delay time Tdelay and performing the current discontinuous mode control, an increase in switching frequency during dimming can be suppressed and switching loss can be reduced as compared with current critical mode control. Further, the ON time of the MOSFET 51 can be lengthened, and the MOSFET 51 can be controlled on and off more reliably.
  • FIG. 8 is a first diagram showing the MOSFET on-time and switching frequency when the delay time is changed in accordance with the dimming rate.
  • a threshold value is provided for the dimming rate, and when the dimming rate exceeds the threshold value, the control unit 9 sets the delay time as the first delay time Tdelay 1st, and the dimming rate is the threshold value.
  • the delay time is the second delay time Tdelay2nd.
  • the second delay time Tdelay2nd is longer than the first delay time Tdelay1st, and is longer as the dimming rate decreases.
  • the threshold, the first delay time Tdelay1st, and the second delay time Tdelay2nd shown in FIG. 8 are set in the control unit 9 in advance.
  • the first delay time Tdelay1st is set when a dimming rate exceeding the threshold is input
  • the second delay time Tdelay2nd is set when a dimming rate less than the threshold is input.
  • the control unit 9 stores the minimum on-time Ton_min.
  • the dimming control can be performed so that the on-time of the MOSFET 51 is not shorter than the minimum on-time Ton_min.
  • FIG. 9 is a second diagram showing the MOSFET on-time and switching frequency when the delay time is changed in accordance with the dimming rate.
  • a plurality of threshold values 1, 2, and 3 are set for the dimming rate.
  • the plurality of thresholds 1, 2, and 3 are higher in the order of threshold 3, threshold 2, and threshold 1.
  • a plurality of delay times Tdelay 1, 2, 3, 4 corresponding to a plurality of threshold values 1, 2, 3 are set. It is assumed that a plurality of threshold values 1, 2, 3 and a plurality of delay times Tdelay 1, 2, 3, 4 are set in the control unit 9.
  • Delay time Tdelay4 is set when a dimming rate of threshold 3 or less is input.
  • the delay time Tdelay3 is set when a dimming rate that exceeds the threshold 3 and is equal to or less than the threshold 2 is input.
  • the delay time Tdelay2 is set when a dimming rate that exceeds the threshold 2 and is equal to or less than the threshold 1 is input.
  • the delay time Tdelay1 is set when a dimming rate exceeding the threshold value 1 is input.
  • the control unit 9 provides a plurality of threshold values for the dimming rate, and controls the switching elements using a plurality of delay times having different lengths according to a range between adjacent threshold values. Specifically, when the delay time Tdelay1 is provided and the light is dimmed in the direction in which the current of the light source 8 decreases and the dimming rate reaches the threshold value 1, the on-time of the MOSFET 51 is the minimum on-time. When the time is shortened to the time Ton_min, the control unit 9 increases the delay time from Tdelay1 to Tdelay2. This can prevent the on time of the MOSFET 51 from becoming shorter than the minimum on time Ton_min.
  • FIG. 10 is a diagram showing changes over time in delay time, MOSFET on-time, and light source dimming rate when the delay time is extended from Tdelay1 to Tdelay2 with threshold value 1 of dimming rate shown in FIG. is there.
  • the delay time Tdelay When the delay time Tdelay is abruptly extended, the switching frequency of the MOSFET 51 suddenly changes, the output of the PFC circuit 5 fluctuates, and the voltage of the smoothing capacitor 6 fluctuates, so that the output current of the current control unit 7 connected to the subsequent stage is constant. Therefore, the light source 8 cannot be lit stably. Therefore, when the delay time Tdelay is extended, the change amount maximum value Tstep of the delay time Tdelay is provided, and the maintenance time Tk that maintains the delay time Tdelay without change is provided, thereby delaying the time change of the delay time Tdelay. be able to. By performing this control, a sudden change in the switching frequency of the MOSFET 51 can be suppressed.
  • the maintenance time Tk for maintaining the delay time Tdelay is set longer than the response time for feedback control of the ON time of the MOSFET 51. As a result, a time during which the ON time of the MOSFET 51 is constant is ensured, and the output of the PFC circuit 5 can be stabilized.
  • FIG. 11 is a flowchart for explaining the operation of the control unit when extending the delay time.
  • the controller 9 When the light source 8 is turned on with the delay time Tdelay1 provided, the controller 9 performs dimming in the direction of decreasing the current of the light source 8 (S11), and when the dimming rate is greater than the threshold 1 (S12, No ), The delay time is not changed (S15). When the dimming rate is equal to or less than the threshold value 1 (S12, Yes), the control unit 9 does not change the delay time unless the delay time maintenance time Tk has elapsed after the final change of the delay time (S13, No). (S15).
  • the control unit 9 does not change the delay time if the delay time is Tdelay2 or more (S14, No) ( S15). If the delay time is smaller than Tdelay2 (S14, Yes), the delay time is extended by Tstep (S16).
  • the control unit 9 changes the delay time from Tdelay2 to Tdelay1. To shorten.
  • FIG. 12 is a diagram showing temporal changes in delay time, MOSFET on-time, and light source dimming rate when the delay time is shortened from Tdelay2 to Tdelay1 with the threshold value 1 of dimming rate shown in FIG. is there.
  • the delay time is sharply shortened, the switching frequency of the MOSFET 51 suddenly changes, the output of the PFC circuit 5 fluctuates, and the voltage of the smoothing capacitor 6 fluctuates, so that the output current of the current control unit 7 connected to the subsequent stage is constant Therefore, the light source 8 cannot be lit stably.
  • the delay time Tdelay is shortened, the change amount maximum value Tstep of the delay time Tdelay is provided, and the maintenance time Tk that maintains the delay time Tdelay without change is provided, thereby delaying the time change of the delay time Tdelay. can do.
  • a sudden change in the switching frequency of the MOSFET 51 can be suppressed.
  • the maintenance time Tk for maintaining the delay time Tdelay is set longer than the response time for feedback control of the ON time of the MOSFET 51. As a result, a time during which the ON time of the MOSFET 51 is constant is ensured, and the output of the PFC circuit 5 can be stabilized.
  • FIG. 13 is a flowchart for explaining the operation of the control unit when the delay time is shortened.
  • the control unit 9 performs dimming in the direction of increasing the current of the light source 8 from the lighting state with the delay time Tdelay2 (S21), and when the dimming rate is equal to or less than the threshold 1 (S22, No), The delay time is not changed (S25). If the dimming rate is larger than the threshold value 1 (S22, Yes), the delay time is not changed (S25) if the delay time maintenance time Tk has not passed after the final change of the delay time (S23, No). When the delay time maintaining time Tk has elapsed after the final change of the delay time (S23, Yes), the control unit 9 does not change the delay time if the delay time is equal to or less than Tdelay1 (S24, No) ( S25). If the delay time is larger than Tdelay1 (S24, Yes), the delay time is shortened by Tstep (S26).
  • the light source 8 was comprised by LED
  • LED Organic EL (Electro Luminescence) may be sufficient.
  • FIG. FIG. 14 is a configuration diagram of a lighting device and a lighting fixture according to the second embodiment.
  • the difference between the lighting fixture 200A according to Embodiment 2 and the lighting fixture 200 according to Embodiment 1 is that the lighting fixture 100A is used instead of the lighting device 100 in the lighting fixture 200A.
  • the difference between the lighting device 100A according to the second embodiment and the lighting device 100 according to the first embodiment is that, in the lighting device 100A, a DC conversion circuit is used instead of the PFC circuit 5, the smoothing capacitor 6, and the current control unit 7. 12, and a control unit 9 ⁇ / b> A is used instead of the control unit 9.
  • the DC conversion circuit 12 is a circuit having the functions of the PFC circuit 5, the smoothing capacitor 6, and the current control unit 7.
  • Embodiment 2 describes an example in which the DC conversion circuit 12 is configured by a flyback circuit.
  • the DC conversion circuit 12 may be configured by a circuit such as a fly forward circuit, a step-down chopper, a step-up chopper, a step-up / step-down chopper circuit, a SEPIC, a Zeta converter, or a Cuk converter.
  • the DC conversion circuit 12 includes a MOSFET 121, a transformer 122, a diode 123, a smoothing capacitor 124, a snubber capacitor 125, a snubber resistor 126, and a snubber diode 127.
  • the MOSFET 121 is disposed between the capacitor 4 and the primary side of the transformer 122 in the negative-side DC bus N.
  • the source of the MOSFET 121 is connected to one end of the capacitor 4 and the rectifier circuit 3.
  • the drain of MOSFET 121 is connected to the anode of snubber diode 127 and transformer 122.
  • Snubber capacitor 125, snubber resistor 126 and snubber diode 127 are arranged between capacitor 4 and the primary side of transformer 122.
  • One end of the snubber resistor 126 is connected to the other end of the capacitor 4, the rectifier circuit 3, one end of the snubber capacitor 125, and the transformer 122 via the positive side DC bus P.
  • the other end of the snubber resistor 126 is connected to the other end of the snubber capacitor 125 and one end of the snubber diode 127.
  • the other end of the snubber capacitor 125 is connected to the other end of the snubber resistor 126 and one end of the snubber diode 127.
  • the diode 123 and the smoothing capacitor 124 are disposed between the secondary side of the transformer 122 and the light source 8.
  • the anode of the diode 123 is connected to the transformer 122, and the cathode of the diode 123 is connected to one end of the smoothing capacitor 124 and one end of the light source 8.
  • the other end of the smoothing capacitor 124 is connected to the transformer 122 and the other end of the light source 8.
  • the primary winding 122a, the secondary winding 122b, and the tertiary winding 122c are formed in the transformer 122 by winding an insulating wire around a core (not shown).
  • the direct current conversion circuit 12 converts the output voltage of the rectifier circuit 3 and outputs a direct current to the light source 8 when the MOSFET 121 is on / off controlled.
  • the control unit 9A includes a target value output unit 91, a zero current detection unit 92, a switching control unit 93A, and a current input unit 94.
  • the difference between the control unit 9 shown in FIG. 1 and the control unit 9A shown in FIG. 14 is that, in the control unit 9A, the voltage detection unit 95 is omitted, and the switching control unit 93A is used instead of the switching control unit 93. That is.
  • FIG. 15 is a timing chart showing the relationship between the current flowing through the windings constituting the DC conversion circuit shown in FIG. 14, the drain voltage of the MOSFET, and the gate voltage of the MOSFET.
  • the current of the AC power source 1 input to the lighting device 100A the current flowing through the primary winding 122a, the current flowing through the tertiary winding 122c, the drain voltage of the MOSFET 121, and the MOSFET 121
  • the gate voltage is shown.
  • the horizontal axis represents time.
  • the current of the AC power supply 1 input to the lighting device 100 ⁇ / b> A is indicated as “input current”.
  • the cycle in which the gate voltage of the MOSFET 121 is turned on / off is shown to be longer than the actual period.
  • the period during which the gate voltage of the MOSFET 121 is turned on / off is equal to the time from when the gate voltage of the MOSFET 121 changes from off to on until when the gate voltage of the MOSFET 121 changes from off to on again.
  • the MOSFET 121 When the ON time set in the switching control unit 93A elapses, the MOSFET 121 is turned off to form a closed circuit of the tertiary winding 122c, the diode 123, and the smoothing capacitor 124. In this closed circuit, the energy stored in the primary winding 122a is released, and the smoothing capacitor 124 is charged.
  • the MOSFET 121 is kept off until the delay time Tdelay elapses after the current flowing through the tertiary winding 122c becomes zero, and the MOSFET 121 is turned on again when the delay time Tdelay elapses.
  • the current flowing through the primary winding 122a has a triangular waveform, and a sine wave envelope whose apex is indicated by a dotted line.
  • the current input from the AC power source 1 is smoothed by the input filter 2, and the average value of the coil current flowing through the coil 21 is input to form a sine wave current waveform.
  • the control unit 9A detects the current flowing through the light source 8, and feedback control is performed so that the detected current follows the target value, whereby the on-time of the MOSFET 121 is controlled.
  • the response time of the feedback control is set so that the loop gain of the feedback control is not less than 1/2 of one cycle of the AC power supply 1 and not more than 1 (0 dB). In other words, the response time of the feedback control is set to be 1 (0 dB) or less at a frequency that is 2 times or less of the frequency of the AC power supply 1.
  • the loop gain of the constant current feedback control is set to be 1 (0 dB) or less at a frequency of 100 Hz or less of a half cycle (half wave) of the power supply frequency, that is, a cycle of 10 msec or more.
  • the constant current feedback control is set so as not to respond in a cycle shorter than 1 ⁇ 2 of the power cycle.
  • the fluctuation of the on-time of the MOSFET 121 is suppressed within a half cycle of the power supply cycle, and the envelope of the peak of the current flowing through the primary winding 122a becomes a sine wave waveform.
  • the same effect can be obtained by setting the on-time update cycle to a cycle corresponding to half the cycle of the AC power supply 1 or a cycle longer than the cycle corresponding to half the cycle of the AC power supply 1.
  • the lighting device 100A and the lighting fixture 200A according to the second embodiment are provided with the delay time Tdelay as in the first embodiment, and when the current critical mode control is performed by switching the MOSFET 121 by the current discontinuous mode control. In comparison, since the switching frequency can be lowered, the switching loss generated in the MOSFET 121 can be reduced.
  • the length of the delay time is an output that the DC conversion circuit 30 outputs to the LED instead of the dimming rate.
  • the determination may be made based on the current target value.
  • the magnitude of the output of the DC conversion circuit may be determined by the dimming rate of the LED, may be determined by the output current target value of the LED, or may be determined by the dimming rate of the organic EL. It may be determined.
  • the magnitude of the output of the DC conversion circuit may be determined from the output current target value of the LED.
  • you may comprise the control part which concerns on Embodiment 1, 2 so that the length of delay time may be changed according to an output current target value instead of a light control rate.
  • FIG. 16 is a configuration diagram of a lighting device and a lighting fixture according to the third embodiment.
  • the difference between the lighting fixture 200B according to Embodiment 3 and the lighting fixture 200 according to Embodiment 1 is that the lighting device 100B is used instead of the lighting device 100 in the lighting fixture 200B.
  • the difference between the lighting device 100B according to the third embodiment and the lighting device 100 according to the first embodiment is that, in the lighting device 100B, the coil 75 is used in the current control unit 7, and the control is performed instead of the control unit 9. The part 9B is used.
  • the current control unit 7 shown in FIG. 16 includes a step-down chopper circuit.
  • a circuit such as a step-up / step-down chopper circuit, a flyback circuit, a fly-forward circuit, a SEPIC, a Zeta converter, or a Cuk converter is used. It may be composed of
  • the current controller 7 includes a MOSFET 71, a coil 75, a diode 73, and a capacitor 74.
  • the coil 75 is disposed between the capacitor 74 and the MOSFET 71 on the positive side DC bus P.
  • a primary winding 75a and a secondary winding 75b are formed on the coil 75 by winding an insulating wire around a core (not shown).
  • One end of the primary winding 75 a is connected to the source of the MOSFET 71 and the cathode of the diode 73.
  • the other end of the primary winding 75 a is connected to one end of the capacitor 74 and one end of the light source 8.
  • One end of the secondary winding 75b is connected to the zero current detection unit 92 in the control unit 9B.
  • the other end of secondary winding 75b is connected to negative side DC bus N.
  • a voltage having a different polarity is applied to the primary winding 75a as the MOSFET 71 is turned on / off.
  • the voltage induced by the secondary winding 75b and generated at both ends of the secondary winding 75b is equal to the voltage corresponding to the applied voltage of the primary winding 75a and the turn ratio n.
  • the MOSFET 71 is disposed on the positive side DC bus P.
  • the drain of the MOSFET 71 is connected to one end of the smoothing capacitor 6.
  • the source of the MOSFET 71 is connected to the cathode of the diode 73 and one end of the primary winding 75 a of the coil 75.
  • the gate of the MOSFET 71 is connected to the switching control unit 93.
  • a control signal output from the switching control unit 93 is input to the gate of the MOSFET 71.
  • the control signal is a signal for controlling on / off of the MOSFET 71.
  • FIG. 17 is a timing chart showing the relationship between the current flowing through the light source, the current flowing through the primary winding, and the control signal of the MOSFET.
  • FIG. 17 shows, in order from the top, the current flowing through the light source 8, the voltage applied between the drain and source of the MOSFET 71, the current flowing through the primary winding 75a, the zero current detection signal, and the control signal of the MOSFET 71. Indicated.
  • the voltage applied between the drain and the source is denoted as “drain voltage”.
  • the horizontal axis represents time.
  • the MOSFET 71 is turned off at time t2 when the on-time Ton set in the switching control unit 93 has elapsed, thereby forming a closed circuit of the primary winding 75a, the capacitor 74, and the diode 73. In this closed circuit, the energy accumulated in the primary winding 75a is released, and the capacitor 74 is charged.
  • the MOSFET 71 is kept off until the delay time Tdelay elapses from time t3 when the current flowing through the primary winding 75a becomes zero.
  • the MOSFET 71 is turned on again. That is, the control signal of the MOSFET 71 remains off from the time when the current flowing through the primary winding 75a becomes zero until the time when the delay time Tdelay has elapsed. Then, when the delay time Tdelay has elapsed, the control signal of the MOSFET 71 changes to the on state.
  • the current flowing through the primary winding 75a has a triangular waveform.
  • the current output from the current control unit 7 to the light source 8 is smoothed by the capacitor 74. Therefore, the average value of the current flowing through the primary winding 75a is output to the light source 8. That is, the current output from the current control unit 7 to the light source 8 has a direct current waveform from which fluctuations have been removed.
  • the current detector 11 detects the current flowing through the light source 8, and transmits the detected current to the controller 9B.
  • the control unit 9B performs feedback control on the on-time Ton of the MOSFET 71 so that the current detected by the current detection unit 11 follows the target value. That is, the control unit 9B increases the on-time Ton of the MOSFET 71 when the detected current is smaller than the target value, and shortens the on-time Ton of the MOSFET 71 when the detected current is larger than the target value.
  • the MOSFET 71 of the current control unit 7 is duty control with a fixed frequency.
  • the MOSFET 71 when the MOSFET 71 is controlled in the current critical mode, the MOSFET 71 operates at a higher switching frequency. Therefore, if the current output to the light source 8 when the MOSFET 71 is current critical mode controlled is equal to the current output to the light source 8 when the MOSFET 71 is duty controlled at a fixed frequency, the current critical mode control Time Ton can be shortened.
  • the on-time Ton is determined by the magnitude of the current output to the light source 8, and is the longest when all the lights are on. At this time, the peak value of the current flowing through the primary winding 75a is also maximized. As the magnitude of the current flowing through the primary winding 75a is smaller, the magnetic flux density generated in the magnetic core constituting the coil 75 is lower, and the size of the core can be reduced.
  • the coil 75 can be reduced in size.
  • the switching control unit 93 performs control to shorten the ON time Ton of the MOSFET 71 in order to reduce the input current of the AC power supply 1. Therefore, in the current critical mode control, the ON time Ton of the MOSFET 71 becomes too short at the time of dimming, the ON / OFF operation of the MOSFET 71 becomes unstable, and the output light of the light source 8 may flicker. The flickering of the output light is equal to the brightness variation of the light source 8.
  • FIG. 18 is a graph showing the on-time and switching frequency characteristics of the MOSFET that change in accordance with the dimming rate.
  • FIG. 18 shows the ON time of the MOSFET 71, the switching frequency, and the dimming rate of the light source 8 in order from the top.
  • the dotted line represents the ON time and switching frequency of the MOSFET 71 when the dimming rate is changed when the current critical mode control is performed without providing the delay time Tdelay.
  • the solid line represents the ON time and switching frequency of the MOSFET 71 when the dimming rate is changed when the current discontinuous mode control is performed with the delay time Tdelay.
  • the delay time Tdelay and controlling the MOSFET 71 in the current discontinuous mode control an increase in switching frequency during dimming can be suppressed and switching loss can be reduced as compared with the current critical mode control. Further, the ON time of the MOSFET 71 can be lengthened, and the MOSFET 71 can be controlled on and off more reliably. In the current control unit 7, if the ON time of the MOSFET 71 becomes too short, the ON / OFF operation of the MOSFET 71 becomes unstable, and the light source 8 may flicker in the output light. By providing, it is possible to ensure the on-time and to perform dimming control without causing flickering in the output light of the light source 8.
  • the length of the on time during which the MOSFET 71 cannot normally be turned on / off is, for example, 0.2 usec or less. Therefore, the control unit 9B stores the minimum on-time Ton_min, and when the light source 8 is dimmed, the dimming control can be performed so that the on-time of the MOSFET 71 is not shorter than the minimum on-time Ton_min.
  • the minimum on-time Ton_min is equal to the length of the on-time at which the MOSFET 71 cannot normally operate on and off.
  • the peak current of the primary winding 75a can be reduced as compared with the case where the duty control is performed as in the case of the current critical mode control. 75 can be further downsized. Furthermore, since the ON time reduction of the MOSFET 71 when the light source 8 is dimmed can be suppressed as compared with the case where the current critical mode control is performed, the occurrence of flickering in the output light of the light source 8 can be suppressed during dimming.
  • the delay time Tdelay is made constant regardless of the dimming rate, so that the switching frequency fluctuation of the MOSFET 71 is suppressed, and the flickering of the output light of the light source 8 is suppressed.
  • FIG. 19 is a first diagram illustrating the operation of the current control unit when the current output to the light source is different.
  • FIG. 20 is a second diagram illustrating the operation of the current control unit when the magnitude of the current output to the light source is different.
  • 19 and 20 in order from the top, the current output to the light source 8, the voltage applied between the drain and source of the MOSFET 71, the current flowing through the primary winding 75a, the zero current detection signal, and the MOSFET 71.
  • Control signals. 19 and 20 the voltage applied between the drain and the source is denoted as “drain voltage”.
  • the horizontal axis represents time.
  • Ton (a) has a relationship of on time Ton (a) at all light> on time Ton (b) at light control.
  • the length of the delay time Tdelay is changed during the period when the light source 8 is turned on, a determination means for changing the delay time Tdelay is required. Therefore, for example, when the determination unit is realized using an arithmetic element such as a microcomputer or a CPU, it is necessary to describe a complicated determination processing instruction, and the memory capacity to be used increases. In addition, when the determination unit is realized using an analog circuit, the number of parts increases and the circuit configuration becomes complicated. Therefore, by making the length of the delay time Tdelay constant regardless of the dimming rate, it is possible to suppress an increase in the memory capacity of an arithmetic element such as a microcomputer or a CPU, and to suppress an increase in the number of components constituting the analog circuit. it can.
  • the control unit 9B turns on the MOSFET 71 near the bottom of the voltage oscillation of the MOSFET 71 during the period in which the drain voltage of the MOSFET 71 is in free oscillation. As a result, steep fluctuations in the drain voltage are suppressed, and noise caused by switching is suppressed.
  • the delay time Tdelay can be provided with certainty by the controller 9B turning on the MOSFET 71 at least at the second and subsequent bottoms among the bottoms of the voltage oscillation of the MOSFET 71 that occurs a plurality of times.
  • the configuration shown in the above third embodiment shows an example of the content of the present invention, and can be combined with another known technique, or can be combined with the configuration shown in the first embodiment. It is.
  • the light source 8 is configured by an LED.
  • the light source 8 is not limited to an LED as long as it can be dimmed, and may be an organic EL.
  • FIG. 21 is a configuration diagram of a lighting device and a lighting fixture according to the fourth embodiment. Note that in the fourth embodiment, parts having the same configurations as those of the lighting device 100B and the lighting fixture 200B according to the third embodiment of FIG.
  • the difference between the lighting fixture 200C according to the fourth embodiment and the lighting fixture 200B according to the third embodiment is that the lighting fixture 100C uses the lighting device 100C instead of the lighting device 100B. Further, the difference between the lighting device 100C according to the fourth embodiment and the lighting device 100B according to the third embodiment is that, in the lighting device 100C, the control unit 9C includes a period measurement unit 96, and the control unit 9C includes a zero current. The detection period Tzcd is measured to determine the delay time Tdelay.
  • FIG. 22 is a first timing chart showing the timing for measuring the zero current detection period Tzcd during the period from when the light source is turned off to when the light source starts to turn on in the fourth embodiment.
  • the cycle in which the gate voltage of the MOSFET 71 is turned on / off is described longer than the actual period.
  • the voltage applied to the light source 8, the current flowing through the light source 8, the voltage applied between the drain and source of the MOSFET 71, the current flowing through the primary winding 75a, and zero current detection A signal and a control signal of the MOSFET 71 are shown.
  • the voltage applied between the drain and the source is denoted as “drain voltage”.
  • the horizontal axis represents time.
  • the current control unit 7 starts on / off control of the MOSFET 71 from time t1.
  • an LED is used as the light source 8
  • no current flows through the light source 8 below the forward voltage threshold Vfth, and therefore only the voltage applied to the light source 8 rises during the period from time t1 to t3.
  • the forward voltage threshold Vfth is equal to a voltage at which a current starts to flow through the LED among voltages applied to the LED, that is, a voltage at which the LED starts to light.
  • the maximum value of the voltage generated at both ends of the secondary winding 75b can be expressed by the product of the turn ratio n of the primary winding 75a and the secondary winding 75b and the voltage applied to the light source 8. Therefore, during the period when the voltage applied to the light source 8 increases from time t1 to t4, the maximum value of the voltage generated at both ends of the secondary winding 75b also increases.
  • the period measuring unit 96 detects the maximum value of the zero current detection signal during the period in which the MOSFET 71 is on at time t2.
  • the cycle measuring unit 96 measures the zero current detection cycle Tzcd after the MOSFET 71 is turned off, and information on the measured zero current detection cycle Tzcd. Is transmitted to the switching control unit 93C.
  • the switching control unit 93C determines the delay time Tdelay based on the zero current detection cycle Tzcd. A method for determining the delay time Tdelay will be described later.
  • the zero current detection period Tzcd includes the parasitic capacitance of the MOSFET 71, the inductance of the primary winding 75a, the parasitic capacitance of the LED used as the light source 8, the wiring parasitic capacitance of the lighting device 100C, and the wiring parasitic inductance of the lighting device 100C. It varies depending on the size. Therefore, the cycle measuring unit 96 measures the zero current detection cycle Tzcd, and the switching control unit 93C determines the delay time Tdelay based on the zero current detection cycle Tzcd.
  • the MOSFET 71 can be turned on at the timing.
  • n is a value exceeding 1.
  • the MOSFET 71 can be turned on at the bottom timing of the free oscillation of the drain voltage of the MOSFET 71.
  • the cycle detection threshold value Sith is set so that the time t2 when the zero current detection cycle Tzcd is measured is before the time t3 when the light source 8 starts to turn on.
  • the configuration example using the maximum value of the zero current detection signal in order to determine the time for the period measurement unit 96 to measure the zero current detection period Tzcd has been described, but the voltage applied to the light source 8 And the time at which the zero current detection period Tzcd is measured may be determined using the detected voltage. Even in this case, the voltage threshold value applied to the light source 8 can be provided so that the time t2 when the zero current detection period Tzcd is measured is before the time t3 when the light source 8 starts to light. However, in this case, it is necessary to provide a voltage detection unit for detecting the voltage applied to the light source 8 in the illumination device 100C.
  • FIG. 23 is a second timing chart showing the timing for measuring the zero current detection period Tzcd during the period from when the light source is turned off to when the light source starts to turn on in the fourth embodiment.
  • the voltage applied to the light source 8, the current flowing through the light source 8, the voltage applied between the drain and source of the MOSFET 71, the current flowing through the primary winding 75a, and zero current detection A signal and a control signal of the MOSFET 71 are shown.
  • the voltage applied between the drain and the source is denoted as “drain voltage”.
  • the horizontal axis represents time.
  • the current control unit 7 starts on / off control of the MOSFET 71 from time t1.
  • an LED is used as the light source 8
  • no current flows through the light source 8 below the forward voltage threshold Vfth, and therefore only the voltage applied to the light source 8 rises during the period from time t1 to t3.
  • the switching control unit 93C causes the cycle measurement unit 96 to start the zero current detection cycle measurement. That is, the switching control unit 93 ⁇ / b> C requests the period measurement unit 96 to start the zero current detection period measurement.
  • the cycle measurement unit 96 When the cycle measurement unit 96 receives a request for starting the zero current detection cycle measurement from the switching control unit 93C, the cycle measurement unit 96 measures the zero current detection cycle Tzcd after the MOSFET 71 is turned off, and performs switching control on information on the measured zero current detection cycle Tzcd. To the unit 93C.
  • the switching control unit 93C When the switching control unit 93C receives information on the zero current detection cycle Tzcd from the cycle measurement unit 96, the switching control unit 93C calculates a delay time Tdelay based on the zero current detection cycle Tzcd. The calculation result of the delay time Tdelay is reflected when the light source 8 is turned off and then the light source 8 is turned on again.
  • the zero current detection period Tzcd includes the parasitic capacitance of the MOSFET 71, the inductance of the primary winding 75a, the parasitic capacitance of the LED used as the light source 8, the wiring parasitic capacitance of the lighting device 100C, and the lighting device 100C. Vary depending on the magnitude of the wiring parasitic inductance.
  • the parasitic capacitance of the MOSFET has a characteristic that depends on the magnitude of the drain voltage. Therefore, by determining the delay time Tdelay based on the zero current detection period Tzcd measured during the period when the light source 8 is lit, the MOSFET 71 is turned on more accurately at the bottom timing of the free oscillation of the drain voltage of the MOSFET 71. be able to.
  • the parasitic capacitance of the MOSFET varies depending on the magnitude of the drain voltage.
  • the oscillation cycle of the drain voltage varies depending on the parasitic capacitance of the MOSFET. From these facts, it can be said that the oscillation period of the drain voltage changes depending on the magnitude of the drain voltage.
  • the delay time Tdelay is changed in accordance with the voltage applied to the light source 8.
  • the length of the delay time Tdelay corresponding to the input voltage of the current control unit 7 is determined in advance, the voltage input to the current control unit 7 during the lighting operation is detected, and the detected voltage is set.
  • n is a value exceeding 1.
  • the MOSFET 71 can be turned on at the bottom timing of the free oscillation of the drain voltage of the MOSFET 71.
  • the delay time Tdelay is changed after the time t3 when the light source 8 is turned on, the current output to the light source 8 fluctuates, and the output light of the light source 8 flickers. Therefore, flickering of the output light of the light source 8 can be suppressed by reflecting the delay time Tdelay calculated from the zero current detection cycle Tzcd immediately before the light source 8 is turned on again.
  • FIG. 24 is a flowchart showing the operation of the lighting device according to the fourth embodiment.
  • the control unit 9C when the light source 8 is in the off state waits for an input of the lighting command for the light source 8 until a lighting command for the light source 8 is input (S301, S302: No).
  • the control unit 9C updates the delay time Tdelay (S303).
  • the switching control unit 93C starts the on / off operation of the MOSFET 71, whereby the current control unit 7 starts the operation (S304).
  • the switching control unit 93C determines whether or not the current detected by the current detection unit 11 has reached the target value.
  • the processing of S305 is repeated and the period measurement unit 96 does not operate. . That is, the measurement of the zero current detection period Tzcd is not executed.
  • the cycle measuring unit 96 measures the zero current detection cycle Tzcd (S306).
  • Information regarding the zero current detection cycle Tzcd is transmitted to the switching control unit 93C.
  • the switching control unit 93C that has received the information regarding the zero current detection cycle Tzcd calculates the delay time Tdelay based on the zero current detection cycle Tzcd, and holds the calculated delay time Tdelay (S307).
  • a predetermined delay time Tdelay is set as an initial value.
  • the configuration shown in the above fourth embodiment shows an example of the contents of the present invention, and can be combined with another known technique, or can be combined with the configuration shown in the first embodiment. It is.
  • the light source 8 is configured by an LED.
  • the light source 8 is not limited to an LED and may be an organic EL as long as the light source 8 can be dimmed.
  • the example in which the length of the delay time is determined according to the value of the output current measured by the current detection unit 11 has been described.
  • the output of the DC conversion circuit 30 is described. You may use the output voltage detection part which detects a voltage, or the input voltage detection part which detects the input voltage of the DC converter circuit 30.
  • FIG. Even if the length of the delay time is determined according to the output voltage detected by the output voltage detector, or the length of the delay time is determined according to the input voltage detected by the input voltage detector The effect is obtained.
  • the configuration described in the above embodiment shows an example of the contents of the present invention, and can be combined with another known technique, and can be combined with other configurations without departing from the gist of the present invention. It is also possible to omit or change the part.

Abstract

The present invention is provided with: a rectification circuit (3) which rectifies AC power; a DC conversion circuit (30) which inhibits higher harmonics of a current and improves the power factor, and converts the power outputted from the rectification circuit (3) into DC power, and supplies said DC power to a light source; and a control unit (9) which controls the DC conversion circuit (30). The DC conversion circuit (30) is provided with: a smoothing capacitor (6); a MOSFET (51) which is disposed between the smoothing capacitor (6) and the rectification circuit (3); and a coil (52) through which the current outputted from the rectification circuit (3) flows. The control unit (9) sets the MOSFET (51) in an off state from the point in time at which the current flowing through the coil (52) becomes zero, until a delay time set in the control unit (9) elapses, and turns the MOSFET (51) on when the delay time has elapsed.

Description

点灯装置及び照明器具Lighting device and lighting apparatus
　本発明は、光源を点灯する点灯装置及び照明器具に関する。 The present invention relates to a lighting device and a lighting fixture for lighting a light source.
　ＬＥＤ（Ｌｉｇｈｔ　Ｅｍｉｔｔｉｎｇ　Ｄｉｏｄｅ）を光源とした照明器具には、入力電流の高調波に関する規制が定められており、日本国内においては、日本工業規格によって入力電流の高調波に限度値が定められている。そのため、点灯装置は、入力電流の高調波を抑制し、力率を改善するための力率改善回路であるＰＦＣ（Ｐｏｗｅｒ　Ｆａｃｔｏｒ　Ｃｏｒｒｅｃｔｉｏｎ）回路を有する。 For lighting fixtures that use LED (Light Emitting Diode) as a light source, regulations on harmonics of input current are stipulated, and in Japan, limit values are set for harmonics of input current by Japanese Industrial Standards. . Therefore, the lighting device has a PFC (Power Factor Correction) circuit that is a power factor correction circuit for suppressing harmonics of the input current and improving the power factor.
　特許文献１には、軽負荷時においてはＰＦＣ回路の動作モードを電流不連続モード制御に切り替えることで、軽負荷時のスイッチング周波数上昇を抑制し、オン時間の減少を抑制する方法が示されている。 Patent Document 1 discloses a method of suppressing an increase in switching frequency at light load and suppressing decrease in on-time by switching the operation mode of the PFC circuit to current discontinuous mode control at light load. Yes.
特許第５１５２５０１号公報Japanese Patent No. 5152501
　特許文献１に示される方法では、高出力時において、電流臨界モード制御によりＰＦＣ回路が動作するため、高い高調波抑制効果がある。ところが電流臨界モード制御では、電流不連続モード制御を行う場合に比べてスイッチング周波数が高いため、スイッチング損失が大きいという問題がある。 The method disclosed in Patent Document 1 has a high harmonic suppression effect because the PFC circuit operates by current critical mode control at high output. However, the current critical mode control has a problem that the switching loss is large because the switching frequency is higher than that in the case of performing the current discontinuous mode control.
　本発明は、上記に鑑みてなされたものであって、入力電流の高調波を抑制しながらスイッチング損失を低減できる点灯装置を得ることを目的とする。 The present invention has been made in view of the above, and an object thereof is to obtain a lighting device capable of reducing switching loss while suppressing harmonics of input current.
　上述した課題を解決し、目的を達成するために、本発明に係る点灯装置は、交流電力を整流する整流回路と、高調波を抑制して力率を改善すると共に整流回路から出力される電力を直流電力に変換して光源に供給する直流変換回路と、直流変換回路を制御する制御部とを備え、直流変換回路は、平滑コンデンサと、平滑コンデンサ及び整流回路の間に配置されるスイッチング素子と、整流回路から出力される電流が流れるコイルとを有し、制御部は、コイルに流れる電流がゼロになった時点から、制御部に設定された遅延時間が経過するまでスイッチング素子をオフ状態にさせて、遅延時間が経過したときにスイッチング素子をオンさせる。 In order to solve the above-described problems and achieve the object, a lighting device according to the present invention includes a rectifier circuit that rectifies AC power, and power that is output from the rectifier circuit while suppressing harmonics to improve the power factor. A DC conversion circuit that converts DC power into DC power and supplies it to the light source, and a control unit that controls the DC conversion circuit, the DC conversion circuit comprising a smoothing capacitor and a switching element disposed between the smoothing capacitor and the rectifier circuit And the coil through which the current output from the rectifier circuit flows, and the control unit turns off the switching element from when the current flowing through the coil becomes zero until the delay time set in the control unit elapses. Thus, the switching element is turned on when the delay time has elapsed.
　本発明に係る点灯装置は、入力電流の高調波を抑制しながらスイッチング損失を低減できるという効果を奏する。 The lighting device according to the present invention has an effect of reducing switching loss while suppressing harmonics of the input current.
実施の形態１に係る点灯装置及び照明器具の構成図Configuration diagram of lighting device and lighting apparatus according to Embodiment 1 図１に示す電流制御部の構成を示す図The figure which shows the structure of the electric current control part shown in FIG. 光源に流れる電流とコイルに流れる電流とＭＯＳＦＥＴ（Ｍｅｔａｌ　Ｏｘｉｄｅ　Ｓｅｍｉｃｏｎｄｕｃｔｏｒ　Ｆｉｅｌｄ　Ｅｆｆｅｃｔ　Ｔｒａｎｓｉｓｔｏｒ）の制御信号との関係を示すタイミングチャートTiming chart showing the relationship between the current flowing through the light source, the current flowing through the coil, and the control signal of the MOSFET (Metal Oxide Semiconductor Field Effect Transistor) 図１に示すＰＦＣ回路を構成するコイルに流れる電流とＭＯＳＦＥＴのドレイン電圧とＭＯＳＦＥＴのゲート電圧との関係を示すタイミングチャート1 is a timing chart showing the relationship between the current flowing through the coil constituting the PFC circuit shown in FIG. 1, the drain voltage of the MOSFET, and the gate voltage of the MOSFET. 遅延時間を設けずに電流臨界モード制御で調光した場合の波形を示す図Diagram showing the waveform when dimming with current critical mode control without delay time 遅延時間を設けて調光した場合の波形を示す図Diagram showing waveform when dimming with delay time 調光率に応じて変化するＭＯＳＦＥＴのオン時間及びスイッチング周波数の特性を示す図The figure which shows the characteristic of the ON time and switching frequency of MOSFET which changes according to the light control rate 調光率に応じて遅延時間を変化させた場合のＭＯＳＦＥＴのオン時間とスイッチング周波数を示す第１の図1st figure which shows the ON time and switching frequency of MOSFET at the time of changing delay time according to a light control rate 調光率に応じて遅延時間を変化させた場合のＭＯＳＦＥＴのオン時間とスイッチング周波数を示す第２の図2nd figure which shows ON time and switching frequency of MOSFET at the time of changing delay time according to a light control rate 図９に示す調光率の閾値１を境にして、遅延時間をＴｄｅｌａｙ１からＴｄｅｌａｙ２に延長する場合の、遅延時間、ＭＯＳＦＥＴのオン時間及び光源の調光率の時間変化を示す図The figure which shows the time change of delay time, MOSFET ON time, and light source dimming rate when delay time is extended from Tdelay1 to Tdelay2 with threshold value 1 of dimming rate shown in FIG. 遅延時間を延長する場合における制御部の動作を説明するためのフローチャートFlowchart for explaining the operation of the control unit when extending the delay time 図９に示す調光率の閾値１を境にして、遅延時間をＴｄｅｌａｙ２からＴｄｅｌａｙ１に短縮する場合の、遅延時間、ＭＯＳＦＥＴのオン時間及び光源の調光率の時間変化を示す図The figure which shows the time change of delay time, MOSFET ON time, and the light control rate of a light source when delay time is shortened from Tdelay2 to Tdelay1 on the threshold value 1 of the light control rate shown in FIG. 遅延時間を短縮する場合における制御部の動作を説明するためのフローチャートFlowchart for explaining the operation of the control unit when the delay time is shortened 実施の形態２に係る点灯装置及び照明器具の構成図Configuration diagram of lighting device and lighting apparatus according to Embodiment 2 図１４に示す直流変換回路を構成する巻線に流れる電流とＭＯＳＦＥＴのドレイン電圧とＭＯＳＦＥＴのゲート電圧との関係を示すタイミングチャート14 is a timing chart showing the relationship between the current flowing through the windings constituting the DC converter circuit shown in FIG. 14, the drain voltage of the MOSFET, and the gate voltage of the MOSFET. 実施の形態３に係る点灯装置及び照明器具の構成図Configuration diagram of lighting device and lighting apparatus according to Embodiment 3 光源に流れる電流とコイルに流れる電流とＭＯＳＦＥＴの制御信号との関係を示すタイミングチャートTiming chart showing relationship between current flowing through light source, current flowing through coil and control signal of MOSFET 調光率に応じて変化するＭＯＳＦＥＴのオン時間及びスイッチング周波数の特性を示す図The figure which shows the characteristic of the ON time and switching frequency of MOSFET which changes according to the light control rate 光源に出力される電流の大きさが異なる場合における電流制御部の動作を示す第１の図1st figure which shows operation | movement of the electric current control part in case the magnitude | size of the electric current output to a light source differs. 光源に出力される電流の大きさが異なる場合における電流制御部の動作を示す第２の図2nd figure which shows operation | movement of the current control part in case the magnitude | size of the electric current output to a light source differs. 実施の形態４に係る点灯装置及び照明器具の構成図Configuration diagram of lighting device and lighting apparatus according to Embodiment 4 実施の形態４において、光源が消灯している状態から光源が点灯を開始するまでの期間に、ゼロ電流検出周期Ｔｚｃｄを測定するタイミングを示す第１のタイミングチャートIn the fourth embodiment, the first timing chart showing the timing for measuring the zero current detection cycle Tzcd during the period from when the light source is turned off to when the light source starts to turn on. 実施の形態４において、光源が消灯している状態から光源が点灯を開始するまでの期間に、ゼロ電流検出周期Ｔｚｃｄを測定するタイミングを示す第２のタイミングチャートIn the fourth embodiment, the second timing chart showing the timing for measuring the zero current detection period Tzcd during the period from when the light source is turned off to when the light source starts to turn on. 実施の形態４に係る点灯装置の動作を示すフローチャートThe flowchart which shows operation | movement of the lighting device which concerns on Embodiment 4. FIG.
　以下に、本発明の実施の形態に係る点灯装置及び照明器具を図面に基づいて詳細に説明する。なお、この実施の形態によりこの発明が限定されるものではない。 Hereinafter, a lighting device and a lighting fixture according to an embodiment of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.
実施の形態１．
　図１は実施の形態１に係る点灯装置及び照明器具の構成図である。照明器具２００は、交流電源１に接続され、交流電源１から出力される交流電流を平滑化する入力フィルタ２を介して交流電源１から供給される電力を光源８に入力可能な直流電流に変換して出力する点灯装置１００と、点灯装置１００から供給される電力により点灯する光源８と、光源８の点灯、消灯又は調光を行うための調光信号を出力する調光器１０とを備える。光源８は、複数のＬＥＤを直接に接続したＬＥＤ群で構成される。ＬＥＤ群の一端は正極側直流母線Ｐに接続され、ＬＥＤ群の他端は負極側直流母線Ｎに接続される。 Embodiment 1 FIG.
FIG. 1 is a configuration diagram of a lighting device and a lighting fixture according to the first embodiment. The luminaire 200 is connected to the AC power source 1 and converts the power supplied from the AC power source 1 through the input filter 2 that smoothes the AC current output from the AC power source 1 into a DC current that can be input to the light source 8. The lighting device 100 that outputs the light, the light source 8 that is turned on by the power supplied from the lighting device 100, and the dimmer 10 that outputs a dimming signal for turning on, turning off, or dimming the light source 8. . The light source 8 is composed of an LED group in which a plurality of LEDs are directly connected. One end of the LED group is connected to the positive side DC bus P, and the other end of the LED group is connected to the negative side DC bus N.
　点灯装置１００は、入力フィルタ２と、入力フィルタ２に接続される整流回路３と、整流回路３に並列接続されるコンデンサ４と、直流変換回路３０と、光源８に流れる電流を検出する電流検出部１１と、ＰＦＣ回路５及び電流制御部７を制御するための制御部９とを備える。 The lighting device 100 includes an input filter 2, a rectifier circuit 3 connected to the input filter 2, a capacitor 4 connected in parallel to the rectifier circuit 3, a DC conversion circuit 30, and a current detection that detects a current flowing through the light source 8. And a control unit 9 for controlling the PFC circuit 5 and the current control unit 7.
　直流変換回路３０は、交流電源１から入力される電流の高調波を抑制して力率を改善すると共に、整流回路３から出力される電力を直流電力に変換して光源８に供給する機能を有する。直流変換回路３０は、交流電源１から入力される電流の高調波を抑制して力率を改善するためのＰＦＣ回路５と、ＰＦＣ回路５の出力電圧を平滑する平滑コンデンサ６と、光源８に出力する電流の大きさを制御する電流制御部７とを備える。 The DC conversion circuit 30 has a function of improving the power factor by suppressing harmonics of the current input from the AC power supply 1 and converting the power output from the rectifier circuit 3 into DC power and supplying it to the light source 8. Have. The DC conversion circuit 30 includes a PFC circuit 5 for improving the power factor by suppressing harmonics of the current input from the AC power supply 1, a smoothing capacitor 6 for smoothing the output voltage of the PFC circuit 5, and a light source 8. And a current control unit 7 for controlling the magnitude of the output current.
　交流電源１と整流回路３との間に配置される入力フィルタ２は、コイル２１及びコンデンサ２２を有し、交流電源１から出力される電流に重畳している高周波ノイズを低減する。コイル２１は交流電源１に直列接続される。コイル２１の一端は交流電源１の一端に接続され、コイル２１の他端はコンデンサ２２及び整流回路３に接続される。コンデンサ２２の他端は、交流電源１及び整流回路３に接続される。 The input filter 2 disposed between the AC power supply 1 and the rectifier circuit 3 includes a coil 21 and a capacitor 22 and reduces high-frequency noise superimposed on the current output from the AC power supply 1. The coil 21 is connected in series to the AC power source 1. One end of the coil 21 is connected to one end of the AC power supply 1, and the other end of the coil 21 is connected to the capacitor 22 and the rectifier circuit 3. The other end of the capacitor 22 is connected to the AC power source 1 and the rectifier circuit 3.
　整流回路３は、入力フィルタ２とＰＦＣ回路５との間に配置され、交流電源１から供給される交流電力を直流電力に変換する。整流回路３は４つのダイオードを組み合わせたダイオードブリッジで構成されている。なお整流回路３の構成はこれに限定されるものではなく、単方向導通素子であるＭＯＳＦＥＴを組み合わせて構成したものでもよい。 The rectifier circuit 3 is disposed between the input filter 2 and the PFC circuit 5 and converts AC power supplied from the AC power source 1 into DC power. The rectifier circuit 3 is composed of a diode bridge in which four diodes are combined. The configuration of the rectifier circuit 3 is not limited to this, and may be configured by combining MOSFETs that are unidirectional conducting elements.
　コンデンサ４は整流回路３の出力に並列接続されており、整流回路３の出力電圧を平滑する。コンデンサ４の一端は正極側直流母線Ｐに接続され、コンデンサ４の他端は負極側直流母線Ｎに接続される。 The capacitor 4 is connected in parallel to the output of the rectifier circuit 3, and smoothes the output voltage of the rectifier circuit 3. One end of the capacitor 4 is connected to the positive side DC bus P, and the other end of the capacitor 4 is connected to the negative side DC bus N.
　ＰＦＣ回路５は、整流回路３と電流制御部７との間に配置される。ＰＦＣ回路５は、スイッチング素子であるＭＯＳＦＥＴ５１と、コイル５２と、ダイオード５３とを有する。ＰＦＣ回路５は、制御部９によってＭＯＳＦＥＴ５１がオンオフ制御されることにより、整流回路３の出力電圧を昇圧し、昇圧した電圧を平滑コンデンサ６に出力する。またＰＦＣ回路５は、後述する制御により、入力電流の高調波を抑制し、力率改善する機能を持つ。実施の形態１では、ＰＦＣ回路５を昇圧チョッパ回路で構成した例を説明する。なおＰＦＣ回路５は、昇圧チョッパ回路の他にも、昇降圧チョッパ回路、フライバック回路、フライフォワード回路、ＳＥＰＩＣ（Ｓｉｎｇｌｅ　Ｅｎｄｅｄ　Ｐｒｉｍａｒｙ　Ｉｎｄｕｃｔｏｒ　Ｃｏｎｖｅｒｔｅｒ）、Ｚｅｔａコンバータ又はＣｕｋコンバータといった回路で構成してもよい。 The PFC circuit 5 is disposed between the rectifier circuit 3 and the current control unit 7. The PFC circuit 5 includes a MOSFET 51 that is a switching element, a coil 52, and a diode 53. The PFC circuit 5 boosts the output voltage of the rectifier circuit 3 by turning on and off the MOSFET 51 by the control unit 9, and outputs the boosted voltage to the smoothing capacitor 6. Further, the PFC circuit 5 has a function of suppressing the harmonics of the input current and improving the power factor by the control described later. In the first embodiment, an example in which the PFC circuit 5 is configured by a boost chopper circuit will be described. In addition to the step-up chopper circuit, the PFC circuit 5 may be configured by a circuit such as a step-up / step-down chopper circuit, a flyback circuit, a flyforward circuit, a SEPIC (Single Ended Primary Inverter Converter), a Zeta converter, or a Cuk converter.
　コイル５２は、正極側直流母線Ｐにおいて、コンデンサ４とＭＯＳＦＥＴ５１との間に配置される。不図示のコアに絶縁性ワイヤを巻くことにより、コイル５２には１次巻線５２ａ及び２次巻線５２ｂが形成される。１次巻線５２ａの一端はコンデンサ４の一端に接続される。１次巻線５２ａの他端はダイオード５３のアノードに接続される。２次巻線５２ｂの一端は制御部９に接続され、２次巻線５２ｂの他端は負極側直流母線Ｎに接続される。１次巻線５２ａには、ＭＯＳＦＥＴ５１のオンオフ動作に伴い、極性が異なる電圧が印加される。２次巻線５２ｂに発生する電圧は、１次巻線５２ａの印加電圧と巻数比ｎとに応じた電圧に等しい。 The coil 52 is disposed between the capacitor 4 and the MOSFET 51 on the positive side DC bus P. A primary winding 52 a and a secondary winding 52 b are formed in the coil 52 by winding an insulating wire around a core (not shown). One end of the primary winding 52 a is connected to one end of the capacitor 4. The other end of the primary winding 52 a is connected to the anode of the diode 53. One end of the secondary winding 52b is connected to the control unit 9, and the other end of the secondary winding 52b is connected to the negative-side DC bus N. A voltage having a different polarity is applied to the primary winding 52a as the MOSFET 51 is turned on / off. The voltage generated in the secondary winding 52b is equal to the voltage corresponding to the applied voltage of the primary winding 52a and the turns ratio n.
　ＭＯＳＦＥＴ５１のドレインは、正極側直流母線Ｐにおいて、１次巻線５２ａとダイオード５３のアノードとに接続される。ＭＯＳＦＥＴ５１のソースは、負極側直流母線Ｎにおいて、コンデンサ４の他端と、２次巻線５２ｂの他端と平滑コンデンサ６の他端とに接続される。ＭＯＳＦＥＴ５１のゲートは制御部９に接続される。ＭＯＳＦＥＴ５１のゲートには、制御部９から出力される制御信号が入力される。制御信号が入力されることによりＭＯＳＦＥＴ５１のオンオフ制御が行われる。 The drain of the MOSFET 51 is connected to the primary winding 52 a and the anode of the diode 53 in the positive side DC bus P. The source of the MOSFET 51 is connected to the other end of the capacitor 4, the other end of the secondary winding 52 b, and the other end of the smoothing capacitor 6 on the negative DC bus N. The gate of the MOSFET 51 is connected to the control unit 9. A control signal output from the control unit 9 is input to the gate of the MOSFET 51. On / off control of the MOSFET 51 is performed by inputting the control signal.
　ダイオード５３は、正極側直流母線Ｐにおいて、ＭＯＳＦＥＴ５１と平滑コンデンサ６との間に配置される。ダイオード５３のアノードはコイル５２及びＭＯＳＦＥＴ５１に接続され、ダイオード５３のカソードは平滑コンデンサ６に接続される。 The diode 53 is disposed between the MOSFET 51 and the smoothing capacitor 6 in the positive side DC bus P. The anode of the diode 53 is connected to the coil 52 and the MOSFET 51, and the cathode of the diode 53 is connected to the smoothing capacitor 6.
　平滑コンデンサ６は、ＰＦＣ回路５と電流制御部７との間に配置される。平滑コンデンサ６の一端は正極側直流母線Ｐに接続され、平滑コンデンサ６の他端は負極側直流母線Ｎに接続される。 The smoothing capacitor 6 is disposed between the PFC circuit 5 and the current control unit 7. One end of the smoothing capacitor 6 is connected to the positive side DC bus P, and the other end of the smoothing capacitor 6 is connected to the negative side DC bus N.
　電流検出部１１は、光源８に流れる電流を検出し、検出された電流値に対応した電流情報を制御部９に出力する。電流検出部１１としては、シャント抵抗又はホールセンサを用いて電流を検出する構成を例示できる。 The current detector 11 detects a current flowing through the light source 8 and outputs current information corresponding to the detected current value to the controller 9. As the current detection unit 11, a configuration in which a current is detected using a shunt resistor or a hall sensor can be exemplified.
　制御部９は、目標値出力部９１、ゼロ電流検出部９２、スイッチング制御部９３、電流入力部９４及び電圧検出部９５を備える。 The control unit 9 includes a target value output unit 91, a zero current detection unit 92, a switching control unit 93, a current input unit 94, and a voltage detection unit 95.
　目標値出力部９１には調光器１０が接続され、目標値出力部９１は、調光器１０から出力される調光信号の種類に対応した出力電流目標値を決定し、決定した出力電流目標値をスイッチング制御部９３に出力する。出力電流目標値は、点灯装置１００が光源８に出力する電流目標値を指定する信号である。 The target value output unit 91 is connected to the dimmer 10, and the target value output unit 91 determines an output current target value corresponding to the type of the dimming signal output from the dimmer 10, and the determined output current The target value is output to the switching control unit 93. The output current target value is a signal that specifies a current target value that the lighting device 100 outputs to the light source 8.
　電圧検出部９５は、平滑コンデンサ６の電圧を検出し、検出した電圧の値に対応した電圧情報をスイッチング制御部９３に出力する。電圧検出部９５としては分圧回路を例示できる。当該分圧回路は、２つの抵抗を直列接続した直列抵抗体の一端が正極側直流母線Ｐに接続されると共に、当該直列抵抗体の他端が負極側直流母線Ｎに接続されることで、平滑コンデンサ６に印加される電圧を分圧する回路である。 The voltage detector 95 detects the voltage of the smoothing capacitor 6 and outputs voltage information corresponding to the detected voltage value to the switching controller 93. An example of the voltage detector 95 is a voltage dividing circuit. In the voltage dividing circuit, one end of a series resistor in which two resistors are connected in series is connected to the positive side DC bus P, and the other end of the series resistor is connected to the negative side DC bus N. This circuit divides the voltage applied to the smoothing capacitor 6.
　スイッチング制御部９３は、目標値出力部９１から出力された出力電流目標値と、電流入力部９４に入力された電流情報とに基づき、電流制御部７を制御するための制御信号を出力する。またスイッチング制御部９３は、ＰＦＣ回路５の出力電圧目標値を予め記憶しており、少なくとも、電圧検出部９５から出力された電圧情報と、記憶された出力電圧目標値とに基づき、ＰＦＣ回路５を制御するための制御信号を出力する。 The switching control unit 93 outputs a control signal for controlling the current control unit 7 based on the output current target value output from the target value output unit 91 and the current information input to the current input unit 94. The switching control unit 93 stores the output voltage target value of the PFC circuit 5 in advance, and based on at least the voltage information output from the voltage detection unit 95 and the stored output voltage target value. A control signal for controlling the signal is output.
　電流制御部７は、スイッチング制御部９３から出力された制御信号に基づき、ＰＦＣ回路５から出力された直流電圧を光源８に入力可能な直流電流に変換する。 The current control unit 7 converts the DC voltage output from the PFC circuit 5 into a DC current that can be input to the light source 8 based on the control signal output from the switching control unit 93.
　図２は図１に示す電流制御部の構成を示す図である。図２に示す電流制御部７は、降圧チョッパ回路で構成されているが、降圧チョッパ回路の他にも、昇降圧チョッパ回路、フライバック回路、フライフォワード回路、ＳＥＰＩＣ、Ｚｅｔａコンバータ又はＣｕｋコンバータといった回路で構成されたものでもよい。 FIG. 2 is a diagram showing a configuration of the current control unit shown in FIG. The current control unit 7 shown in FIG. 2 includes a step-down chopper circuit. In addition to the step-down chopper circuit, a circuit such as a step-up / step-down chopper circuit, a flyback circuit, a fly-forward circuit, a SEPIC, a Zeta converter, or a Cuk converter is used. It may be composed of
　電流制御部７は、ＭＯＳＦＥＴ７１、コイル７２、ダイオード７３及びコンデンサ７４により構成される。ＭＯＳＦＥＴ７１は正極側直流母線Ｐに配置される。ＭＯＳＦＥＴ７１のドレインは、図１に示す平滑コンデンサ６の一端とダイオード５３のカソードとに接続される。ＭＯＳＦＥＴ７１のソースは、ダイオード７３のカソードとコイル７２の一端とに接続される。ＭＯＳＦＥＴ７１のゲートはスイッチング制御部９３に接続される。ＭＯＳＦＥＴ７１のゲートには、スイッチング制御部９３から出力される制御信号が入力される。当該制御信号はＭＯＳＦＥＴ７１をオンオフ制御するための信号である。 The current control unit 7 includes a MOSFET 71, a coil 72, a diode 73, and a capacitor 74. MOSFET 71 is arranged on positive side DC bus P. The drain of the MOSFET 71 is connected to one end of the smoothing capacitor 6 and the cathode of the diode 53 shown in FIG. The source of the MOSFET 71 is connected to the cathode of the diode 73 and one end of the coil 72. The gate of the MOSFET 71 is connected to the switching control unit 93. A control signal output from the switching control unit 93 is input to the gate of the MOSFET 71. The control signal is a signal for controlling on / off of the MOSFET 71.
　コイル７２の一端は、ＭＯＳＦＥＴ７１のソースとダイオード７３のカソードとに接続される。コイル７２の他端は、コンデンサ７４の一端と図１に示す光源８の一端とに接続される。ダイオード７３のカソードは、ＭＯＳＦＥＴ７１のソースとコイル７２の一端とに接続される。ダイオード７３のアノードは、図１に示す平滑コンデンサ６の他端とコンデンサ７４の他端と図１に示す光源８の他端とに接続される。 One end of the coil 72 is connected to the source of the MOSFET 71 and the cathode of the diode 73. The other end of the coil 72 is connected to one end of the capacitor 74 and one end of the light source 8 shown in FIG. The cathode of the diode 73 is connected to the source of the MOSFET 71 and one end of the coil 72. The anode of the diode 73 is connected to the other end of the smoothing capacitor 6 shown in FIG. 1, the other end of the capacitor 74, and the other end of the light source 8 shown in FIG.
　図３は光源に流れる電流とコイルに流れる電流とＭＯＳＦＥＴの制御信号との関係を示すタイミングチャートである。図３には上から順に、光源８に流れる電流と、コイル７２に流れる電流と、ＭＯＳＦＥＴ７１の制御信号とが示される。横軸は時間を表す。 FIG. 3 is a timing chart showing the relationship between the current flowing through the light source, the current flowing through the coil, and the control signal of the MOSFET. FIG. 3 shows the current flowing through the light source 8, the current flowing through the coil 72, and the control signal of the MOSFET 71 in order from the top. The horizontal axis represents time.
　スイッチング周期Ｔｓｗは、ＭＯＳＦＥＴ７１の制御信号がオフからオンに変化した時点から、再びＭＯＳＦＥＴ７１の制御信号がオフからオンに変化するまでの時間に等しい。スイッチング周期Ｔｓｗは、予めスイッチング制御部９３に設定されている。オン時間Ｔｏｎは、ＭＯＳＦＥＴ７１の制御信号がオフからオンに変化した時点から、オンからオフに変化するまでの時間に等しい。 The switching cycle Tsw is equal to the time from when the control signal of the MOSFET 71 changes from OFF to ON until the control signal of the MOSFET 71 changes from OFF to ON again. The switching period Tsw is set in the switching control unit 93 in advance. The on time Ton is equal to the time from when the control signal of the MOSFET 71 changes from off to on until it changes from on to off.
　ＭＯＳＦＥＴ７１の制御信号がオフからオンの状態に変化すると、ＭＯＳＦＥＴ７１がオン状態になるため、平滑コンデンサ６、ＭＯＳＦＥＴ７１、コイル７２及びコンデンサ７４に電流が流れる電流経路が形成され、図３に示すようにコイル７２に流れる電流が増加する。 When the control signal of the MOSFET 71 changes from OFF to ON, the MOSFET 71 is turned ON, so that a current path through which current flows through the smoothing capacitor 6, the MOSFET 71, the coil 72, and the capacitor 74 is formed, as shown in FIG. The current flowing through 72 increases.
　ＭＯＳＦＥＴ７１の制御信号がオンからオフの状態に変化すると、ＭＯＳＦＥＴ７１がオフ状態になるため、コイル７２、コンデンサ７４及びダイオード７３に電流が流れる電流経路が形成され、図３に示すコイル７２に流れる電流がゼロまで減少する。スイッチング周期Ｔｓｗが経過した時点で、ＭＯＳＦＥＴ７１の制御信号がオフからオンに変化する。これによりＭＯＳＦＥＴ７１が再びオン状態になる。 When the control signal of the MOSFET 71 changes from on to off, the MOSFET 71 is turned off, so that a current path through which current flows through the coil 72, the capacitor 74, and the diode 73 is formed, and the current flowing through the coil 72 shown in FIG. Decrease to zero. When the switching cycle Tsw elapses, the control signal of the MOSFET 71 changes from off to on. As a result, the MOSFET 71 is turned on again.
　このときコイル７２に流れる電流は三角波状の波形になるが、光源８に出力される電流は、コンデンサ７４により平滑化され、コイル７２に流れる電流の平均値が電流制御部７から出力される。 At this time, the current flowing through the coil 72 has a triangular waveform, but the current output to the light source 8 is smoothed by the capacitor 74, and the average value of the current flowing through the coil 72 is output from the current control unit 7.
　光源８を調光するために光源８に流れる電流を制御する場合、スイッチング制御部９３は、ＭＯＳＦＥＴ７１をターンオンするスイッチング周期Ｔｓｗを一定とし、出力電流の目標値によってオン時間Ｔｏｎを変化させる。このようにオン時間Ｔｏｎを調整することにより特定の出力を得る制御方法は、スイッチング周期Ｔｓｗに対するオン時間Ｔｏｎの割合をデューティーと呼ぶことから、デューティー制御と呼ばれる。 When controlling the current flowing through the light source 8 in order to dim the light source 8, the switching control unit 93 makes the switching period Tsw for turning on the MOSFET 71 constant, and changes the on-time Ton according to the target value of the output current. The control method for obtaining a specific output by adjusting the on-time Ton in this way is called duty control because the ratio of the on-time Ton to the switching period Tsw is called duty.
　スイッチング素子であるＭＯＳＦＥＴ５１，７１は、シリコン系材料で構成される。但し、ＭＯＳＦＥＴ５１，７１の素材は、シリコン系材料に限定されず、ＭＯＳＦＥＴ５１，７１は、炭化珪素、窒化ガリウム系材料又はダイヤモンドといったワイドバンドギャップ半導体で構成してもよい。 The MOSFETs 51 and 71 that are switching elements are made of a silicon-based material. However, the material of the MOSFETs 51 and 71 is not limited to a silicon-based material, and the MOSFETs 51 and 71 may be formed of a wide band gap semiconductor such as silicon carbide, a gallium nitride-based material, or diamond.
　スイッチング素子にワイドバンドギャップ半導体を用いることで、スイッチング素子の通電損失を低減できる。また、ワイドバンドギャップ半導体で構成されるスイッチング素子は、耐熱性が高い。また、ワイドバンドギャップ半導体で構成されるスイッチング素子は、シリコン系材料で構成されるスイッチング素子に比べて、スイッチングスピードが速く、スイッチング時に発生する損失が小さい。従って、スイッチング周波数すなわち駆動周波数を高周波化することで、スイッチング素子が高速にスイッチングされても、スイッチング素子で発生した熱を放熱するための放熱部品を小型化できる。このため、ＰＦＣ回路５及び電流制御部７に設けられる放熱部品を小型化でき、又は当該放熱部品を省くことができる。その結果、点灯装置１００の小型化及び低コスト化を実現できる。 通電 By using a wide band gap semiconductor for the switching element, the conduction loss of the switching element can be reduced. Moreover, the switching element comprised with a wide band gap semiconductor has high heat resistance. In addition, a switching element made of a wide band gap semiconductor has a higher switching speed and a smaller loss at the time of switching than a switching element made of a silicon-based material. Therefore, by increasing the switching frequency, that is, the driving frequency, even if the switching element is switched at high speed, the heat dissipation component for radiating the heat generated by the switching element can be reduced in size. For this reason, the heat dissipation component provided in the PFC circuit 5 and the current control unit 7 can be reduced in size, or the heat dissipation component can be omitted. As a result, the lighting device 100 can be reduced in size and cost.
　次にＰＦＣ回路５の動作を詳細に説明する。 Next, the operation of the PFC circuit 5 will be described in detail.
　図４は図１に示すＰＦＣ回路を構成するコイルに流れる電流とＭＯＳＦＥＴのドレイン電圧とＭＯＳＦＥＴのゲート電圧との関係を示すタイミングチャートである。図４には上から順に、点灯装置１００に入力される交流電源１の電流と、コイル５２に流れる電流と、ＭＯＳＦＥＴ５１のドレイン電圧と、ＭＯＳＦＥＴ５１のゲート電圧とが示される。横軸は時間を表す。図４では、点灯装置１００に入力される交流電源１の電流が「入力電流」として示される。 FIG. 4 is a timing chart showing the relationship between the current flowing through the coil constituting the PFC circuit shown in FIG. 1, the drain voltage of the MOSFET, and the gate voltage of the MOSFET. FIG. 4 shows, in order from the top, the current of the AC power source 1 input to the lighting device 100, the current flowing through the coil 52, the drain voltage of the MOSFET 51, and the gate voltage of the MOSFET 51. The horizontal axis represents time. In FIG. 4, the current of the AC power supply 1 input to the lighting device 100 is indicated as “input current”.
　図４では、説明の便宜上、ＭＯＳＦＥＴ５１のゲート電圧がオンオフされる周期を、実際よりも長く記載している。ＭＯＳＦＥＴ５１のゲート電圧がオンオフされる周期は、ＭＯＳＦＥＴ５１のゲート電圧がオフからオンに変化した時点から、再びＭＯＳＦＥＴ５１のゲート電圧がオフからオンに変化するまでの時間に等しい。 In FIG. 4, for convenience of explanation, the cycle in which the gate voltage of the MOSFET 51 is turned on and off is shown longer than the actual period. The period when the gate voltage of the MOSFET 51 is turned on and off is equal to the time from when the gate voltage of the MOSFET 51 changes from off to on until when the gate voltage of the MOSFET 51 changes from off to on again.
　ＭＯＳＦＥＴ５１がオンされたとき、交流電源１、整流回路３、コイル５２及びＭＯＳＦＥＴ５１により閉回路が形成され、交流電源１がコイル５２を介して短絡される。そのため閉回路に電源電流が流れ、コイル５２に流れる電流が増加し、コイル５２にエネルギーが蓄積される。 When the MOSFET 51 is turned on, a closed circuit is formed by the AC power source 1, the rectifier circuit 3, the coil 52 and the MOSFET 51, and the AC power source 1 is short-circuited via the coil 52. As a result, the power source current flows through the closed circuit, the current flowing through the coil 52 increases, and energy is stored in the coil 52.
　スイッチング制御部９３に設定されたオン時間が経過すると、ＭＯＳＦＥＴ５１がオフされることにより、コイル５２、ダイオード５３及び平滑コンデンサ６の閉回路が形成される。この閉回路においてコイル５２に蓄積されたエネルギーが放出され、平滑コンデンサ６が充電される。 When the ON time set in the switching control unit 93 has elapsed, the MOSFET 51 is turned off, thereby forming a closed circuit of the coil 52, the diode 53, and the smoothing capacitor 6. In this closed circuit, the energy accumulated in the coil 52 is released, and the smoothing capacitor 6 is charged.
　コイル５２に流れる電流がゼロになった時点から遅延時間Ｔｄｅｌａｙが経過するまで、ＭＯＳＦＥＴ５１のオフ状態は維持され、遅延時間Ｔｄｅｌａｙが経過したときにＭＯＳＦＥＴ５１は再びオン状態になる。すなわち、コイル５２に流れる電流がゼロになった時点から遅延時間Ｔｄｅｌａｙが経過した時点まで、ＭＯＳＦＥＴ５１の制御信号はオフ状態を維持し、遅延時間Ｔｄｅｌａｙが経過した時点でＭＯＳＦＥＴ５１の制御信号はオン状態に変化する。 The OFF state of the MOSFET 51 is maintained from when the current flowing through the coil 52 becomes zero until the delay time Tdelay elapses, and when the delay time Tdelay elapses, the MOSFET 51 is turned on again. That is, the control signal of the MOSFET 51 remains off until the delay time Tdelay elapses from the time when the current flowing through the coil 52 becomes zero, and the control signal of the MOSFET 51 is turned on when the delay time Tdelay elapses. Change.
　ＭＯＳＦＥＴ５１の一連のオンオフ動作により、コイル５２に流れる電流は、三角波状の波形となり、その頂点が点線で示すような正弦波の包絡線になる。 Due to the series of on / off operations of the MOSFET 51, the current flowing through the coil 52 has a triangular waveform, and the apex thereof becomes a sine wave envelope as indicated by a dotted line.
　このとき、交流電源１から入力される電流は、入力フィルタ２により平滑化され、コイル２１に流れるコイル電流の平均値が入力され、正弦波状の電流波形となる。 At this time, the current input from the AC power source 1 is smoothed by the input filter 2, and the average value of the coil current flowing through the coil 21 is input to form a sine wave current waveform.
　制御部９が平滑コンデンサ６の印加電圧を検出して、検出された電圧が目標値に追従するようフィードバック制御されることで、ＭＯＳＦＥＴ５１のオン時間が制御される。 The control unit 9 detects the voltage applied to the smoothing capacitor 6 and performs feedback control so that the detected voltage follows the target value, whereby the on-time of the MOSFET 51 is controlled.
　ＭＯＳＦＥＴ５１のオン時間をフィードバック制御する際、オン時間が大きく変化してしまうと、コイル５２に流れる電流の頂点の包絡線が正弦波にならず、交流電源１の入力電流を正弦波状にすることができない。そのため制御部９では、フィードバック制御の応答時間が、フィードバック制御のループゲインを交流電源１の１周期の１／２周期以上で１倍（０ｄＢ）以下となるように、設定される。言い換えると、フィードバック制御の応答時間は、交流電源１の周波数の２倍以下の周波数で１倍（０ｄＢ）以下となるように設定される。 When the on-time of the MOSFET 51 is feedback-controlled, if the on-time changes greatly, the envelope of the peak of the current flowing through the coil 52 does not become a sine wave, and the input current of the AC power supply 1 may be made a sine wave. Can not. Therefore, in the control unit 9, the response time of the feedback control is set so that the loop gain of the feedback control becomes 1 time (0 dB) or less after being 1/2 of 1 cycle of the AC power supply 1. In other words, the response time of the feedback control is set to be 1 (0 dB) or less at a frequency that is 2 times or less of the frequency of the AC power supply 1.
　具体的に説明すると、電源周波数が５０Ｈｚの場合、電源周波数の半周期（半波）の周波数１００Ｈｚ以下、すなわち周期１０ｍｓｅｃ以上で、フィードバック制御のループゲインを１倍（０ｄＢ）以下とすることにより、フィードバック制御は電源周期の１／２より短い周期で応答しないように設定される。これにより電源周期の１／２周期以内においては、ＭＯＳＦＥＴ５１のオン時間の変動が抑制され、コイル５２に流れる電流の頂点の包絡線が正弦波状の波形となる。 More specifically, when the power supply frequency is 50 Hz, the feedback control loop gain is set to 1 (0 dB) or less at a frequency of 100 Hz or less of the half cycle (half wave) of the power supply frequency, that is, a cycle of 10 msec or more, The feedback control is set so as not to respond in a cycle shorter than ½ of the power cycle. As a result, fluctuations in the ON time of the MOSFET 51 are suppressed within a half cycle of the power supply cycle, and the envelope at the apex of the current flowing through the coil 52 becomes a sine wave waveform.
　またフィードバック制御において、オン時間の更新周期を、交流電源１の周期の半分に相当する周期、又は交流電源１の周期の半分に相当する周期よりも長い周期とすることによっても、同様の効果を得ることができる。 In the feedback control, the same effect can be obtained by setting the on-time update cycle to a cycle corresponding to half the cycle of the AC power supply 1 or a cycle longer than the cycle corresponding to half the cycle of the AC power supply 1. Obtainable.
　上記の特許文献１に開示される技術では、遅延時間Ｔｄｅｌａｙを設けない電流臨界モード制御により、ＭＯＳＦＥＴ５１がスイッチング制御されるため、コイル５２に流れる電流の平均値が完全な正弦波状になり、高い力率改善効果が期待できる。 In the technique disclosed in Patent Document 1 described above, the MOSFET 51 is switching-controlled by current critical mode control without providing the delay time Tdelay. Therefore, the average value of the current flowing through the coil 52 becomes a complete sine wave, and high power A rate improvement effect can be expected.
　これに対して実施の形態１に係る点灯装置１００は、遅延時間Ｔｄｅｌａｙを設け、電流不連続モード制御によりＭＯＳＦＥＴ５１をスイッチング制御することで、電流臨界モード制御する場合に比べて、スイッチング周波数を低くすることができるため、ＭＯＳＦＥＴ５１で発生するスイッチング損失を低減できる。 On the other hand, the lighting device 100 according to the first embodiment provides the delay time Tdelay and performs switching control of the MOSFET 51 by current discontinuous mode control, thereby lowering the switching frequency compared to the case of current critical mode control. Therefore, the switching loss generated in the MOSFET 51 can be reduced.
　このとき遅延時間Ｔｄｅｌａｙを長くし過ぎると、コイル５２の電流平均値が正弦波でなくなり、力率改善効果が低下して高調波が増加する。そのため遅延時間Ｔｄｅｌａｙは、高調波の増加が許容できる範囲内に設定する必要がある。高調波の増加が許容できる範囲の一例としては、日本工業規格で定められる電流高調波限度値以内とすることが挙げられる。具体的な遅延時間Ｔｄｅｌａｙの設け方としては、ＭＯＳＦＥＴ５１のドレイン電圧が自由振動している期間において、制御部９は、ＭＯＳＦＥＴ５１の電圧振動のボトム付近でＭＯＳＦＥＴ５１をオンさせることで、ドレイン電圧の急峻な変動を抑制し、スイッチングに起因するノイズを抑制できる。電圧振動とは、ドレイン電圧の振動を表し、ボトムとは、ドレイン電圧の振動の谷の部分を表す。また、ＭＯＳＦＥＴ５１の電圧振動のボトムの少なくとも２回目以降のボトムにおいて制御部９がＭＯＳＦＥＴ５１をオンすることで、確実に遅延時間を設けることができる。 At this time, if the delay time Tdelay is made too long, the current average value of the coil 52 is not a sine wave, the power factor improving effect is lowered, and the harmonics are increased. Therefore, it is necessary to set the delay time Tdelay within a range in which an increase in harmonics can be allowed. An example of a range in which an increase in harmonics is allowable is within a current harmonic limit value defined by Japanese Industrial Standards. As a specific method of providing the delay time Tdelay, during the period in which the drain voltage of the MOSFET 51 is free oscillating, the control unit 9 turns on the MOSFET 51 near the bottom of the voltage oscillation of the MOSFET 51 so that the drain voltage has a steep drain voltage. It is possible to suppress fluctuations and suppress noise caused by switching. The voltage oscillation represents the drain voltage oscillation, and the bottom represents the valley portion of the drain voltage oscillation. In addition, the control unit 9 turns on the MOSFET 51 at least at the second and subsequent bottoms of the bottom of the voltage oscillation of the MOSFET 51, so that a delay time can be provided with certainty.
　光源８を調光する場合、交流電源１の入力電流を小さくするため、スイッチング制御部９３は、ＭＯＳＦＥＴ５１のオン時間を短くするように制御を行う。 When the light source 8 is dimmed, the switching control unit 93 performs control so as to shorten the ON time of the MOSFET 51 in order to reduce the input current of the AC power supply 1.
　図５は遅延時間を設けずに電流臨界モード制御で調光した場合の波形を示す図であり、図６は遅延時間を設けて調光した場合の波形を示す図である。図５及び図６は、光源８を調光する際におけるＰＦＣ回路５のスイッチング動作の概要を説明するためのものである。図５及び図６のそれぞれには、図４と同様に、交流電源１の入力電流と、コイル５２に流れる電流と、ＭＯＳＦＥＴ５１のドレイン電圧と、ＭＯＳＦＥＴ５１のゲート電圧とが示される。横軸は時間を表す。 FIG. 5 is a diagram showing a waveform when dimming with current critical mode control without providing a delay time, and FIG. 6 is a diagram showing a waveform when dimming with a delay time. 5 and 6 are for explaining an outline of the switching operation of the PFC circuit 5 when the light source 8 is dimmed. Each of FIGS. 5 and 6 shows the input current of the AC power supply 1, the current flowing through the coil 52, the drain voltage of the MOSFET 51, and the gate voltage of the MOSFET 51, as in FIG. 4. The horizontal axis represents time.
　図６に示すように遅延時間Ｔｄｅｌａｙを設けて調光した場合、図５に示すように電流臨界モード制御で調光した場合に比べて、ＭＯＳＦＥＴ５１のスイッチング周波数が低下してスイッチング損失を低減できる。 As shown in FIG. 6, when the light is adjusted with the delay time Tdelay, the switching frequency of the MOSFET 51 is lowered and the switching loss can be reduced as compared with the case where the light is controlled by the current critical mode control as shown in FIG.
　図７は調光率に応じて変化するＭＯＳＦＥＴのオン時間及びスイッチング周波数の特性を示す図である。図７には上から順に、遅延時間Ｔｄｅｌａｙと、ＭＯＳＦＥＴ５１のオン時間と、ＭＯＳＦＥＴ５１を制御する制御信号のスイッチング周波数と、光源８の調光率とが示される。 FIG. 7 is a graph showing the on-time and switching frequency characteristics of the MOSFET, which change according to the dimming rate. FIG. 7 shows, in order from the top, the delay time Tdelay, the ON time of the MOSFET 51, the switching frequency of the control signal for controlling the MOSFET 51, and the dimming rate of the light source 8.
　点線は、電流臨界モード制御が行われている場合に調光率を変化させたときの、遅延時間Ｔｄｅｌａｙ、ＭＯＳＦＥＴ５１のオン時間及びスイッチング周波数を表す。実線は、遅延時間を設定した電流不連続モード制御が行われている場合に調光率を変化させたときの、遅延時間Ｔｄｅｌａｙ、ＭＯＳＦＥＴ５１のオン時間及びスイッチング周波数を表す。 The dotted line represents the delay time Tdelay, the ON time of the MOSFET 51, and the switching frequency when the dimming rate is changed when the current critical mode control is performed. A solid line represents the delay time Tdelay, the ON time of the MOSFET 51, and the switching frequency when the dimming rate is changed when the current discontinuous mode control in which the delay time is set is performed.
　遅延時間Ｔｄｅｌａｙを設けて電流不連続モード制御することで、電流臨界モード制御と比較して、調光時におけるスイッチング周波数の上昇を抑制することができ、スイッチング損失を低減できる。また、ＭＯＳＦＥＴ５１のオン時間を長くすることができ、より確実にＭＯＳＦＥＴ５１をオンオフ制御できる。 By providing the delay time Tdelay and performing the current discontinuous mode control, an increase in switching frequency during dimming can be suppressed and switching loss can be reduced as compared with current critical mode control. Further, the ON time of the MOSFET 51 can be lengthened, and the MOSFET 51 can be controlled on and off more reliably.
　また遅延時間Ｔｄｅｌａｙは一定の長さではなく、調光率に応じて変化させることができる。図８は調光率に応じて遅延時間を変化させた場合のＭＯＳＦＥＴのオン時間とスイッチング周波数を示す第１の図である。 Also, the delay time Tdelay is not a fixed length but can be changed according to the dimming rate. FIG. 8 is a first diagram showing the MOSFET on-time and switching frequency when the delay time is changed in accordance with the dimming rate.
　図８に示すように調光率には閾値が設けられ、制御部９は、調光率が閾値を上回る場合には、遅延時間を一定の第１の遅延時間Ｔｄｅｌａｙ１ｓｔとし、調光率が閾値以下である場合には、遅延時間を第２の遅延時間Ｔｄｅｌａｙ２ｎｄとする。第２の遅延時間Ｔｄｅｌａｙ２ｎｄは、第１の遅延時間Ｔｄｅｌａｙ１ｓｔよりも長い時間であって、調光率が低下するほど長くなる時間である。 As shown in FIG. 8, a threshold value is provided for the dimming rate, and when the dimming rate exceeds the threshold value, the control unit 9 sets the delay time as the first delay time Tdelay 1st, and the dimming rate is the threshold value. In the following cases, the delay time is the second delay time Tdelay2nd. The second delay time Tdelay2nd is longer than the first delay time Tdelay1st, and is longer as the dimming rate decreases.
　図８に示す閾値、第１の遅延時間Ｔｄｅｌａｙ１ｓｔ及び第２の遅延時間Ｔｄｅｌａｙ２ｎｄは、予め制御部９に設定されているものとする。第１の遅延時間Ｔｄｅｌａｙ１ｓｔは、閾値を上回る調光率が入力されたときに設定され、第２の遅延時間Ｔｄｅｌａｙ２ｎｄは、閾値以下の調光率が入力されたときに設定される。 Suppose that the threshold, the first delay time Tdelay1st, and the second delay time Tdelay2nd shown in FIG. 8 are set in the control unit 9 in advance. The first delay time Tdelay1st is set when a dimming rate exceeding the threshold is input, and the second delay time Tdelay2nd is set when a dimming rate less than the threshold is input.
　ＭＯＳＦＥＴ５１のオン時間が短くなりすぎると、ＭＯＳＦＥＴ５１が正常にオンオフ動作できなくなることがある。ＭＯＳＦＥＴ５１が正常にオンオフ動作できなくなるオン時間の長さは例えば０．２ｕｓｅｃ以下である。そのため制御部９には最小オン時間Ｔｏｎ＿ｍｉｎが記憶されており、光源８を調光する際、ＭＯＳＦＥＴ５１のオン時間が最小オン時間Ｔｏｎ＿ｍｉｎよりも短くならないように調光制御することができる。 If the ON time of the MOSFET 51 becomes too short, the MOSFET 51 may not be able to normally operate on and off. The length of the on time during which the MOSFET 51 cannot normally be turned on / off is, for example, 0.2 usec or less. Therefore, the control unit 9 stores the minimum on-time Ton_min. When the light source 8 is dimmed, the dimming control can be performed so that the on-time of the MOSFET 51 is not shorter than the minimum on-time Ton_min.
　図９は調光率に応じて遅延時間を変化させた場合のＭＯＳＦＥＴのオン時間とスイッチング周波数を示す第２の図である。図９に示すように調光率に対して複数の閾値１,２,３が設定されている。複数の閾値１,２,３は、閾値３、閾値２及び閾値１の順で高い値となる。また図９に示すように複数の閾値１,２,３に対応する複数の遅延時間Ｔｄｅｌａｙ１,２,３,４が設定されている。複数の閾値１,２,３及び複数の遅延時間Ｔｄｅｌａｙ１,２,３,４は、制御部９に設定されているものとする。 FIG. 9 is a second diagram showing the MOSFET on-time and switching frequency when the delay time is changed in accordance with the dimming rate. As shown in FIG. 9, a plurality of threshold values 1, 2, and 3 are set for the dimming rate. The plurality of thresholds 1, 2, and 3 are higher in the order of threshold 3, threshold 2, and threshold 1. Further, as shown in FIG. 9, a plurality of delay times Tdelay 1, 2, 3, 4 corresponding to a plurality of threshold values 1, 2, 3 are set. It is assumed that a plurality of threshold values 1, 2, 3 and a plurality of delay times Tdelay 1, 2, 3, 4 are set in the control unit 9.
　遅延時間Ｔｄｅｌａｙ４は、閾値３以下の調光率が入力されたときに設定される。遅延時間Ｔｄｅｌａｙ３は、閾値３を上回りかつ閾値２以下の調光率が入力されたときに設定される。遅延時間Ｔｄｅｌａｙ２は、閾値２を上回りかつ閾値１以下の調光率が入力されたときに設定される。遅延時間Ｔｄｅｌａｙ１は、閾値１を上回る調光率が入力されたときに設定される。 Delay time Tdelay4 is set when a dimming rate of threshold 3 or less is input. The delay time Tdelay3 is set when a dimming rate that exceeds the threshold 3 and is equal to or less than the threshold 2 is input. The delay time Tdelay2 is set when a dimming rate that exceeds the threshold 2 and is equal to or less than the threshold 1 is input. The delay time Tdelay1 is set when a dimming rate exceeding the threshold value 1 is input.
　制御部９は、調光率に複数の閾値を設けて、隣接する閾値同士の間の範囲に応じて互いに異なる長さの複数の遅延時間を用いてスイッチング素子を制御する。具体的には、遅延時間Ｔｄｅｌａｙ１を設けて点灯している状態から、光源８の電流が低下する方向に調光されて、調光率が閾値１に達したとき、ＭＯＳＦＥＴ５１のオン時間が最小オン時間Ｔｏｎ＿ｍｉｎまで短くなると、制御部９は、遅延時間をＴｄｅｌａｙ１からＴｄｅｌａｙ２に増加させる。これにより、ＭＯＳＦＥＴ５１のオン時間が最小オン時間Ｔｏｎ＿ｍｉｎよりも短くなることを防止できる。 The control unit 9 provides a plurality of threshold values for the dimming rate, and controls the switching elements using a plurality of delay times having different lengths according to a range between adjacent threshold values. Specifically, when the delay time Tdelay1 is provided and the light is dimmed in the direction in which the current of the light source 8 decreases and the dimming rate reaches the threshold value 1, the on-time of the MOSFET 51 is the minimum on-time. When the time is shortened to the time Ton_min, the control unit 9 increases the delay time from Tdelay1 to Tdelay2. This can prevent the on time of the MOSFET 51 from becoming shorter than the minimum on time Ton_min.
　図１０は図９に示す調光率の閾値１を境にして、遅延時間をＴｄｅｌａｙ１からＴｄｅｌａｙ２に延長する場合の、遅延時間、ＭＯＳＦＥＴのオン時間及び光源の調光率の時間変化を示す図である。 FIG. 10 is a diagram showing changes over time in delay time, MOSFET on-time, and light source dimming rate when the delay time is extended from Tdelay1 to Tdelay2 with threshold value 1 of dimming rate shown in FIG. is there.
　遅延時間Ｔｄｅｌａｙを急激に延長すると、ＭＯＳＦＥＴ５１のスイッチング周波数が急変し、ＰＦＣ回路５の出力が変動し、平滑コンデンサ６が電圧変動する影響により、後段に接続される電流制御部７の出力電流が一定値とならず、光源８を安定して点灯することができない。そこで、遅延時間Ｔｄｅｌａｙを延長する場合、遅延時間Ｔｄｅｌａｙの変化量最大値Ｔｓｔｅｐを設けると共に、遅延時間Ｔｄｅｌａｙを変化させずに維持する維持時間Ｔｋを設けることによって、遅延時間Ｔｄｅｌａｙの時間変化を遅くすることができる。この制御を行うことで、ＭＯＳＦＥＴ５１のスイッチング周波数が急変することを抑制できる。 When the delay time Tdelay is abruptly extended, the switching frequency of the MOSFET 51 suddenly changes, the output of the PFC circuit 5 fluctuates, and the voltage of the smoothing capacitor 6 fluctuates, so that the output current of the current control unit 7 connected to the subsequent stage is constant. Therefore, the light source 8 cannot be lit stably. Therefore, when the delay time Tdelay is extended, the change amount maximum value Tstep of the delay time Tdelay is provided, and the maintenance time Tk that maintains the delay time Tdelay without change is provided, thereby delaying the time change of the delay time Tdelay. be able to. By performing this control, a sudden change in the switching frequency of the MOSFET 51 can be suppressed.
　このとき、遅延時間Ｔｄｅｌａｙを維持するための維持時間Ｔｋは、ＭＯＳＦＥＴ５１のオン時間をフィードバック制御する応答時間よりも長く設定される。これによりＭＯＳＦＥＴ５１のオン時間が一定値になる時間が確保され、ＰＦＣ回路５の出力を安定させることができる。 At this time, the maintenance time Tk for maintaining the delay time Tdelay is set longer than the response time for feedback control of the ON time of the MOSFET 51. As a result, a time during which the ON time of the MOSFET 51 is constant is ensured, and the output of the PFC circuit 5 can be stabilized.
　次に図１１を用いて、遅延時間をＴｄｅｌａｙ１からＴｄｅｌａｙ２に延長する場合の制御に関してより詳細に説明する。図１１は遅延時間を延長する場合における制御部の動作を説明するためのフローチャートである。 Next, with reference to FIG. 11, the control when the delay time is extended from Tdelay1 to Tdelay2 will be described in more detail. FIG. 11 is a flowchart for explaining the operation of the control unit when extending the delay time.
　制御部９は、遅延時間Ｔｄｅｌａｙ１を設けて光源８が点灯している状態から、光源８の電流を減少させる方向に調光し（Ｓ１１）、調光率が閾値１より大きい場合（Ｓ１２，Ｎｏ）、遅延時間を変更しない（Ｓ１５）。調光率が閾値１以下の場合（Ｓ１２，Ｙｅｓ）、制御部９は、遅延時間の最終変更後、遅延時間の維持時間Ｔｋが経過していなければ（Ｓ１３，Ｎｏ）、遅延時間を変更しない（Ｓ１５）。制御部９は、遅延時間の最終変更後、遅延時間の維持時間Ｔｋが経過している場合（Ｓ１３，Ｙｅｓ）、遅延時間がＴｄｅｌａｙ２以上であれば（Ｓ１４，Ｎｏ）、遅延時間を変更しない（Ｓ１５）。遅延時間がＴｄｅｌａｙ２より小さければ（Ｓ１４，Ｙｅｓ）、遅延時間をＴｓｔｅｐ延長する（Ｓ１６）。 When the light source 8 is turned on with the delay time Tdelay1 provided, the controller 9 performs dimming in the direction of decreasing the current of the light source 8 (S11), and when the dimming rate is greater than the threshold 1 (S12, No ), The delay time is not changed (S15). When the dimming rate is equal to or less than the threshold value 1 (S12, Yes), the control unit 9 does not change the delay time unless the delay time maintenance time Tk has elapsed after the final change of the delay time (S13, No). (S15). If the delay time maintenance time Tk has elapsed after the final change of the delay time (S13, Yes), the control unit 9 does not change the delay time if the delay time is Tdelay2 or more (S14, No) ( S15). If the delay time is smaller than Tdelay2 (S14, Yes), the delay time is extended by Tstep (S16).
　反対に、遅延時間Ｔｄｅｌａｙ２を設けて点灯している状態から光源８の電流を増加する方向に調光し、調光率が閾値１に達した場合、制御部９は、遅延時間をＴｄｅｌａｙ２からＴｄｅｌａｙ１に短縮する。 On the other hand, when the light is adjusted in the direction of increasing the current of the light source 8 from the lighting state with the delay time Tdelay2 and the dimming rate reaches the threshold value 1, the control unit 9 changes the delay time from Tdelay2 to Tdelay1. To shorten.
　図１２は図９に示す調光率の閾値１を境にして、遅延時間をＴｄｅｌａｙ２からＴｄｅｌａｙ１に短縮する場合の、遅延時間、ＭＯＳＦＥＴのオン時間及び光源の調光率の時間変化を示す図である。遅延時間を急激に短縮すると、ＭＯＳＦＥＴ５１のスイッチング周波数が急変し、ＰＦＣ回路５の出力が変動し、平滑コンデンサ６が電圧変動する影響により、後段に接続される電流制御部７の出力電流が一定値とならず、光源８を安定して点灯することができない。そこで、遅延時間Ｔｄｅｌａｙを短縮する場合に、遅延時間Ｔｄｅｌａｙの変化量最大値Ｔｓｔｅｐを設けると共に、遅延時間Ｔｄｅｌａｙを変化させずに維持する維持時間Ｔｋを設けることによって、遅延時間Ｔｄｅｌａｙの時間変化を遅くすることができる。この制御を行うことで、ＭＯＳＦＥＴ５１のスイッチング周波数が急変することを抑制できる。 FIG. 12 is a diagram showing temporal changes in delay time, MOSFET on-time, and light source dimming rate when the delay time is shortened from Tdelay2 to Tdelay1 with the threshold value 1 of dimming rate shown in FIG. is there. When the delay time is sharply shortened, the switching frequency of the MOSFET 51 suddenly changes, the output of the PFC circuit 5 fluctuates, and the voltage of the smoothing capacitor 6 fluctuates, so that the output current of the current control unit 7 connected to the subsequent stage is constant Therefore, the light source 8 cannot be lit stably. Therefore, when the delay time Tdelay is shortened, the change amount maximum value Tstep of the delay time Tdelay is provided, and the maintenance time Tk that maintains the delay time Tdelay without change is provided, thereby delaying the time change of the delay time Tdelay. can do. By performing this control, a sudden change in the switching frequency of the MOSFET 51 can be suppressed.
　このとき、遅延時間Ｔｄｅｌａｙを維持する維持時間Ｔｋは、ＭＯＳＦＥＴ５１のオン時間をフィードバック制御する応答時間よりも長く設定される。これによりＭＯＳＦＥＴ５１のオン時間が一定値になる時間が確保され、ＰＦＣ回路５の出力を安定させることができる。 At this time, the maintenance time Tk for maintaining the delay time Tdelay is set longer than the response time for feedback control of the ON time of the MOSFET 51. As a result, a time during which the ON time of the MOSFET 51 is constant is ensured, and the output of the PFC circuit 5 can be stabilized.
　次に図１３を用いて、遅延時間をＴｄｅｌａｙ２からＴｄｅｌａｙ１に短縮する場合の制御に関してより詳細に説明する。図１３は遅延時間を短縮する場合における制御部の動作を説明するためのフローチャートである。 Next, the control when the delay time is shortened from Tdelay2 to Tdelay1 will be described in detail with reference to FIG. FIG. 13 is a flowchart for explaining the operation of the control unit when the delay time is shortened.
　制御部９は、遅延時間Ｔｄｅｌａｙ２を設けて点灯している状態から、光源８の電流を増加する方向に調光し（Ｓ２１）、調光率が閾値１以下の場合（Ｓ２２，Ｎｏ）は、遅延時間を変更しない（Ｓ２５）。調光率が閾値１より大きい場合（Ｓ２２，Ｙｅｓ）、遅延時間の最終変更後、遅延時間の維持時間Ｔｋが経過していなければ（Ｓ２３，Ｎｏ）、遅延時間を変更しない（Ｓ２５）。制御部９は、遅延時間の最終変更後、遅延時間の維持時間Ｔｋが経過している場合（Ｓ２３，Ｙｅｓ）、遅延時間がＴｄｅｌａｙ１以下であれば（Ｓ２４，Ｎｏ）、遅延時間を変更しない（Ｓ２５）。遅延時間がＴｄｅｌａｙ１より大きければ（Ｓ２４，Ｙｅｓ）、遅延時間をＴｓｔｅｐ短縮する（Ｓ２６）。 The control unit 9 performs dimming in the direction of increasing the current of the light source 8 from the lighting state with the delay time Tdelay2 (S21), and when the dimming rate is equal to or less than the threshold 1 (S22, No), The delay time is not changed (S25). If the dimming rate is larger than the threshold value 1 (S22, Yes), the delay time is not changed (S25) if the delay time maintenance time Tk has not passed after the final change of the delay time (S23, No). When the delay time maintaining time Tk has elapsed after the final change of the delay time (S23, Yes), the control unit 9 does not change the delay time if the delay time is equal to or less than Tdelay1 (S24, No) ( S25). If the delay time is larger than Tdelay1 (S24, Yes), the delay time is shortened by Tstep (S26).
　光源８の調光率を変更し、調光率が閾値２、閾値３となる場合に関しても、閾値１の場合と同様の制御が行われる。 When the dimming rate of the light source 8 is changed and the dimming rate becomes the threshold value 2 and the threshold value 3, the same control as in the case of the threshold value 1 is performed.
　なお実施の形態１では光源８がＬＥＤで構成されている場合について説明したが、光源８は調光可能なものであればＬＥＤに限定されず、有機ＥＬ（Ｅｌｅｃｔｒｏ　Ｌｕｍｉｎｅｓｃｅｎｃｅ）でもよい。 In addition, although the case where the light source 8 was comprised by LED was demonstrated in Embodiment 1, if the light source 8 can be dimmed, it will not be limited to LED, Organic EL (Electro Luminescence) may be sufficient.
実施の形態２．
　図１４は実施の形態２に係る点灯装置及び照明器具の構成図である。なお実施の形態２では、図１の実施の形態１に示す点灯装置１００及び照明器具２００と同一の構成を有する部位には、同一の符号を付してその説明を省略する。 Embodiment 2. FIG.
FIG. 14 is a configuration diagram of a lighting device and a lighting fixture according to the second embodiment. In the second embodiment, parts having the same configurations as those of the lighting device 100 and the lighting fixture 200 shown in the first embodiment of FIG.
　実施の形態２に係る照明器具２００Ａと、実施の形態１に係る照明器具２００との相違点は、照明器具２００Ａでは、点灯装置１００の代わりに点灯装置１００Ａが用いられていることである。また実施の形態２に係る点灯装置１００Ａと、実施の形態１に係る点灯装置１００との相違点は、点灯装置１００Ａでは、ＰＦＣ回路５、平滑コンデンサ６及び電流制御部７の代わりに直流変換回路１２が用いられ、さらに制御部９の代わりに制御部９Ａが用いられていることである。直流変換回路１２は、ＰＦＣ回路５、平滑コンデンサ６及び電流制御部７の機能を併せ持つ回路である。 The difference between the lighting fixture 200A according to Embodiment 2 and the lighting fixture 200 according to Embodiment 1 is that the lighting fixture 100A is used instead of the lighting device 100 in the lighting fixture 200A. The difference between the lighting device 100A according to the second embodiment and the lighting device 100 according to the first embodiment is that, in the lighting device 100A, a DC conversion circuit is used instead of the PFC circuit 5, the smoothing capacitor 6, and the current control unit 7. 12, and a control unit 9 </ b> A is used instead of the control unit 9. The DC conversion circuit 12 is a circuit having the functions of the PFC circuit 5, the smoothing capacitor 6, and the current control unit 7.
　実施の形態２では、直流変換回路１２をフライバック回路で構成した例を説明する。なお直流変換回路１２は、フライバック回路の他にも、フライフォワード回路、降圧チョッパ、昇圧チョッパ、昇降圧チョッパ回路、ＳＥＰＩＣ、Ｚｅｔａコンバータ又はＣｕｋコンバータといった回路で構成してもよい。 Embodiment 2 describes an example in which the DC conversion circuit 12 is configured by a flyback circuit. In addition to the flyback circuit, the DC conversion circuit 12 may be configured by a circuit such as a fly forward circuit, a step-down chopper, a step-up chopper, a step-up / step-down chopper circuit, a SEPIC, a Zeta converter, or a Cuk converter.
　直流変換回路１２は、ＭＯＳＦＥＴ１２１、トランス１２２、ダイオード１２３、平滑コンデンサ１２４、スナバコンデンサ１２５、スナバ抵抗１２６及びスナバダイオード１２７を備える。 The DC conversion circuit 12 includes a MOSFET 121, a transformer 122, a diode 123, a smoothing capacitor 124, a snubber capacitor 125, a snubber resistor 126, and a snubber diode 127.
　ＭＯＳＦＥＴ１２１は、負極側直流母線Ｎにおいて、コンデンサ４とトランス１２２の１次側との間に配置される。ＭＯＳＦＥＴ１２１のソースはコンデンサ４の一端と整流回路３とに接続される。ＭＯＳＦＥＴ１２１のドレインは、スナバダイオード１２７のアノードとトランス１２２とに接続される。スナバコンデンサ１２５、スナバ抵抗１２６及びスナバダイオード１２７は、コンデンサ４とトランス１２２の１次側との間に配置される。 The MOSFET 121 is disposed between the capacitor 4 and the primary side of the transformer 122 in the negative-side DC bus N. The source of the MOSFET 121 is connected to one end of the capacitor 4 and the rectifier circuit 3. The drain of MOSFET 121 is connected to the anode of snubber diode 127 and transformer 122. Snubber capacitor 125, snubber resistor 126 and snubber diode 127 are arranged between capacitor 4 and the primary side of transformer 122.
　スナバ抵抗１２６の一端は、正極側直流母線Ｐを介してコンデンサ４の他端と、整流回路３と、スナバコンデンサ１２５の一端と、トランス１２２とに接続される。スナバ抵抗１２６の他端は、スナバコンデンサ１２５の他端とスナバダイオード１２７の一端とに接続される。スナバコンデンサ１２５の他端は、スナバ抵抗１２６の他端とスナバダイオード１２７の一端とに接続される。ダイオード１２３及び平滑コンデンサ１２４は、トランス１２２の二次側と光源８との間に配置される。ダイオード１２３のアノードはトランス１２２に接続され、ダイオード１２３のカソードは平滑コンデンサ１２４の一端と光源８の一端とに接続される。平滑コンデンサ１２４の他端は、トランス１２２と光源８の他端とに接続される。 One end of the snubber resistor 126 is connected to the other end of the capacitor 4, the rectifier circuit 3, one end of the snubber capacitor 125, and the transformer 122 via the positive side DC bus P. The other end of the snubber resistor 126 is connected to the other end of the snubber capacitor 125 and one end of the snubber diode 127. The other end of the snubber capacitor 125 is connected to the other end of the snubber resistor 126 and one end of the snubber diode 127. The diode 123 and the smoothing capacitor 124 are disposed between the secondary side of the transformer 122 and the light source 8. The anode of the diode 123 is connected to the transformer 122, and the cathode of the diode 123 is connected to one end of the smoothing capacitor 124 and one end of the light source 8. The other end of the smoothing capacitor 124 is connected to the transformer 122 and the other end of the light source 8.
　不図示のコアに絶縁性ワイヤを巻くことにより、トランス１２２には、１次巻線１２２ａ、２次巻線１２２ｂ及び３次巻線１２２ｃが形成される。 The primary winding 122a, the secondary winding 122b, and the tertiary winding 122c are formed in the transformer 122 by winding an insulating wire around a core (not shown).
　直流変換回路１２は、ＭＯＳＦＥＴ１２１がオンオフ制御されることにより、整流回路３の出力電圧を変換し、光源８に直流電流を出力する。 The direct current conversion circuit 12 converts the output voltage of the rectifier circuit 3 and outputs a direct current to the light source 8 when the MOSFET 121 is on / off controlled.
　制御部９Ａは、目標値出力部９１、ゼロ電流検出部９２、スイッチング制御部９３Ａ及び電流入力部９４を備える。図１に示す制御部９と図１４に示す制御部９Ａとの相違点は、制御部９Ａでは、電圧検出部９５が省かれ、スイッチング制御部９３の代わりにスイッチング制御部９３Ａが用いられていることである。 The control unit 9A includes a target value output unit 91, a zero current detection unit 92, a switching control unit 93A, and a current input unit 94. The difference between the control unit 9 shown in FIG. 1 and the control unit 9A shown in FIG. 14 is that, in the control unit 9A, the voltage detection unit 95 is omitted, and the switching control unit 93A is used instead of the switching control unit 93. That is.
　直流変換回路１２の動作を詳細に説明する。 The operation of the DC conversion circuit 12 will be described in detail.
　図１５は図１４に示す直流変換回路を構成する巻線に流れる電流とＭＯＳＦＥＴのドレイン電圧とＭＯＳＦＥＴのゲート電圧との関係を示すタイミングチャートである。図１５には、上から順に、点灯装置１００Ａに入力される交流電源１の電流と、１次巻線１２２ａに流れる電流と、３次巻線１２２ｃに流れる電流と、ＭＯＳＦＥＴ１２１のドレイン電圧と、ＭＯＳＦＥＴ１２１のゲート電圧とが示される。横軸は時間を表す。図１５では、点灯装置１００Ａに入力される交流電源１の電流が「入力電流」として示される。 FIG. 15 is a timing chart showing the relationship between the current flowing through the windings constituting the DC conversion circuit shown in FIG. 14, the drain voltage of the MOSFET, and the gate voltage of the MOSFET. 15, in order from the top, the current of the AC power source 1 input to the lighting device 100A, the current flowing through the primary winding 122a, the current flowing through the tertiary winding 122c, the drain voltage of the MOSFET 121, and the MOSFET 121 The gate voltage is shown. The horizontal axis represents time. In FIG. 15, the current of the AC power supply 1 input to the lighting device 100 </ b> A is indicated as “input current”.
　図１５では、説明の便宜上、ＭＯＳＦＥＴ１２１のゲート電圧がオンオフされる周期を、実際よりも長く記載している。ＭＯＳＦＥＴ１２１のゲート電圧がオンオフされる周期は、ＭＯＳＦＥＴ１２１のゲート電圧がオフからオンに変化した時点から、再びＭＯＳＦＥＴ１２１のゲート電圧がオフからオンに変化するまでの時間に等しい。 In FIG. 15, for convenience of explanation, the cycle in which the gate voltage of the MOSFET 121 is turned on / off is shown to be longer than the actual period. The period during which the gate voltage of the MOSFET 121 is turned on / off is equal to the time from when the gate voltage of the MOSFET 121 changes from off to on until when the gate voltage of the MOSFET 121 changes from off to on again.
　ＭＯＳＦＥＴ１２１がオンされたとき、交流電源１、整流回路３、１次巻線１２２ａ及びＭＯＳＦＥＴ１２１により閉回路が形成され、交流電源１が１次巻線１２２ａを介して短絡される。そのため閉回路に電源電流が流れ、１次巻線１２２ａに流れる電流が増加し、１次巻線１２２ａにエネルギーが蓄積される。 When the MOSFET 121 is turned on, a closed circuit is formed by the AC power source 1, the rectifier circuit 3, the primary winding 122a, and the MOSFET 121, and the AC power source 1 is short-circuited through the primary winding 122a. As a result, the power source current flows through the closed circuit, the current flowing through the primary winding 122a increases, and energy is stored in the primary winding 122a.
　スイッチング制御部９３Ａに設定されたオン時間が経過すると、ＭＯＳＦＥＴ１２１がオフされることにより、３次巻線１２２ｃ、ダイオード１２３及び平滑コンデンサ１２４の閉回路が形成される。この閉回路において１次巻線１２２ａに蓄えられたエネルギーが放出され、平滑コンデンサ１２４が充電される。 When the ON time set in the switching control unit 93A elapses, the MOSFET 121 is turned off to form a closed circuit of the tertiary winding 122c, the diode 123, and the smoothing capacitor 124. In this closed circuit, the energy stored in the primary winding 122a is released, and the smoothing capacitor 124 is charged.
　３次巻線１２２ｃに流れる電流がゼロになった時点から遅延時間Ｔｄｅｌａｙが経過するまで、ＭＯＳＦＥＴ１２１のオフ状態は維持され、遅延時間Ｔｄｅｌａｙが経過したときにＭＯＳＦＥＴ１２１は再びオン状態になる。 The MOSFET 121 is kept off until the delay time Tdelay elapses after the current flowing through the tertiary winding 122c becomes zero, and the MOSFET 121 is turned on again when the delay time Tdelay elapses.
　ＭＯＳＦＥＴ１２１の一連のオンオフ動作により、１次巻線１２２ａに流れる電流は、三角波状の波形となり、その頂点が点線で示すような正弦波の包絡線になる。 Due to a series of on / off operations of the MOSFET 121, the current flowing through the primary winding 122a has a triangular waveform, and a sine wave envelope whose apex is indicated by a dotted line.
　このとき、交流電源１から入力される電流は、入力フィルタ２により平滑化され、コイル２１に流れるコイル電流の平均値が入力され、正弦波状の電流波形となる。 At this time, the current input from the AC power source 1 is smoothed by the input filter 2, and the average value of the coil current flowing through the coil 21 is input to form a sine wave current waveform.
　制御部９Ａが光源８に流れる電流を検出して、検出された電流が目標値に追従するようフィードバック制御されることで、ＭＯＳＦＥＴ１２１のオン時間が制御される。 The control unit 9A detects the current flowing through the light source 8, and feedback control is performed so that the detected current follows the target value, whereby the on-time of the MOSFET 121 is controlled.
　ＭＯＳＦＥＴ１２１のオン時間をフィードバック制御する際、オン時間が大きく変化してしまうと、１次巻線１２２ａに流れる電流の頂点の包絡線が正弦波にならず、交流電源１の入力電流を正弦波状にすることができない。そのため制御部９Ａでは、フィードバック制御の応答時間が、フィードバック制御のループゲインを交流電源１の１周期の１／２周期以上で１倍（０ｄＢ）以下となるように、設定される。言い換えると、フィードバック制御の応答時間は、交流電源１の周波数の２倍以下の周波数で１倍（０ｄＢ）以下となるように設定される。 When the on-time of the MOSFET 121 is feedback-controlled, if the on-time greatly changes, the envelope of the peak of the current flowing through the primary winding 122a does not become a sine wave, and the input current of the AC power supply 1 becomes a sine wave. Can not do it. Therefore, in the control unit 9A, the response time of the feedback control is set so that the loop gain of the feedback control is not less than 1/2 of one cycle of the AC power supply 1 and not more than 1 (0 dB). In other words, the response time of the feedback control is set to be 1 (0 dB) or less at a frequency that is 2 times or less of the frequency of the AC power supply 1.
　具体的に説明すると、電源周波数が５０Ｈｚの場合、電源周波数の半周期（半波）の周波数１００Ｈｚ以下、すなわち周期１０ｍｓｅｃ以上で、定電流フィードバック制御のループゲインを１倍(０ｄＢ)以下とすることにより、定電流フィードバック制御は電源周期の１／２より短い周期で応答しないように設定される。これにより電源周期の１／２周期以内においては、ＭＯＳＦＥＴ１２１のオン時間の変動が抑制され、１次巻線１２２ａに流れる電流の頂点の包絡線が正弦波状の波形となる。 More specifically, when the power supply frequency is 50 Hz, the loop gain of the constant current feedback control is set to be 1 (0 dB) or less at a frequency of 100 Hz or less of a half cycle (half wave) of the power supply frequency, that is, a cycle of 10 msec or more. Thus, the constant current feedback control is set so as not to respond in a cycle shorter than ½ of the power cycle. As a result, the fluctuation of the on-time of the MOSFET 121 is suppressed within a half cycle of the power supply cycle, and the envelope of the peak of the current flowing through the primary winding 122a becomes a sine wave waveform.
　またフィードバック制御において、オン時間の更新周期を、交流電源１の周期の半分に相当する周期、又は交流電源１の周期の半分に相当する周期よりも長い周期とすることによっても、同様の効果を得ることができる。 In the feedback control, the same effect can be obtained by setting the on-time update cycle to a cycle corresponding to half the cycle of the AC power supply 1 or a cycle longer than the cycle corresponding to half the cycle of the AC power supply 1. Obtainable.
　実施の形態２に係る点灯装置１００Ａ及び照明器具２００Ａは、実施の形態１と同様に遅延時間Ｔｄｅｌａｙを設けて、電流不連続モード制御によりＭＯＳＦＥＴ１２１をスイッチング制御することで、電流臨界モード制御する場合に比べて、スイッチング周波数を低くすることができるため、ＭＯＳＦＥＴ１２１で発生するスイッチング損失を低減できる。 The lighting device 100A and the lighting fixture 200A according to the second embodiment are provided with the delay time Tdelay as in the first embodiment, and when the current critical mode control is performed by switching the MOSFET 121 by the current discontinuous mode control. In comparison, since the switching frequency can be lowered, the switching loss generated in the MOSFET 121 can be reduced.
　なお実施の形態１，２では調光率に応じて遅延時間の長さを変える例を説明したが、遅延時間の長さは、調光率の代わりに直流変換回路３０がＬＥＤに出力する出力電流目標値により判定してもよい。またこの場合、直流変換回路の出力の大きさは、ＬＥＤの調光率により判定されたものでもよいし、ＬＥＤの出力電流目標値により判定されたものでもよいし、有機ＥＬの調光率により判定されたものでもよい。また直流変換回路の出力の大きさは、ＬＥＤの出力電流目標値より判定されるものでもよい。また実施の形態１，２に係る制御部は、調光率の代わりに、出力電流目標値に応じて遅延時間の長さを変えるように構成してもよい。 In the first and second embodiments, the example in which the length of the delay time is changed according to the dimming rate has been described. However, the length of the delay time is an output that the DC conversion circuit 30 outputs to the LED instead of the dimming rate. The determination may be made based on the current target value. In this case, the magnitude of the output of the DC conversion circuit may be determined by the dimming rate of the LED, may be determined by the output current target value of the LED, or may be determined by the dimming rate of the organic EL. It may be determined. The magnitude of the output of the DC conversion circuit may be determined from the output current target value of the LED. Moreover, you may comprise the control part which concerns on Embodiment 1, 2 so that the length of delay time may be changed according to an output current target value instead of a light control rate.
実施の形態３．
　図１６は実施の形態３に係る点灯装置及び照明器具の構成図である。なお実施の形態３では、図１の実施の形態１に係る点灯装置１００及び照明器具２００と同一の構成を有する部位には、同一の符号を付してその説明を省略する。 Embodiment 3 FIG.
FIG. 16 is a configuration diagram of a lighting device and a lighting fixture according to the third embodiment. In the third embodiment, parts having the same configurations as those of the lighting device 100 and the lighting fixture 200 according to the first embodiment of FIG.
　実施の形態３に係る照明器具２００Ｂと、実施の形態１に係る照明器具２００との相違点は、照明器具２００Ｂでは、点灯装置１００の代わりに点灯装置１００Ｂが用いられていることである。また実施の形態３に係る点灯装置１００Ｂと、実施の形態１に係る点灯装置１００との相違点は、点灯装置１００Ｂでは、電流制御部７においてコイル７５が用いられ、制御部９の代わりに制御部９Ｂが用いられていることである。 The difference between the lighting fixture 200B according to Embodiment 3 and the lighting fixture 200 according to Embodiment 1 is that the lighting device 100B is used instead of the lighting device 100 in the lighting fixture 200B. The difference between the lighting device 100B according to the third embodiment and the lighting device 100 according to the first embodiment is that, in the lighting device 100B, the coil 75 is used in the current control unit 7, and the control is performed instead of the control unit 9. The part 9B is used.
　図１６に示す電流制御部７は、スイッチング制御部９３から出力された制御信号に基づき、ＰＦＣ回路５から出力された直流電圧を、光源８に入力可能な直流電流に変換する。 16 converts the DC voltage output from the PFC circuit 5 into a DC current that can be input to the light source 8, based on the control signal output from the switching control unit 93. The current control unit 7 illustrated in FIG.
　図１６に示す電流制御部７は、降圧チョッパ回路で構成されているが、降圧チョッパ回路の他にも、昇降圧チョッパ回路、フライバック回路、フライフォワード回路、ＳＥＰＩＣ、Ｚｅｔａコンバータ又はＣｕｋコンバータといった回路で構成されたものでもよい。 The current control unit 7 shown in FIG. 16 includes a step-down chopper circuit. In addition to the step-down chopper circuit, a circuit such as a step-up / step-down chopper circuit, a flyback circuit, a fly-forward circuit, a SEPIC, a Zeta converter, or a Cuk converter is used. It may be composed of
　電流制御部７は、ＭＯＳＦＥＴ７１、コイル７５、ダイオード７３及びコンデンサ７４により構成される。 The current controller 7 includes a MOSFET 71, a coil 75, a diode 73, and a capacitor 74.
　コイル７５は、正極側直流母線Ｐにおいて、コンデンサ７４とＭＯＳＦＥＴ７１との間に配置される。不図示のコアに絶縁性ワイヤを巻くことにより、コイル７５には１次巻線７５ａ及び２次巻線７５ｂが形成される。 The coil 75 is disposed between the capacitor 74 and the MOSFET 71 on the positive side DC bus P. A primary winding 75a and a secondary winding 75b are formed on the coil 75 by winding an insulating wire around a core (not shown).
　１次巻線７５ａの一端はＭＯＳＦＥＴ７１のソースと、ダイオード７３のカソードとに接続される。１次巻線７５ａの他端は、コンデンサ７４の一端と、光源８の一端とに接続される。２次巻線７５ｂの一端は、制御部９Ｂ内のゼロ電流検出部９２に接続される。２次巻線７５ｂの他端は負極側直流母線Ｎに接続される。１次巻線７５ａには、ＭＯＳＦＥＴ７１のオンオフ動作に伴い、極性が異なる電圧が印加される。２次巻線７５ｂに誘導されて、２次巻線７５ｂの両端に発生する電圧は、１次巻線７５ａの印加電圧と巻数比ｎとに応じた電圧に等しい。 One end of the primary winding 75 a is connected to the source of the MOSFET 71 and the cathode of the diode 73. The other end of the primary winding 75 a is connected to one end of the capacitor 74 and one end of the light source 8. One end of the secondary winding 75b is connected to the zero current detection unit 92 in the control unit 9B. The other end of secondary winding 75b is connected to negative side DC bus N. A voltage having a different polarity is applied to the primary winding 75a as the MOSFET 71 is turned on / off. The voltage induced by the secondary winding 75b and generated at both ends of the secondary winding 75b is equal to the voltage corresponding to the applied voltage of the primary winding 75a and the turn ratio n.
　ＭＯＳＦＥＴ７１は正極側直流母線Ｐに配置される。ＭＯＳＦＥＴ７１のドレインは、平滑コンデンサ６の一端に接続される。ＭＯＳＦＥＴ７１のソースは、ダイオード７３のカソードとコイル７５の１次巻線７５ａの一端とに接続される。ＭＯＳＦＥＴ７１のゲートは、スイッチング制御部９３に接続される。ＭＯＳＦＥＴ７１のゲートには、スイッチング制御部９３から出力される制御信号が入力される。当該制御信号はＭＯＳＦＥＴ７１をオンオフ制御するための信号である。 The MOSFET 71 is disposed on the positive side DC bus P. The drain of the MOSFET 71 is connected to one end of the smoothing capacitor 6. The source of the MOSFET 71 is connected to the cathode of the diode 73 and one end of the primary winding 75 a of the coil 75. The gate of the MOSFET 71 is connected to the switching control unit 93. A control signal output from the switching control unit 93 is input to the gate of the MOSFET 71. The control signal is a signal for controlling on / off of the MOSFET 71.
　次に電流制御部７の動作を詳細に説明する。 Next, the operation of the current control unit 7 will be described in detail.
　図１７は光源に流れる電流と１次巻線に流れる電流とＭＯＳＦＥＴの制御信号との関係を示すタイミングチャートである。図１７には上から順に、光源８に流れる電流と、ＭＯＳＦＥＴ７１のドレイン－ソース間に印加される電圧と、１次巻線７５ａに流れる電流と、ゼロ電流検出信号と、ＭＯＳＦＥＴ７１の制御信号とが示される。図１７では、ドレイン－ソース間に印加される電圧が「ドレイン電圧」と表記される。なお、横軸は時間を表す。 FIG. 17 is a timing chart showing the relationship between the current flowing through the light source, the current flowing through the primary winding, and the control signal of the MOSFET. FIG. 17 shows, in order from the top, the current flowing through the light source 8, the voltage applied between the drain and source of the MOSFET 71, the current flowing through the primary winding 75a, the zero current detection signal, and the control signal of the MOSFET 71. Indicated. In FIG. 17, the voltage applied between the drain and the source is denoted as “drain voltage”. The horizontal axis represents time.
　時刻ｔ１でＭＯＳＦＥＴ７１がオンされたとき、平滑コンデンサ６、ＭＯＳＦＥＴ７１、１次巻線７５ａ及びコンデンサ７４により閉回路が形成され、１次巻線７５ａに流れる電流が増加し、１次巻線７５ａと、コンデンサ７４にエネルギーが蓄積される。 When the MOSFET 71 is turned on at time t1, a closed circuit is formed by the smoothing capacitor 6, the MOSFET 71, the primary winding 75a and the capacitor 74, and the current flowing through the primary winding 75a is increased. Energy is stored in the capacitor 74.
　スイッチング制御部９３に設定されたオン時間Ｔｏｎが経過した時刻ｔ２で、ＭＯＳＦＥＴ７１がオフされることにより、１次巻線７５ａ、コンデンサ７４及びダイオード７３の閉回路が形成される。この閉回路において１次巻線７５ａに蓄積されたエネルギーが放出され、コンデンサ７４が充電される。 The MOSFET 71 is turned off at time t2 when the on-time Ton set in the switching control unit 93 has elapsed, thereby forming a closed circuit of the primary winding 75a, the capacitor 74, and the diode 73. In this closed circuit, the energy accumulated in the primary winding 75a is released, and the capacitor 74 is charged.
　１次巻線７５ａに流れる電流がゼロになった時点である時刻ｔ３から遅延時間Ｔｄｅｌａｙが経過するまで、ＭＯＳＦＥＴ７１のオフ状態は維持される。遅延時間Ｔｄｅｌａｙが経過した時刻ｔ４に、ＭＯＳＦＥＴ７１は再びオン状態になる。すなわち、１次巻線７５ａに流れる電流がゼロになった時点から遅延時間Ｔｄｅｌａｙが経過した時点まで、ＭＯＳＦＥＴ７１の制御信号はオフ状態を維持する。そして、遅延時間Ｔｄｅｌａｙが経過した時点で、ＭＯＳＦＥＴ７１の制御信号はオン状態に変化する。 The MOSFET 71 is kept off until the delay time Tdelay elapses from time t3 when the current flowing through the primary winding 75a becomes zero. At time t4 when the delay time Tdelay has elapsed, the MOSFET 71 is turned on again. That is, the control signal of the MOSFET 71 remains off from the time when the current flowing through the primary winding 75a becomes zero until the time when the delay time Tdelay has elapsed. Then, when the delay time Tdelay has elapsed, the control signal of the MOSFET 71 changes to the on state.
　ＭＯＳＦＥＴ７１の一連のオンオフ動作により、１次巻線７５ａに流れる電流は、三角波状の波形となる。 Due to a series of on / off operations of the MOSFET 71, the current flowing through the primary winding 75a has a triangular waveform.
　このとき、電流制御部７から光源８へ出力される電流は、コンデンサ７４により平滑化される。従って、１次巻線７５ａに流れる電流の平均値が光源８に出力される。すなわち、電流制御部７から光源８へ出力される電流は、変動が除去された直流波形となる。 At this time, the current output from the current control unit 7 to the light source 8 is smoothed by the capacitor 74. Therefore, the average value of the current flowing through the primary winding 75a is output to the light source 8. That is, the current output from the current control unit 7 to the light source 8 has a direct current waveform from which fluctuations have been removed.
　電流検出部１１は光源８に流れる電流を検出し、検出された電流を制御部９Ｂに送信する。制御部９Ｂは、電流検出部１１で検出された電流が目標値に追従するように、ＭＯＳＦＥＴ７１のオン時間Ｔｏｎをフィードバック制御する。すなわち、制御部９Ｂは、検出された電流が目標値より小さい場合、ＭＯＳＦＥＴ７１のオン時間Ｔｏｎを長くし、検出された電流が目標値より大きい場合、ＭＯＳＦＥＴ７１のオン時間Ｔｏｎを短くする。 The current detector 11 detects the current flowing through the light source 8, and transmits the detected current to the controller 9B. The control unit 9B performs feedback control on the on-time Ton of the MOSFET 71 so that the current detected by the current detection unit 11 follows the target value. That is, the control unit 9B increases the on-time Ton of the MOSFET 71 when the detected current is smaller than the target value, and shortens the on-time Ton of the MOSFET 71 when the detected current is larger than the target value.
　実施の形態１に係る点灯装置１００では、電流制御部７のＭＯＳＦＥＴ７１を、固定周波数のデューティ制御とする例を示した。これに対して、ＭＯＳＦＥＴ７１を電流臨界モード制御すると、ＭＯＳＦＥＴ７１がより高いスイッチング周波数で動作する。そのため、ＭＯＳＦＥＴ７１を電流臨界モード制御したときに光源８へ出力される電流が、ＭＯＳＦＥＴ７１を固定周波数のデューティ制御したときに光源８へ出力される電流と同等である場合、電流臨界モード制御では、オン時間Ｔｏｎを短くできる。オン時間Ｔｏｎは、光源８に出力する電流の大きさによって決まり、全光点灯時に最長となる。また、このとき１次巻線７５ａに流れる電流のピーク値も最大となる。１次巻線７５ａに流れる電流の大きさが小さいほど、コイル７５を構成する磁性体コアに発生する磁束密度が低く、コアの大きさを小型化できるため、ＭＯＳＦＥＴ７１を電流臨界モード制御することにより、コイル７５を小型化できる。 In the lighting device 100 according to the first embodiment, an example in which the MOSFET 71 of the current control unit 7 is duty control with a fixed frequency is shown. On the other hand, when the MOSFET 71 is controlled in the current critical mode, the MOSFET 71 operates at a higher switching frequency. Therefore, if the current output to the light source 8 when the MOSFET 71 is current critical mode controlled is equal to the current output to the light source 8 when the MOSFET 71 is duty controlled at a fixed frequency, the current critical mode control Time Ton can be shortened. The on-time Ton is determined by the magnitude of the current output to the light source 8, and is the longest when all the lights are on. At this time, the peak value of the current flowing through the primary winding 75a is also maximized. As the magnitude of the current flowing through the primary winding 75a is smaller, the magnetic flux density generated in the magnetic core constituting the coil 75 is lower, and the size of the core can be reduced. The coil 75 can be reduced in size.
　しかしながら、光源８を調光する場合、交流電源１の入力電流を小さくするため、スイッチング制御部９３は、ＭＯＳＦＥＴ７１のオン時間Ｔｏｎを短くするように制御を行う。従って、電流臨界モード制御では、調光時にＭＯＳＦＥＴ７１のオン時間Ｔｏｎが短くなりすぎ、ＭＯＳＦＥＴ７１のオンオフ動作が不安定になり、光源８の出力光にちらつきが発生してしまう可能性がある。出力光のちらつきは光源８の明るさの変動に等しい。 However, when the light source 8 is dimmed, the switching control unit 93 performs control to shorten the ON time Ton of the MOSFET 71 in order to reduce the input current of the AC power supply 1. Therefore, in the current critical mode control, the ON time Ton of the MOSFET 71 becomes too short at the time of dimming, the ON / OFF operation of the MOSFET 71 becomes unstable, and the output light of the light source 8 may flicker. The flickering of the output light is equal to the brightness variation of the light source 8.
　図１８は調光率に応じて変化するＭＯＳＦＥＴのオン時間及びスイッチング周波数の特性を示す図である。図１８には上から順に、ＭＯＳＦＥＴ７１のオン時間と、スイッチング周波数と、光源８の調光率とが示される。 FIG. 18 is a graph showing the on-time and switching frequency characteristics of the MOSFET that change in accordance with the dimming rate. FIG. 18 shows the ON time of the MOSFET 71, the switching frequency, and the dimming rate of the light source 8 in order from the top.
　点線は、遅延時間Ｔｄｅｌａｙを設けずに電流臨界モード制御が行われている場合に調光率を変化させたときの、ＭＯＳＦＥＴ７１のオン時間及びスイッチング周波数を表す。実線は、遅延時間Ｔｄｅｌａｙを設けて電流不連続モード制御が行われている場合に調光率を変化させたときの、ＭＯＳＦＥＴ７１のオン時間及びスイッチング周波数を表す。 The dotted line represents the ON time and switching frequency of the MOSFET 71 when the dimming rate is changed when the current critical mode control is performed without providing the delay time Tdelay. The solid line represents the ON time and switching frequency of the MOSFET 71 when the dimming rate is changed when the current discontinuous mode control is performed with the delay time Tdelay.
　遅延時間Ｔｄｅｌａｙを設けてＭＯＳＦＥＴ７１を電流不連続モード制御することで、電流臨界モード制御と比較して、調光時におけるスイッチング周波数の上昇を抑制することができ、スイッチング損失を低減できる。また、ＭＯＳＦＥＴ７１のオン時間を長くすることができ、より確実にＭＯＳＦＥＴ７１をオンオフ制御できる。電流制御部７において、ＭＯＳＦＥＴ７１のオン時間が短くなりすぎてしまうと、ＭＯＳＦＥＴ７１のオンオフ動作が不安定になり、光源８に出力光のちらつきが発生してしまう可能性があるため、遅延時間Ｔｄｅｌａｙを設けることで、オン時間を確保し、光源８の出力光にちらつきを生じることなく、調光制御することができる。ＭＯＳＦＥＴ７１が正常にオンオフ動作できなくなるオン時間の長さは、例えば０．２ｕｓｅｃ以下である。そのため制御部９Ｂには最小オン時間Ｔｏｎ＿ｍｉｎが記憶されており、光源８を調光する際、ＭＯＳＦＥＴ７１のオン時間が最小オン時間Ｔｏｎ＿ｍｉｎよりも短くならないように調光制御することができる。最小オン時間Ｔｏｎ＿ｍｉｎは、ＭＯＳＦＥＴ７１が正常にオンオフ動作できなくなるオン時間の長さに等しい。 By providing the delay time Tdelay and controlling the MOSFET 71 in the current discontinuous mode control, an increase in switching frequency during dimming can be suppressed and switching loss can be reduced as compared with the current critical mode control. Further, the ON time of the MOSFET 71 can be lengthened, and the MOSFET 71 can be controlled on and off more reliably. In the current control unit 7, if the ON time of the MOSFET 71 becomes too short, the ON / OFF operation of the MOSFET 71 becomes unstable, and the light source 8 may flicker in the output light. By providing, it is possible to ensure the on-time and to perform dimming control without causing flickering in the output light of the light source 8. The length of the on time during which the MOSFET 71 cannot normally be turned on / off is, for example, 0.2 usec or less. Therefore, the control unit 9B stores the minimum on-time Ton_min, and when the light source 8 is dimmed, the dimming control can be performed so that the on-time of the MOSFET 71 is not shorter than the minimum on-time Ton_min. The minimum on-time Ton_min is equal to the length of the on-time at which the MOSFET 71 cannot normally operate on and off.
　以上から、遅延時間Ｔｄｅｌａｙを設けてＭＯＳＦＥＴ７１を電流不連続モード制御すると、電流臨界モード制御の場合と同様に、デューティ制御する場合に比べて、１次巻線７５ａのピーク電流を小さくできるため、コイル７５をより小型化できる。さらに、電流臨界モード制御する場合に比べて、光源８を調光した際のＭＯＳＦＥＴ７１のオン時間減少を抑制できため、調光時に、光源８の出力光にちらつきが発生することを抑制できる。 From the above, when the MOSFET 71 is controlled in the current discontinuous mode with the delay time Tdelay, the peak current of the primary winding 75a can be reduced as compared with the case where the duty control is performed as in the case of the current critical mode control. 75 can be further downsized. Furthermore, since the ON time reduction of the MOSFET 71 when the light source 8 is dimmed can be suppressed as compared with the case where the current critical mode control is performed, the occurrence of flickering in the output light of the light source 8 can be suppressed during dimming.
　光源８を点灯している期間において、遅延時間Ｔｄｅｌａｙの長さを変更してしまうと、ＭＯＳＦＥＴ７１のスイッチング周波数が変動してしまうことから、光源８に出力される電流が変動し、光源８の出力光にちらつきが発生する。そのため、光源８の点灯開始後は、遅延時間Ｔｄｅｌａｙの長さを、調光率によらず、一定にすることで、ＭＯＳＦＥＴ７１のスイッチング周波数変動が抑制され、光源８の出力光のちらつきが抑制される。 If the length of the delay time Tdelay is changed while the light source 8 is turned on, the switching frequency of the MOSFET 71 will fluctuate, so the current output to the light source 8 fluctuates and the output of the light source 8 changes. Flickering occurs in the light. Therefore, after the lighting of the light source 8 is started, the delay time Tdelay is made constant regardless of the dimming rate, so that the switching frequency fluctuation of the MOSFET 71 is suppressed, and the flickering of the output light of the light source 8 is suppressed. The
　図１９は光源に出力される電流の大きさが異なる場合における電流制御部の動作を示す第１の図である。図２０は光源に出力される電流の大きさが異なる場合における電流制御部の動作を示す第２の図である。図１９，２０には、上から順に、光源８へ出力される電流と、ＭＯＳＦＥＴ７１のドレイン－ソース間に印加される電圧と、１次巻線７５ａに流れる電流と、ゼロ電流検出信号と、ＭＯＳＦＥＴ７１の制御信号とが示される。図１９，２０では、ドレイン－ソース間に印加される電圧が「ドレイン電圧」と表記される。なお、横軸は時間を表す。 FIG. 19 is a first diagram illustrating the operation of the current control unit when the current output to the light source is different. FIG. 20 is a second diagram illustrating the operation of the current control unit when the magnitude of the current output to the light source is different. 19 and 20, in order from the top, the current output to the light source 8, the voltage applied between the drain and source of the MOSFET 71, the current flowing through the primary winding 75a, the zero current detection signal, and the MOSFET 71. Control signals. 19 and 20, the voltage applied between the drain and the source is denoted as “drain voltage”. The horizontal axis represents time.
　光源８を調光することで光源８へ出力される電流を小さくする場合、ＭＯＳＦＥＴ７１の制御信号のオン時間を短くするため、全光時のオン時間Ｔｏｎ（ａ）と、調光時のオン時間Ｔｏｎ（ａ）とは、全光時のオン時間Ｔｏｎ（ａ）＞調光時のオン時間Ｔｏｎ（ｂ）の関係となる。一方で、遅延時間Ｔｄｅｌａｙの長さは、調光率によらず、一定であるため、全光時の遅延時間Ｔｄｅｌａｙ（ａ）と調光時の遅延時間Ｔｄｅｌａｙ（ｂ）とは、全光時の遅延時間Ｔｄｅｌａｙ（ａ）＝調光時の遅延時間Ｔｄｅｌａｙ（ｂ）の関係となる。 When the current output to the light source 8 is reduced by dimming the light source 8, the on-time Ton (a) for all light and the on-time for dimming are used to shorten the on-time of the control signal of the MOSFET 71. Ton (a) has a relationship of on time Ton (a) at all light> on time Ton (b) at light control. On the other hand, since the length of the delay time Tdelay is constant regardless of the dimming rate, the delay time Tdelay (a) in all lights and the delay time Tdelay (b) in dimming are The delay time Tdelay (a) = the delay time Tdelay (b) during dimming.
　また、光源８を点灯している期間において、遅延時間Ｔｄｅｌａｙの長さを変更する場合、遅延時間Ｔｄｅｌａｙを変更するための判定手段が必要になる。そのため、例えば、マイコン又はＣＰＵといった演算素子を用いて、判定手段を実現する場合、複雑な判定処理の命令を記述する必要があり、使用するメモリ容量が増加してしまう。また、アナログ回路を用いて、判定手段を実現する場合、部品点数が増加し、回路構成が複雑化してしまう。そのため、遅延時間Ｔｄｅｌａｙの長さを、調光率によらず、一定にすることで、マイコン又はＣＰＵといった演算素子のメモリ容量の増加を抑制でき、またアナログ回路を構成する部品点数の増加を抑制できる。 Further, when the length of the delay time Tdelay is changed during the period when the light source 8 is turned on, a determination means for changing the delay time Tdelay is required. Therefore, for example, when the determination unit is realized using an arithmetic element such as a microcomputer or a CPU, it is necessary to describe a complicated determination processing instruction, and the memory capacity to be used increases. In addition, when the determination unit is realized using an analog circuit, the number of parts increases and the circuit configuration becomes complicated. Therefore, by making the length of the delay time Tdelay constant regardless of the dimming rate, it is possible to suppress an increase in the memory capacity of an arithmetic element such as a microcomputer or a CPU, and to suppress an increase in the number of components constituting the analog circuit. it can.
　具体的な遅延時間Ｔｄｅｌａｙの設け方としては、ＭＯＳＦＥＴ７１のドレイン電圧が自由振動している期間において、制御部９Ｂは、ＭＯＳＦＥＴ７１の電圧振動のボトム付近でＭＯＳＦＥＴ７１をオンさせる。これにより、ドレイン電圧の急峻な変動が抑制され、スイッチングに起因するノイズが抑制される。また、複数回生じるＭＯＳＦＥＴ７１の電圧振動のボトムの内、少なくとも２回目以降のボトムにおいて、制御部９ＢがＭＯＳＦＥＴ７１をオンすることで、確実に遅延時間Ｔｄｅｌａｙを設けることができる。 As a specific method of providing the delay time Tdelay, the control unit 9B turns on the MOSFET 71 near the bottom of the voltage oscillation of the MOSFET 71 during the period in which the drain voltage of the MOSFET 71 is in free oscillation. As a result, steep fluctuations in the drain voltage are suppressed, and noise caused by switching is suppressed. In addition, the delay time Tdelay can be provided with certainty by the controller 9B turning on the MOSFET 71 at least at the second and subsequent bottoms among the bottoms of the voltage oscillation of the MOSFET 71 that occurs a plurality of times.
　以上の実施の形態３に示した構成は、本発明の内容の一例を示すものであり、別の公知の技術と組み合わせることも可能であるし、実施の形態１に示す構成と組み合わせることも可能である。 The configuration shown in the above third embodiment shows an example of the content of the present invention, and can be combined with another known technique, or can be combined with the configuration shown in the first embodiment. It is.
　なお実施の形態３では、光源８がＬＥＤで構成されている場合について説明したが、光源８は、調光可能なものであれば、ＬＥＤに限定されず、有機ＥＬでもよい。 In the third embodiment, the case where the light source 8 is configured by an LED has been described. However, the light source 8 is not limited to an LED as long as it can be dimmed, and may be an organic EL.
実施の形態４．
　図２１は実施の形態４に係る点灯装置及び照明器具の構成図である。なお実施の形態４では、図１６の実施の形態３に係る点灯装置１００Ｂ及び照明器具２００Ｂと同一の構成を有する部位には、同一の符号を付してその説明を省略する。 Embodiment 4 FIG.
FIG. 21 is a configuration diagram of a lighting device and a lighting fixture according to the fourth embodiment. Note that in the fourth embodiment, parts having the same configurations as those of the lighting device 100B and the lighting fixture 200B according to the third embodiment of FIG.
　実施の形態４に係る照明器具２００Ｃと、実施の形態３に係る照明器具２００Ｂとの相違点は、照明器具２００Ｃでは、点灯装置１００Ｂの代わりに点灯装置１００Ｃが用いられていることである。また実施の形態４に係る点灯装置１００Ｃと、実施の形態３に係る点灯装置１００Ｂとの相違点は、点灯装置１００Ｃでは、制御部９Ｃが周期測定部９６を備え、制御部９Ｃが、ゼロ電流検出周期Ｔｚｃｄを測定して、遅延時間Ｔｄｅｌａｙを決定することである。 The difference between the lighting fixture 200C according to the fourth embodiment and the lighting fixture 200B according to the third embodiment is that the lighting fixture 100C uses the lighting device 100C instead of the lighting device 100B. Further, the difference between the lighting device 100C according to the fourth embodiment and the lighting device 100B according to the third embodiment is that, in the lighting device 100C, the control unit 9C includes a period measurement unit 96, and the control unit 9C includes a zero current. The detection period Tzcd is measured to determine the delay time Tdelay.
　次に周期測定部９６の動作を詳細に説明する。 Next, the operation of the period measuring unit 96 will be described in detail.
　図２２は実施の形態４において、光源が消灯している状態から光源が点灯を開始するまでの期間に、ゼロ電流検出周期Ｔｚｃｄを測定するタイミングを示す第１のタイミングチャートである。図２２には、説明の便宜上、ＭＯＳＦＥＴ７１のゲート電圧がオンオフされる周期を、実際よりも長く記載している。図２２には上から順に、光源８に印加される電圧と、光源８に流れる電流と、ＭＯＳＦＥＴ７１のドレイン－ソース間に印加される電圧と、１次巻線７５ａに流れる電流と、ゼロ電流検出信号と、ＭＯＳＦＥＴ７１の制御信号とが示される。図２２では、ドレイン－ソース間に印加される電圧が「ドレイン電圧」と表記される。なお、横軸は時間を表す。 FIG. 22 is a first timing chart showing the timing for measuring the zero current detection period Tzcd during the period from when the light source is turned off to when the light source starts to turn on in the fourth embodiment. In FIG. 22, for convenience of explanation, the cycle in which the gate voltage of the MOSFET 71 is turned on / off is described longer than the actual period. In FIG. 22, in order from the top, the voltage applied to the light source 8, the current flowing through the light source 8, the voltage applied between the drain and source of the MOSFET 71, the current flowing through the primary winding 75a, and zero current detection A signal and a control signal of the MOSFET 71 are shown. In FIG. 22, the voltage applied between the drain and the source is denoted as “drain voltage”. The horizontal axis represents time.
　電流制御部７は、時刻ｔ１からＭＯＳＦＥＴ７１のオンオフ制御を開始する。光源８としてＬＥＤが用いられている場合、順電圧閾値Ｖｆｔｈ以下では光源８に電流が流れないため、時刻ｔ１～ｔ３の期間においては、光源８に印加される電圧のみが上昇する。順電圧閾値Ｖｆｔｈは、ＬＥＤに印加される電圧の内、ＬＥＤに電流が流れ始める電圧、すなわちＬＥＤが点灯を開始する電圧に等しい。 The current control unit 7 starts on / off control of the MOSFET 71 from time t1. When an LED is used as the light source 8, no current flows through the light source 8 below the forward voltage threshold Vfth, and therefore only the voltage applied to the light source 8 rises during the period from time t1 to t3. The forward voltage threshold Vfth is equal to a voltage at which a current starts to flow through the LED among voltages applied to the LED, that is, a voltage at which the LED starts to light.
　時刻ｔ３において、光源８に印加される電圧が順電圧閾値Ｖｆｔｈを超えると、ＬＥＤに電流が流れ始め、ＬＥＤが点灯を開始する。ＬＥＤの点灯開始後、光源８に流れる電流が増加し、時刻ｔ４において、光源８に流れる電流が目標値に到達すると、光源８に流れる電流の増加が終了し、時刻ｔ４以降に光源８に流れる電流の値が一定になる。 At time t3, when the voltage applied to the light source 8 exceeds the forward voltage threshold Vfth, current starts to flow through the LED, and the LED starts to light. After the lighting of the LED starts, the current flowing through the light source 8 increases, and when the current flowing through the light source 8 reaches the target value at time t4, the increase in the current flowing through the light source 8 ends and flows into the light source 8 after time t4. The current value becomes constant.
　２次巻線７５ｂの両端に発生する電圧の最大値は、１次巻線７５ａ及び２次巻線７５ｂの巻数比ｎと、光源８に印加される電圧の積とで表すことができる。そのため、時刻ｔ１からｔ４において、光源８に印加される電圧が上昇する期間においては、２次巻線７５ｂの両端に発生する電圧の最大値も上昇する。周期測定部９６は、時刻ｔ２において、ＭＯＳＦＥＴ７１がオンしている期間にゼロ電流検出信号の最大値を検出する。そして、周期測定部９６は、検出したゼロ電流検出信号の最大値が周期検出閾値Ｓｉｔｈに達すると、ＭＯＳＦＥＴ７１がオフした後に、ゼロ電流検出周期Ｔｚｃｄを測定し、測定したゼロ電流検出周期Ｔｚｃｄに関する情報をスイッチング制御部９３Ｃに送信する。 The maximum value of the voltage generated at both ends of the secondary winding 75b can be expressed by the product of the turn ratio n of the primary winding 75a and the secondary winding 75b and the voltage applied to the light source 8. Therefore, during the period when the voltage applied to the light source 8 increases from time t1 to t4, the maximum value of the voltage generated at both ends of the secondary winding 75b also increases. The period measuring unit 96 detects the maximum value of the zero current detection signal during the period in which the MOSFET 71 is on at time t2. Then, when the maximum value of the detected zero current detection signal reaches the cycle detection threshold value Sith, the cycle measuring unit 96 measures the zero current detection cycle Tzcd after the MOSFET 71 is turned off, and information on the measured zero current detection cycle Tzcd. Is transmitted to the switching control unit 93C.
　スイッチング制御部９３Ｃは、周期測定部９６からゼロ電流検出周期Ｔｚｃｄに関する情報を受信すると、ゼロ電流検出周期Ｔｚｃｄをもとに遅延時間Ｔｄｅｌａｙを決定する。遅延時間Ｔｄｅｌａｙの決定方法については後述する。 When the switching control unit 93C receives information on the zero current detection cycle Tzcd from the cycle measurement unit 96, the switching control unit 93C determines the delay time Tdelay based on the zero current detection cycle Tzcd. A method for determining the delay time Tdelay will be described later.
　ゼロ電流検出周期Ｔｚｃｄは、ＭＯＳＦＥＴ７１の寄生容量と、１次巻線７５ａのインダクタンスと、光源８として用いられるＬＥＤの寄生容量と、点灯装置１００Ｃの配線寄生容量と、点灯装置１００Ｃの配線寄生インダクタンスの大きさに依存して変化する。そのため、周期測定部９６がゼロ電流検出周期Ｔｚｃｄを測定し、スイッチング制御部９３Ｃがゼロ電流検出周期Ｔｚｃｄをもとに遅延時間Ｔｄｅｌａｙを決定することで、より正確にＭＯＳＦＥＴ７１のドレイン電圧自由振動のボトムタイミングで、ＭＯＳＦＥＴ７１をオンすることができる。 The zero current detection period Tzcd includes the parasitic capacitance of the MOSFET 71, the inductance of the primary winding 75a, the parasitic capacitance of the LED used as the light source 8, the wiring parasitic capacitance of the lighting device 100C, and the wiring parasitic inductance of the lighting device 100C. It varies depending on the size. Therefore, the cycle measuring unit 96 measures the zero current detection cycle Tzcd, and the switching control unit 93C determines the delay time Tdelay based on the zero current detection cycle Tzcd. The MOSFET 71 can be turned on at the timing.
　これにより、ＭＯＳＦＥＴ７１のドレイン電圧の急峻な変動が抑制され、スイッチングに起因するノイズが抑制され、ノイズフィルタ回路を小型化できる。 Thereby, steep fluctuations in the drain voltage of the MOSFET 71 are suppressed, noise due to switching is suppressed, and the noise filter circuit can be miniaturized.
　遅延時間Ｔｄｅｌａｙの決定方法としては、遅延時間Ｔｄｅｌａｙをゼロ電流検出周期Ｔｚｃｄのｎ倍の長さにする方法が考えられる。ｎは１を超える値である。例えば、遅延時間Ｔｄｅｌａｙをゼロ電流検出周期Ｔｚｃｄの１．５倍の長さにすることで、ＭＯＳＦＥＴ７１のドレイン電圧自由振動のボトムタイミングで、ＭＯＳＦＥＴ７１をオンすることができる。 As a method for determining the delay time Tdelay, a method of setting the delay time Tdelay to be n times the zero current detection cycle Tzcd is conceivable. n is a value exceeding 1. For example, by setting the delay time Tdelay to 1.5 times the zero current detection period Tzcd, the MOSFET 71 can be turned on at the bottom timing of the free oscillation of the drain voltage of the MOSFET 71.
　光源８が点灯している時刻ｔ３以降に遅延時間Ｔｄｅｌａｙを変更してしまうと、光源８に出力する電流が変動し、光源８の出力光にちらつきが発生してしまう。そのため、ゼロ電流検出周期Ｔｚｃｄが測定される時刻ｔ２は、光源８が点灯を開始する時刻ｔ３以前になるように、周期検出閾値Ｓｉｔｈを設ける。 If the delay time Tdelay is changed after the time t3 when the light source 8 is turned on, the current output to the light source 8 fluctuates, and the output light of the light source 8 flickers. For this reason, the cycle detection threshold value Sith is set so that the time t2 when the zero current detection cycle Tzcd is measured is before the time t3 when the light source 8 starts to turn on.
　ここまでは、周期測定部９６がゼロ電流検出周期Ｔｚｃｄを測定するための時刻を決定するために、ゼロ電流検出信号の最大値を利用する構成例を説明したが、光源８に印加される電圧を検出して、検出された電圧を利用して、ゼロ電流検出周期Ｔｚｃｄを測定する時刻を決定してもよい。この場合においても、ゼロ電流検出周期Ｔｚｃｄを測定する時刻ｔ２が、光源８が点灯を開始する時刻ｔ３以前になるように、光源８に印加される電圧閾値を設けることができる。但し、この場合、照明装置１００Ｃには、光源８に印加される電圧を検出するための電圧検出部を設ける必要がある。 Up to this point, the configuration example using the maximum value of the zero current detection signal in order to determine the time for the period measurement unit 96 to measure the zero current detection period Tzcd has been described, but the voltage applied to the light source 8 And the time at which the zero current detection period Tzcd is measured may be determined using the detected voltage. Even in this case, the voltage threshold value applied to the light source 8 can be provided so that the time t2 when the zero current detection period Tzcd is measured is before the time t3 when the light source 8 starts to light. However, in this case, it is necessary to provide a voltage detection unit for detecting the voltage applied to the light source 8 in the illumination device 100C.
　図２３は実施の形態４において、光源が消灯している状態から光源が点灯を開始するまでの期間に、ゼロ電流検出周期Ｔｚｃｄを測定するタイミングを示す第２のタイミングチャートである。図２３には上から順に、光源８に印加される電圧と、光源８に流れる電流と、ＭＯＳＦＥＴ７１のドレイン－ソース間に印加される電圧と、１次巻線７５ａに流れる電流と、ゼロ電流検出信号と、ＭＯＳＦＥＴ７１の制御信号とが示される。図２３では、ドレイン－ソース間に印加される電圧が「ドレイン電圧」と表記される。なお、横軸は時間を表す。 FIG. 23 is a second timing chart showing the timing for measuring the zero current detection period Tzcd during the period from when the light source is turned off to when the light source starts to turn on in the fourth embodiment. In FIG. 23, in order from the top, the voltage applied to the light source 8, the current flowing through the light source 8, the voltage applied between the drain and source of the MOSFET 71, the current flowing through the primary winding 75a, and zero current detection A signal and a control signal of the MOSFET 71 are shown. In FIG. 23, the voltage applied between the drain and the source is denoted as “drain voltage”. The horizontal axis represents time.
　電流制御部７は、時刻ｔ１からＭＯＳＦＥＴ７１のオンオフ制御を開始する。光源８としてＬＥＤが用いられている場合、順電圧閾値Ｖｆｔｈ以下では光源８に電流が流れないため、時刻ｔ１～ｔ３の期間においては、光源８に印加される電圧のみが上昇する。 The current control unit 7 starts on / off control of the MOSFET 71 from time t1. When an LED is used as the light source 8, no current flows through the light source 8 below the forward voltage threshold Vfth, and therefore only the voltage applied to the light source 8 rises during the period from time t1 to t3.
　時刻ｔ３において光源８に印加される電圧が順電圧閾値Ｖｆｔｈを超えると、ＬＥＤに電流が流れ始め、ＬＥＤが点灯を開始する。点灯開始後、光源８に流れる電流が増加し、時刻ｔ４において光源８に流れる電流が目標値に到達すると、光源８に流れる電流の増加が終了し、時刻ｔ４以降に光源８に流れる電流の値が一定になる。 When the voltage applied to the light source 8 exceeds the forward voltage threshold Vfth at time t3, a current starts to flow through the LED, and the LED starts to light. When the lighting starts, the current flowing through the light source 8 increases, and when the current flowing through the light source 8 reaches the target value at time t4, the increase in the current flowing through the light source 8 ends, and the value of the current flowing through the light source 8 after time t4 is reached. Becomes constant.
　スイッチング制御部９３Ｃは、電流検出部１１で検出された電流が目標値に到達したとき、周期測定部９６にゼロ電流検出周期測定を開始させる。すなわち、スイッチング制御部９３Ｃは、周期測定部９６に対して、ゼロ電流検出周期測定開始の要求を行う。 When the current detected by the current detection unit 11 reaches the target value, the switching control unit 93C causes the cycle measurement unit 96 to start the zero current detection cycle measurement. That is, the switching control unit 93 </ b> C requests the period measurement unit 96 to start the zero current detection period measurement.
　周期測定部９６は、スイッチング制御部９３Ｃからゼロ電流検出周期測定開始の要求を受けると、ＭＯＳＦＥＴ７１がオフした後、ゼロ電流検出周期Ｔｚｃｄを測定し、測定したゼロ電流検出周期Ｔｚｃｄに関する情報をスイッチング制御部９３Ｃに送信する。 When the cycle measurement unit 96 receives a request for starting the zero current detection cycle measurement from the switching control unit 93C, the cycle measurement unit 96 measures the zero current detection cycle Tzcd after the MOSFET 71 is turned off, and performs switching control on information on the measured zero current detection cycle Tzcd. To the unit 93C.
　スイッチング制御部９３Ｃは、周期測定部９６からゼロ電流検出周期Ｔｚｃｄに関する情報を受信すると、ゼロ電流検出周期Ｔｚｃｄをもとに遅延時間Ｔｄｅｌａｙを演算する。遅延時間Ｔｄｅｌａｙの演算結果は、光源８が消灯し、その後光源８が再び点灯する際に反映される。 When the switching control unit 93C receives information on the zero current detection cycle Tzcd from the cycle measurement unit 96, the switching control unit 93C calculates a delay time Tdelay based on the zero current detection cycle Tzcd. The calculation result of the delay time Tdelay is reflected when the light source 8 is turned off and then the light source 8 is turned on again.
　前述したように、ゼロ電流検出周期Ｔｚｃｄは、ＭＯＳＦＥＴ７１の寄生容量と、１次巻線７５ａのインダクタンスと、光源８として用いられるＬＥＤの寄生容量と、点灯装置１００Ｃの配線寄生容量と、点灯装置１００Ｃの配線寄生インダクタンスの大きさに依存して変化する。特に、ＭＯＳＦＥＴの寄生容量はドレイン電圧の大きさに依存する特性を持っている。そのため、光源８が点灯している期間に測定されたゼロ電流検出周期Ｔｚｃｄをもとに遅延時間Ｔｄｅｌａｙを決定することで、より正確にＭＯＳＦＥＴ７１のドレイン電圧自由振動のボトムタイミングで、ＭＯＳＦＥＴ７１をオンすることができる。 As described above, the zero current detection period Tzcd includes the parasitic capacitance of the MOSFET 71, the inductance of the primary winding 75a, the parasitic capacitance of the LED used as the light source 8, the wiring parasitic capacitance of the lighting device 100C, and the lighting device 100C. Vary depending on the magnitude of the wiring parasitic inductance. In particular, the parasitic capacitance of the MOSFET has a characteristic that depends on the magnitude of the drain voltage. Therefore, by determining the delay time Tdelay based on the zero current detection period Tzcd measured during the period when the light source 8 is lit, the MOSFET 71 is turned on more accurately at the bottom timing of the free oscillation of the drain voltage of the MOSFET 71. be able to.
　なお、ＭＯＳＦＥＴの寄生容量は、ドレイン電圧の大きさに依存して変化する。また、ドレイン電圧の振動周期は、ＭＯＳＦＥＴの寄生容量によって変化する。これらのことから、ドレイン電圧の振動周期は、ドレイン電圧の大きさによって変化すると言える。ゼロ電流検出周期Ｔｚｃｄが変化した場合に、遅延時間Ｔｄｅｌａｙを決定する簡易な方法には以下の方法がある。１つ目の方法は、光源８に印加される電圧に対応する遅延時間Ｔｄｅｌａｙの長さを予め定めておき、点灯動作時に光源８へ印加される電圧を検出し、検出された電圧に対応する遅延時間Ｔｄｅｌａｙを決定する方法である。すなわち光源８に印加される電圧に応じて遅延時間Ｔｄｅｌａｙを変化させる方法である。２つ目の方法は、電流制御部７の入力電圧に対応する遅延時間Ｔｄｅｌａｙの長さを予め定めておき、点灯動作時に電流制御部７へ入力される電圧を検出し、検出された電圧に対応する遅延時間Ｔｄｅｌａｙを決定する方法である。すなわち、電流制御部７の入力の電圧に応じて遅延時間Ｔｄｅｌａｙを変化させる方法がある。 Note that the parasitic capacitance of the MOSFET varies depending on the magnitude of the drain voltage. Further, the oscillation cycle of the drain voltage varies depending on the parasitic capacitance of the MOSFET. From these facts, it can be said that the oscillation period of the drain voltage changes depending on the magnitude of the drain voltage. There are the following simple methods for determining the delay time Tdelay when the zero current detection period Tzcd changes. In the first method, the length of the delay time Tdelay corresponding to the voltage applied to the light source 8 is determined in advance, the voltage applied to the light source 8 during the lighting operation is detected, and the detected voltage is handled. This is a method for determining the delay time Tdelay. That is, the delay time Tdelay is changed in accordance with the voltage applied to the light source 8. In the second method, the length of the delay time Tdelay corresponding to the input voltage of the current control unit 7 is determined in advance, the voltage input to the current control unit 7 during the lighting operation is detected, and the detected voltage is set. This is a method for determining the corresponding delay time Tdelay. That is, there is a method of changing the delay time Tdelay according to the input voltage of the current control unit 7.
　これにより、ＭＯＳＦＥＴ７１のドレイン電圧の急峻な変動が抑制され、スイッチングに起因するノイズが抑制され、ノイズフィルタ回路を小型化できる。 Thereby, steep fluctuations in the drain voltage of the MOSFET 71 are suppressed, noise due to switching is suppressed, and the noise filter circuit can be miniaturized.
　遅延時間Ｔｄｅｌａｙの決定方法としては、遅延時間Ｔｄｅｌａｙをゼロ電流検出周期Ｔｚｃｄのｎ倍の長さにする方法が考えられる。ｎは１を超える値である。例えば、遅延時間Ｔｄｅｌａｙをゼロ電流検出周期Ｔｚｃｄの１．５倍の長さにすることで、ＭＯＳＦＥＴ７１のドレイン電圧自由振動のボトムタイミングで、ＭＯＳＦＥＴ７１をオンすることができる。 As a method for determining the delay time Tdelay, a method of setting the delay time Tdelay to be n times the zero current detection cycle Tzcd is conceivable. n is a value exceeding 1. For example, by setting the delay time Tdelay to 1.5 times the zero current detection period Tzcd, the MOSFET 71 can be turned on at the bottom timing of the free oscillation of the drain voltage of the MOSFET 71.
　光源８が点灯している時刻ｔ３以降に遅延時間Ｔｄｅｌａｙを変更してしまうと、光源８に出力する電流が変動し、光源８の出力光にちらつきが発生してしまう。そのため、ゼロ電流検出周期Ｔｚｃｄから演算した遅延時間Ｔｄｅｌａｙを、光源８が消灯後に再び点灯する直前に反映することで、光源８の出力光のちらつきを抑制できる。 If the delay time Tdelay is changed after the time t3 when the light source 8 is turned on, the current output to the light source 8 fluctuates, and the output light of the light source 8 flickers. Therefore, flickering of the output light of the light source 8 can be suppressed by reflecting the delay time Tdelay calculated from the zero current detection cycle Tzcd immediately before the light source 8 is turned on again.
　次に図２４のフローチャートを用いて、光源８点灯後に遅延時間Ｔｄｅｌａｙを演算し、光源８消灯後に遅延時間Ｔｄｅｌａｙを反映する場合の制御に関してより詳細に説明する。図２４は実施の形態４に係る点灯装置の動作を示すフローチャートである。 Next, with reference to the flowchart of FIG. 24, the control when the delay time Tdelay is calculated after the light source 8 is turned on and the delay time Tdelay is reflected after the light source 8 is turned off will be described in detail. FIG. 24 is a flowchart showing the operation of the lighting device according to the fourth embodiment.
　光源８が消灯状態のときの制御部９Ｃは、光源８の点灯命令が入力されるまで、光源８の点灯命令の入力を待機する（Ｓ３０１、Ｓ３０２：Ｎｏ）。 The control unit 9C when the light source 8 is in the off state waits for an input of the lighting command for the light source 8 until a lighting command for the light source 8 is input (S301, S302: No).
　光源８の点灯命令が入力されたとき（Ｓ３０２：Ｙｅｓ）、制御部９Ｃは、遅延時間Ｔｄｅｌａｙを更新する（Ｓ３０３）。制御部９Ｃは、遅延時間Ｔｄｅｌａｙの更新が完了すると、スイッチング制御部９３ＣがＭＯＳＦＥＴ７１のオンオフ動作を開始することにより、電流制御部７が動作を開始する（Ｓ３０４）。 When the lighting instruction of the light source 8 is input (S302: Yes), the control unit 9C updates the delay time Tdelay (S303). In the control unit 9C, when the update of the delay time Tdelay is completed, the switching control unit 93C starts the on / off operation of the MOSFET 71, whereby the current control unit 7 starts the operation (S304).
　次に、スイッチング制御部９３Ｃは、電流検出部１１で検出された電流が目標値に到達したか否かを判定する。光源８に流れる電流が目標値に到達していない場合、すなわち光源８に流れる電流の値が目標値未満である場合（Ｓ３０５：Ｙｅｓ）、Ｓ３０５の処理が繰り返され、周期測定部９６は動作しない。つまり、ゼロ電流検出周期Ｔｚｃｄの測定は実行されない。 Next, the switching control unit 93C determines whether or not the current detected by the current detection unit 11 has reached the target value. When the current flowing through the light source 8 has not reached the target value, that is, when the value of the current flowing through the light source 8 is less than the target value (S305: Yes), the processing of S305 is repeated and the period measurement unit 96 does not operate. . That is, the measurement of the zero current detection period Tzcd is not executed.
　光源８に流れる電流が目標値に到達した場合、すなわち光源８に流れる電流の値が目標値を超えた場合（Ｓ３０５：Ｎｏ）、周期測定部９６はゼロ電流検出周期Ｔｚｃｄを測定する（Ｓ３０６）。ゼロ電流検出周期Ｔｚｃｄに関する情報は、スイッチング制御部９３Ｃに送信される。 When the current flowing through the light source 8 reaches the target value, that is, when the value of the current flowing through the light source 8 exceeds the target value (S305: No), the cycle measuring unit 96 measures the zero current detection cycle Tzcd (S306). . Information regarding the zero current detection cycle Tzcd is transmitted to the switching control unit 93C.
　ゼロ電流検出周期Ｔｚｃｄに関する情報を受信したスイッチング制御部９３Ｃは、ゼロ電流検出周期Ｔｚｃｄをもとに遅延時間Ｔｄｅｌａｙを演算し、演算した遅延時間Ｔｄｅｌａｙを保持する（Ｓ３０７）。なお、点灯装置１００Ｃが初めて動作する場合においては、予め定める遅延時間Ｔｄｅｌａｙを初期値として設定しておく。 The switching control unit 93C that has received the information regarding the zero current detection cycle Tzcd calculates the delay time Tdelay based on the zero current detection cycle Tzcd, and holds the calculated delay time Tdelay (S307). When the lighting device 100C operates for the first time, a predetermined delay time Tdelay is set as an initial value.
　光源８の消灯命令が入力されていない場合（Ｓ３０８：Ｎｏ）、点灯装置１００Ｃでは、光源８の点灯状態が継続され（Ｓ３０９）、Ｓ３０８の処理が行われる。光源８の消灯命令が入力された場合（Ｓ３０８：Ｙｅｓ）、点灯装置１００Ｃは光源８を消灯し（Ｓ３１０）、点灯装置１００Ｃは消灯命令の入力を待機する。 When the command to turn off the light source 8 is not input (S308: No), in the lighting device 100C, the lighting state of the light source 8 is continued (S309), and the process of S308 is performed. When an instruction to turn off the light source 8 is input (S308: Yes), the lighting device 100C turns off the light source 8 (S310), and the lighting device 100C waits for an input of the turning-off command.
　以上の実施の形態４に示した構成は、本発明の内容の一例を示すものであり、別の公知の技術と組み合わせることも可能であるし、実施の形態１に示す構成と組み合わせることも可能である。 The configuration shown in the above fourth embodiment shows an example of the contents of the present invention, and can be combined with another known technique, or can be combined with the configuration shown in the first embodiment. It is.
　なお実施の形態４では、光源８がＬＥＤで構成されている場合について説明したが、光源８は、調光可能なものであれば、ＬＥＤに限定されず、有機ＥＬでもよい。 In the fourth embodiment, the case where the light source 8 is configured by an LED has been described. However, the light source 8 is not limited to an LED and may be an organic EL as long as the light source 8 can be dimmed.
　なお本実施の形態では、電流検出部１１で測定された出力電流の値に応じて遅延時間の長さを決定する例を説明したが、電流検出部１１の代わりに、直流変換回路３０の出力電圧を検出する出力電圧検出部、又は、直流変換回路３０の入力電圧を検出する入力電圧検出部を用いてもよい。出力電圧検出部で検出された出力電圧に応じて、遅延時間の長さを決定し、又は入力電圧検出部で検出された入力電圧に応じて、遅延時間の長さを決定しても、同様の効果が得られる。 In this embodiment, the example in which the length of the delay time is determined according to the value of the output current measured by the current detection unit 11 has been described. However, instead of the current detection unit 11, the output of the DC conversion circuit 30 is described. You may use the output voltage detection part which detects a voltage, or the input voltage detection part which detects the input voltage of the DC converter circuit 30. FIG. Even if the length of the delay time is determined according to the output voltage detected by the output voltage detector, or the length of the delay time is determined according to the input voltage detected by the input voltage detector The effect is obtained.
　以上の実施の形態に示した構成は、本発明の内容の一例を示すものであり、別の公知の技術と組み合わせることも可能であるし、本発明の要旨を逸脱しない範囲で、構成の一部を省略、変更することも可能である。 The configuration described in the above embodiment shows an example of the contents of the present invention, and can be combined with another known technique, and can be combined with other configurations without departing from the gist of the present invention. It is also possible to omit or change the part.
　１　交流電源、２　入力フィルタ、３　整流回路、４，２２，７４　コンデンサ、５　ＰＦＣ回路、６，１２４　平滑コンデンサ、７　電流制御部、８　光源、９，９Ａ，９Ｂ，９Ｃ　制御部、１０　調光器、１１　電流検出部、１２，３０　直流変換回路、２１，５２，７２，７５　コイル、５１，７１，１２１　ＭＯＳＦＥＴ、５２ａ，７５ａ，１２２ａ　１次巻線、５２ｂ，７５ｂ，１２２ｂ　２次巻線、５３，７３，１２３　ダイオード、９１　目標値出力部、９２　ゼロ電流検出部、９３，９３Ａ，９３Ｃ　スイッチング制御部、９４　電流入力部、９５　電圧検出部、９６　周期測定部、１００，１００Ａ，１００Ｂ，１００Ｃ　点灯装置、１２２　トランス、１２２ｃ　３次巻線、１２５　スナバコンデンサ、１２６　スナバ抵抗、１２７　スナバダイオード、２００，２００Ａ，２００Ｂ，２００Ｃ　照明器具。 1 AC power supply, 2 input filter, 3 rectifier circuit, 4,22,74 capacitor, 5 PFC circuit, 6,124 smoothing capacitor, 7 current control unit, 8 light source, 9, 9A, 9B, 9C control unit, 10 dimming 11, current detection unit, 12, 30 DC conversion circuit, 21, 52, 72, 75 coil, 51, 71, 121 MOSFET, 52a, 75a, 122a primary winding, 52b, 75b, 122b secondary winding, 53, 73, 123 diode, 91 target value output unit, 92 zero current detection unit, 93, 93A, 93C switching control unit, 94 current input unit, 95 voltage detection unit, 96 period measurement unit, 100, 100A, 100B, 100C Lighting device, 122 transformer, 122c tertiary winding, 125 snubber capacitor, 126 snubber Resistance, 127 snubber diode, 200, 200A, 200B, 200C luminaire.

Claims (20)

  1. 　交流電力を整流する整流回路と、
    　高調波を抑制して力率を改善すると共に前記整流回路から出力される電力を直流電力に変換して光源に供給する直流変換回路と、
    　直流変換回路を制御する制御部と
    　を備え、
    　前記直流変換回路は、平滑コンデンサと、前記平滑コンデンサ及び前記整流回路の間に配置されるスイッチング素子と、前記整流回路から出力される電流が流れるコイルとを有し、
    　前記制御部は、前記コイルに流れる電流がゼロになった時点から、前記制御部に設定された遅延時間が経過するまで前記スイッチング素子をオフ状態にさせて、前記遅延時間が経過したときに前記スイッチング素子をオンさせる点灯装置。     A rectifier circuit for rectifying AC power;
    A DC conversion circuit that suppresses higher harmonics to improve the power factor and converts the power output from the rectifier circuit to DC power and supplies it to the light source;
    A control unit for controlling the DC conversion circuit,
    The DC conversion circuit includes a smoothing capacitor, a switching element disposed between the smoothing capacitor and the rectifier circuit, and a coil through which a current output from the rectifier circuit flows.
    The control unit turns off the switching element until the delay time set in the control unit elapses from when the current flowing through the coil becomes zero, and when the delay time elapses, A lighting device that turns on a switching element.
  2. 　前記制御部は、前記直流変換回路の出力の大きさに応じて前記遅延時間の長さを変える請求項１に記載の点灯装置。 The lighting device according to claim 1, wherein the control unit changes a length of the delay time according to a magnitude of an output of the DC conversion circuit.
  3. 　前記制御部は、前記出力の大きさに閾値を設けて、前記出力が前記閾値を上回る場合には前記遅延時間を一定の長さとし、前記出力が前記閾値以下である場合には、前記出力が低下するほど前記遅延時間を長くする請求項２に記載の点灯装置。 The control unit sets a threshold for the magnitude of the output, sets the delay time to a certain length when the output exceeds the threshold, and outputs the output when the output is less than or equal to the threshold. The lighting device according to claim 2, wherein the delay time is lengthened as it decreases.
  4. 　前記制御部は、前記出力の大きさに複数の閾値を設けて、隣接する閾値同士の間の範囲に応じて互いに異なる長さの複数の前記遅延時間を用いて前記スイッチング素子を制御する請求項２に記載の点灯装置。 The said control part provides a some threshold value in the magnitude | size of the said output, and controls the said switching element using the said some delay time of mutually different length according to the range between adjacent threshold values. 2. The lighting device according to 2.
  5. 　前記制御部は、前記スイッチング素子をオフしている期間において、前記スイッチング素子の電圧振動が２回目以降のボトムとなるタイミングで前記スイッチング素子をオンさせる請求項１から４の何れか一項に記載の点灯装置。 5. The control unit according to claim 1, wherein the control unit turns on the switching element at a timing when the voltage oscillation of the switching element becomes a bottom after the second time in a period in which the switching element is turned off. Lighting device.
  6. 　前記制御部は、前記スイッチング素子の最小オン時間を設けて、前記出力の大きさに応じて前記遅延時間の長さを変えることにより、前記最小オン時間以上のオン時間で前記スイッチング素子を動作させる請求項２から５の何れか一項に記載の点灯装置。 The control unit operates the switching element with an on-time that is equal to or greater than the minimum on-time by providing a minimum on-time of the switching element and changing the length of the delay time according to the magnitude of the output. The lighting device according to any one of claims 2 to 5.
  7. 　前記制御部は、予め設定された維持時間において前記遅延時間の変化量最大値を設けて前記遅延時間の長さを変える請求項２から６の何れか一項に記載の点灯装置。 The lighting device according to any one of claims 2 to 6, wherein the control unit changes the length of the delay time by providing a maximum change amount of the delay time in a preset maintenance time.
  8. 　前記光源はＬＥＤで構成される請求項１から７の何れか一項に記載の点灯装置。 The lighting device according to any one of claims 1 to 7, wherein the light source is configured by an LED.
  9. 　前記出力の大きさは、前記ＬＥＤの調光率により判定される請求項８に記載の点灯装置。 The lighting device according to claim 8, wherein the magnitude of the output is determined by a dimming rate of the LED.
  10. 　前記出力の大きさは、前記ＬＥＤの出力電流目標値により判定される請求項８に記載の点灯装置。 The lighting device according to claim 8, wherein the magnitude of the output is determined by an output current target value of the LED.
  11. 　前記光源は有機ＥＬで構成される請求項１から７の何れか一項に記載の点灯装置。 The lighting device according to any one of claims 1 to 7, wherein the light source is configured by an organic EL.
  12. 　前記出力の大きさは、前記有機ＥＬの調光率により判定される請求項１１に記載の点灯装置。 The lighting device according to claim 11, wherein the magnitude of the output is determined by a dimming rate of the organic EL.
  13. 　前記制御部は、前記光源が点灯している状態において、前記遅延時間の長さを一定にする請求項１に記載の点灯装置。 The lighting device according to claim 1, wherein the control unit makes the length of the delay time constant in a state where the light source is turned on.
  14. 　前記制御部は、前記光源が消灯している状態において、前記遅延時間の長さを変化させる請求項１又は１３に記載の点灯装置。 The lighting device according to claim 1 or 13, wherein the control unit changes the length of the delay time in a state where the light source is turned off.
  15. 　前記制御部は、前記コイルに流れる電流がゼロになる周期を測定する周期測定部を備え、
    　前記制御部は、前記周期測定部で測定された前記周期に応じて、前記遅延時間の長さを決定する請求項１３又は１４に記載の点灯装置。     The control unit includes a cycle measuring unit that measures a cycle in which the current flowing through the coil becomes zero,
    The lighting device according to claim 13 or 14, wherein the control unit determines the length of the delay time according to the cycle measured by the cycle measurement unit.
  16. 　前記周期測定部は、前記直流変換回路が動作を開始した後、前記光源が点灯する以前に、前記周期を測定し、
    　前記制御部は、測定された前記周期に応じて、前記遅延時間の長さを変更する請求項１５に記載の点灯装置。     The period measurement unit measures the period after the DC conversion circuit starts operation and before the light source is turned on.
    The lighting device according to claim 15, wherein the control unit changes the length of the delay time according to the measured period.
  17. 　前記周期測定部は、前記直流変換回路が動作を開始した後、前記光源が点灯した後に、前記周期を測定し、
    　前記制御部は、測定された前記周期に応じて、前記光源を消灯した後に、前記遅延時間の長さを変更する請求項１５に記載の点灯装置。     The cycle measurement unit measures the cycle after the light source is turned on after the DC conversion circuit starts operation.
    The lighting device according to claim 15, wherein the control unit changes the length of the delay time after the light source is turned off according to the measured period.
  18. 　前記制御部は、前記直流変換回路の出力電圧を検出する出力電圧検出部を備え、前記出力電圧に応じて、前記遅延時間の長さを決定する請求項１３又は１４に記載の点灯装置。 The lighting device according to claim 13 or 14, wherein the control unit includes an output voltage detection unit that detects an output voltage of the DC conversion circuit, and determines the length of the delay time according to the output voltage.
  19. 　前記制御部は、前記直流変換回路の入力電圧を検出する入力電圧検出部を備え、前記入力電圧に応じて、前記遅延時間の長さを決定する請求項１３又は１４に記載の点灯装置。 The lighting device according to claim 13 or 14, wherein the control unit includes an input voltage detection unit that detects an input voltage of the DC conversion circuit, and determines the length of the delay time according to the input voltage.
  20. 　請求項１から１９の何れか一項に記載の点灯装置を備えた照明器具。 A lighting fixture comprising the lighting device according to any one of claims 1 to 19.
PCT/JP2017/025307 2016-12-28 2017-07-11 Lighting device and illumination apparatus WO2018123115A1 (en)

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