JP5527130B2 - Lighting device and lighting fixture provided with the lighting device - Google Patents

Description

  The present invention relates to a lighting device for dimming and lighting a light source such as a light emitting diode or a discharge lamp.

When using a power factor correction circuit mainly composed of a boost chopper, appropriate control operation is performed over a certain range of load, so dimming is possible, but when the load becomes extremely light due to deep dimming In addition, an abnormal control operation occurs, intermittent oscillation occurs, and the output fluctuates. When a DC converter is further provided after the boost chopper, the DC converter may be in a state where it can be operated so as to perform output stabilization control. However, the control operation is a power supply fluctuation, that is, an output fluctuation of the power factor improvement circuit. If it is impossible to follow the above, there is a problem that the light output of the light emitting diode fluctuates and flickering occurs.
In order to solve such problems, the output of the power factor correction circuit is controlled according to the dimming signal, and when the light output of the light emitting diode falls below a predetermined level, the operation of the power factor correction circuit is stopped and light emission is performed. The flickering of the diode is prevented (for example, Patent Document 1).

JP 2010-40400 A

  However, in the conventional apparatus, the operation of the power factor correction circuit is completely stopped at the time of deep dimming, so that the input current is limited to a narrow period of about 90 degrees electrical angle as in the case of the capacitor input type rectifier circuit. However, there is a problem that the power factor decreases and the high frequency component of the input current increases.

  The present invention has been made to solve the above-described problems, and suppresses a decrease in power factor and an increase in high-frequency components of input current even when dimming is deepened and the load is extremely light. An object is to provide a lighting device.

  A lighting device according to the present invention is a load light source by connecting a power factor correction circuit including a boost converter to the output side of a rectifying circuit for full-wave rectification of an AC power supply and supplying the output power to a light source lighting unit. Turn on the light-emitting diode or discharge lamp. The light source lighting unit further includes a means for inputting a dimming signal, and the light source lighting unit performs dimming lighting of the light source of the load according to the dimming signal. Here, when a dimming signal with a deep dimming level is input to the dimming degree discriminating unit, the boost converter control unit generates a drive signal that stops the operation of the switching element for a predetermined period across the zero cross of the AC power supply. The operation period of the power factor correction circuit is controlled.

  According to the lighting device according to the present invention, when the dimming degree becomes equal to or lower than a predetermined level by dimming, the power factor correction circuit is stopped for a predetermined period over the zero cross of the AC power supply, and the predetermined over the zero cross of the AC power supply is performed. Since the power factor correction circuit is operated outside the period, even when the light is deeply dimmed and the load is extremely light, it is possible to suppress a decrease in the power factor and an increase in the high frequency component of the input current.

It is a circuit diagram which shows the lighting device at the time of the light emitting diode connection of Embodiment 1 of this invention. It is a circuit diagram which shows the lighting device at the time of the fluorescent lamp connection of Embodiment 1 of this invention. It is a wave form diagram which shows the on-off period of the PWM light control signal of Embodiment 1 of this invention. It is a wave form diagram which shows the threshold value of the rectification voltage of Embodiment 1 of this invention, and the on-off period of a power factor improvement circuit. It is a wave form diagram which shows the two threshold values of the rectification voltage of Embodiment 1 of this invention, and the on-off period of a power factor improvement circuit. It is a wave form diagram explaining the voltage waveform of the alternating current power supply of Embodiment 1 of this invention, and the ON-OFF period of a power factor improvement circuit. FIG. 7 is a waveform diagram of a pattern different from FIG. 6 for explaining the voltage waveform of the AC power supply and the ON / OFF period of the power factor correction circuit according to Embodiment 1 of the present invention. It is a characteristic view of the light source output (dimming degree) of Embodiment 1 of this invention, and the output voltage of a power factor improvement circuit. It is a table | surface which shows the relationship between the light control degree of the conventional and the light source of this invention, and the operation stability of a power factor improvement circuit. It is a characteristic view of the electrical angle and power factor at the time of light control of Embodiment 1 of this invention. It is an AC power supply voltage at the time of the power factor improvement circuit stop of Embodiment 1 of this invention, and the wave form diagram of input current. It is a table | surface which shows the example of a suitable setting of an electrical angle at the time of providing a Ton period symmetrically centering | focusing on zero crossing. It is a wave form diagram which shows the relationship between the frequency of the rectification voltage of Embodiment 2 of this invention, and a threshold value. It is a wave form diagram which shows the time from the threshold value of a rectification voltage of Embodiment 2 of this invention, and an operation start signal output to an operation stop signal. It is a wave form diagram which shows the time from the threshold value of a rectification voltage of Embodiment 2 of this invention, and zero crossing to signal output.

Embodiment 1 FIG.
Hereinafter, a lighting device according to Embodiment 1 of the present invention will be described with reference to FIGS.

  1 is a circuit diagram showing a lighting device when a light-emitting diode is connected, FIG. 2 is a circuit diagram showing a lighting device when a fluorescent lamp is connected, FIG. 3 is a waveform diagram showing a cycle of turning on and off a PWM dimming signal, and FIG. Is a waveform diagram showing the threshold value of the rectified voltage and the on / off period of the power factor correction circuit, FIG. 5 is a waveform diagram showing the two threshold values of the rectified voltage and the on / off period of the power factor correction circuit, and FIG. Is a waveform diagram for explaining the on / off period of the AC power supply voltage waveform and the power factor correction circuit, and FIG. 7 is a pattern different from FIG. 6 for explaining the on / off period of the AC power supply voltage waveform and the power factor improvement circuit. FIG.

In the present embodiment, the lighting device is configured as shown in the circuit diagrams of FIGS.
Rectification circuit 200, rectification voltage detection unit 300, power factor improvement circuit 400, light source lighting circuit 500, dimming signal input unit 600, dimming degree discrimination unit 700, rectification voltage discrimination unit 800, load light source connected to AC power supply 100 The light emitting diode 910 or the discharge lamp 920 is provided.

  As an example, a configuration and circuit operation when a light emitting diode 910 is connected to a load will be described below.

  The rectifier circuit 200 includes a diode bridge whose AC voltage input side is connected in parallel to the AC power supply 100, converts the AC voltage input from the AC power supply 100 into a non-smooth DC voltage, and improves the power factor through the rectified voltage detection unit 300. Output to the circuit 400.

  The rectified voltage detector 300 is connected to the DC output terminal of the rectifier circuit 200, and outputs a signal detected by monitoring the rectified voltage to the rectified voltage determiner 800.

  The rectified voltage determination unit 800 includes a voltage threshold value detection unit 810 and a voltage frequency detection unit 820, and outputs a control signal to the boost converter control unit 440.

  The power factor correction circuit 400 includes a capacitor 410 connected to the output terminal of the rectified voltage detector 300, a series circuit of an inductor 420 and a switching element 450, a diode 430 and an output capacitor 470 connected in parallel to the switching element 450, and a boost converter controller. It is comprised by the step-up converter provided with 440. The switching element 450 is formed of a semiconductor element such as a MOS FET.

  Boost converter control unit 440 switches switching element 450 at a high frequency, performs control so that the envelope of the current peak value of switching element 450 substantially corresponds to the sine wave of AC power supply 100, and performs a power factor improvement operation. . As a signal generating means for realizing such an operation principle of power factor improvement, an integrated circuit for power factor improvement is known.

  The output voltage detection resistor 461 and the output voltage detection resistor 462 are connected in series to constitute a voltage dividing circuit 460. The voltage dividing circuit 460 is connected in parallel to the output capacitor 470, divides the voltage applied to both ends thereof, and outputs the terminal voltage of the output voltage detection resistor 462 to the boost converter control unit 440.

  When the light emitting diode 910 is used as a load, the light source lighting circuit 500 is lit by performing current control of the load with a buck converter or the like and can realize dimming. A series circuit of a switching element 511 and a diode 513 connected between both ends of the output capacitor 470 at the output end of the power factor correction circuit 400, a series circuit of an inductor 512 and a smoothing capacitor 514 connected in parallel to the diode 513, and a series of the light emitting diode 910 , And a DC voltage conversion operation is performed under the control of the light source control unit 520. Note that the switching element 511 is formed of a semiconductor element such as a MOS FET.

  The light source control unit 520 supplies a drive signal composed of a pulse voltage to the switching element 511 of the buck converter. Further, feedback control is performed so that the load current controlled and input from the load detection resistor 515 of the light source lighting circuit 500 becomes constant, and the drive signal is PWM-controlled according to the dimming signal.

  The dimming signal input unit 600 is connected to a wiring or the like for inputting a dimming signal from the outside, and outputs the input dimming signal to the dimming degree determination unit 700.

  The dimming degree determination unit 700 converts the dimming signal input from the dimming signal input unit 600 into a control signal, and outputs the control signal to the switching element 450 of the power factor correction circuit 400 and the light source control unit 520 of the light source lighting circuit 500.

  A plurality of light emitting diodes 910 are connected in series, and are connected to both ends of the smoothing capacitor 514 via a load detection resistor 515.

  Next, the circuit operation of the lighting device of the present embodiment will be described.

  The rectifier circuit 200 performs full-wave rectification on the AC voltage input from the AC power supply 100 using a diode bridge, converts it to a non-smooth DC voltage, and outputs the non-smooth DC voltage to the power factor correction circuit 400 through the rectified voltage detector 300.

  The power factor of the lighting device is improved by the operation of the boost converter of the power factor correction circuit 400 and is boosted so as to be higher than the voltage of the AC power supply 100, and the direct current smoothed by the output capacitor 470 from the power factor improvement circuit 400. The voltage is output to the light source lighting circuit 500.

  The light source lighting circuit 500 performs a step-down operation and outputs a DC voltage adjusted to a required value to the light emitting diode 910 of the load. As a result, a direct current flows through the light emitting diode 910 connected as a load to the output side of the light source lighting circuit 500, and the light emitting diode 910 is turned on. This lighting is performed under constant current control by the load detection resistor 515 and the light source controller 520 of the light source lighting circuit 500.

  The dimming signal output from the dimming signal input unit 600 is input to the dimming degree determination unit 700, where the dimming signal is converted into a dimming control signal and output to the light source control unit 520. The light source control unit 520 generates a PWM-controlled drive signal corresponding to the input dimming control signal, and supplies the drive signal to the switching element 511 of the load power supply unit 510 of the light source lighting circuit 500. As a result, the reference value for constant current control of the load current is changed according to the dimming control signal, and thus the light emitting diode 910 performs dimming lighting of the light output corresponding to the dimming control signal.

  Further, for example, when the H period becomes longer than the phase indicated by Ta in FIG. 3 (in this case, a waveform corresponding to a predetermined level of dimming 40%), the dimming degree discriminating unit 700 notifies the boost converter control unit 440 of this. Output a control signal. The determination of whether or not the H period exceeds Ta is realized by measuring the time from the falling Te of the illustrated dimming signal (for example, 1 kHz periodic signal). Alternatively, the DC signal is converted into a smoothed DC voltage, and the dimming degree is determined by the voltage value. When the dimming degree is larger than Ta, the boost converter control unit 440 does not determine that the output signal from the rectified voltage determination unit 800 is a valid signal, and shifts to the neglected “PFC operation mode”. Control to always operate. When the dimming degree becomes Ta or less, the boost converter control unit 440 to which the output signal of the dimming degree discriminating unit 700 is inputted determines that the output signal from the rectified voltage discriminating unit 800 is a valid signal “PFC partial stop mode” The operation of the power factor correction circuit 400 is controlled by an output signal from the rectified voltage determination unit 800.

The operations of the rectified voltage detection unit 300 and the rectified voltage determination unit 800 in the “PFC partial stop mode” will be described separately in two cases.
First, the case where the operation stop and operation start of the power factor correction circuit 400 are determined based on the threshold value of the rectified voltage will be described.

  The rectified voltage detector 300 monitors the rectified voltage rectified by the rectifier circuit 200 as shown in FIG. The voltage threshold detector 810 monitors the fall of the rectified voltage, and when the rectified voltage falls below a predetermined threshold, the rectified voltage discriminator 800 stops the operation of the boost converter controller 440 of the power factor correction circuit 400. A signal is output, and the operation of the power factor correction circuit 400 is stopped. When the power factor correction circuit 400 is stopped, the voltage threshold detection unit 810 monitors the rising of the rectified voltage, and when the rectified voltage exceeds a predetermined threshold, the boost converter control unit 440 receives an operation start signal. Is output, and the operation of the power factor correction circuit 400 is started.

  In FIG. 4, the period Ton during which the power factor correction circuit 400 is operating is from when the boost converter control unit 440 receives the operation start signal to when the operation stop signal is input as described above for the operation. Similarly, the period from when the boost converter control unit 440 receives the operation stop signal to when the operation start signal is input is the period Toff during which the power factor correction circuit 400 stops operating. The definitions of Ton and Toff are the same as those in FIG. 4 in FIGS. 5 to 7, 14, and 15.

  Next, the case where the operation stop of the power factor correction circuit 400 is determined by the threshold value 1 of the rectified voltage and the operation start is determined by the threshold value 2 of the rectified voltage will be described.

  The rectified voltage detector 300 monitors the rectified voltage rectified by the rectifier circuit 200 as shown in FIG. The voltage threshold detector 810 monitors the fall of the rectified voltage, and when the rectified voltage falls below the threshold 1 for stopping the operation of the power factor correction circuit 400, the rectifier voltage determination unit 800 starts the power factor correction circuit. An operation stop signal is output to the boost converter control unit 440 of 400 to stop the operation of the power factor correction circuit 400. When the power factor correction circuit 400 is stopped, the voltage threshold value detection unit 810 monitors the rising of the rectified voltage, and the rectified voltage exceeds the threshold value 2 for starting the operation of the power factor correction circuit 400. Then, an operation start signal is output to the boost converter 440, and the operation of the power factor correction circuit 400 is started.

  In this way, when the threshold value of the rectified voltage for determining the operation stop and operation start of the power factor correction circuit 400 is set to a different value, compared with the above-described conditions in which the operation stop threshold value and the operation start threshold value are made the same. The configuration of the rectified voltage detection unit 300 becomes complicated. However, the threshold value 2 of the rectified voltage is set lower than the threshold value 1, and the power factor correction circuit 400 starts operating when the voltage value of the AC power supply 100 is as low as possible (close to the zero cross). it can. As a result, the rush current flowing at the start of the operation of the power factor correction circuit 400 can be suppressed, so that the effect of reducing the stress applied to the components constituting the circuit can be obtained.

  The operation stop signal and the operation start signal of the power factor correction circuit 400 output from the rectified voltage determination unit 800 described above are not more than a predetermined level Ta (see FIG. 3) from the dimming degree determination unit 700 to the boost converter control unit 440. This is valid only in the “PFC partial stop mode” when an output signal indicating that the Note that the operation start signal may be set to be effective regardless of the dimming degree unless the threshold is changed according to the dimming degree. This is because, under this condition, the power factor correction circuit 400 must be in operation if the rectified voltage is equal to or greater than the threshold value regardless of the dimming level. As a result, when the circuit is simplified or a microcomputer is used, the effect of simplifying the program can be obtained.

  The step-up converter control unit 440 can be configured in combination with the step-up converter by a microcomputer different from the dimming degree determination unit 700, the rectified voltage determination unit 800, and the light source control unit 520, and the power factor improvement circuit 400 including the step-up converter. A driving signal composed of a pulse voltage is supplied to the switching element 450. In addition, the duty of the drive signal is controlled by performing feedback control so that the output voltage input from the voltage voltage dividing circuit 460 including the output voltage detection resistor 461 and the output voltage detection resistor 462 becomes a predetermined value.

  For example, if the boost converter control unit 440 is a power factor correction integrated circuit having an analog multiplier using a sine wave input voltage waveform, for example, in a period other than Ton, a voltage obtained by deleting the sine wave voltage is used as a signal. By supplying, the switching element 450 can be driven only during the Ton period. If the dimming degree is 40% or less in this way, the switching element 450 of the boost converter can be obtained as shown in FIG. 6 based on the output signal of the dimming degree discriminating unit 700 and the output signal of the rectified voltage discriminating unit 800 described above. During the period Toff, the operation is stopped.

  Control of the operation stop and operation start of the power factor correction circuit 400 by the boost converter control unit 440 is performed only in the “PFC partial stop mode” in which the dimming level is equal to or lower than the predetermined level Ta. The output signal of the dimming degree discriminating unit 700 has priority over the output signal. That is, if the dimming degree is larger than the predetermined level Ta, the boost converter control unit 440 controls the switching element 450 so that the power factor correction circuit 400 does not stop even if the rectified voltage determination unit 800 outputs an operation stop signal.

  Since it is not necessary to make the Toff period symmetrical about the zero cross point, for example, as shown in FIG. 7, the operation stop period of the power factor correction circuit 400 after the zero cross is shortened compared to FIG. The operation start of the rate improvement circuit 400 may be advanced. As described above, this has the effect of suppressing the rush current that flows when the operation of the power factor correction circuit 400 starts.

  In this way, in the case of deep dimming, that is, light load, the boost converter stops operating during the Toff period. Further, since the output voltage due to the capacitor input type operation is continuously supplied from the power factor correction circuit 400 even during the period of Toff, unnecessary intermittent operation of the boost converter due to light load can be prevented.

  If the load is a discharge lamp 920, the lamp current is controlled by changing the output frequency with a half-bridge inverter, and the light can be dimmed in the same manner as in the case of the light-emitting diode 910. A circuit diagram when the load is the discharge lamp 920 is as shown in FIG. At this time, a capacitor 921 is connected to the discharge lamp.

  In any load of the light emitting diode 910 and the discharge lamp 920, a plurality of lamps or one lamp (for one LED row) can be appropriately applied.

  As described above, the power factor correction circuit 400 can be operated even with a deep dimming degree, and it is possible to provide a lighting device that suppresses a decrease in power factor and an increase in high-frequency components of input current.

Hereinafter, the range of the light control degree to which the present invention is applied will be described.
FIG. 8 is a characteristic diagram of the light source output (dimming degree) and the output voltage of the power factor correction circuit according to the first embodiment.

  In FIG. 8, the horizontal axis indicates the output (dimming degree) (%) of the light source, and the vertical axis indicates the output voltage (%) of the power factor correction circuit. The broken line indicates a straight line having a proportional relationship, which is an ideal characteristic, but the actual characteristic is as shown by the solid line. The reason is that the load output voltage and the output power of the power factor correction circuit do not change at the same ratio, not only when the load is a discharge lamp but also when it is a light emitting diode. This is because the power from the power factor correction circuit tends to increase due to the increase in power.

  For example, when the output of the load exceeds 40% (dimming degree 40%), the input power exceeds 40%, and normal operation can be performed without providing a special operation stop period in the power factor correction circuit. Is almost.

  Moreover, the relationship between the light control degree of the light source of the present invention and this invention and the operation stability of the power factor correction circuit is as shown in FIG. In the conventional lighting device, the operation of the power factor correction circuit starts to become unstable when the dimming degree is 40% or less.

  Therefore, the present invention is appropriate if it is applied at least when the output of the load light source is 40% or less.

  Further, when the dimming degree of the dimming signal input to the dimming signal input unit 600 is 100%, the operation of the power factor correction circuit 400 is not stopped and the power factor improvement circuit 400 of the power factor improvement circuit 400 decreases as the dimming degree decreases. A method of outputting a control signal from the dimming degree determination unit 700 to the boost converter control unit 440 so as to increase the operation time Ton (see FIG. 6) may be used. When this method is used, for example, when the dimming rate is 40%, the operation period of the power factor correction circuit 400 can be made longer than when the dimming rate is 10%, so that the power factor can be increased.

Hereinafter, the relationship between the operation period of the power factor correction circuit and the power factor will be described.
FIG. 10 is a characteristic diagram of the electrical angle and power factor during dimming, and FIG. 11 is a waveform diagram of the AC power supply voltage and input current when the power factor correction circuit is stopped.

  When the power factor correction circuit 400 provides a period in which operation is stopped near the zero cross of each cycle of the AC power supply 100, the power factor changes depending on the length of the operation period Ton (see FIG. 6).

  In FIG. 10, the horizontal axis represents the Ton period in electrical angle, and the vertical axis represents the power factor.

  Although the power factor slightly changes depending on the performance of the power factor correction circuit 400 and the power supply state, the characteristic of FIG. 10 is equivalent to the capacitor input type rectifier circuit without operating the power factor correction circuit 400. Compare with the case.

  In the capacitor input type operation, as shown in FIG. 11, the input current flows for a narrow period T near the peak of the sine wave of the power supply voltage. The current inflow period (the width of the current waveform) depends on the capacitor capacity of the circuit, but is about 30 to 40 degrees in electrical angle.

  In the apparatus of the present invention, even if a Toff period is provided, the Ton period is 45 degrees or more in electrical angle (that is, the total of Toff periods in each half cycle is an electrical angle by the action of the power factor correction circuit 400. If it is less than 135 degrees, it is possible to make the power factor close to 70% higher than the power factor (generally about 50 to 60%) in this capacitor input type, which is effective.

  In order to achieve a power factor of 85% or more, which is defined as a high power factor in JIS standards, etc., the Ton period is 75 degrees or more in electrical angle (that is, the total of Toff periods in each half cycle is 105 in electrical angle. Less).

  FIG. 12 is a table showing a preferred setting example of the electrical angle when the Ton period is provided symmetrically around the zero cross. It shows that stable circuit operation can be expected by decreasing the Ton period and increasing the Toff period, that is, increasing the operation stop period of the power factor correction circuit 400 as the dimming degree decreases. When the Ton period is fixed, the electrical angle may be set to about 90 degrees. This is because the Toff period can be made relatively long despite the power factor of about 90%, and stable operation of the power factor correction circuit 400 can be expected for various dimming levels.

Embodiment 2. FIG.
Hereinafter, the lighting device according to the second embodiment of the present invention will be described with reference to FIGS.

FIG. 13 is a waveform diagram showing the relationship between the frequency of the rectified voltage and the threshold value. Each of the two waves, the frequency of the AC power source indicates the rectified voltage waveform rectifier circuit 200 is output when the 50Hz and 60Hz, again the threshold from the voltage waveform of T ₁ is 60Hz falls below the threshold time until more than a value, T ₂ is the voltage waveform of 50Hz indicates the time until again above the threshold value from becoming below a threshold. Note that T ₂ > T ₁ .

In the case of the capacitor input type power supply circuit operation, since the input current tends to be less when the frequency of the AC power supply 100 is 60 Hz than when the frequency of the AC power supply 100 is 50 Hz, even if T ₁ is lengthened and T ₂ is shortened. Good.

  FIG. 14 is a waveform diagram showing the threshold value of the rectified voltage and the time from the operation stop signal to the operation start signal output. The rectified voltage waveform has a power supply frequency of 50 Hz or 60 Hz. Based on FIG. 14, the control method of the power factor correction circuit 400 in the “PFC partial stop mode” will be described using the power supply frequency of the AC power supply 100 and the threshold voltage.

The rectified voltage output from the rectifier circuit 200 is detected by the rectified voltage detector 300 and output to the voltage threshold detector 810 and the voltage frequency detector 820 in the rectified voltage discriminator 800. When the voltage frequency detector 820 determines whether the frequency of the AC power supply 100 is 50 Hz or 60 Hz, the rectified voltage output from the rectifier circuit 200 is monitored by the voltage threshold detector 810, and the rectified voltage falls below the threshold The rectified voltage discriminating unit 800 outputs an operation stop signal to the power factor correction circuit 400. The rectified voltage discriminating unit 800 inputs an operation start signal after a predetermined time t ₁ after the operation of the power factor correction circuit 400 stops, and starts the operation of the power factor improvement circuit 400. In this case, the predetermined time t ₁ and the operation stop time Toff of the power factor correction circuit 400 are the same length.

The operation start voltage of the power factor correction circuit 400 may be the same voltage value as the threshold value of the rectified voltage that stops the power factor improvement circuit 400, or may be set lower than the threshold voltage value. This is to suppress the rush current flowing at the start of the operation of the power factor correction circuit 400, similarly to the case of the first embodiment in which two threshold values of the rectified voltage are used and the operation stop voltage and the operation start voltage are set to different voltage values. Because. In this case, by changing the predetermined time t _1, to obtain the desired operation start voltage value.

In order to maintain the maximum power factor in each dimming degree, when performing control to shorten the operation period of the power factor correction circuit 400 as the dimming degree decreases, the boost converter control unit 440 is configured with a microcomputer or the like. The length of t ₁ is controlled so that the optimum electrical angle is as follows. This is because the control circuit is different from the case where the operation start voltage of the power factor improvement circuit 400 is changed using two different threshold values for the operation stop and operation start of the power factor improvement circuit 400 shown in the first embodiment. There is an effect that can be simplified.

FIG. 15 is a waveform diagram showing the threshold value of the rectified voltage and the time from the zero cross to the signal output. The rectified voltage waveform has a power supply frequency of 50 Hz or 60 Hz. Based on FIG. 15, the time t ₂ until the operation stop signal is output after the power supply frequency and voltage of the AC power supply 100 become zero and the time t ₃ until the operation start signal is output are used. A control method of the power factor correction circuit 400 in the “PFC partial stop mode” will be described.

The rectified voltage output from the rectifier circuit 200 is detected by the rectified voltage detector 300 and output to the voltage threshold detector 810 and the voltage frequency detector 820 in the rectified voltage discriminator 800. After the voltage frequency detection unit 820 determines whether the frequency of the AC power supply 100 is 50 Hz or 60 Hz, the rectified voltage output from the rectifier circuit 200 is monitored by the voltage threshold value detection unit 810, and predetermined from the time when the rectified voltage becomes zero. After time t _{2 has} elapsed, the rectified voltage determination unit 800 inputs an operation start signal to the power factor correction circuit 400 to start the operation. Similarly, after a predetermined time t _{3 has} elapsed from the time when the rectified voltage becomes zero, the rectified voltage determination unit 800 inputs an operation stop signal to the power factor correction circuit 400 to stop the operation.

  According to the present embodiment, the voltage frequency detection unit 820 must be provided in the rectified voltage determination unit 800. However, since the threshold voltage of the rectified voltage detected by the rectified voltage detection unit 300 is only one, the rectified voltage The detection unit can be simplified, and the operation stop time and the operation start time of the power factor correction circuit 400 can be set more easily than when two threshold values of the rectified voltage are used. Control for extending the operation stop time of the rate improvement circuit 400 can be realized.

  100 AC power supply, 200 rectifier circuit, 300 rectified voltage detector, 400 power factor correction circuit, 410 capacitor, 420 inductor, 430 diode, 440 boost converter controller, 450 switching element, 460 voltage divider circuit, 461 output voltage detection resistor 462, output voltage detection resistor, 470 output capacitor, 500 light source lighting circuit, 510 load power supply unit, 511 switching element, 512 inductor, 513 diode, 514 smoothing capacitor, 515 load detection resistor, 520 light source control unit, 600 dimming signal Input unit, 700 dimming degree determining unit, 800 rectified voltage determining unit, 810 voltage threshold value detecting unit, 820 voltage frequency detecting unit, 910 light emitting diode, 920 discharge lamp, 921 capacitor.

Claims (7)

A power rectifier circuit for rectifying an AC voltage input from an AC power source;
An output of the power supply rectifier circuit, and a power factor correction circuit including a boost converter;
A light source lighting circuit that receives the output of the power factor correction circuit as an input;
A dimming signal input unit to which an external dimming signal is input;
A dimming degree determining unit for determining a dimming degree of the dimming signal input to the dimming signal input unit;
Control means for stopping the operation of the power factor correction circuit for a predetermined period across the zero cross of the AC power supply when the dimming level detected by the dimming level determination unit is equal to or lower than a predetermined level;
A lighting device comprising: A power rectifier circuit for rectifying an AC voltage input from an AC power source;
An output of the power supply rectifier circuit, and a power factor correction circuit including a boost converter;
A light source lighting circuit that receives the output of the power factor correction circuit as an input;
A dimming signal input unit to which an external dimming signal is input;
A dimming degree determining unit for determining a dimming degree of the dimming signal input to the dimming signal input unit;
A rectified voltage detector for monitoring the output voltage of the power rectifier circuit;
The output of the rectified voltage detector is input, and a rectified voltage discriminator having a voltage threshold detector;
When the dimming level detected by the dimming level determining unit is equal to or lower than a predetermined level and the rectified voltage detected by the voltage threshold level detecting unit is equal to or lower than a first threshold value, an operation stop signal is output from the rectified voltage determining unit. The power factor improvement circuit stops operating and outputs an operation start signal when the rectified voltage exceeds a second threshold value, and the power factor improvement is performed for a predetermined period across the zero cross of the AC power supply. Control means for stopping the operation of the circuit;
A lighting device comprising: A power rectifier circuit for rectifying an AC voltage input from an AC power source;
An output of the power supply rectifier circuit, and a power factor correction circuit including a boost converter;
A light source lighting circuit that receives the output of the power factor correction circuit as an input;
A dimming signal input unit to which an external dimming signal is input;
A dimming degree determining unit for determining a dimming degree of the dimming signal input to the dimming signal input unit;
A rectified voltage detector for monitoring the output voltage of the power rectifier circuit;
The output of the rectified voltage detector is input, and a rectified voltage discriminator having a voltage threshold detector;
When the dimming level detected by the dimming level determining unit is not more than a predetermined level and the rectified voltage detected by the voltage threshold level detecting unit is not more than a threshold value, an operation stop signal is input from the rectified voltage determining unit. Control means for outputting an operation start signal when a predetermined time has elapsed since the detection of the zero cross, and stopping the operation of the power factor improvement circuit for a predetermined period across the zero cross of the AC power supply. When,
A lighting device comprising: A voltage frequency detection unit provided in the rectified voltage determination unit;
When the voltage frequency detector monitors the frequency of the rectified voltage and detects that the dimming level is equal to or lower than a predetermined level and the rectified voltage is equal to or lower than a threshold value, the power factor correction circuit is deactivated. And a control means having a different operation start time of the power factor correction circuit when the detected frequency of the rectified voltage is 50 Hz or 60 Hz,
The lighting device according to claim 3, further comprising:   The power factor improvement circuit is not stopped when the dimming degree is equal to or higher than a predetermined level, and control means is provided for extending the stop time of the power factor improvement circuit as the dimming degree becomes lower than the predetermined level. The lighting device according to claim 1, wherein:   The dimming signal input to the dimming level discrimination unit is a pulse width modulation signal, and the dimming level is discriminated based on a pulse width of the dimming signal or a DC signal voltage level obtained by smoothing the dimming signal. The lighting device according to any one of claims 1 to 5, wherein: A lighting device according to any one of claims 1 to 6,
An instrument body for fixing the lighting device;
A lighting apparatus comprising: