JP2013251951A - Power-supply device and lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power-supply device capable of improving the power factor even when a load becomes light, and to provide a lighting device having the power-supply device.SOLUTION: A power-supply device 100 is connected to a commercial power supply 1 and includes a rectifier circuit 10; a power-factor improvement circuit 40 provided at an output side of the rectifier circuit 10 and having, at a pre-stage, a capacitor section 20 configured by a plurality of capacitors 21, 22, 23, 24, and 25 connected in parallel; a DC/DC converter 50 provided at an output side of the power-factor improvement circuit 40 and supplying a current to a light source 200 as a load; a dimming control section 60 for dimming the light source 200; and an adjustment section 70 for adjusting the capacitance of the capacitor section 20 configured by the plurality of capacitors 21, 22, 23, 24, and 25. The adjustment section 70 adjusts the capacitance of the capacitor section 20 determined by the plurality of capacitors 21 to 25 so that the capacitance becomes large or small according to the amount of the current supplied to the light source 200.

Description

  The present invention relates to a power supply device including a power factor correction circuit and a lighting device including the power supply device.

  In recent years, lighting devices using light emitting diodes (LEDs) as light sources have been developed for various applications, and replacement of lighting devices using conventional light sources such as incandescent bulbs and fluorescent lamps is being performed. In addition, lighting devices having a dimming function capable of adjusting the light source to a desired brightness have already been commercialized.

  Such an illuminating device includes a power supply device for rectifying an AC voltage, converting the rectified voltage into a required voltage, and supplying the voltage to a load. And since such a power supply device is provided with the smoothing capacitor for smoothing the voltage after rectification, an input current flows only for a short period near the peak value of the voltage waveform after rectification. For this reason, the power factor of a power supply device and an illuminating device falls. Therefore, many of such power supply devices include a power factor correction circuit (see Patent Document 1).

  FIG. 7 is an explanatory diagram showing an example of a conventional power factor correction circuit. The power factor correction circuit 300 is provided on the output side of the rectifier circuit 301 that rectifies the AC voltage supplied from the commercial power supply 1, and turns on / off the capacitor 302, the inductor 303, the diode 304, the resistors 305 and 306, the FET 307, and the FET 307. And a smoothing capacitor 309.

  The control circuit 308 outputs a rectangular pulse waveform to the gate of the FET 307, thereby turning on / off the FET 307 at a high frequency.

  The power factor correction circuit 300 switches (on / off) the FET 307 at a high frequency higher than the frequency (50 Hz or 60 Hz) of the commercial power supply so that the input current I becomes a sine wave similar to the input voltage V. Control the current waveform.

  FIG. 8 is an explanatory diagram showing an example of current waveform control by the power factor correction circuit 300. FIG. 8 schematically shows the input voltage V, the input current I, the average value of the input current I, and the voltage Vg applied to the gate of the FET 307. For example, the frequency of the voltage Vg is limited to that shown in FIG. Is not to be done. As shown in FIG. 8, the input voltage V is a sine wave. By outputting the pulse waveform Vg from the control circuit 308 to the gate of the FET 307, the FET 307 is repeatedly turned on / off at a high frequency.

  When the FET 307 is in the on state, the current Ia increases when the current Ia flows through the inductor 303. When the FET 307 changes from the on state to the off state, no current flows through the FET 307, and thus the current Ia flowing through the inductor 303 decreases. To do. Since the input current I repeatedly increases and decreases similarly to the current Ia flowing through the inductor 303, as shown in FIG. 8, the envelope of the peak value of the input current I has a sine wave shape, and the average value of the input current I also has a sine wave shape. become. In this way, the power factor is improved.

JP 2012-64503 A

  However, in the lighting device provided with the conventional power factor correction circuit disclosed in Patent Document 1, for example, by performing dimming control, deep dimming (that is, the current flowing through the load as the light source is reduced). When the load becomes light, the input current cannot be controlled to be a sine wave, and the waveform of the input current is distorted. When the input current is distorted, harmonic components become prominent, and adverse effects on other devices connected to the AC power supply or commercial power supply supplying the input voltage (for example, malfunction of electric devices, Interference, malfunction of circuit breaker or earth leakage breaker). Such a problem exists not only in the so-called inductor current discontinuous mode power factor correction circuit as shown in FIG. 8, but also in the inductor current continuous mode or inductor current critical mode power factor correction circuit.

  The reason why the power factor correction circuit does not operate normally when the load is light and the waveform control of the input current cannot be performed is, for example, that the current Id to be output to the load due to the light load is If it decreases, the period of the current flowing through the inductor 303 or the capacitor 302 becomes too short according to the decrease in the load current Id, and the current can be increased or decreased following the on / off operation of the FET 307. Because it becomes impossible.

  This invention is made | formed in view of such a situation, and it aims at providing a power supply device which can perform a power factor improvement even if it is a light load, and an illuminating device provided with this power supply device.

  The power supply device according to the present invention has a rectifier circuit that rectifies an AC voltage applied from an AC power supply, and a capacitor unit on the input side, and controls a current waveform to improve a power factor for the AC power supply. In a power supply device provided with a circuit and a DC / DC converter that is provided on the output side of the power factor correction circuit and supplies a current to a load, the capacitance of the capacitor unit depends on the amount of current supplied to the load. An adjustment unit for adjusting the size to be larger or smaller is provided.

  The present invention includes a power factor correction circuit that has a capacitor unit on the input side and controls the current waveform to improve the power factor for the AC power supply. The adjustment unit adjusts the capacitance of the capacitor unit to be large or small according to the amount of current supplied to the load. The capacitor unit includes one or a plurality of capacitors. That is, the adjustment unit adjusts the capacitance of the capacitor unit to be small when the current supplied to the load is small (when the load is light). If the capacitance of the capacitor portion is reduced, the peak of the current flowing in the capacitor portion can be suppressed by the amount of the smaller capacitance, and as a result, the period of the current flowing in the capacitor portion can be lengthened. The longer the period of current flowing through the capacitor section, the more normally the power factor correction circuit can be operated, and the power factor can be improved even with a light load.

  In particular, in order to increase the power factor, it is necessary to make the input current waveform closer to a sine wave by switching the FET in the power factor correction circuit at a high frequency. In this case, the higher the switching frequency, the more the current flows to the capacitor section. The current period is shortened. By adjusting the capacitance of the capacitor unit, the operation of the power factor correction circuit at a light load can be ensured while increasing the power factor. Moreover, since the power factor can be improved, the generation of higher harmonics can also be suppressed.

  The power supply apparatus according to the present invention includes a current control unit that outputs a control signal for controlling a current supplied to the load to the DC / DC converter, and the adjustment unit adjusts the capacity based on the control signal. It is characterized by the above.

  In the present invention, the current control unit outputs a control signal for controlling the current supplied to the load to the DC / DC converter. For example, when the load is a light source, the control signal can be a dimming signal for dimming the light source. That is, the control signal corresponds to the current flowing through the load. The adjustment unit adjusts the capacitance of the capacitor unit based on the control signal. For example, when the control signal is a signal for reducing the current flowing through the load (light load), the adjustment unit reduces the capacitance of the capacitor unit. Thereby, even if it is a light load, a power factor improvement can be performed.

  The power supply device according to the present invention includes a current detection unit that detects a current flowing through the load, and the adjustment unit adjusts the capacity to be large or small based on the amount of current detected by the current detection unit. It is characterized by the above.

  In the present invention, the current detector detects the current flowing through the load. The adjustment unit adjusts the capacitance of the capacitor unit to be large or small based on the amount of current detected by the current detection unit. For example, when the current detected by the current detection unit is small (when the load is light), the adjustment unit reduces the capacitance of the capacitor unit. Thereby, even if it is a light load, a power factor improvement can be performed.

  The power supply device according to the present invention includes a voltage detection unit that detects an AC voltage applied to the rectifier circuit, and the adjustment unit is configured to reduce the capacitance based on a voltage level detected by the voltage detection unit. It is characterized by being adjusted as necessary.

  In the present invention, the voltage detection unit detects an AC voltage applied to the rectifier circuit. The AC voltage is generally an AC voltage supplied from a commercial power source. Considering not only Japan but also overseas, the AC voltage varies in a range of about 100V to 242V. The voltage detection unit can detect, for example, whether the input voltage applied to the rectifier circuit is 100V, 200V, or another voltage. If the power consumption of the load is a predetermined value regardless of the level of the AC voltage applied to the rectifier circuit, the higher the AC voltage, the smaller the current flowing through the power factor correction circuit will be in proportion to the input current. This is equivalent to the case where the current flowing through the load is small. Therefore, the adjustment unit adjusts the capacitance of the capacitor unit to be small or large based on the voltage level detected by the voltage detection unit. For example, when the voltage detected by the voltage detection unit is high (for example, 200 V), the adjustment unit reduces the capacitance of the capacitor unit. Thereby, even if it is a light load, a power factor improvement can be performed.

  In the power supply device according to the present invention, the capacitor unit includes a plurality of capacitors connected in parallel, and includes a plurality of switching elements that are connected in series with each of the plurality of capacitors and open and close an electric circuit. The capacitance is adjusted by opening and closing the plurality of switching elements.

  In the present invention, the capacitor unit includes a plurality of capacitors connected in parallel, and includes a plurality of switching elements that are connected in series with the plurality of capacitors and open and close the electric circuit. For example, the switching element may be a switching element such as an FET, or a relay (including a non-contact relay). The adjustment unit adjusts the capacitance by opening and closing a plurality of opening and closing elements. For example, when each of a plurality of capacitors has a different capacity, a relatively simple configuration can be obtained by closing any one of the switching elements connected in series to each of the plurality of capacitors and opening the other remaining switching elements. The capacity can be adjusted with. In addition, when each of the capacitors has the same capacitance, the capacitance can be adjusted with a relatively simple configuration by changing the number of switching elements that are closed among the switching elements connected in series to each of the plurality of capacitors. can do.

  An illumination device according to the present invention includes a power supply device according to any one of the above-described inventions, and a light source to which current is supplied from the power supply device.

  In the present invention, it is possible to provide an illumination device that can improve the power factor even with a light load.

  According to the present invention, the power factor can be improved even with a light load.

3 is a block diagram illustrating an example of a configuration of a lighting device according to Embodiment 1. FIG. It is explanatory drawing which shows an example of the adjustment method of the capacity | capacitance of a capacitor | condenser part. It is explanatory drawing which shows the other example of the adjustment method of the capacity | capacitance of a capacitor | condenser part. FIG. 10 is a block diagram illustrating an example of a configuration of a lighting device according to a second embodiment. FIG. 10 is a block diagram illustrating an example of a configuration of a lighting apparatus according to a third embodiment. FIG. 10 is a block diagram illustrating an example of a configuration of a lighting device according to a fourth embodiment. It is explanatory drawing which shows an example of the conventional power factor improvement circuit. It is explanatory drawing which shows an example of control of the current waveform by a power factor improvement circuit.

(Embodiment 1)
Hereinafter, the present invention will be described with reference to the drawings illustrating embodiments thereof. FIG. 1 is a block diagram illustrating an example of a configuration of the lighting apparatus according to the first embodiment. The lighting device of this embodiment includes a power supply device 100, a light source 200, and the like. The power supply apparatus 100 can supply a required current, voltage, or power to the light source 200 as a load.

  The light source 200 has, for example, a configuration in which a plurality of LEDs are connected in series. The light source 200 may have a configuration in which a plurality of series LED groups in which a plurality of LEDs are connected in series are connected in parallel.

  The power supply device 100 is provided on the output side of the rectifier circuit 10 for rectifying the AC voltage applied from the commercial power supply 1 (AC power supply), and a plurality of capacitors 21, 22, 23, 24 connected in parallel. A power factor improving circuit 40 having a capacitor unit 20 composed of 25 on the input side, a DC / DC converter 50 provided on the output side of the power factor improving circuit 40, and supplying a current to the light source 200 as a load, A dimming control unit 60 for dimming, an adjustment unit 70 for adjusting the capacitance of the capacitor unit 20 including a plurality of capacitors 21, 22, 23, 24, and 25 are provided.

  The capacitance (capacitance) of each of the plurality of capacitors 21, 22, 23, 24, and 25 is C21, C22, C23, C24, and C25. The number of capacitors is not limited to five, but may be two to four, or six or more as long as it is plural.

  The power factor correction circuit 40 is a so-called step-up type power factor correction circuit, and is a switch that is connected in series with each of the plurality of capacitors 21, 22, 23, 24, 25 in addition to the capacitor unit 20, and opens and closes the electric circuit. Open / close unit 30 composed of a plurality of open / close elements 31, 32, 33, 34, 35, inductor 41, FET 42, diode 43, resistors 44, 45, control circuit 46 for controlling on / off of FET 42, smoothing capacitor 47 Etc. The power factor improvement circuit 40 improves the power factor for the commercial power supply 1 by controlling the input current waveform to be a sine wave like the input voltage waveform (AC voltage waveform) by switching the FET 42 at a high frequency. .

  The switching elements 31 to 35 may be, for example, switching elements such as FETs and transistors, or relays such as contact relays or contactless relays.

  Capacitance of the capacitor unit 20 determined by the plurality of capacitors 21, 22, 23, 24, 25 connected in parallel on the output side of the rectifier circuit 10 by closing any one or some of the switching elements 31 to 35. Can be adjusted.

  An inductor 41 is connected in series with the positive output terminal of the rectifier circuit 10 at the subsequent stage of the capacitor unit 20 and the opening / closing unit 30. A diode 43 is connected in series with the inductor 41, and a drain and a source are connected between a connection node between the inductor 41 and the diode 43 and a negative output terminal (also referred to as a reference level or a ground level) of the rectifier circuit 10. An FET 42 is provided.

  The input end of the DC / DC converter 50 is connected to the output side of the diode 43. Further, resistors 44 and 45 and a smoothing capacitor 47 connected in series are connected between the connection node of the diode 43 and the DC / DC converter 50 and the reference level.

  The input terminal of the control circuit 46 is connected to a connection node between the resistor 44 and the resistor 45, and the voltage obtained by dividing the voltage at the input terminal of the DC / DC converter 50 by the resistors 44 and 45 is the input terminal of the control circuit 46. Is output.

  The control circuit 46 includes an oscillator that can output a signal having a predetermined frequency (a frequency higher than the frequency of the commercial power supply) therein, and the output terminal so that the voltage applied to the input terminal has a predetermined voltage value. The duty ratio of the pulse signal output to the gate of the FET 42 can be adjusted. Thereby, the FET 42 can perform an on / off (switching) operation at a high frequency.

  When the FET 42 is on, the current flowing through the inductor 41 increases, and when the FET 42 changes from the on state to the off state, the current flowing through the inductor 41 decreases. Since the input current of the power supply device 100 (current on the input side of the rectifier circuit 10) repeatedly increases and decreases like the current flowing through the inductor 41, the envelope of the peak value of the input current becomes a sine wave, and the average value of the input current Becomes sinusoidal.

  The DC / DC converter 50 includes switching elements such as FETs, elements such as diodes, inductors, and capacitors, and converts (steps down) the DC voltage smoothed by the smoothing capacitor 47 to a voltage output to the light source 200.

  The dimming control unit 60 includes, for example, a PWM circuit and has a function as a current control unit that outputs a control signal for controlling a current supplied to the light source 200 to the DC / DC converter 50. For example, the dimming control unit 60 outputs a control signal to the DC / DC converter 50 based on a dimming signal acquired from a remote controller (remote operation device) (not shown). The DC / DC converter 50 controls the current flowing through the light source 200 by adjusting the ON / OFF operation period of the switching element based on the control signal output from the dimming control unit 60. That is, the control signal corresponds to the current flowing through the light source 200.

  In addition, the dimming control unit 60 outputs a control signal to be output to the DC / DC converter 50 to the adjustment unit 70.

  The adjustment unit 70 can be configured by a microcomputer or the like, and adjusts the capacitance of the capacitor unit 20 determined by the plurality of capacitors 21 to 25 according to the amount of current supplied to the light source 200. . That is, when the current supplied to the light source 200 is reduced (when the load is light), the adjustment unit 70 adjusts the capacitance determined by the plurality of capacitors 21 to 25 to be small.

  More specifically, the adjustment unit 70 adjusts the capacitance determined by the plurality of capacitors 21 to 25 based on the control signal output from the dimming control unit 60. That is, in the present embodiment, it is determined whether the amount of current supplied to the light source 200 is large or small based on the control signal output from the dimming control unit 60, and for example, the current that the control signal flows to the light source 200 is reduced. In the case of a signal for (light load), the adjustment unit 70 reduces the capacitance determined by the plurality of capacitors 21 to 25.

  The adjustment unit 70 adjusts the capacitance of the capacitor unit 20 by individually opening and closing each of the switching elements 31 to 35 of the switching unit 30.

  If the capacitance determined by the plurality of capacitors 21 to 25 is reduced, the peak of the current flowing through the capacitor unit 20 can be suppressed by the smaller capacitance, and as a result, the period of the current flowing through the capacitor unit 20 can be lengthened. it can. As the period of the current flowing through the capacitor unit 20 becomes longer, the power factor correction circuit 40 can be operated normally, and the power factor can be improved even with a light load.

  In particular, in order to increase the power factor, it is necessary to make the input current waveform closer to a sine wave by switching the FET 42 in the power factor correction circuit 40 at a high frequency. In this case, the higher the switching frequency, the higher the capacitor unit 20. The period of the current flowing through is shortened. By adjusting the capacity determined by the plurality of capacitors 21 to 25, it is possible to ensure the operation of the power factor correction circuit at a light load while increasing the power factor. Moreover, since the power factor can be improved, the generation of higher harmonics can also be suppressed.

  Since harmonic components of the input current can be reduced, adverse effects on other devices connected to the AC power supply or the commercial power supply 1 that supplies the input voltage (for example, malfunctions of electrical devices, electronic devices, etc.) Mutual interference, malfunction of circuit breaker or earth leakage breaker, etc.) can be prevented.

  FIG. 2 is an explanatory diagram illustrating an example of a method for adjusting the capacitance of the capacitor unit 20. The example of FIG. 2 shows a case where the capacitors C21 to C25 of the capacitors 21 to 25 are different, and for example, it is assumed that C21 <C22 <C23 <C24 <C25. As shown in FIG. 2, when the capacitors 21 to 25 have different capacities, one of the switch elements 31 to 35 that are switches connected in series to the capacitors 21 to 25 is closed. Open the other remaining switch elements.

  For example, when the load current flowing through the light source 200 is the smallest, the open / close element 31 is turned on (closed), and the other open / close elements are turned off (open). The capacity of the capacitor unit 20 is C21.

  Similarly, when the load current flowing through the light source 200 is larger than the minimum load current, the open / close element 32 is turned on (closed) and the other open / close elements are turned off (open). The capacity of the capacitor unit 20 is C22.

  When the load current flowing through the light source 200 is the largest, the open / close element 35 is turned on (closed) and the other open / close elements are turned off (open). The capacity of the capacitor unit 20 is C25.

  With the method illustrated in FIG. 2, the capacitance of the capacitor unit 20 can be adjusted with a relatively simple configuration.

  FIG. 3 is an explanatory diagram showing another example of a method for adjusting the capacitance of the capacitor unit 20. The example of FIG. 3 shows a case where the capacitors C21 to C25 of the capacitors 21 to 25 have the same value. For example, it is assumed that C21 = C22 = C23 = C24 = C25 = C. As shown in FIG. 3, when the capacitances of the plurality of capacitors 21 to 25 have the same value, the switching elements 31 to 35 that are switches connected in series to the capacitors 21 to 25 are closed. Change the number of elements.

  For example, when the load current flowing through the light source 200 is the smallest, only the switching element 31 is turned on (closed), and all the other switching elements are turned off (opened). The capacity of the capacitor unit 20 is C.

  Similarly, when the load current flowing through the light source 200 is larger than the minimum, the open / close elements 31 and 32 are turned on (closed), and the other open / close elements are turned off (open). The capacity of the capacitor unit 20 is 2 × C.

  When the load current flowing through the light source 200 is the largest, all the open / close elements 31 to 35 are turned on (closed). The capacity of the capacitor unit 20 is 5 × C.

  With the method illustrated in FIG. 3, the capacitance of the capacitor unit 20 can be adjusted with a relatively simple configuration. The capacitance of the capacitor unit 20 can be adjusted within a range of about 0.1 μF to 2 μF, for example, but the capacitance adjustment range is not limited to this, and the specifications of the power supply device 100 or the lighting device It can set suitably according to etc.

(Embodiment 2)
In the first embodiment described above, the adjustment unit 70 is configured to adjust the capacitance determined by the plurality of capacitors 21 to 25 based on the control signal output from the dimming control unit 60, but is not limited thereto. It is not something.

  FIG. 4 is a block diagram illustrating an example of the configuration of the lighting apparatus according to the second embodiment. The difference from the first embodiment is that the power supply device 110 includes a resistor 80 as a current detection unit that detects a current flowing through the light source 200. Note that parts similar to those of the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  As illustrated in FIG. 4, the adjustment unit 70 adjusts the capacitance determined by the plurality of capacitors 21 to 25 based on the amount of current detected by the resistor 80. For example, when the current detected by the resistor 80 is small (when the load is light), the adjustment unit 70 reduces the capacitance determined by the plurality of capacitors 21 to 25. Thereby, even if it is a light load, a power factor improvement can be performed. Also in the second embodiment, the method shown in FIGS. 2 and 3 can be applied.

  In the second embodiment, since the current that actually flows through the light source 200 is detected, the capacitance of the capacitor unit 20 can be adjusted more accurately according to the light load state.

  In FIG. 4, the current flowing through the resistor 80 may be detected, and the detected current may be output (feedback) to the dimming control unit 60. The dimming control unit 60 changes the control signal (for example, changes the duty ratio of the PWM modulation) based on the current detected by the resistor 80, and sets the output current of the DC / DC converter 50 to a desired value. Can do.

  Further, instead of the configuration in which the current detected by the resistor 80 is directly output to the adjustment unit 70, the current detected by the resistor 80 is output to the dimming control unit 60, and the dimming control unit 60 is detected by the resistor 80. A control signal to be output to the DC / DC converter 50 may be output to the adjustment unit 70 based on the current. Further, the current detection method is not limited to the configuration using the resistor 80, and other configurations may be used.

(Embodiment 3)
FIG. 5 is a block diagram illustrating an example of a configuration of the lighting apparatus according to the third embodiment. The difference from the first embodiment is that the power supply device 120 includes a voltage detection unit 90 that detects an AC voltage input to the rectifier circuit 10.

  As shown in FIG. 5, the voltage detection unit 90 includes diodes 11 and 12, resistors 13, 14, and 15. A series circuit of a diode 11 and a resistor 13 is connected to one power supply line from the commercial power supply 1, and a series circuit of a diode 12 and a resistor 14 is connected to the other power supply line. Then, one ends of the resistors 13 and 14 are connected to each other, and the resistor 15 and the input end of the adjusting unit 70 are connected to the connection node.

  With this configuration, the adjustment unit 70 is applied with a voltage obtained by dividing the input voltage by the resistors 13 and 14 or the resistors 14 and 15, so that the adjustment unit 70 detects the AC voltage input to the rectifier circuit 10. can do.

  The AC voltage is generally an AC voltage supplied from a commercial power source. Considering not only Japan but also overseas, the AC voltage varies in a range of about 100V to 242V. For example, the voltage detector 90 can detect whether the input voltage input to the rectifier circuit 10 is 100 V, 200 V, or another voltage. If the power consumption of the load is a predetermined value regardless of the level of the AC voltage input to the rectifier circuit 10, the current flowing through the power factor correction circuit 40 is proportional to the input current as the AC voltage increases. It becomes a state equivalent to the case where there is little and the electric current which flows into the light source 200 is small. That is, since the amount of current supplied to the light source 200 changes according to the level of the AC voltage input to the rectifier circuit 10, the amount of current supplied to the light source 200 is determined by detecting the value of the AC voltage. Can do. More specifically, by detecting the value of the AC voltage, it is possible to determine the range in which the amount of current supplied to the light source 200 varies based on the control signal output from the dimming control unit 60.

  Therefore, the adjustment unit 70 is turned on (closed) to reduce the capacitance of the capacitor unit 20 determined by the plurality of capacitors 21 to 25 based on the voltage level detected by the voltage detection unit 90. The selection range of the elements 31 to 35 is adjusted. That is, the selection range of the capacitor capacity is determined. For example, when the voltage detected by the voltage detection unit 90 is high (for example, 200 V), the adjustment unit 70 is turned on (closed) so that the capacitance determined by the plurality of capacitors 21 to 25 becomes small. The selection range of ~ 35 is adjusted. As a result, the power factor can be improved even with a light load regardless of the level of the input AC voltage.

  In the third embodiment, when the example of FIG. 2 is applied, for example, when the voltage detected by the voltage detection unit 90 is low (for example, 100 V to 120 V), the adjustment unit 70 includes a plurality of capacitors 21 to 25. Among them, only the capacitors 23 to 25 having a relatively large capacity are selected, and the capacitors 21 and 22 having a relatively small capacity are not selected.

  Then, the adjusting unit 70 turns on (closes) one of the switching elements 33 to 35 corresponding to the capacitors 23 to 25 and turns off (opens) the other switching elements according to the load current. More specifically, the adjustment unit 70 adjusts the capacitance determined by the plurality of capacitors 23 to 25 based on the control signal output from the dimming control unit 60. That is, it is determined whether the amount of current supplied to the light source 200 is large or small based on the control signal output from the dimming control unit 60, for example, for reducing the current that the control signal flows to the light source 200 (light load). When the signal is a signal, the adjustment unit 70 reduces the capacitance determined by the plurality of capacitors 23 to 25. Thereby, the capacity | capacitance of the capacitor | condenser part 20 can be adjusted in the range of a comparatively big value.

  Further, when the voltage detected by the voltage detection unit 90 is high (for example, 200V to 240V, etc.), the adjustment unit 70 selects only the capacitors 21 to 23 having a relatively small capacity among the plurality of capacitors 21 to 25. The capacitors 24 and 25 having a relatively large capacity are not selected.

  Then, in accordance with the load current, the adjustment unit 70 turns on (closes) one of the switch elements 31 to 33 corresponding to the capacitors 21 to 23 and turns off (opens) the other switch elements. More specifically, the adjustment unit 70 adjusts the capacitance determined by the plurality of capacitors 21 to 23 based on the control signal output from the dimming control unit 60. That is, it is determined whether the amount of current supplied to the light source 200 is large or small based on the control signal output from the dimming control unit 60, for example, for reducing the current that the control signal flows to the light source 200 (light load). In the case of a signal, the adjustment unit 70 reduces the capacitance determined by the plurality of capacitors 21 to 23. Thereby, the capacity | capacitance of the capacitor | condenser part 20 can be adjusted in the range of a comparatively small value.

  In Embodiment 3, when the example of FIG. 3 is applied, for example, when the voltage detected by the voltage detection unit 90 is low (for example, 100 V to 120 V, etc.), the adjustment unit 70 includes a plurality of capacitors 21. Select all of ~ 25. And the adjustment part 70 increases / decreases the number of the switching elements 31-35 to turn on (close) according to load current. Also in this case, it is determined whether the amount of current supplied to the light source 200 is large or small based on the control signal output from the dimming control unit 60, and for example, the current that the control signal flows to the light source 200 is reduced (light load). The adjustment unit 70 reduces the capacitance determined by the plurality of capacitors 21 to 25. Thereby, the capacity | capacitance of the capacitor | condenser part 20 can be adjusted to a big value.

  Moreover, when the voltage detected by the voltage detection unit 90 is high (for example, 200V to 240V, etc.), the adjustment unit 70 selects, for example, three capacitors 21 to 23 from among the plurality of capacitors 21 to 25, and the like. The capacitors 24 and 25 are not selected. And the adjustment part 70 increases / decreases the number of the switching elements 31-33 to turn on (close) according to load current. Also in this case, it is determined whether the amount of current supplied to the light source 200 is large or small based on the control signal output from the dimming control unit 60, and for example, the current that the control signal flows to the light source 200 is reduced (light load). For example, the adjustment unit 70 reduces the capacitance determined by the plurality of capacitors 21 to 23. Thereby, the capacity | capacitance of the capacitor | condenser part 20 can be adjusted in the range of a comparatively small value.

(Embodiment 4)
FIG. 6 is a block diagram illustrating an example of a configuration of the lighting apparatus according to the fourth embodiment. The difference from the second embodiment is that the power supply device 130 includes a voltage detection unit 90 that detects an AC voltage input to the rectifier circuit 10. Note that the voltage detection unit 90 is the same as that of the third embodiment, and a description thereof will be omitted.

  Also in the fourth embodiment, as in the third embodiment, the amount of current supplied to the light source 200 changes according to the level of the AC voltage input to the rectifier circuit 10, so that the value of the AC voltage is detected. The amount of current supplied to the light source 200 can be determined. More specifically, by detecting the value of the AC voltage, it is possible to determine the range in which the amount of current supplied to the light source 200 varies based on the control signal output from the dimming control unit 60.

  Therefore, the adjustment unit 70 is turned on (closed) to reduce the capacitance of the capacitor unit 20 determined by the plurality of capacitors 21 to 25 based on the voltage level detected by the voltage detection unit 90. The selection range of the elements 31 to 35 is adjusted. That is, the selection range of the capacitor capacity is determined. For example, when the voltage detected by the voltage detection unit 90 is high (for example, 200 V), the adjustment unit 70 is turned on (closed) so that the capacitance determined by the plurality of capacitors 21 to 25 becomes small. The selection range of ~ 35 is adjusted. As a result, the power factor can be improved even with a light load regardless of the level of the input AC voltage.

  In the fourth embodiment, when the example of FIG. 2 is applied, it is the same as in the third embodiment. For example, when the voltage detected by the voltage detection unit 90 is low (for example, 100 V to 120 V), the adjustment unit 70 selects only the capacitors 23 to 25 having a relatively large capacity among the plurality of capacitors 21 to 25 and does not select the capacitors 21 and 22 having a relatively small capacity.

  Then, the adjusting unit 70 turns on (closes) one of the switching elements 33 to 35 corresponding to the capacitors 23 to 25 and turns off (opens) the other switching elements according to the load current. More specifically, the adjustment unit 70 adjusts the capacitance determined by the plurality of capacitors 23 to 25 based on the amount of current detected by the resistor 80. For example, when the current detected by the resistor 80 is small (when the load is light), the adjustment unit 70 reduces the capacitance determined by the plurality of capacitors 23 to 25. Thereby, the capacity | capacitance of the capacitor | condenser part 20 can be adjusted in the range of a comparatively big value.

  Further, when the voltage detected by the voltage detection unit 90 is high (for example, 200V to 240V, etc.), the adjustment unit 70 selects only the capacitors 21 to 23 having a relatively small capacity among the plurality of capacitors 21 to 25. The capacitors 24 and 25 having a relatively large capacity are not selected.

  Then, in accordance with the load current, the adjustment unit 70 turns on (closes) one of the switch elements 31 to 33 corresponding to the capacitors 21 to 23 and turns off (opens) the other switch elements. More specifically, the adjustment unit 70 adjusts the capacitance determined by the plurality of capacitors 21 to 23 based on the amount of current detected by the resistor 80. For example, when the current detected by the resistor 80 is small (when the load is light), the adjustment unit 70 reduces the capacitance determined by the plurality of capacitors 21 to 23. Thereby, the capacity | capacitance of the capacitor | condenser part 20 can be adjusted in the range of a comparatively small value.

  In the fourth embodiment, when the example of FIG. 3 is applied, as in the third embodiment, for example, when the voltage detected by the voltage detection unit 90 is low (for example, 100 V to 120 V, etc.), adjustment is performed. The unit 70 selects all of the plurality of capacitors 21 to 25. And the adjustment part 70 increases / decreases the number of the switching elements 31-35 to turn on (close) according to load current. More specifically, the adjustment unit 70 adjusts the capacitance determined by the plurality of capacitors 21 to 25 based on the amount of current detected by the resistor 80. For example, when the current detected by the resistor 80 is small (when the load is light), the adjustment unit 70 reduces the capacitance determined by the plurality of capacitors 21 to 25. Thereby, the capacity | capacitance of the capacitor | condenser part 20 can be adjusted to a big value.

  Moreover, when the voltage detected by the voltage detection unit 90 is high (for example, 200V to 240V, etc.), the adjustment unit 70 selects, for example, three capacitors 21 to 23 from among the plurality of capacitors 21 to 25, and the like. The capacitors 24 and 25 are not selected. And the adjustment part 70 increases / decreases the number of the switching elements 31-33 to turn on (close) according to load current. More specifically, the adjustment unit 70 adjusts the capacitance determined by the plurality of capacitors 21 to 23 based on the amount of current detected by the resistor 80. For example, when the current detected by the resistor 80 is small (when the load is light), the adjustment unit 70 reduces the capacitance determined by the plurality of capacitors 21 to 23. Thereby, the capacity | capacitance of the capacitor | condenser part 20 can be adjusted in the range of a comparatively small value.

  The configuration of the voltage detection unit 90 is not limited to the configuration illustrated in FIGS. 5 and 6, and any configuration is possible as long as the level of the AC voltage input to the rectifier circuit 10 can be detected. It may be configured.

  In the above-described embodiment, the capacitor unit has a configuration in which a plurality of individual capacitors are connected in parallel, and switching elements are connected in series to the respective capacitors. However, the present invention is not limited to this, and the individual switching elements are not limited thereto. For example, a configuration in which series circuits of capacitors and switching elements are connected in a vertical and horizontal matrix may be used as long as the capacitance of the entire capacitor unit can be varied by controlling the opening and closing of the capacitor.

  Further, the capacitor unit may be configured to include one capacitor whose capacity can be varied. The variable capacity capacitor is, for example, a variable capacitor (variable capacitor). In this case, the adjusting unit includes a rotating unit that rotates the rotating shaft of the variable capacitor, and the capacity can be adjusted by rotating the rotating shaft.

  In the above-described embodiment, an example in which an LED is used as a light source has been described. However, the present invention is not limited to an LED, and other light sources such as EL (Electro-Luminescence) may be used.

DESCRIPTION OF SYMBOLS 10 Rectification circuit 20 Capacitor part 21,22,23,24,25 Capacitor 30 Opening / closing part 31,32,33,34,35 Opening / closing element 40 Power factor improvement circuit 50 DC / DC converter 60 Dimming control part (current control part)
70 Adjustment unit 80 Resistance (current detection unit)
90 Voltage detector 100 Power supply 200 Light source (load)

Claims (6)

A rectifier circuit for rectifying an AC voltage applied from an AC power source, a power factor improving circuit for improving a power factor for the AC power source by controlling a current waveform by having a capacitor portion on the input side, and the power factor improving circuit In the power supply device provided with a DC / DC converter provided on the output side of the power supply and supplying a current to the load
A power supply apparatus comprising: an adjustment unit that adjusts the capacitance of the capacitor unit to be large or small according to the amount of current supplied to the load. A current control unit for outputting a control signal for controlling a current supplied to the load to the DC / DC converter;
The adjustment unit is
The power supply apparatus according to claim 1, wherein the capacity is adjusted based on the control signal. A current detection unit for detecting a current flowing through the load;
The adjustment unit is
2. The power supply device according to claim 1, wherein the capacity is adjusted to increase or decrease based on the amount of current detected by the current detection unit. A voltage detector for detecting an AC voltage applied to the rectifier circuit;
The adjustment unit is
4. The power supply according to claim 1, wherein the capacitance is adjusted to be small or large based on a voltage level detected by the voltage detection unit. 5. apparatus. The capacitor section is
Having a plurality of capacitors connected in parallel;
A plurality of switching elements connected in series with each of the plurality of capacitors and opening and closing the electric circuit,
The adjustment unit is
The power supply device according to any one of claims 1 to 4, wherein the capacitance is adjusted by opening and closing the plurality of opening and closing elements.   An illumination device comprising: the power supply device according to claim 1; and a light source to which current is supplied from the power supply device.

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