JP2013030417A - Light emitting element lighting device and illumination apparatus using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light emitting element lighting device capable of reducing the peak value of an input current to a smoothing section including a partial smoothing circuit, and an illumination apparatus using the light emitting element lighting device.SOLUTION: The light emitting element lighting device includes: a rectifier 1 that rectifies an AC voltage which is output from a commercial power source AC1; a smoothing section 2 for smoothing pulsating voltage output from the rectifier 1; a power source section 3 having a switching element Q1 to convert the output voltage from the smoothing section 2 into a predetermined DC voltage by switching the ON/OFF of the switching element Q1 to output the voltage; and a control circuit 30 that controls the ON/OFF of the switching element Q1. The smoothing section 2 has a partial smoothing circuit for partially smoothing a period of low voltage of the pulsating voltage output from the rectifier 1. The power source section 3 supplies a lighting power to a light source section 4 including plural organic EL elements 40. The smoothing section 2 is connected to a normal mode choke coil L1 at the input end thereof.

Description

  The present invention relates to a light emitting element lighting device for lighting a light emitting element such as a light emitting diode, and a lighting fixture using the same.

  In recent years, LED lighting fixtures using light emitting diodes as light sources have been provided, for example, as disclosed in Patent Document 1. The LED lighting apparatus described in Patent Document 1 includes an LED light-emitting unit including a light-emitting diode and a lighting circuit unit that supplies a current for lighting the light-emitting diode to the LED light-emitting unit. Consists of a switching power supply circuit section and a filter circuit section. The switching power supply circuit unit is a non-insulated step-down chopper circuit, and is switching-controlled by a control circuit that also serves as a power switching element (for example, MIP552 manufactured by Matsushita Electric Industrial Co., Ltd.). In this LED lighting apparatus, when the ambient temperature changes, the light output is made substantially constant by controlling the current to flow through the light emitting diode to increase the light output when the temperature is changed from low to high.

JP 2009-134946 A Japanese Patent No. 3263194 Japanese Patent No. 3327013

  By the way, an input capacitor for smoothing the voltage that has been full-wave rectified by the full-wave rectifier is connected to the input terminal of the switching power supply circuit portion of the conventional example. When the capacitance value of this input capacitor is small, the ripple component of the load current flowing through the LED light emitting unit is large.For example, when imaging with a video camera or the like, except when the shutter speed is synchronized with the power frequency of the commercial power supply, There is a risk of flickering on the screen. This ripple component can be reduced by increasing the capacitance value of the output capacitor connected to the output terminal of the switching power supply circuit, but it is very large to fill the valley of the load current that occurs at the time of zero crossing of the power supply voltage. Requires an electrolytic capacitor.

  As a remedy for the above problems, there is a method of increasing the capacitance value of the input capacitor by employing an electrolytic capacitor as the input capacitor. If the smoothing voltage by the input capacitor can maintain a certain level or more even at the time of zero crossing of the power supply voltage, a constant load current can always flow through the constant current circuit connected to the subsequent stage of the switching power supply circuit unit. That is, by increasing the capacitance value of the input capacitor, the ripple component of the load current can be removed without increasing the capacitance value of the output capacitor so much. However, in this case, since it becomes a so-called capacitor input type smoothing circuit, the conduction angle of the input current (charging current to the input capacitor) is narrowed, the power factor is as bad as 0.6 or less, and the harmonic distortion also increases. There is a problem.

  Here, in order to simultaneously reduce the ripple component of the output current (load current) of the switching power supply circuit unit and improve the power factor, a power factor correction circuit (PFC) circuit is provided in the previous stage of the constant current circuit. It is common to employ a so-called two-converter system. However, in this case, there is a problem that adding a power factor correction circuit, which is a high-frequency switching circuit, not only increases noise but also complicates the circuit.

  Therefore, instead of the input capacitor, a partial smoothing circuit that partially smoothes the low voltage period of the pulsating voltage output from the full-wave rectifier is provided as a smoothing unit, thereby reducing the ripple component of the load current and improving the power factor. A configuration to be achieved is disclosed in, for example, Patent Documents 2 and 3. With this configuration, the output voltage of the partial smoothing circuit becomes a certain level or more even in the low voltage period, so that a constant load current can be always flowed by the constant current circuit connected in the subsequent stage, and the load current ripple Ingredients can be removed. Further, the power factor can be improved as compared with the case where a capacitor input type smoothing circuit is employed.

  However, when the partial smoothing circuit is employed as described above, there is a problem that the peak value of the input current of the partial smoothing circuit increases due to a steep charging current flowing through the capacitor constituting the partial smoothing circuit. . In this case, since it is necessary to use parts with high current resistance performance, it is necessary to increase the thickness of the wires and the capacity of the switch and breaker, resulting in a problem of increasing costs and increasing the size of the device. End up.

  The present invention has been made in view of the above points, and provides a light-emitting element lighting device capable of reducing a peak value of an input current of a smoothing portion including a partial smoothing circuit and a lighting fixture using the same. With the goal.

  The light-emitting element lighting device of the present invention includes a rectifying unit that rectifies an AC voltage output from an external power source, a smoothing unit that smoothes a pulsating voltage output from the rectifying unit, a switching element, and the switching element is turned on. A power supply unit that converts the output voltage of the smoothing unit into a predetermined DC voltage and outputs the voltage by switching on / off, and a control unit that controls on / off of the switching element, and the smoothing unit includes the rectifier Comprising a partial smoothing circuit that partially smoothes the low voltage period of the pulsating voltage output by the unit, wherein the power supply unit supplies lighting power to a light source unit comprising one or more light emitting elements, and is connected to an input terminal of the smoothing unit. An inductor element is connected.

  In this light-emitting element lighting device, it is preferable that the inductance element is inserted into either a high-voltage side line or a low-voltage side line between the rectifying unit and the smoothing unit.

  In this light-emitting element lighting device, it is preferable that the control unit performs control so that the switching frequency of the switching element is lowered as the output voltage of the smoothing unit decreases.

  In this light emitting element lighting device, it is preferable that the power supply unit is composed of a step-up / down chopper circuit.

  In this light emitting element lighting device, it is preferable that the power supply unit is composed of a step-down chopper circuit.

  In the light emitting element lighting device, the light emitting element is preferably either an organic electroluminescent element or a light emitting diode.

  The lighting fixture of this invention is equipped with one of the said light emitting element lighting devices, and the fixture main body holding the said light emitting element lighting device, It is characterized by the above-mentioned.

  The present invention has the effect of reducing the peak value of the input current of the smoothing section formed of the partial smoothing circuit.

It is the circuit schematic which shows Embodiment 1 of the light emitting element lighting device which concerns on this invention. (A) is a waveform diagram of the output voltage of the partial smoothing circuit in the above light emitting element lighting device, and (b) is a waveform diagram of the output current of the step-down chopper circuit in the above light emitting element lighting device. (A) is a waveform diagram of an input current of a conventional partial smoothing circuit, and (b) is a waveform diagram of an input current of a smoothing unit in the above light emitting element lighting device. (A)-(c) is an operation | movement waveform diagram in the light emitting element lighting device same as the above. It is a figure which shows Embodiment 2 of the light emitting element lighting device which concerns on this invention, (a) is a circuit schematic, (b)-(d) is an operation | movement waveform diagram. It is the circuit schematic which shows Embodiment 3 of the light emitting element lighting device which concerns on this invention. It is the circuit schematic which shows Embodiment 4 of the light emitting element lighting device which concerns on this invention. (A)-(c) is an operation | movement waveform diagram in the light emitting element lighting device same as the above. (A), (b) is the schematic which shows embodiment of the lighting fixture which concerns on this invention.

(Embodiment 1)
Hereinafter, Embodiment 1 of the light emitting element lighting device according to the present invention will be described with reference to the drawings. In the present embodiment, as shown in FIG. 1, a rectifying unit 1 that rectifies an AC voltage of a commercial power source (external power source) AC1, a smoothing unit 2 that smoothes an output voltage of the rectifying unit 1, and a plurality of light emitting elements are connected in series. And a power source unit 3 for supplying lighting power to the light source unit 4 connected to the. In the present embodiment, the organic electroluminescence element (organic EL element) 40 is used as the light emitting element, but other light emitting elements such as a light emitting diode 41 (see FIG. 6) may be used. In the present embodiment, the power supply voltage of the commercial power supply AC1 is 100V.

  The rectification unit 1 is a full-wave rectification circuit composed of a diode bridge, and rectifies an AC voltage from the commercial power supply AC1 to output a pulsating voltage. Note that a fuse F1, a surge protection element Z1, and a capacitor C1 for removing harmonics are connected between the commercial power supply AC1 and the rectifying unit 1. In addition, a capacitor C2 that forms an LC filter with a normal mode choke coil L1 (inductance element) to be described later is connected to the output terminal of the rectifying unit 1.

  The smoothing unit 2 is a partial smoothing circuit that partially smoothes the low voltage period of the pulsating voltage output from the rectifying unit 1, and includes capacitors C3 and C4 having substantially the same capacity, a resistor R1, and diodes D1 to D3. Consists of. Between the negative electrode of the capacitor C3 and the positive electrode of the capacitor C4, a diode D2 and a resistor R1 are connected in the direction in which the charging current flows. A diode D1 is connected between the negative electrode of the capacitor C3 and the negative electrode of the capacitor C4 in the direction in which the discharge current of the capacitor C3 flows. A diode D3 is connected between the positive electrode of the capacitor C3 and the positive electrode of the capacitor C4 in the direction in which the discharge current of the capacitor C4 flows. The smoothing unit 2 partially smoothes the pulsating voltage output from the rectifying unit 1 only during the low voltage period (see FIG. 2A). Hereinafter, this low voltage period is referred to as a “valley”, and the other period is referred to as a “mountain”.

  The power supply unit 3 is composed of a step-down chopper circuit that steps down and outputs the output voltage of the smoothing unit 2 to a predetermined DC voltage, and includes a switching element Q1 composed of an inductor L2, a diode D4, a capacitor C5, a field effect transistor (FET), and A control circuit 30 (control unit) is provided. In the present embodiment, since the switching element Q1 is installed on the ground line side, stable switching control can be performed.

  The control circuit 30 is a driving IC that controls on / off of the switching element Q1, and in this embodiment, HV9910 (manufactured by Supertex) is used. This HV9910 has a constant off-time mode in which the OFF period of the switching element Q1 is controlled to a fixed period. A detection resistor R2 for detecting the drain current of the switching element Q1 is connected in series to the switching element Q1. In the present embodiment, the switching element Q1 and the control circuit 30 are provided separately. However, the control circuit 30 may be configured by a driving IC that incorporates the switching element Q1.

  Hereinafter, the operation of the power supply unit 3 of the present embodiment will be described. In the present embodiment, the power consumption of the light source unit 4 is 5 to 25 W, and the switching frequency of the switching element Q1 is several tens to several hundreds kHz. First, when the switching element Q1 is switched on by the control circuit 30, a current flows through a path of the light source unit 4 → the inductor L2 → the switching element Q1 → the detection resistor R2 → the ground. At this time, the rising speed of the current flowing through the inductor L2 (the drain current of the switching element Q1) changes based on the level of the input voltage of the power supply unit 3 (the output voltage of the smoothing unit 2). That is, when the output voltage of the smoothing unit 2 is low (for example, a valley), the rising speed of the current flowing through the inductor L2 is slow, and when the output voltage of the smoothing unit 2 is high (for example, a peak), the inductor L2 The rising speed of the current flowing through becomes faster.

  When the current flowing through the inductor L2 rises, the voltage across the detection resistor R2 also rises. When the voltage across the resistor exceeds a threshold voltage preset by the control circuit 30, the control circuit 30 switches the switching element Q1 off. When the switching element Q1 is switched off, a current flows in a closed loop of the inductor L2, the diode D4, and the light source unit 4, and the current flowing through the inductor L2 gradually decreases. The control circuit 30 switches the switching element Q1 on again after a predetermined time has elapsed since the switching element Q1 was switched off.

  As described above, the control circuit 30 controls the timing for switching the switching element Q1 from on to off in the Peak-Current mode, and controls the timing for switching the switching element Q1 from off to on in the constant off-time mode. Thereafter, by repeating the above operation, the control circuit 30 controls the switching element Q1 in the current continuous mode. Thereby, the output voltage of the power supply unit 3 is controlled to be constant, and the load current flowing through the light source unit 4 is also controlled to be constant (see FIG. 2B).

  As described above, in the present embodiment, a voltage higher than a certain level can be secured even in the valley of the output voltage of the smoothing unit 2, so that the power source unit 3 can always output a constant current. For this reason, the ripple component superimposed on the output current of the power supply unit 3, that is, the load current can be reduced. Further, in this embodiment, since the smoothing unit 2 is configured by a partial smoothing circuit, it is possible to suppress the conduction angle of the input current from being narrowed as compared with the capacitor input type smoothing circuit, and the power factor is 0. It is possible to improve to .85 or more. Furthermore, since the power factor can be prevented from lowering by using the partial smoothing circuit, there is no need to use a power factor correction circuit as in the prior art, and the circuit configuration is not complicated.

  Here, as shown in FIG. 3A, the input current of the smoothing unit 2 has a peak due to an increase in the input current during the low voltage period of the pulsating voltage output from the rectifying unit 1 (as shown in FIG. 3A). Arrows (1), (3)). Further, the input current of the smoothing unit 2 has a peak (see arrow (2) in the figure) due to a steep charging current flowing through the capacitors C3 and C4 of the partial smoothing circuit. The peak at the end of the input current waveform (see arrow (1) in the figure) appears near a phase angle of 0 to 70 degrees, and the peak near the center of the input current waveform (see arrow (2) in the figure). ) Appears around a phase angle of 60 to 90 degrees. In the present embodiment, the normal mode choke coil L1 is inserted in the high-voltage side line between the output end of the rectifying unit 1 and the input end of the smoothing unit 2. The LC filter formed by the normal mode choke coil L1 and the capacitor C2 can reduce the peak value of the input current of the smoothing unit 2 generated when the capacitors C3 and C4 constituting the partial smoothing circuit are charged. That is, by inserting the normal mode choke coil L1, as shown in FIG. 3 (b), it is possible to suppress a steep charging current from flowing through the capacitors C3 and C4 of the partial smoothing circuit, and the peak of the input current. The value (see arrow (2) in the figure) can be reduced.

  Therefore, for example, when a plurality of the present embodiments are used, it is not necessary to use a component having a large current resistance performance. Therefore, it is possible to reduce the thickness of the electric wire or reduce the capacity of the switch or the breaker. . Further, by lowering the peak value in the vicinity of the center of the input current of the smoothing unit 2, the input current waveform becomes slanted as a whole, and the effect of reducing noise and reducing stress on the components constituting the circuit is also obtained. be able to. Furthermore, since the normal mode choke coil L1 is used in the present embodiment, the normal mode inductor component can be increased even if the size is small compared to the case where the common mode choke coil is used. Therefore, in this embodiment, it is possible to effectively reduce the peak value of the input current of the smoothing unit 2 and reduce noise.

  By the way, the ON period of the switching element Q1 corresponds to a period from when the switching element Q1 is switched on until the current flowing through the inductor L2 reaches the peak value set by the control circuit 30. As described above, since the rising speed of the current flowing through the inductor L2 changes based on the level of the output voltage of the smoothing unit 2, the ON period of the switching element Q1 is based on the level of the output voltage of the smoothing unit 2. (Refer to FIGS. 4A to 4C). In the present embodiment, the off period of the switching element Q1 is constant by the control of the control circuit 30 in the constant off-time mode. Therefore, when the ON period of the switching element Q1 varies, the switching frequency of the switching element Q1 spreads without being constant. The switching frequency is lowest at the valley of the output voltage of the smoothing unit 2.

  As described above, in this embodiment, since the switching frequency is diffused by changing the switching frequency based on the level of the output voltage of the smoothing unit 2, the noise accompanying the switching control of the switching element Q1 is reduced. Can do. When the smoothing unit 2 is configured by a capacitor input type smoothing circuit, the output voltage of the smoothing unit 2 is smoothed to a constant voltage, so that the switching frequency cannot be spread. Therefore, it is desirable to configure the smoothing unit 2 with a partial smoothing circuit whose output voltage varies as in this embodiment.

  In particular, in the present embodiment, the control circuit 30 performs control so that the switching frequency of the switching element Q1 is lowered as the output voltage of the smoothing unit 2 decreases. As a result, compared to the case where the switching element Q1 is operated at a constant high frequency over one cycle, the noise can be reduced as a whole and the switching loss can be reduced when there is a period during which the switching element Q1 is operated at a low frequency. can do. As described above, in this embodiment, the ripple component of the load current can be reduced, the power factor can be improved, and the noise can be reduced with a simple circuit configuration.

  Here, the light output of the organic EL element 40 and the light emitting diode 41 which are light emitting elements constituting the light source unit 4 is proportional to the load current flowing through the element. For this reason, if the ripple component superimposed on the load current increases, it causes a flicker in the optical output as it is. Therefore, this embodiment that reduces the ripple component of the load current is more effective when the light emitting element is the organic EL element 40 or the light emitting diode 41. In particular, since the organic EL element 40 is a surface light source, the organic EL element 40 has a high capacity component. If the ripple component is large, the charge / discharge current increases and the loss may increase. For this reason, this embodiment can demonstrate an effect more if the light emitting element is the organic EL element 40. FIG.

  For example, HV9961 (manufactured by Supertex) may be adopted as the control circuit 30, and the timing of switching the switching element Q1 from on to off may be controlled by the Average-Current mode instead of the Peak-Current mode. That is, in this HV9961, when the average value of the drain current of the switching element Q1 flowing through the detection resistor R2 exceeds a preset threshold current, the switching element Q1 is controlled to be turned off. When controlling in this Average-Current mode, the variation in the output current of the power supply unit 3 can be further suppressed.

  Further, as the control circuit 30, L6562A (manufactured by STMicroelectronics) may be adopted. However, since this driving IC does not have a function for controlling the OFF period of the switching element Q1 to be constant (constant off-time mode), a circuit for controlling the OFF period of the switching element Q1 to be constant is separately provided. It is necessary to provide it. For details, refer to AN2928 (http://www.st.com/internet/com/TECHNICAL_RESOURCES/TECHNICAL_LITERATURE/APPLICATION_NOTE/CD00222928.pdf) of Application Note of STMicroelectronics.

  Of course, if only the effect of reducing the peak value of the input current of the smoothing unit 2 is to be exhibited, the control circuit 30 does not perform the control for changing the switching frequency of the switching element Q1 as described above, and the switching frequency is reduced. You may control so that it may become fixed.

(Embodiment 2)
Hereinafter, Embodiment 2 of the light emitting element lighting device according to the present invention will be described with reference to the drawings. However, since the basic configuration of the present embodiment is common to that of the first embodiment, common portions are denoted by the same reference numerals and description thereof is omitted. In the present embodiment, as shown in FIG. 5A, a current flowing through the inductor L2, that is, a secondary winding L20 of the inductor L2 for detecting the load current is provided, as shown in FIGS. 5B to 5D. Thus, the control circuit 30 is characterized by controlling the switching element Q1 in the current critical mode. In the present embodiment, a line filter LF1 is provided between the commercial power supply AC1 and the rectifying unit 1 instead of the surge protection element Z1.

  Hereinafter, the operation of the power supply unit 3 of the present embodiment will be described. First, when the switching element Q1 is switched on by the control circuit 30, a current flows through a path of the light source unit 4 → the inductor L2 → the switching element Q1 → the detection resistor R2 → the ground. At this time, the rising speed of the current flowing through the inductor L2 changes based on the level of the output voltage of the smoothing unit 2. That is, when the output voltage of the smoothing unit 2 is low (for example, a valley), the rising speed of the current flowing through the inductor L2 is slow, and when the output voltage of the smoothing unit 2 is high (for example, a peak), the inductor L2 The rising speed of the current flowing through becomes faster.

  When the current flowing through the inductor L2 rises, the voltage across the detection resistor R2 also rises. When the voltage across the resistor exceeds a threshold voltage preset by the control circuit 30, the control circuit 30 switches the switching element Q1 off. When the switching element Q1 is switched off, a current flows in a closed loop of the inductor L2, the diode D4, and the light source unit 4, and the current flowing through the inductor L2 gradually decreases. The control circuit 30 detects the current flowing through the inductor L2 by the voltage induced in the secondary winding L20 of the inductor L2, and when it detects that the current becomes zero, it switches the switching element Q1 on again.

  In this way, the control circuit 30 controls the timing at which the switching element Q1 is switched from on to off in the Peak-Current mode, and detects the zero crossing of the current flowing through the inductor L2 at the timing at which the switching element Q1 is switched from off to on. To control. Thereafter, by repeating the above operation, the control circuit 30 controls the switching element Q1 in the current critical mode. Thereby, the output voltage of the power supply unit 3 is controlled to be constant, and the load current flowing through the light source unit 4 is also controlled to be constant.

  Here, the ON period of the switching element Q1 corresponds to a period from when the switching element Q1 is switched on until the current flowing through the inductor L2 reaches the peak value set by the control circuit 30. As described above, since the rising speed of the current flowing through the inductor L2 changes based on the level of the output voltage of the smoothing unit 2, the ON period of the switching element Q1 is based on the level of the output voltage of the smoothing unit 2. (See FIGS. 5B to 5D). Therefore, when the ON period of the switching element Q1 varies, the switching frequency of the switching element Q1 spreads without being constant. The switching frequency is lowest at the valley of the output voltage of the smoothing unit 2.

  As described above, in the present embodiment, as in the first embodiment, the switching frequency is diffused by changing the switching frequency based on the level of the output voltage of the smoothing unit 2, so that the switching control of the switching element Q1 is performed. Can be reduced. In the present embodiment, since the control circuit 30 controls the switching element Q1 in the current critical mode, noise can be more effectively reduced and higher efficiency can be achieved.

  As the control circuit 30, for example, L6562A (manufactured by STMicroelectronics) may be employed, or SSL2108x (manufactured by NXP Semiconductors) may be employed. Further, instead of the above-described Peak-Current mode, the timing at which the switching element Q1 switches from on to off may be controlled in the Average-Current mode, as in the first embodiment. When controlling in this Average-Current mode, the variation in the output current of the power supply unit 3 can be further suppressed.

  By the way, in this embodiment, the current flowing through the inductor L2 is detected by the secondary winding L20 of the inductor L2, and when the current falls below a preset threshold current, the control circuit 30 switches on the switching element Q1. You may control. In this case, the control circuit 30 controls the switching element Q1 not in the current critical mode but in the current continuous mode. In this embodiment, the current flowing through the inductor L2 is detected by the secondary winding L20 of the inductor L2, but the current flowing through the inductor L2 may be detected by other means.

(Embodiment 3)
Hereinafter, Embodiment 3 of the light emitting element lighting device according to the present invention will be described with reference to the drawings. However, since the basic configuration of the present embodiment is common to that of the first embodiment, common portions are denoted by the same reference numerals and description thereof is omitted. As shown in FIG. 6, the present embodiment is characterized in that the power supply unit 3 is configured by a step-up / step-down chopper circuit. In the present embodiment, a light emitting diode 41 is employed as the light emitting element of the light source unit 4. Moreover, in this embodiment, the output voltage of the power supply part 3 is about 60-80V.

  Here, it is generally known that if the power consumption of the light source unit 4 is the same, the circuit efficiency improves as the load voltage applied to the light source unit 4 increases. Therefore, the circuit efficiency can be improved by increasing the output voltage of the power supply unit 3 and increasing the load voltage of the light source unit 4. However, when the power supply unit 3 is configured by a step-down chopper circuit as in the first and second embodiments, it is necessary to control the output voltage of the power supply unit 3 to be lower than the minimum value of the output voltage of the smoothing unit 2. is there. If there is a period in which the output voltage of the power supply unit 3 is higher than the output voltage of the smoothing unit 2, the output voltage of the smoothing unit 2 is not boosted in this period, so that a trough occurs in the output voltage of the power supply unit 3. A valley portion is also generated in the load current.

  On the other hand, in the present embodiment, since the power supply unit 3 is configured by a step-up / step-down chopper circuit, even if there is a period in which the output voltage of the power supply unit 3 is higher than the output voltage of the smoothing unit 2, The output voltage of the smoothing unit 2 is boosted. For this reason, unlike the case where the power supply unit 3 is configured by a step-down chopper circuit, there is no possibility that a valley portion is generated in the load current, and stable constant current control can be performed. Thus, in this embodiment, since the output voltage of the power supply part 3 can be raised irrespective of the low voltage period of the output voltage of the smoothing part 2, circuit efficiency can be improved more. In particular, the present embodiment is effective when the power consumption of the light source unit 4 is high to some extent (for example, 5 W or more).

  In the present embodiment, the normal mode choke coil L1 is inserted into the ground-side line between the output end of the rectifying unit 1 and the input end of the smoothing unit 2. In this way, noise can be reduced more effectively by inserting the normal mode choke coil L1 into the same line as the switching element Q1.

(Embodiment 4)
Hereinafter, Embodiment 4 of the light emitting element lighting device according to the present invention will be described with reference to the drawings. However, since the basic configuration of the present embodiment is common to that of the second embodiment, common portions are denoted by the same reference numerals and description thereof is omitted. As shown in FIG. 7, the basic configuration of the present embodiment is the same as that of the second embodiment, but the output voltage of the smoothing unit 2 increases with time in the valley of the output voltage of the smoothing unit 2. This is characterized in that the capacitances of the capacitors C3 and C4 of the smoothing unit 2 are reduced so as to decrease. In the figure, the detection resistor R2 and the control circuit 30 are omitted, and the switching element Q1 is simplified.

  As in the first embodiment, the control circuit 30 according to the present embodiment controls the timing at which the switching element Q1 is switched from on to off in the Peak-Current mode, and the timing at which the switching element Q1 is switched from off to on is constant off-time. Control by mode. However, in the present embodiment, the control circuit 30 controls the switching element Q1 in the current discontinuous mode by setting the off period of the switching element Q1 longer than that in the first embodiment (FIG. 8B, (See (c)).

  The capacitors C3 and C4 of the smoothing unit 2 are charged during a period other than the low voltage period of the pulsating voltage output from the rectifying unit 1, and are discharged during the low voltage period. In the present embodiment, by reducing the capacitance of the capacitors C3 and C4 of the smoothing unit 2, the capacitors C3 and C4 are discharged at the valleys of the output voltage of the smoothing unit 2, so that the output voltage of the smoothing unit 2 is reduced. It gradually decreases with a predetermined inclination (see FIG. 8A). Therefore, in the present embodiment, the on-period of the switching element Q1 varies as the output voltage varies even in the valley of the output voltage of the smoothing unit 2, and the switching frequency is more diffused than in the first to third embodiments. be able to. For this reason, in this embodiment, noise can be reduced more effectively.

  In the present embodiment, as shown in FIG. 7, the switching element Q1 is installed in the line on the high voltage side. As a result, the ground-side line is stabilized, and noise can be reduced. Further, in the present embodiment, the normal mode choke coil L1 is inserted into the high voltage side line between the output end of the rectifying unit 1 and the input end of the smoothing unit 2. In this way, noise can be reduced more effectively by inserting the normal mode choke coil L1 into the same line as the switching element Q1. In this embodiment, the capacitor C2 is not connected to the output terminal of the rectifying unit 2, but an LC filter is formed between the capacitors C3 and C4 of the smoothing unit 2 and the normal mode choke coil L1.

  By the way, in this embodiment, although the power supply part 3 is comprised with the pressure | voltage fall chopper circuit, you may comprise with a buck-boost chopper circuit similarly to Embodiment 3. FIG. In this case, as shown in FIG. 8A, if the output voltage of the power supply unit 3 is controlled so as to be higher than the minimum value of the output voltage of the smoothing unit 2 (see the arrow c in FIG. 8), a stable constant value is obtained. Current control can be performed. In addition, if the output voltage of the power supply unit 3 is controlled to be higher than the voltage value at the valley of the output voltage of the smoothing unit 2 (see the arrow b in the figure), the ripple component of the output current can be greatly reduced. it can. Furthermore, the circuit efficiency can be improved by controlling the output voltage of the power supply unit 3 to be a voltage value (see arrow a in the figure) larger than the trough portion of the output voltage of the smoothing unit 2.

  Hereinafter, embodiments of a lighting apparatus according to the present invention will be described with reference to the drawings. First, an embodiment of a lighting fixture using an organic EL element 40 as a light emitting element of the light source unit 4 will be described. In addition, the light emitting element lighting device A1 in the present embodiment uses the lighting device in any one of the above embodiments.

  In this embodiment, as shown in FIG. 9A, a plurality of (four in the figure) light source units 4 which are panel type illumination modules using the organic EL elements 40 as light emitting elements, and each light source unit 4 are mounted. It is comprised with the panel-type instrument main body 5 made. The light emitting element lighting device A1 installed separately from the fixture body 5 and each light source unit 4 are electrically connected to each light source unit 4 from the light emitting element lighting device A1 by electrically connecting the light source unit 4 with a cable or the like (not shown). Supply lighting power.

  As described above, in the present embodiment, by using the light emitting element lighting device A1 of any one of the above embodiments, the same effects as any of the above embodiments can be achieved. Moreover, in this embodiment, since the organic EL element 40 which is a surface light source is used as a light emitting element, a thin lighting fixture can be implement | achieved and it can utilize suitably, for example for indoor illumination.

  Next, an embodiment of a lighting fixture using a light emitting diode 41 as a light emitting element of the light source unit 4 will be described. In the following description, the vertical direction in FIG. 9B is defined as the vertical direction. In addition, the lighting device A1 in this embodiment uses the lighting device in any one of the above embodiments.

  As shown in FIG. 9 (b), the present embodiment is composed of a light source unit 4 using a light emitting diode 41 as a light emitting element and an instrument body 6 that houses the light source unit 4, and the instrument body 6 is embedded in the ceiling. It is arranged. The instrument body 6 is made of metal such as aluminum die casting, for example, and is formed in a bottomed cylindrical shape having an open lower end. A light source unit 4 including a plurality of (four in the drawing) light emitting diodes 41 and a substrate 42 on which a series circuit of the light emitting diodes 41 is mounted is disposed inside the instrument body 6. Each light emitting diode 41 is arranged so that the direction of light irradiation is downward in order to irradiate the external space with light from the lower end of the instrument body 6. In addition, a light diffusing plate 7 for diffusing light from each light emitting diode 41 is provided in the opening at the lower end of the instrument body 6.

  A heat radiating plate 8 is disposed on the upper surface of the substrate 42, and heat generated by each light emitting diode 41 is released to the instrument body 6 via the heat radiating plate 8. In addition, a light emitting element lighting device A1 is disposed on the upper side of the light source unit 4 inside the instrument body 6, and the light emitting element lighting device A1 and the light source unit 4 are connected by a lead wire 9.

  As described above, in the present embodiment, by using the light emitting element lighting device A1 of any one of the above embodiments, the same effects as any of the above embodiments can be achieved.

DESCRIPTION OF SYMBOLS 1 Rectification part 2 Smoothing part 3 Power supply part 30 Control circuit (control part)
4 Light source 40 Organic EL element (light emitting element)
AC1 Commercial power supply (external power supply)
L1 Normal mode choke coil (inductor element)
Q1 switching element

Claims (7)

  A rectifier that rectifies an AC voltage output from an external power source, a smoother that smoothes a pulsating voltage output from the rectifier, and a smoothing unit that includes a switching element and switches on / off the switching element. A power supply unit that converts the output voltage into a predetermined DC voltage and outputs the power, and a control unit that controls on / off of the switching element, and the smoothing unit reduces a pulsating voltage output from the rectifying unit. It comprises a partial smoothing circuit that partially smoothes the voltage period, the power supply unit supplies lighting power to a light source unit comprising one or more light emitting elements, and an inductor element is connected to the input terminal of the smoothing unit. A light emitting element lighting device.   The light emitting element lighting device according to claim 1, wherein the inductance element is inserted into either a high voltage side line or a low voltage side line between the rectifying unit and the smoothing unit.   3. The light emitting element lighting device according to claim 1, wherein the control unit performs control so as to lower a switching frequency of the switching element as the output voltage of the smoothing unit decreases.   The light-emitting element lighting device according to claim 1, wherein the power supply unit includes a step-up / down chopper circuit.   The light-emitting element lighting device according to claim 1, wherein the power supply unit includes a step-down chopper circuit.   The light-emitting element lighting device according to claim 1, wherein the light-emitting element is an organic electroluminescence element or a light-emitting diode. An illumination fixture comprising: the light-emitting element lighting device according to any one of claims 1 to 6; and a fixture main body that holds the light-emitting element lighting device.

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