JP6072460B2 - Lighting device and power supply device - Google Patents

Description

  The present invention relates to a lighting device and a power feeding device using LEDs (Light Emitting Diodes).

  In recent years, replacement of incandescent light bulbs with LED lighting has been accelerated, and LED lighting has been widely used even outdoors. In LED lighting installed outdoors, it is necessary to route a long electric wire from the power source to the LED light source.

  The power supply method to the LED light source is roughly classified into a direct current method and an alternating current method. The direct current method is a method in which a commercial power source is converted to direct current on the power supply side, and direct current is supplied to the LED light source via a power transmission line. The AC method is a method in which commercial current is supplied as it is from the power supply side to the LED light source via the power transmission line and rectified on the LED light source side (see, for example, Patent Document 1). In the direct current method, no reactive power is generated unlike the alternating current method, and in principle, a period lower than the forward voltage drop Vf of the LED does not occur. Therefore, it is highly efficient and has little flicker.

  Outdoors are more susceptible to rain and moisture than indoors, so electrolytic corrosion and ion migration are likely to occur outdoors. Since electrolytic corrosion and ion migration can be suppressed if moisture does not enter the metal part or circuit part, it is desirable to perform complete waterproofing. However, a complete increase in cost is required to completely waterproof the LED element, socket, and wiring.

  Electrolytic corrosion proceeds when an electrolyte solution exists between metals to which a voltage is applied, and the high-potential metal elutes into ions by electrolysis. In the AC method in which the anode and the cathode are periodically changed, the occurrence of electrolytic corrosion can be greatly suppressed as compared with the DC method in which the potential is fixed and ionization proceeds.

JP 2008-263203 A

  As described above, the conventional DC method and the AC method have advantages and disadvantages. Under such circumstances, the present inventor has developed a new power supply system for the LED light source.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a power supply system to an LED light source that has excellent electrolytic corrosion resistance, high efficiency, and low cost.

  In order to solve the above-described problem, an illumination device according to an aspect of the present invention includes an LED light source device having a rectifying function and a power supply device that supplies current to the LED light source device. The power supply apparatus includes an alternating direct current generation circuit that alternately generates direct currents having different polarities.

  Another aspect of the present invention is a power feeding device. This device is a power supply device that supplies current to an LED light source device that has a rectifying function, and includes an alternating direct current generation circuit that alternately generates direct currents having different polarities.

  It should be noted that any combination of the above-described constituent elements and a representation obtained by converting the expression of the present invention between apparatuses, methods, systems, etc. are also effective as an aspect of the present invention.

  According to the present invention, the LED light source can be fed with excellent electrolytic corrosion resistance, high efficiency and low cost.

It is a figure for demonstrating an alternating current drive system. It is a figure which shows the structure of the illuminating device using the alternate direct current drive system based on Embodiment 1 of this invention. It is a figure which shows the circuit structural example of the alternating direct current generation circuit of FIG. 2, and a LED light source device. FIGS. 4A and 4B are diagrams for explaining a drive current generated by the power supply apparatus according to the first embodiment. It is a figure which shows the structure of the illuminating device using the alternate direct current drive system based on Embodiment 2 of this invention. It is a figure which shows the circuit structural example 1 of the alternating direct current generation circuit of FIG. 5, and a LED light source device. It is a figure which shows the circuit structural example 2 of the alternating direct current generation circuit of FIG. 5, and a LED light source device. FIGS. 8A to 8C are diagrams illustrating an example of alternating DC current on which a lighting control signal is superimposed.

  First, before describing the embodiment of the present invention, the LED driving method will be described. The LED driving methods are roughly classified into a DC driving method and an AC driving method. A general direct current driving method is a method of supplying a constant current to the LED. A general AC driving method is a method in which a sine wave current is rectified and supplied to an LED.

  FIG. 1 is a diagram for explaining an AC driving method. The waveform shown in FIG. 1 is a waveform obtained by full-wave rectifying a sine wave. For example, it is a waveform obtained by full-wave rectification of commercial power. In the AC drive method, this full-wave rectified AC current is supplied to the LED. As shown in FIG. 1, even if the sine wave is full-wave rectified, the peak voltage Vp of the sine wave after rectification becomes high, and a section exceeding the forward voltage drop Vf of the LED is generated. In FIG. 1, a reactive power period T1 indicates a period in which energy is not consumed only by LEDs and the remaining energy is generated as heat. The extinguishing period T2 indicates a period in which the LED is extinguished because the voltage applied to the LED falls below the forward voltage drop Vf. Since the response speed of the LED is fast, the LED is turned off instantaneously when it falls below the forward voltage drop Vf.

  As described above, the AC driving method generates wasteful power. In addition, flickering occurs because the LED is turned off. By providing a smoothing capacitor in the subsequent stage of the rectifier circuit, they can be mitigated, but the cost increases. When an unspecified number of LEDs are connected in parallel as in decorative lighting, many capacitors are required, and a separate capacity design is required, which is not practical.

  An LED is basically an element suitable for a direct current drive system. The DC drive method is highly efficient because almost no reactive power is generated. Further, since a relatively high voltage near the peak value is not applied to the LED, the durability of the LED is improved. In addition, since the section below the forward drop voltage Vf does not basically occur, the flicker hardly occurs. The incandescent lamp is more suitable for the AC drive method because the filament life is shorter in the DC drive method.

  Although a direct current drive method is basically suitable for LEDs, the direct current drive method has a problem that the above-described electrolytic corrosion is likely to occur. Since the LED light source itself is small, it is relatively easy to completely waterproof, but it is difficult to completely waterproof the entire power feeding system including the socket and the power transmission line. In general plastic packaging, it is difficult to completely prevent water leakage. Complete waterproofing requires packaging or coating using expensive materials such as glass, metal and natural rubber, which increases costs. In particular, when it is necessary to construct a large-scale wiring network such as decorative lighting, the cost is greatly increased.

  The present inventor has developed an LED driving system that improves all of these problems. The driving method is a method of alternately supplying direct currents having different polarities to the LED light source. Hereinafter, this driving method is referred to as an alternating DC driving method in this specification. Hereinafter, the alternating DC driving method will be described in detail.

  FIG. 2 is a diagram showing a configuration of lighting apparatus 500 using the alternating DC driving method according to Embodiment 1 of the present invention. The illumination device 500 includes a power supply device 100 and an LED light source device 200. The power supply device 100 and the LED light source device 200 are connected by a power transmission line 300, and the power supply device 100 supplies a drive current to the LED light source device 200 through the power transmission line 300.

  The LED light source device 200 is installed outdoors. The power feeding apparatus 100 is installed indoors. The power transmission line 300 has a part installed indoors and a part installed outdoors. In the present specification, the LED light source device 200 is assumed to be used as decorative lighting for lighting up a building or a tree.

  The LED light source device 200 is an LED light source having a rectifying action. An existing LED light source for AC driving to which commercial power is input can be used as it is. The power feeding apparatus 100 includes an AC-DC converter 20 and an alternating direct current generation circuit 10. The AC-DC converter 20 converts AC power from the commercial power supply 50 into DC power. At that time, the AC-DC converter 20 steps down the voltage of the commercial power supply 50 according to the rated voltage of the LED light source device 200. The AC-DC converter 20 supplies the converted DC power to the alternating DC generation circuit 10.

  In this specification, the commercial power source 50 is assumed as the power source of the LED light source device 200, but a battery may be used instead of the commercial power source 50. When using a battery, a DC-DC converter is used instead of the AC-DC converter 20.

  The alternating direct current generating circuit 10 alternately generates direct currents having different polarities. More specifically, positive DC current and negative DC current in which energy symmetry is maintained are generated alternately. A specific circuit configuration will be described below.

  FIG. 3 is a diagram illustrating a circuit configuration example of the alternating DC generation circuit 10 and the LED light source device 200 of FIG. The LED light source device 200 includes a rectifier circuit, an LED (D5), and a resistor R1.

  The rectifier circuit is composed of a diode bridge circuit. The diode bridge circuit includes a first rectifying diode D1, a second rectifying diode D2, a third rectifying diode D3, and a fourth rectifying diode D4. The first power transmission line 300a is connected to the coupling point between the anode terminal of the first rectifying diode D1 and the cathode terminal of the third rectifying diode D3. The second power transmission line 300b is connected to the coupling point between the anode terminal of the second rectifying diode D2 and the cathode terminal of the fourth rectifying diode D4. The anode terminal of the LED (D5) is connected to the coupling point between the cathode terminal of the first rectifying diode D1 and the cathode terminal of the second rectifying diode D2. The cathode terminal of the LED (D5) is connected to a coupling point between the anode terminal of the third rectifying diode D3 and the anode terminal of the fourth rectifying diode D4 via the resistor R1.

  When commercial power is supplied to the LED light source device 200, the current having the waveform shown in FIG. 1 is supplied to the LED (D5). The AC drive LED light source is not limited to the circuit configuration shown in FIG. 3, and a circuit configuration in which a plurality of LEDs are anti-parallel connected may be employed. In this case, a rectifier circuit is not necessary, but only half the number of LEDs are turned on instantaneously.

  The alternating DC generation circuit 10 includes an oscillation circuit 11, an inverter IN1, and an H bridge circuit 12. The power supply terminal of the H bridge circuit 12 is connected to the output terminal of a direct current power supply (AC-DC converter 20 in the present embodiment). In the H-bridge circuit 12, a first switch series circuit and a second switch series circuit are provided in parallel between a power supply terminal and a ground terminal. The first switch series circuit is a circuit in which the first switch S1 and the second switch S2 are connected in series, and the second switch series circuit is a circuit in which the third switch S3 and the fourth switch S4 are connected in series. A connection point between the first switch S1 and the second switch S2 is connected to the first power transmission line 300a, and a connection point between the third switch S3 and the fourth switch S4 is connected to the second power transmission line 300b. For example, a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) or a relay can be adopted as the first switch S1, the second switch S2, the third switch S3, and the fourth switch S4.

  The oscillation circuit 11 generates a rectangular wave that is to be input to the H-bridge circuit 12 and whose polarity is alternately switched. The oscillation circuit 11 outputs the generated rectangular wave signal to the control terminals of the first switch S1 and the fourth switch S4 and the input terminal of the inverter IN1. The output terminal of the inverter IN1 is connected to the control terminals of the second switch S2 and the third switch S3. The inverter IN1 inverts the phase of the rectangular wave signal input from the oscillation circuit 11, and outputs the rectangular wave signal having the opposite phase to the control terminals of the second switch S2 and the third switch S3.

  During a period in which a positive pulse is generated by the oscillation circuit 11, the first switch S1 and the fourth switch S4 are turned on, and the second switch S2 and the third switch S3 are turned off. In this case, a current is supplied via the first power transmission line 300a, and the second power transmission line 300b becomes a ground line. On the other hand, during the period in which the negative pulse is generated, the second switch S2 and the third switch S3 are turned on, and the first switch S1 and the fourth switch S4 are turned off. In this case, a current is supplied via the second power transmission line 300b, and the first power transmission line 300a becomes a ground line.

  An inexpensive commercially available motor driver IC can be adopted for the H bridge circuit 12 and the inverter IN1. An LED does not generate a large inrush current unlike an incandescent light bulb, and the power supply voltage is low, so an inexpensive motor driver IC is sufficient.

  The designer can arbitrarily adjust the polarity switching interval by arbitrarily adjusting the oscillation frequency of the oscillation circuit 11. When the commercial power supply 50 is directly connected to the LED light source device 200, the polarity is switched at a commercial frequency (50 Hz / 60 Hz in Japan). However, if the turn-off timing of the LED (D5) due to the zero cross of the sine wave and the exposure timing of the camera are synchronized, an image with the LED (D5) turned off is captured.

  In recent years, high-speed cameras of 60/120/240 fps have been put into practical use. When an existing AC drive type LED illumination is taken with a high-speed camera, a frame in which the LED illumination light is not captured is easily generated. On the other hand, the frequency can be arbitrarily adjusted in the alternating DC drive system according to the present embodiment. Therefore, if the frequency is set so as to be synchronized with the frame rate of the camera, it is possible to prevent the generation of a frame in which the LED illumination light is not reflected.

  In general, a dead time is inserted into the rectangular wave signal supplied to the H-bridge circuit in order to reliably suppress the through current and perform zero crossing during switching. Also in this embodiment, it is preferable to provide a time lag between adjacent pulses of the rectangular wave signal generated by the oscillation circuit 11. In this case, a time lag adding circuit (not shown) is inserted after the oscillation circuit 11. In the dead time due to this time lag, the first switch S1, the second switch S2, the third switch S3, and the fourth switch S4 are all turned off, and at that moment, the power supplied to the LED light source device 200 becomes zero.

  A buffer for adjusting the slew rate may be provided at the output stage of the H-bridge circuit 12. Noise can be reduced by lowering the slew rate of the output current of the power supply apparatus 100.

  FIGS. 4A and 4B are diagrams for explaining the drive current generated by the power supply apparatus 100 according to the first embodiment. 4A shows a current waveform output from the power supply apparatus 100, and FIG. 4B shows a current waveform supplied to the LED (D5). The rectifier circuit of the LED light source device 200 rectifies the current shown in FIG. 4A and outputs the current shown in FIG. The period T3 in FIG. 4B occurs when the slew rate of the output current of the power supply apparatus 100 is reduced for noise suppression. When the slew rate is lowered, the slopes of the rising edge and the falling edge become gentle, so that a period in which the current is reduced occurs when the polarity is switched. However, the frequency can be arbitrarily adjusted in the alternating DC driving method according to the present embodiment. Accordingly, if the frequency is set higher than the frequency at which human eyes can detect flicker, flicker can be prevented from being detected.

  As described above, according to the first embodiment, a direct current is supplied to the LED light source device 200 having a rectifying function for alternating current driving by alternately switching the polarity every predetermined time. As a result, the electrodes are alternately replaced, so that electrolytic corrosion is less likely to occur as in the case of normal AC driving. At that time, the balance between the corrosive action and the anticorrosive action of both electrodes can be maintained by maintaining the electrical symmetry of the positive DC current and the negative DC current. Since electrolytic corrosion is less likely to occur, the power transmission line and the socket can be kept simply waterproof. Therefore, an increase in cost for waterproofing can be suppressed.

  Also, the alternating DC drive system according to the present embodiment hardly generates reactive power unlike the normal AC drive system. Therefore, the driving efficiency similar to that of the normal DC driving method can be obtained. That is, it can be driven with higher efficiency than a normal AC drive system. If the same power as that used in the normal AC driving method is used, the alternating DC driving method according to the present embodiment can brighten the LED illumination light.

  Moreover, in the alternating DC drive system according to the present embodiment, the timing for switching the polarity can be freely adjusted. Therefore, it is possible to switch faster than the commercial frequency. In this case, it is possible to adjust the flicker that is detected by the human eye in the normal AC driving method to flicker that is not detected by the human eye. In addition, it is possible to suppress the moment when the LED illumination is turned off due to the zero cross in the video photographed by the camera.

  FIG. 5 is a diagram showing a configuration of an illumination device 500 using an alternating DC drive method according to Embodiment 2 of the present invention. The lighting device 500 according to the second embodiment is obtained by adding a lighting control function of an LED light source to the lighting device 500 according to the first embodiment. As shown in FIG. 5, in lighting apparatus 500 according to Embodiment 2, lighting control apparatus 400 is added to lighting apparatus 500 according to Embodiment 1.

  The lighting control device 400 is connected to the alternating DC generation circuit 10. The lighting control device 400 is a device for controlling blinking, dimming, color, and the like of the LED light source. The lighting control device 400 executes these lighting controls due to user operations or sensor outputs. For example, it includes a dimmer, a dimmer switch, a blinker, a light mixer, and the like for receiving a user operation. Moreover, you may provide the illumination intensity sensor which detects the surrounding brightness. The lighting control device 400 controls dimming according to the output value of the illuminance sensor. For example, the dimming ratio is controlled to increase as the surroundings become darker.

  The dimmer is equipped with a dial-type volume knob, and 0 to 100% dimming is possible. The dimmer switch can dimm in multiple stages. For example, dimming in five stages of 40%, 55%, 70%, 85%, and 100% is possible. The blinker can specify various blink patterns. The light mixer can specify various production patterns including color settings.

  Generally, there are a phase control method and a signal line method as the lighting control method of the LED light source. The phase control method is a method for lighting control by directly adjusting the power from the power supply device to the LED light source device. The signal line method is a method in which a control signal is transmitted from the power feeding device to the LED light source device, and the LED light source is controlled to be lit on the LED light source device side. In general, a PWM signal (duty signal) or a 0-10V signal is used as the lighting control signal.

  In lighting apparatus 500 according to the present embodiment, the lighting control signal is superimposed on the alternating direct current supplied from power supply apparatus 100 to LED light source apparatus 200 via first power transmission line 300a and second power transmission line 300b. For example, the lighting control signal may be superimposed by controlling each pulse width of the alternating DC current having a rectangular wave shape. Further, the lighting control signal may be superimposed on the dead time between pulses. In addition, a lighting control signal may be superimposed between main current pulses. In either case, control is performed so that the sum of energy of positive current pulses is equal to the sum of energy of negative current pulses. A specific circuit configuration will be described below.

  FIG. 6 is a diagram illustrating a circuit configuration example 1 of the alternating DC generation circuit 10 and the LED light source device 200 of FIG. The alternate DC generation circuit 10 of FIG. 6 has a configuration in which a fifth switch S5 is added to the configuration of the alternating DC generation circuit 10 of FIG. The fifth switch S5 is inserted between the DC power supply (AC-DC converter 20 in the present embodiment) and the power supply terminal of the H bridge circuit 12. The fifth switch S5 is controlled by a lighting control signal from the lighting control device 400. The voltage supplied to the H bridge circuit 12 is PWM-controlled by turning on / off the fifth switch S5 controlled by the lighting control device 400.

  The LED light source device 200 of FIG. 6 has a configuration in which a control circuit 60 and a sixth switch S6 are added to the LED light source device 200 of FIG. The control circuit 60 is connected to a cathode side output terminal of a rectifier circuit configured by a diode bridge circuit. The control circuit 60 may be configured by a microprocessor or a dedicated logic circuit.

  The sixth switch S6 is inserted between the cathode side output terminal of the above-described rectifier circuit and the anode terminal of the LED (D5). The control circuit 60 reads the lighting control signal superimposed on the alternating DC current supplied from the power supply apparatus 100, and performs on / off control of the sixth switch S6 according to the control signal. Thereby, the current supplied to the LED (D5) is PWM-controlled, and the lighting of the LED (D5) is controlled.

  Although only one LED (D5) is depicted in FIG. 6, a plurality of LEDs that emit different colors may be connected in parallel. For example, three primary color LEDs may be connected in parallel. The control circuit 60 can express various colors by individually adjusting the duty ratio of the current supplied to each LED.

  An amplifier may be provided instead of the sixth switch S6. The control circuit 60 adjusts the gain of the amplifier according to the read lighting control signal. In this case, blinking control is not possible, but dimming control is possible.

  FIG. 7 is a diagram showing a circuit configuration example 2 of the alternating DC generation circuit 10 and the LED light source device 200 of FIG. The LED light source device 200 of FIG. 7 has the same circuit configuration as the LED light source device 200 of FIG. 7 has a configuration in which a superposition circuit 13 is added to the configuration of the alternating DC generation circuit 10 in FIG.

  The superimposing circuit 13 is inserted between the oscillation circuit 11 and the inverter IN1. The superimposing circuit 13 superimposes the lighting control signal from the lighting control device 400 on the rectangular wave signal generated by the oscillation circuit 11. The rectangular wave signal on which the lighting control signal is superimposed by the superimposing circuit 13 is input to the control terminals of the first switch S1 and the fourth switch S4 and the input terminal of the inverter IN1. The rectangular wave signal having the opposite phase on which the lighting control signal is superimposed and output from the inverter IN1 is input to the control terminals of the second switch S2 and the third switch S3. Thereby, the alternating direct current output from the H-bridge circuit 12 is PWM-controlled.

  FIGS. 8A to 8C are diagrams illustrating an example of alternating DC current on which a lighting control signal is superimposed. FIG. 8A shows an example in which signals are superimposed by current pulse widths W1 and W2. The control circuit 60 of the LED light source device 200 reads information transmitted from the power supply device 100 by detecting the current pulse width. FIG. 8B shows an example in which a signal is superimposed on the dead time between current pulses. FIG. 8B shows an example in which the amplitude of the superimposed signal is also adjusted. When adjusting the amplitude, an amplifier (not shown) may be provided after the H bridge circuit 12 to adjust the gain of the amplifier. FIG. 8C shows an example in which a signal is superimposed on a current pulse.

  Further, the signal to be superimposed is not limited to the lighting control signal, and may be a signal for controlling another connected device. Alternatively, a signal having a larger amount of information may be divided and transmitted by being divided into a plurality of times. Multiple signals may be included. For example, a configuration in which the illumination device 500 includes both the LED light source device 200 and an actuator device for changing the light irradiation direction of the LED light source device 200 is conceivable. The power supply apparatus 100 supplies the LED light source apparatus 200 and the actuator device with alternating direct current in which the lighting control signal of the LED light source apparatus 200 and the control signal of the irradiation direction of the actuator apparatus are superimposed.

  As described above, according to the second embodiment, in addition to the effects according to the first embodiment described above, the following effects are further obtained. That is, by superimposing the lighting control signal on the alternating direct current, the control signal can be transmitted from the power supply apparatus 100 to the LED light source apparatus 200 without providing a separate signal line unlike the above-described signal line system. In addition, since the polarity switching timing can be freely adjusted, the control signal can be flexibly superimposed as compared with the above-described phase control method.

  The present invention has been described based on the embodiments. This embodiment is an exemplification, and it will be understood by those skilled in the art that various modifications can be made to combinations of the respective constituent elements, and such modifications are also within the scope of the present invention.

  500 lighting device, 100 power supply device, 10 alternating DC generation circuit, 11 oscillation circuit, 12 H bridge circuit, 13 superposition circuit, S1 first switch, S2 second switch, S3 third switch, S4 fourth switch, S5 fifth Switch, IN1 inverter, 20 AC-DC converter, 200 LED light source device, D1 first rectifier diode, D2 second rectifier diode, D3 third rectifier diode, D4 fourth rectifier diode, D5 LED, R1 resistor, S6 6th switch, 60 control circuit, 300 power transmission line, 300a 1st power transmission line, 300b 2nd power transmission line, 400 lighting control apparatus, 50 commercial power supply.

Claims (12)

An LED (Light Emitting Diode) light source device having a rectifying action;
A power supply device for supplying current to the LED light source device,
The power supply device
Have a alternating DC generation circuit for generating a different direct current of alternating polarity,
The alternating direct current generation circuit includes:
An H-bridge circuit connected to a DC power supply;
An oscillating circuit for generating a rectangular wave whose polarity should be switched alternately, to be input to the H-bridge circuit;
A switch inserted between the DC power supply and the H-bridge circuit,
The switch is controlled by a lighting control signal for controlling lighting of the LED light source device. An LED (Light Emitting Diode) light source device having a rectifying action;
A power supply device for supplying current to the LED light source device,
The power supply device
It has an alternating direct current generation circuit that alternately generates direct currents with different polarities,
The alternating direct current generation circuit includes:
An H-bridge circuit connected to a DC power supply;
An oscillating circuit for generating a rectangular wave whose polarity should be switched alternately, to be input to the H-bridge circuit;
The oscillation circuit into a square wave to be generated, a superimposing circuit for superimposing an arbitrary signal, wherein the to that lighting device including Mukoto a. The lighting device according to claim 2 , wherein the arbitrary signal is a lighting control signal for controlling lighting of the LED light source device. The alternating current generator circuit, the lighting device according to any one of claims 1 to 3, characterized in that to generate the symmetry sustained positive direct current and negative direct current energy. The said LED light source device is for outdoor installations, The illuminating device in any one of Claim 1 to 3 characterized by the above-mentioned. The DC power source, the lighting device according to any one of claims 1 to 5, characterized in that the AC-DC converter for converting a commercial power into DC power. The LED light source device and the power supply device, the lighting device according to any one of claims 1 to 6, characterized in that it is connected by two transmission lines. The lighting device according to claim 1, wherein the alternating DC generation circuit controls each pulse width of the rectangular-wave alternating DC current to superimpose a lighting control signal. The lighting apparatus according to claim 1, wherein the alternating DC generation circuit superimposes a lighting control signal on a dead time between pulses of an alternating DC current having a rectangular wave shape. The lighting device according to any one of claims 1 to 7, wherein the alternating DC generation circuit superimposes a lighting control signal between main current pulses of an alternating DC current having a rectangular wave shape. A power supply device that supplies current to an LED (Light Emitting Diode) light source device having a rectifying action,
Have a alternating DC generation circuit for generating a different direct current of alternating polarity,
The alternating direct current generation circuit includes:
An H-bridge circuit connected to a DC power supply;
An oscillating circuit for generating a rectangular wave whose polarity should be switched alternately, to be input to the H-bridge circuit;
A switch inserted between the DC power supply and the H-bridge circuit,
The power supply device , wherein the switch is controlled by a lighting control signal for controlling lighting of the LED light source device. A power supply device that supplies current to an LED (Light Emitting Diode) light source device having a rectifying action,
It has an alternating direct current generation circuit that alternately generates direct currents with different polarities,
The alternating direct current generation circuit includes:
An H-bridge circuit connected to a DC power supply;
An oscillating circuit for generating a rectangular wave whose polarity should be switched alternately, to be input to the H-bridge circuit;
And a superimposing circuit for superimposing an arbitrary signal on the rectangular wave generated by the oscillation circuit .

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