KR20140065228A - Led power supply and led lighting apparatus using the same - Google Patents

Abstract

An LED power supply device comprises: a first rectifying unit for rectifying alternating current power to be supplied to a light emitting unit including one or more LEDs; a smoothing element which is connected between the light emitting unit and a ground terminal to smooth a ripple current component of the rectified alternating current power; an inductance element having one terminal connected to the light emitting unit; a second rectifying unit for rectifying the alternating current power; a switching control unit for generating a high frequency signal based on a signal rectified by the second rectifying unit; and a switching element for selectively connecting the other terminal of the inductance and the ground terminal according to the high frequency signal in the switching control unit, wherein the reactance of the smoothing element is reduced and the reactance of the inductance element is increased as the frequency of the high frequency signal is increased.

Description

LED POWER SUPPLY AND LED LIGHTING APPARATUS USING THE SAME <br> <br> <br> Patents - stay tuned to the technology LED POWER SUPPLY AND LIGHTING APPARATUS USING THE SAME

The present invention relates to an LED power supply and an LED lighting apparatus using the LED power supply.

2. Description of the Related Art A light emitting diode (LED) is a device capable of generating light of a high luminance with low power, and has recently been used as a light source in various fields. The LED lighting device using the LED lighting device is expected to solve the disadvantages of conventional lighting devices such as incandescent lamps and fluorescent lamps because of its small power consumption and long lifetime. A conventional LED lighting apparatus uses a DC voltage for driving the LED. To this end, a separate converter circuit or SMPS for converting an AC voltage to a DC voltage is added. The additional converter circuit increases the cost and increases the volume of the LED lighting device.

Therefore, for the configuration of the LED lighting device, it is necessary to operate so as to be able to be driven from a commercial AC power source without a separate power conversion circuit such as a converter. In this regard, in the related art, a plurality of light emitting diodes are connected in an anti-parallel structure and an AC voltage is rectified and supplied, so that an AC light emitting diode can be realized with a relatively simple structure. For example, full-wave rectification of the AC power is provided to the LED through the bridge rectifier circuit. However, when such a configuration is adopted, there is a problem that the harmonic or power factor characteristics are deteriorated in relation to the power quality of the power supply, or flicker phenomenon occurs. For example, due to the characteristics of the light emitting diode, the light emitting diode is in the OFF state until a predetermined voltage is applied to the light emitting diode, and there is a state in which the input current does not flow until the input voltage reaches the threshold voltage of the light emitting diode , So that the power factor represented by the ratio of the input effective power to the input effective power is lowered or the harmonic component is increased.

To solve this problem, a power factor correction circuit (PFC) is added to the front or rear of the bridge rectifier circuit. However, since an electrolytic capacitor having a considerable capacity is used for such a power factor compensating circuit, the lifetime of the electrolytic capacitor is shorter than the lifetime of the LED, so that the replacement cycle of the LED driving circuit is shorter than the replacement cycle of the LED . Further, due to the volume of the electrolytic capacitor, it is difficult to miniaturize the LED driving circuit.

On the other hand, Korean Patent Laid-Open Publication No. 2012-0056162 (entitled "LED power supply device") discloses a light emitting device having at least one LED. A rectifying unit for rectifying an AC voltage applied from an external power supply; A power supply unit including an inductor connected to an output terminal of the light emitting unit and supplying driving power to the light emitting unit; A reference voltage proportional to a voltage output from the rectifier is applied to the rectifier, and the reference voltage and the current flowing through the inductor are detected to compare the generated input voltage, A switch controller for turning on / off the switch such that the waveform connecting the peak of the current flowing through the inductor is proportional to the waveform represented by the input voltage, and a power supply connected to the switch controller, And a switch for controlling the LED power supply.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems of the conventional art and it is an object of the present invention to provide an LED power supply device capable of minimizing the problem of occurrence of flicker in AC driving without employing an electrolytic capacitor, An object of the present invention is to provide an LED straight tube lamp.

According to a first aspect of the present invention, there is provided an LED power supply apparatus including: a first rectifying unit rectifying an AC power to provide a light emitting unit including at least one LED; A smoothing element connected between the ground terminals for smoothing a ripple component of the rectified AC power supply, an inductance element connected to the light emitting portion at one end, a second rectification section for rectifying the AC power supply, a signal rectified by the second rectification section, And a switching element for selectively connecting the other terminal of the inductance to the ground terminal according to a high frequency signal of the switching controller, wherein, when the frequency of the high frequency signal is increased, The reactance of the smoothing element decreases and the reactance of the inductance element increases.

According to a second aspect of the present invention, there is provided an LED lighting apparatus comprising a light emitting unit including at least one LED, a housing having the light emitting unit, a first coupling unit coupled to one side of the housing and coupled with the socket, And a power supply unit connected to the external AC power source through the first coupling unit and integrated in the housing or the first coupling unit, The power supply does not include an electrolytic capacitor.

According to a third aspect of the present invention, there is provided an LED power supply apparatus comprising: a smoothing element which drives a light emitting unit including at least one LED, the smoothing element being coupled to one terminal of the light emitting unit to which rectified AC power is supplied; An inductance element coupled to the terminal, and a switching portion for selectively connecting the inductance element to the ground terminal in accordance with the high-frequency signal, and does not include the electrolytic capacitor.

The LED power supply according to the fourth aspect of the present invention minimizes flicker while emitting an LED array based on a rectified AC power supply. The LED power supply includes an electrolytic capacitor Do not.

According to the present invention, the volume of the LED power supply device or the LED lighting device can be minimized without using the electrolytic capacitor while minimizing the flicker due to the AC driving of the LED. In addition, the use of electrolytic capacitors with shorter life spans than LEDs is avoided, which can prolong the replacement period of LED power supplies or LED lighting fixtures.

1 is a view illustrating an LED lighting apparatus according to an embodiment of the present invention.
2 is a block diagram illustrating a configuration of an LED illumination device according to an embodiment of the present invention.
3 is a circuit diagram showing a detailed configuration of an LED lighting apparatus according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

Throughout the specification, when a part is referred to as being "connected / connected" with another part, it is not only the case where it is "directly connected", but also the "electrically connecting / connecting" And the like. Also, when an element is referred to as "comprising ", it means that it can include other elements as well, without departing from the other elements unless specifically stated otherwise.

1 is a view illustrating an LED lighting apparatus according to an embodiment of the present invention.

The illustrated LED lighting apparatus corresponds to an example for illustrating the technical idea of the present invention, and the LED power supply apparatus of the present invention can be applied to various types of LEDs It can be applied to a lighting apparatus.

The structure of the LED straight tube lamp 10 is the same as that of the conventional fluorescent lamp, the diameter of the tube, the length of the tube, and the connection pin, but the internal structure and driving method are completely different. The LED straight tube lamp 10 includes a first coupling portion 20, a housing 30, a second coupling portion 40, and an LED array 50. The shape and size of the first coupling portion 20, the second coupling portion 40, and the housing 30 are substantially the same as the shape and size of a standard fluorescent lamp, and can be coupled to the fluorescent lamp socket.

The first coupling portion 20 and the second coupling portion 40 are respectively coupled to a conventional fluorescent lamp socket, and the first coupling portion 20 includes a power supply terminal. The first coupling portion 20 includes a first electrode 22 and a second electrode 24 connected to an external power source applied through a fluorescent lamp socket and each electrode 22 and 24 is connected to an LED power supply Not shown). Meanwhile, the second coupling portion 40 may include a projection 42 or 44 coupled to a socket of a fluorescent lamp, but may not include an electrode or the like. That is, power may be supplied through only the first coupling portion 20.

On the other hand, the LED power supply device coupled to the first coupling unit 20 is a power supply device that supplies power to the LED array 50. The LED power supply device drives the LED according to the AC drive method, It can be implemented in a form embedded in the LED straight tube lamp 10 by minimizing its volume. For example, the LED power supply device may be embedded in the first coupling portion 20 or the first coupling portion 20 and the second coupling portion 40 to combine circuit components on a small PCB . Alternatively, the LED power supply may be embedded in the housing 30, in particular, in the interior space of the heat sink formed on one side of the housing 30. [

Since the LED straight tube lamp 10 has a built-in power supply unit, it is possible to connect the commercial AC power source through the first electrode 22 and the second electrode 24 of the first coupling unit 20 It is not necessary to provide a separate circuit device such as a stabilizer for driving a fluorescent lamp or an external converter dedicated to an LED.

2 is a block diagram illustrating a configuration of an LED illumination device according to an embodiment of the present invention.

The LED lighting apparatus 100 includes an AC power source 110, a first rectifying unit 120, a power factor compensating unit 130, a smoothing device 140, a light emitting unit 150, a second rectifying unit 160, a switching control unit 170 An inductance element 180, a switching unit 190, and a constant current unit 200. [

The AC power source 110 may be configured to transmit commercial AC power to the LED lighting apparatus 100. The frequency and voltage value of the commercial AC power may vary depending on the region or the country. The AC power source 110 may include an electrode connected to the external AC power source and transmitting AC power to each component of the LED lighting apparatus 100.

The first rectifying unit 120 rectifies the AC power and transmits the rectified AC power to the power factor compensating unit 130. For example, the first rectification section 120 may include a full-wave rectification circuit such as a bridge rectification circuit.

The power factor compensating unit 130 suppresses the AC component of the AC power source and compensates the phase difference between the load input current and the voltage generated by the smoothing element 140 to improve the power factor.

The smoothing element 140 is coupled to the light emitting portion 150 to eliminate the pulsation of the full-wave rectified power supply. Even when the AC power is rectified, flicker phenomenon occurs in which the LED blinks in the goal of the pulsating current which is the point where the voltage of the AC power source is lowest when the AC power is rectified. To remove such a flicker, a smoothing element 140 such as a capacitor is usually coupled. In order to smooth the AC power close to DC, a capacitor having a capacity of several hundred microfarads is used. In order to solve the power factor reduction problem due to the use of the smoothing element 140, the power factor compensator 130 is employed as described above.

In the case of an intrinsic lamp having a power consumption of 20 W, a converter for converting an alternating current dedicated to an LED into a direct current is driven with a voltage as low as 40 V or less, so the driving current is as high as 500 to 1000 mA and a high capacitance is required. As a result, an electrolytic capacitor capable of high capacitance is used. On the other hand, in the present invention, since an AC power source of 100 to 220 V is directly used as an input power source, the input current is reduced to 100 mA, so that a capacitor having a capacitance of 1/5 to 1/10 can be used.

Further, in the present invention, by adopting such a configuration that the same capacitance as the electrolytic capacitor can be supplied in using the smoothing element 140, the electrolytic capacitor can be substituted. For example, capacitors of the same type as MFC (Metallized Film Capacitor) can be used. Accordingly, various problems due to a large volume or short life of the electrolytic capacitor can be solved.

The light emitting portion 150 includes one or more LEDs, and may include a plurality of LEDs connected in series, for example. Further, according to the embodiment, a configuration including a plurality of LED arrays connected in series can be used.

In order to increase the capacitance of the smoothing element 140, the present invention includes a second rectification part 160, a switching control part 170, an inductance element 180, and a switching part 190.

The second rectification unit 160 rectifies the AC power to the switching control unit 160 and may include a full wave rectification circuit similar to the first rectification unit 120. As described above, a parallel structure in which different rectifying sections 120 and 160 are connected to an AC power source can be used.

The switching control unit 170 generates a high frequency based on the AC power that is full-wave rectified through the second rectifying unit 160, and supplies the generated high frequency to the switching unit 190.

The inductance element 180 is coupled between the light emitting portion 150 and the switching portion 190 to bear the reactance that the smoothing element 140 must provide for flicker removal. That is, since the inductance element 180 is connected to the ground terminal at a high speed by the switching unit 190, the reactance provided by the inductance element 180 increases, and the reactance of the smoothing element 140 decreases accordingly , The capacitor capacity of the smoothing element 140 can be reduced. On the other hand, as the frequency component increases in the inductive reactance 2? FL of the inductance element 180 due to the high-speed switching, a sufficiently high reactance can be provided by the inductance element 180 having a small inductance.

The switching unit 190 selectively connects between the inductance element 180 and the ground terminal on the basis of the output signal of the switching control unit 170. The switching timing is adjusted according to the frequency of the output signal, 180 are also changed. That is, as the frequency of the output signal rises, the inductance also increases. On the other hand, the capacitive reactance of the smoothing element also decreases in accordance with the change of the frequency of the output signal, so that the smoothing element 140 can exhibit the same performance without using a capacitor having a large capacitance like an electrolytic capacitor.

The constant current unit 200 limits the current output from the light emitting unit 150 to a certain level. For example, the constant current unit 200 can set a target current level by connecting a constant current diode (CRD) in parallel. Specific details will be described later.

3 is a circuit diagram showing a detailed configuration of an LED lighting apparatus according to an embodiment of the present invention.

The first rectification part 120 includes a bridge rectification circuit composed of four diodes D1 to D4 and a resistance element R1 coupled between the AC power source 110 and the bridge rectification circuit. The resistor element R1 functions as a means for protecting the circuit from a high current, and can be replaced with another configuration according to the user's selection.

The connection node of the first diode D1 and the third diode D3 of the bridge rectifier circuit is connected to one end of the resistor element R1 and the connection node of the second diode D2 and the fourth diode D4 is connected to one end of the resistor element R1, And is connected to the AC power supply 110 through some passive elements L1 and C1 of the compensation unit 130. [ The AC power source which is full-wave rectified between the connection node of the first diode D1 and the second diode D2 and the connection node of the third diode D3 and the fourth diode D4 is outputted, The light is transmitted to the light emitting portion 150 through the passive elements L2 and C2 and the smoothing element 140 of the light source 130. [

The power factor compensating unit 130 includes a capacitor C1 and an inductor L1 connected in parallel between the connection node of the second diode D2 and the fourth diode D4 of the bridge rectifying circuit and the AC power source, A second capacitor C2 and a second inductor L2 connected in series to the connection node between the first diode D1 and the second diode D2 and the connection node between the third diode D3 and the fourth diode D4, .

However, the configuration of the power factor compensating unit 130 can be changed according to the user's selection, and the configuration shown in the figure corresponds to an example. For example, the capacitor C1 and the inductor L1 can compensate the power factor corresponding to the frequency of the input AC power. In addition, the capacitor C2 and the inductor L2 can compensate the power factor corresponding to the frequency of the full-wave rectified AC power. That is, if the frequency of the input AC power source is 60 Hz, the capacitors C1 and L1 can compensate the power factor corresponding to the frequency of the input AC power, and the capacitors C2 and L2 can compensate the power factor Can be compensated.

The smoothing element 140 may include a bridge rectifying circuit, a power factor correcting portion, and a capacitor C3 connected between the connection node of the light emitting portion and the ground terminal. At this time, a capacitor other than an electrolytic capacitor can be used as the capacitor C3. For example, in order to smooth the pulsating current, a high-capacity capacitor of about 220 uF is used. However, according to the present invention, the same smoothing performance can be achieved through a low capacitance capacitor according to the configuration of the switching unit 190 switched at a high frequency .

The light emitting unit 150 may include a plurality of LEDs (LED1 to LEDn) connected in series, and may include a plurality of LED arrays connected in series in a parallel connection manner.

The second rectification part 160 includes a bridge rectification circuit composed of four diodes D5 to D8 and a capacitor C5 coupled between the AC power supply 110 and the bridge rectification circuit. And the signal rectified through the second rectifier 160 is applied to the switching controller 170. At this time, the second rectifier 160 may be additionally provided instead of the first rectifier 120 to operate the switching controller 170 independently of the LED light emission. Meanwhile, the capacitor C5 lowers the voltage of the AC power source 110 and is transmitted to the second rectifying unit 160. [

The connection node between the fifth diode D5 and the seventh diode D7 of the bridge rectifying circuit is connected to one end of the capacitor C5 and the connection node between the sixth diode D6 and the eighth diode D8 is connected to the one end of the capacitor C5, (110). Further, AC power which is full-wave rectified between the connection node of the fifth diode D5 and the sixth diode D6 and the connection node of the seventh diode D7 and the eighth diode D8 is outputted, 170).

The switching control unit 170 generates a high frequency based on the AC power which is full-wave rectified through the second rectifying unit 160 and transmits the generated high frequency to the switching unit 190. The switching control section 170 includes an IC element IC for generating a high frequency, a resistance element R2 connected between the input terminal of the IC element and the second rectification section 160, an input terminal of the IC element IC, And a zener diode (ZD1) connected to the output terminal.

The IC element (IC) is a oscillation element that generates a high frequency and can generate a frequency of approximately 500 Hz to 250 KHz.

The resistance element R2 functions to limit the input current to be transmitted to the IC element IC through the second rectification part 160. [

The Zener diode ZD1 supplies a DC voltage of a certain level or higher to the IC element IC. The DC voltage is supplied according to the characteristics of the zener diode ZD1, and a DC voltage of 18 V or more can be supplied, for example.

A signal rectified by the second rectifier 160 may include a pulsating signal as a full-wave rectified signal. To minimize the ripple signal, a capacitor (not shown) may be further coupled to the front end of the resistor R2. have.

In this configuration, the switching controller 170 generates a high frequency in a range of approximately 500 Hz to 250 kHz and transmits the generated high frequency to the switching unit 190.

The inductance element 180 is connected between the output terminal of the light emitting portion 150 or between the constant current portion 200 and the switching portion 190, and an inductor, a choke coil element, or the like can be connected. The inductive reactance of the inductance element 180 is increased by the switching unit 190 switched at a high speed by the high frequency and accordingly the reactance to be borne by the smoothing element 140 is shared. So that the smoothing element 140 can be used. That is, in order to eliminate the flicker phenomenon, a reactance of a predetermined amount or more is required. Since the reactance is increased by coupling the inductance element 180 and selectively connecting the inductance element 180 to the ground at high speed, the amount of reactance that the smoothing element 140 must bear So that a capacitor having a low capacitance can be used as the smoothing element 140 as a result.

The switching unit 190 includes a switching element for switching between the inductance element 180 and the ground according to an output signal of the switching control unit 170. For example, the switching unit 190 receives the output signal of the switching control unit 170 as a gate, connects the inductance element 180 and the drain terminal, and includes a MOS switch to which the ground and the source terminal are connected as a switching element can do. At this time, a resistance element R3 may be additionally connected between the gate and the source terminal.

The output signal of the switching controller 170 is, for example, a square wave signal having a frequency of 10 KHz. Since the switching unit 190 is switched at a high speed according to the application of the signal, the smoothing element 140 and the inductance element 180 can be controlled, thereby minimizing the flicker phenomenon. For example, as the switching frequency increases, the reactance of the smoothing element 140 decreases and the reactance of the inductance element 180 increases.

The constant current unit 200 limits the current output from the light emitting unit 150 to a certain level. For example, the constant current unit 200 can set a target current level by connecting a constant current diode (CRD) in parallel. That is, when five constant current diodes (CRD) capable of supplying a constant current of 20 mA are connected in parallel, a constant current of 100 mA can be supplied.

Meanwhile, the constant current unit 200 may further include a capacitor C4 connected in parallel with the constant current diode. The capacitor C4 may be used for decreasing the voltage applied to the constant current diode.

Alternatively, the constant current unit 200 may be connected to the output terminal of the light emitting unit 150. Alternatively, the constant current unit 200 may be connected between the output terminal of the first rectifying unit 120 and the light emitting unit 150. [ In this embodiment, the current may be limited to a predetermined level and output from the pulsation output from the first rectification unit 120.

Meanwhile, since the switching unit 190 is connected to the constant current unit 200, the load of the constant current diode included in the constant current unit 200 can be reduced to reduce the heat generation as much as possible.

It will be understood by those skilled in the art that the foregoing description of the present invention is for illustrative purposes only and that those of ordinary skill in the art can readily understand that various changes and modifications may be made without departing from the spirit or essential characteristics of the present invention. will be. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. For example, each component described as a single entity may be distributed and implemented, and components described as being distributed may also be implemented in a combined form.

The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents are to be construed as being included within the scope of the present invention do.

110: AC power supply 120: First rectification part
130: power factor compensator 140: smoothing element
150: light emitting portion 160: second rectifying portion
170: switching control unit 180: inductance element
190: switching part 200: constant current part

Claims (14)

In an LED power supply,
A first rectifying section for rectifying the AC power and providing the AC power to a light emitting section including one or more LEDs,
A smoothing element connected between the light emitting portion and the ground terminal for smoothing a ripple component of the rectified AC power,
An inductance element whose one end is connected to the light emitting portion,
A second rectifying unit for rectifying the AC power,
A switching control unit for generating a high-frequency signal based on the signal rectified by the second rectifying unit,
And a switching element for selectively connecting the other terminal of the inductance to the ground terminal according to a high frequency signal of the switching controller,
Wherein as the frequency of the high frequency signal increases, the reactance of the smoothing element decreases and the reactance of the inductance element increases. The method according to claim 1,
And a power factor compensating unit connected between the first rectifying unit and the light emitting unit to compensate the power factor. The method according to claim 1,
Wherein the switching control unit comprises:
An IC element for receiving a signal rectified by the second rectifying section and outputting a high frequency signal,
A zener diode connected between the input terminal of the IC device and the ground terminal for supplying a fixed DC voltage,
And a resistance element connected between the second rectification part and an input terminal of the IC element, for controlling the input current. The method according to claim 1,
Wherein the high frequency signal has a frequency in the range of 500Hz to 250KHz. The method according to claim 1,
And a constant current unit connected to an output terminal of the light emitting unit and configured to constantly limit an output current of the light emitting unit. In the LED lighting fixture,
A light emitting portion including at least one LED,
A housing having the light emitting portion,
A first coupling portion coupled to one side of the housing and coupled with the socket,
A second engaging portion coupled to the other side of the housing and coupled with the socket,
And a power supply connected to the external AC power source through the first coupling unit and coupled to the housing or the first coupling unit,
Wherein the power supply does not include an electrolytic capacitor. The method according to claim 6,
The power supply device includes:
A first rectifying unit rectifying the AC power and supplying the rectified AC power to the light emitting unit,
A smoothing element connected between the light emitting portion and the ground terminal for smoothing a ripple component of the rectified AC power,
An inductance element whose one end is connected to the light emitting portion,
A second rectifying unit for rectifying the AC power,
A switching control unit for generating a high-frequency signal based on the signal rectified by the second rectifying unit,
And a switching element for switching between the inductance and the ground terminal according to a high-frequency signal of the switching controller,
Wherein as the switching frequency of the switching element increases, the reactance of the smoothing element decreases and the reactance of the inductance element increases. The method according to claim 6,
Wherein the switching control unit comprises:
An IC element for receiving a signal rectified by the second rectifying section and outputting a high frequency signal,
A zener diode connected between the input terminal of the IC device and the ground terminal for supplying a fixed DC voltage,
And a resistance element connected between the second rectifying part and an input terminal of the IC element, for controlling the input current. The method according to claim 6,
Wherein the diameter of the housing and the length of the tube are the same as those of the standard fluorescent lamp, the diameter of the tube and the length of the tube. 1. An LED power supply apparatus for alternately driving a light emitting unit including at least one LED,
A smoothing element coupled to one terminal of the light emitting unit to which the rectified AC power is supplied,
An inductance element coupled to the other terminal of the light emitting portion,
And a switching unit selectively connecting the inductance element to the ground terminal according to a high frequency signal,
The LED power supply does not include an electrolytic capacitor. 11. The method of claim 10,
A first rectifying unit for rectifying the AC power and providing the AC power to the light emitting unit,
A second rectifying section for rectifying the AC power source,
And a switching controller for generating a high frequency signal based on the signal rectified by the second rectifier and providing the high frequency signal to the switching unit,
Wherein as the frequency of the high frequency signal of the switching control section increases, the reactance of the smoothing element decreases and the reactance of the inductance element increases. 12. The method of claim 11,
Wherein the switching control unit comprises:
An IC element for receiving a signal rectified by the second rectifying section and outputting a high frequency signal,
A zener diode connected between the input terminal of the IC device and the ground terminal for supplying a fixed DC voltage,
And a resistance element connected between the second rectification part and an input terminal of the IC element, for controlling the input current. 1. An LED power supply apparatus for minimizing flicker phenomenon while emitting an LED array based on a rectified AC power source,
Wherein the LED power supply does not include an electrolytic capacitor. 14. The method of claim 13,
The LED power supply
A smoothing element connected to one terminal of the LED array,
An inductance element connected to the other terminal of the LED array and
And a switching unit that is switched according to a high-frequency signal to selectively connect the inductance element and the ground terminal,
Wherein as the frequency of the high frequency signal increases, the reactance of the smoothing element decreases and the reactance of the inductance element increases.

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