KR102489727B1 - Switching Mode Power Supply for Light-Emitting Diode Lighting Equipment - Google Patents

Abstract

Disclosed in an embodiment of the present invention is a switching mode power supply (SMPS) for light-emitting diode lighting equipment, which enables wireless control of turning on/off and brightness of lighting equipment using light-emitting diodes. The disclosed SMPS for light-emitting diode lighting equipment comprises: one transformer; a first rectifier; a switching and power factor control unit for switching a DC voltage applied to a primary side of the transformer at high speed and compensating for a power factor according to a feedback control signal; a second rectifier which rectifies a high-frequency AC signal induced on a secondary side of the transformer to provide constant current power for driving light-emitting diodes; a brightness control and feedback unit which receives the output and brightness and on/off control signals of the second rectifier to generate the feedback control signal to maintain the output of the second rectifier at a constant current and turn on/off the light-emitting diodes or control the amount of light thereof, and feed the feedback control signal back to the switching and power factor control unit; a third rectifier which outputs a DC voltage for a control circuit by rectifying a high-frequency AC voltage induced on the secondary side of the transformer; a constant voltage converter which regulates the DC voltage of the third rectifier to provide a stabilized constant voltage for the control circuit; and a low-voltage detection and compensation unit which provides the output of the second rectifier to the constant voltage converter when the DC voltage of the third rectifier becomes lower than a reference voltage.

Description

Switching Mode Power Supply for Light-Emitting Diode Lighting Equipment}

The present invention relates to a power supply device for a light emitting diode lighting device capable of wirelessly controlling the brightness and on/off of a lighting device using a light emitting diode, and more particularly, to a constant current power supply for a light emitting diode and brightness and on/off of the light emitting diode. The present invention relates to a switching mode power supply for a light emitting diode lighting device capable of providing a constant voltage power supply for a control circuit for wirelessly controlling power off by using a single transformer.

In general, a switching mode power supply (SMPS) is a power supply device that converts AC power supplied from commercial power into various types of power according to needs. In other words, the switching mode power supply (SMPS) rectifies the AC input voltage to DC voltage, converts the DC voltage into high-frequency voltage by switching the DC voltage at high speed with a semiconductor switching element, converts it to a required level through a high-frequency transformer, and rectifies it again. It creates stable voltage or current through constant voltage or constant current control circuit and smoothing circuit. These SMPS are classified into non-isolation type and isolation type. Non-isolation type is subdivided into Buck type, Boost type, and Buck-boost type. Insulation type is classified into Flyback type, Forward type, Pull- It is subdivided into push method, half-bridge method, and full-bridge method.

On the other hand, as light emitting diodes are widely used in lighting devices, they have developed into highly efficient and eco-friendly lighting devices that can replace existing incandescent lamps, fluorescent lamps, and mercury lamps. In particular, a control device such as a microcomputer is combined with a lighting device and connected to a computer or network, enabling remote control of brightness, on/off, etc., enabling energy saving as well as responding to various needs of users.

In order to connect a microcomputer or the like to a typical lighting device, a power supply for a control circuit such as a microcomputer is required separately from a power source for driving a light emitting diode. That is, since light emitting diodes require constant current driving due to load characteristics, a relatively high voltage constant current source of about 30 to 50 V is required as a power supply for driving light emitting diodes to improve efficiency, but power for control circuits such as microcomputers is very low 3 to 5 Use a constant voltage source with a small current for the voltage of V.

On the other hand, in the case of controlling only brightness without an off function in a switching mode power supply (SMPS) used in lighting equipment for light emitting diodes controlled by wireless or infrared such as WiFi or Bluetooth, one switching circuit and one A constant current power source for driving a light emitting diode and a constant voltage power source for driving a microcomputer can be made and used by using a transformer.

However, in a switching mode power supply (SMPS) that includes an on/off function, when lighting equipment is turned off wirelessly, the voltage of the light emitting diode driving power supply generated from the secondary side of the transformer of the SMPS is lowered, and at the same time, the secondary side of the same transformer is separately The voltage for the control circuit, such as the microcomputer, which is made in the winding is also lowered, which can cause a problem that the microcomputer does not operate normally. That is, when the light emitting diode is turned on by the output of the second rectifier, the output voltage of the third rectifier for the microcomputer is about 10 to 15V, and a microcomputer voltage of about 5V can be efficiently made. However, when the light emitting diode is turned off wirelessly, the output voltage of the third rectifier is also lowered to about 4 to 8V, and the normal operation of the microcomputer is not performed, so the control function is lost. At this time, when the voltage of the third rectifier is designed not to be lowered, another problem occurs in that the efficiency of the constant voltage conversion circuit deteriorates.

In order to solve this problem, conventionally, as shown in FIG. 1, a separate switching constant voltage circuit for driving a microcomputer or the like is added separately from a constant current power supply device for a light emitting diode.

1 is a block diagram showing the configuration of a conventional switching mode power supply for a light emitting diode capable of controlling brightness and on/off.

Referring to FIG. 1, a conventional switch mode power supply (SMPS) for a light emitting diode includes a first rectifier 10, a constant current power supply 20 for a light emitting diode, and a constant voltage power supply 30 for a control circuit. The first rectifier 10 receives the noise filter 12 by removing noise from the AC input power and the AC power from which noise is removed by the noise filter 12, and full-wave rectifies the direct current (DC) voltage for switching. It is composed of a first rectifier 14 that outputs.

The constant current power supply unit 20 for light emitting diode controls power factor correction and constant current while high-speed switching and applying DC power output from the first transformer 21 and the first rectifier 14 to the primary winding of the first transformer 21. A first switching power factor correction constant current control unit 22 for performing a function and a second rectifier 23 for outputting a constant current for driving a light emitting diode by rectifying the high frequency AC power induced in the secondary side of the first transformer 21 And, the brightness control unit 24 for controlling the brightness of the lighting device according to the brightness and on/off control signals, the control signal of the brightness control unit 24 and the monitoring output of the second rectifier 23 are converted into a first switching power factor correction constant current control unit It is composed of a first feedback unit 25 for feeding back to (22).

In addition, the constant voltage power supply unit 30 for the control circuit fast-switches the DC power output from the second transformer 31 and the first rectifier 14 and applies the power factor correction and constant voltage to the primary winding of the second transformer 31. A second switching power factor correction constant voltage controller 32 for performing a control function, a third rectifier 33 for outputting low voltage DC by rectifying the high frequency AC power induced in the secondary side of the second transformer 31, 3 For the second feedback unit 34 for feeding back the monitoring output of the rectifier to the second switching power factor correction constant voltage control unit 32, and for a control circuit for regulating the low voltage DC of the third rectifier 33 to drive a microcomputer, etc. It is composed of a constant voltage converter 35 for outputting a constant voltage.

However, when the constant current circuit and the constant voltage circuit are separately configured using two switching circuits and two transformers, there is a problem in that the structure of the SMPS becomes complicated and the cost increases. That is, in order to satisfy a high power factor and strict electromagnetic regulation while integrating a power supply with constant current characteristics and a power supply with constant voltage characteristics into one power supply device, the configuration of the power supply device becomes complicated and the cost increases, so that it cannot be supplied inexpensively to consumers. there is.

KR 10-1544120 B1 KR 10-2108329 B1

The present invention has been proposed to solve the conventional problems as described above in a switch mode power supply (SMPS) for light emitting diode lighting devices capable of controlling brightness and on/off, and an object of the present invention is to provide a structure using a single transformer It is to provide a switching mode power supply for a light emitting diode lighting device that simplifies and reduces manufacturing cost and enables stable operation of a micom even when the light emitting diode is turned off wirelessly.

An embodiment of the present invention discloses a switched mode power supply (SMPS) for a light emitting diode lighting device capable of controlling brightness and on/off.

The disclosed switching mode power supply (SMPS) for light emitting diode lighting devices is a switching mode power supply for light emitting diodes having brightness and on/off control functions by wireless. It is characterized in that the constant voltage power supply for the control circuit to be provided is provided using one transformer without configuring a separate transformer.

The voltage generated from the third rectifier for the constant voltage power supply for the control circuit is not higher than 2 to 3 times higher than the constant voltage for the control circuit even when the light emitting diode operates, so that the efficiency of the constant voltage conversion unit connected to the third rectifier is maintained high and stable. It is to provide a constant voltage for the control circuit.

In order to maintain the output voltage to the constant voltage conversion unit connected to the third rectifier as a voltage necessary for driving a control circuit such as a micom, when the light emitting diode is turned off wirelessly, the output voltage of the second rectifier is changed when the light emitting diode is turned off. The brightness control and feedback unit is set so that the normal voltage is maintained, and when the light emitting diode is turned off wirelessly, the output voltage of the second rectifier is superimposed on the output terminal of the third rectifier to obtain a stable constant voltage for the control circuit. It is characterized by providing

In addition, when the light emitting diode is turned off wirelessly, the low voltage detection and compensation unit compares the output voltage of the third rectifier with the reference voltage set by the zener diode, and turns on the transistor when the output voltage of the third rectifier is lower than the reference voltage. 2 This is so that the output voltage of the rectifier can be superimposed on the input terminal of the constant voltage converter.

Another embodiment of the present invention discloses a switched mode power supply (SMPS) for a light emitting diode lighting device capable of controlling brightness and on/off.

A switched mode power supply (SMPS) for a light emitting diode lighting device disclosed herein includes a transformer, a first rectifier for rectifying AC power and applying a DC voltage to the primary side of the transformer, and the primary side of the transformer according to a feedback control signal. A switching and power factor control unit for switching the DC voltage applied to the DC voltage at high speed and compensating for the power factor, and a second rectifier for rectifying the high-frequency AC signal induced in the secondary side of the transformer to provide a constant current power source for driving a light emitting diode; By receiving the output of the second rectifier and the brightness and on/off control signals transmitted from the outside, the output of the second rectifier maintains a constant current and generates a feedback control signal for turning on/off the light emitting diode or adjusting the amount of light. A brightness control and feedback unit for feeding back to the switching and power factor controller, a third rectifier for outputting a DC voltage for a control circuit by rectifying the high-frequency AC voltage induced in the secondary side of the transformer, and regulating the DC voltage of the third rectifier and a constant voltage conversion unit that provides a stabilized constant voltage for the control circuit, and is connected between the second rectifier and the third rectifier to convert the output of the second rectifier to the constant voltage when the DC voltage of the third rectifier is lower than the reference voltage It includes a low voltage detection and compensation unit provided as a unit.

The brightness control and feedback unit sets the feedback control signal so that the output voltage of the second rectifier is maintained as a normal voltage when the light emitting diode is turned off wirelessly, and the low voltage detection and compensation unit sets the third A zener diode for setting a reference voltage for detecting the low voltage of the rectifier, and turned on when the output voltage of the third rectifier is less than the reference voltage set by the zener diode, and connecting the output voltage of the second rectifier to the constant voltage converter It consists of transistors for

The second rectifier may further include a ripple removal circuit for removing high frequency ripples.

A switching mode power supply (SMPS) according to an embodiment of the present invention is a constant current power supply for a light emitting diode capable of controlling brightness and on/off wirelessly and a constant voltage power supply for driving a microcomputer, etc. with one transformer and one power factor correction and control It has the effect of simplifying the structure and reducing the manufacturing cost by configuring the circuit.

In addition, the switching mode power supply (SMPS) according to an embodiment of the present invention adds a low voltage detection and compensation circuit to the secondary side of the transformer so that the voltage for control circuits such as microcomputers does not decrease even when the light emitting diode is wirelessly turned off. Stable operation of microcomputers can be guaranteed.

1 is a configuration block diagram of a switching mode power supply for a light emitting diode lighting device capable of controlling brightness and on/off in a conventional manner in which a constant voltage circuit for driving a microcomputer is independently configured;
2 is a block diagram of a switching mode power supply for a light emitting diode lighting device according to an embodiment of the present invention;
3 is a circuit diagram showing a specific circuit of a low voltage detection and compensation unit according to an embodiment of the present invention;
4 is an overall circuit diagram of a switching mode power supply for a light emitting diode lighting device capable of controlling brightness and on/off according to an embodiment of the present invention.

The technical problems achieved by the present invention and its practice will become clearer with the preferred embodiments of the present invention described below. The following examples are merely illustrative of the present invention, and are not intended to limit the scope of the present invention.

2 is a configuration block diagram of a switching mode power supply for a light emitting diode lighting device according to an embodiment of the present invention.

As shown in FIG. 2, a switch mode power supply 100 for a light emitting diode lighting device according to an embodiment of the present invention includes a noise filter 102, a first rectifier 104, one transformer 106, and one switching and a power factor control unit 110, a second rectifier 120 for supplying constant current power for driving a light emitting diode, receiving brightness and on/off control signals from the outside and receiving an output of the second rectifier 120 to generate a feedback control signal. Brightness control and feedback units 130 & 140 for feeding back to the switching and power factor controller 110, a third rectifier 150, a low voltage detection and compensation unit 160 for detecting and compensating for the low voltage of the third rectifier 150, It consists of a constant voltage converter 170 that stabilizes the output of the third rectifier 150 and provides a constant voltage for driving the microcomputer.

Referring to FIG. 2, the noise filter 102 is a line filter that removes noise from an externally applied AC input. At this time, the noise filter 102 may include a surge absorption circuit that protects the power supply from damage from a high pulse voltage input from an external AC input terminal.

The first rectifier 104 includes a bridge diode (BD) for full-wave rectification of AC power applied from the outside and converting it to DC, and a capacitor for smoothing the DC power output from the bridge diode, and the AC that passes through the noise filter 102. The power is full-wave rectified, converted into DC voltage for switching, and applied to the primary winding 106a of the transformer 106.

The transformer 106 includes a primary winding 106a connected to the first rectifier 104 and the switching and power factor controller 110, a secondary winding 106b-1 connected to the second rectifier 120, 3. Including the secondary winding 106b-2 connected to the rectifier 150, the voltage of the primary winding is transferred to the secondary winding according to each winding ratio. At this time, the DC voltage applied to the primary winding is switched at high speed by the semiconductor switching element so that it is induced to the secondary winding, thereby enabling the use of a high frequency transformer having a smaller size than the low frequency transformer.

The switching and power factor controller 110 converts the DC power rectified in the first rectifier 104 into a high-frequency alternating current in the switching circuit, applies it to the primary side of the transformer 106, and simultaneously controls the feedback of the secondary side of the transformer 106. The output of the second rectifier 120 is controlled to be a constant current by the signal, and various characteristics such as power factor correction are controlled. In addition, the switching and power factor controller 110 includes a reference voltage generator for generating a reference voltage, an oscillation circuit for driving a switching transistor to convert the DC output voltage of the first rectifier 104 into a high-frequency AC voltage, and an AC input A power factor correction function to maintain a high power factor by controlling the AC input current according to the phase of the voltage, constant current control of the second rectifier 120 through the brightness control and feedback unit 130 & 140, overvoltage output limitation, and brightness control, It may include a comparison operational amplifier that receives an on/off control signal and performs various control functions such as control of a lighting device.

The second rectifier 120 rectifies the high-frequency AC power step-down at the secondary side of the transformer 106. To this end, the second rectifier 120 is composed of a diode D8 for rectifying the output from the transformer 106 and a smoothing capacitor C12 for smoothing the rectified DC voltage. It may include an AC ripple removal circuit 124 for removing flicker of light.

The feedback unit 130 and the brightness control unit 140 (hereinafter referred to as 'brightness control and feedback unit') detect a current value so that the output of the second rectifier 120 maintains a constant current, and suppresses overvoltage at no load The signal for this is fed back to the switching and power factor controller 110 on the primary side of the transformer 106. Also, the brightness control and feedback units 130 & 140 have functions of setting and limiting the minimum output voltage. That is, when the light emitting diode (lighting device) is on, if the voltage of the second rectifier 120 is 50V at maximum brightness, about 40V is output at minimum brightness. The voltage of the second rectifier 120 is lowered from about 30V or less to about several V. At this time, the voltage of the second rectifier 120 is maintained at about 20V. To this end, the brightness control and feedback units 130 & 140 include a reference voltage generation and comparison operation and output circuit (IC2) for brightness and on/off control, and these signals are transferred to the primary side switching and power factor control unit 110 of the transformer 106 It includes a photocoupler (PC1) for feedback to .

The third rectifier 150 is a rectifier for rectifying the AC voltage from the winding 106b-2 added to the secondary side of the transformer 106 to make a constant voltage of 3V to 5V DC required for driving the micom, etc. A diode and a smoothing capacitor may be included. At this time, the output voltage of the third rectifier 150 is set so that approximately 10 to 15V DC is output in a state where the light emitting diode is turned on (for example, when the constant voltage for the control circuit is 5V, it is doubled or tripled). If this voltage is set higher than 15V DC, the efficiency of the constant voltage converter 170 may decrease.

The low voltage detection and compensating unit 160 detects that the output voltage of the third rectifier 150 is greatly changed by controlling the brightness and on/off of the light emitting diode and falls below a set value to output the output of the second rectifier 120. This is to prevent the output voltage of the constant voltage converter 170 from being lowered by overlapping the voltage with the output of the third rectifier 150 . To this end, the low voltage detection and compensating unit 160 outputs a relatively high voltage (about 20V DC) is superimposed on the input terminal of the constant voltage converter 170 through the transistor Q50 and the diode D51 to prevent the constant voltage output for the microcomputer (for the control circuit) from being lowered.

The constant voltage conversion unit 170 is to prevent the output voltage of the third rectifier 150 from changing according to the change in the output voltage and output current of the second rectifier 120 to make it a constant voltage power supply. To this end, the constant voltage conversion unit 170 consists of a constant voltage circuit for generating a constant DC voltage for the microcomputer, consists of a switching downconverter or a downconverter such as a series regulator to avoid electromagnetic noise generated in the switching circuit, , electrolytic capacitors, and the like.

3 is a circuit diagram illustrating a low voltage detection and compensation unit according to an embodiment of the present invention.

As shown in FIG. 3, the low voltage detection and compensation unit 160 according to an embodiment of the present invention includes a second rectifier 120 for providing constant current power for light emitting diodes and a third for generating DC voltage for microcomputers. A zener diode D52 is connected between the rectifier 150 and sets a reference voltage for detecting a low voltage of the third rectifier 150, and a reference voltage for which the voltage of the third rectifier 150 is set by the zener diode D52. (eg, 10V) or less, the transistor Q50 is turned on to connect the high voltage (about 20V DC) of the second rectifier 120 to the constant voltage conversion unit 170, and to block current flow in the reverse direction. It is composed of a diode D51.

Referring to FIG. 3, when the brightness of the light emitting diode (LED) is maximum, if the output voltage of the second rectifier 120 output to the light emitting diode is 50V, the constant current when the brightness of the light emitting diode is minimized immediately before being turned off. The output voltage is maintained at about 40V. In addition, the voltage when the light emitting diode is turned off repeatedly rises and falls between several volts and tens of volts when there is no low voltage control function. At this time, in the embodiment of the present invention, when the light emitting diode is off, the output voltage of the second rectifier 120 is higher than the output voltage of the third rectifier 150 while turning off the light emitting diode (this is referred to as 'normal voltage when the light emitting diode is off'). ) The brightness control and feedback units 130 & 140 are set to maintain about 20V so that the output voltage of the second rectifier 120 is maintained at about 20V even when the light emitting diode is off.

And in the embodiment of the present invention, a low voltage detection and compensation unit 160 composed of a zener diode D52 and a transistor Q50 is added between the second rectifier 120 and the third rectifier 150 as shown in FIG. When the light emitting diode is turned off (the lighting device is turned off), when the voltage of the third rectifier 150 is lower than the reference voltage set by the zener diode D52, the transistor Q50 is turned on and the second rectifier 120 controls the voltage of the transistor Q50 Current flows from the collector to the emitter so that the voltage at the output terminal of the third rectifier 150 does not fall below 9V, so that the constant voltage converter 170 can output a stable 5V microcomputer driving voltage. That is, when the voltage of the zener diode D52 is 10V when the lighting device is turned off, the base-emitter voltage of the transistor Q50 is about 0.6V and the forward voltage of the general diode D51 connected from the emitter to the third rectifier 150 When the output voltage of the third rectifier 150 is lower than about 9V, which is the voltage obtained by subtracting the drop of 0.4 to 0.6V, the transistor Q50 is turned on to convert the output of the second rectifier 120 (the normal voltage when the light emitting diode is off) to a constant voltage. It is connected to the conversion unit 170.

Therefore, according to an embodiment of the present invention, even when the light emitting diode (lighting device) is turned off wirelessly, the voltage for control circuits such as microcomputers is maintained at 5V DC to ensure stable operation of control circuits such as microcomputers. .

4 is an overall circuit diagram of a switched mode power supply (SMPS) for a light emitting diode lighting device capable of controlling brightness and on/off according to an embodiment of the present invention.

Referring to FIG. 4, the AC input input to the noise filter 102 through the power terminal is full-wave rectified in the first rectifier 104 composed of bridge diodes (BD) after filtering out impulse noise. After the ripple is removed by the smoothing capacitor C3, it is applied to the primary side winding 106a of the transformer 106.

The switching and power factor control unit 110 switches the DC output of the first rectifier 104 applied to the primary side winding 106a at high speed while the constant current control signal and brightness control signal fed back from the secondary side through the photo coupler PC1. (That is, the feedback control signal) controls the pulse width of the PWM signal to control the magnitude of the voltage induced in the secondary windings 106b-1 and 106b-2 of the transformer 106.

[Operating when the lighting device is turned on]

If the light emitting diode lighting device is turned on by a dimming signal applied from the outside, the brightness control and feedback units 130 & 140 feed back the corresponding brightness control signal (light on) to the switching and power factor controller 110.

The switching and power factor control unit 110 switches the DC output of the first rectifier 104 applied to the primary side winding at high speed while controlling the pulse width of the PWM signal to be large according to the brightness control signal (lighting lamp on).

The high-frequency power induced in the secondary winding through high-speed switching is half-wave rectified by the second rectifier 120, primary filtered by the smoothing circuit, and high-frequency ripple is removed by the ripple removal circuit 124 to obtain a stable DC constant current. The light emitting diode is supplied to the side of the light emitting diode element so that the light emitting diode is turned on. At this time, the output voltage of the second rectifier 120 is set to be output as an appropriate voltage between the voltage of maximum brightness (eg, 50V) and the voltage of minimum brightness (eg, 40V) of the lighting device.

The third rectifier 150 half-wave rectifies the high-frequency power induced in the secondary winding through high-speed switching and outputs a 10 to 15V DC voltage to the constant voltage conversion unit 170, and the constant voltage conversion unit 170 regulates this voltage. The stable DC 5V voltage is supplied to the control circuit composed of the microcomputer, etc., and the microcomputer, etc. operates normally.

[Lighting Device Dimming Control]

When the brightness of the lighting device is controlled by the dimming signal while the lighting device is on, the brightness control and feedback units 130 & 140 feed back the corresponding brightness control signal (dimming signal) to the switching and power factor control unit 110, Accordingly, the switching and power factor control unit 110 adjusts the magnitude of the voltage induced toward the second rectifier 120 according to the brightness control signal so that the light intensity of the light emitting diode can be adjusted.

[Operation when lighting device is off]

If a light emitting diode off (lighting device off) signal is input from the outside, the brightness control and feedback units 130 & 140 feed back the corresponding brightness control signal (light off) to the switching and power factor control unit 110.

The switching and power factor controller 110 switches the DC output of the first rectifier 104 applied to the primary winding at high speed while controlling the pulse width of the PWM signal to be small according to the brightness control signal (lighting off).

The high-frequency power induced in the secondary winding through high-speed switching is half-wave rectified by the second rectifier 120 and filtered first by a smoothing circuit. At this time, the output voltage of the second rectifier 120 is maintained at about 20V (normal voltage when the light emitting diode is off), and since this 20V voltage is lower than the voltage (40V) for minimum brightness of the light emitting diode, the light emitting diode is turned off.

In addition, the third rectifier 150 outputs a DC voltage of about 4 to 8V by half-wave rectifying the high-frequency power induced in the secondary winding through high-speed switching.

As such, when the output voltage of the second rectifier 150 is lower than the reference voltage set by the zener diode D52, the transistor Q50 of the low voltage detection and compensating unit 160 is turned on to turn on the second rectifier 120. The output voltage (normal voltage when the light emitting diode is off) is transmitted to the constant voltage conversion unit 170, and accordingly, the constant voltage conversion unit 170 continuously outputs a 5V constant voltage so that the microcomputer or the like can stably operate.

In the above, the present invention has been described with reference to one embodiment shown in the drawings, but those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom.

102: noise filter 104: first rectifier
106: transformer 110: switching and power factor controller
120: second rectifier 124: ripple removal circuit
130: feedback unit 140: brightness control unit
150: third rectifier 160: low voltage detection and compensation unit
170: constant voltage converter

Claims (8)

delete delete delete delete one transformer;
a first rectifier for rectifying AC power and applying a DC voltage to the primary side of the transformer;
a switching and power factor controller for high-speed switching of the DC voltage applied to the primary side of the transformer according to a feedback control signal and compensating for a power factor;
a second rectifier rectifying the high-frequency AC signal induced in the secondary side of the transformer to provide constant current power for driving a light emitting diode;
By receiving the output of the second rectifier and the brightness and on/off control signals transmitted from the outside, the output of the second rectifier maintains a constant current and generates a feedback control signal for turning on/off the light emitting diode or adjusting the amount of light. a brightness control and feedback unit for feeding back to the switching and power factor control unit;
a third rectifier outputting a DC voltage for a control circuit by rectifying the high-frequency AC voltage induced in the secondary side of the transformer;
a constant voltage converter providing a stabilized constant voltage for a control circuit by regulating the DC voltage of the third rectifier; and
A switching light emitting diode lighting apparatus including a low voltage detection and compensation unit connected between the second rectifier and the third rectifier and providing an output of the second rectifier to the constant voltage conversion unit when the DC voltage of the third rectifier is lower than the reference voltage. mod power supply. The method of claim 5, wherein the brightness control and feedback unit
When the light emitting diode is turned off wirelessly, the feedback control signal is set so that the output voltage of the second rectifier is maintained as a normal voltage when the light emitting diode is turned off. The method of claim 5, wherein the low voltage detection and compensation unit
A zener diode for setting a reference voltage for detecting the low voltage of the third rectifier;
A switching mode power supply for a light emitting diode lighting device comprising a transistor that is turned on when the output voltage of the third rectifier is equal to or less than the reference voltage set by the zener diode and connects the output voltage of the second rectifier to the constant voltage converter. . The method of claim 5, wherein the second rectifier
Switch mode power supply for light emitting diode lighting equipment, characterized in that it further comprises a ripple elimination circuit for removing high frequency ripple.

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