KR20120080098A - Switching-mode power supply for lighting of light emitting diode with static current controlling function - Google Patents

Abstract

PURPOSE: A switching-mode power feeder for an LED(Light Emitting Diode) lamp is provided to have an enough protective function by dualizing an input filter for eliminating harmonic waves. CONSTITUTION: An LED driver IC(Integrated Circuit)(120) comprises a primary side constant current control function of a transformer. An input power source matching unit(141) is connected with the LED driver IC. The input power source matching unit matches an input power source through variable time constant. A load change adaptation time constant selection unit(142) is connected with the LED driver IC and the input power source matching unit. The load change adaptation time constant selection unit adaptively selects time constant in response to the change of an LED lamp.

Description

Switching-mode power supply for lighting of light emitting diode with static current controlling function}

The present invention relates to a power supply for light emitting diode lighting, and more particularly, to a switching-mode power supply for LED lighting having a constant current control function for driving an LED lamp using an LED driver IC having a primary side constant current control function. (Switching-Mode Power Supply: SMPS).

Light emitting diodes (LEDs) have advantages in that they are smaller in size, longer in life, and have less power and efficiency because electrical energy is directly converted into light energy. Due to these characteristics, as well as display devices of various electronic devices, it is in the spotlight for lighting devices replacing conventional incandescent lamps and fluorescent lamps such as indoor and outdoor lighting, signage lighting and general residential lighting.

In order to use LEDs in such lighting devices, an LED module composed of a plurality of LEDs is used. These LED modules require a constant current to shine properly and maintain their lifetime. Since these LEDs use a DC power supply, a switching mode power supply (SMPS) is used to rectify the 220 volt AC to DC and convert the rectified DC voltage to the required DC voltage. do.

1 is a view showing a light emitting diode lighting apparatus according to the prior art.

Referring to FIG. 1, the LED lighting apparatus according to the related art converts AC power into DC power using SMPS in order to use LED for lighting, and converts LEDs D1 to Dn in parallel with the converted DC power. Connect. At this time, in order to match and protect each of the LEDs D1 to Dn, the resistors R1 to Rn are connected in series with each of the LEDs D1 to Dn. Although one LED and one resistor are shown to be connected to each path, a plurality of LEDs may be used in series with the resistors as shown in FIG. 1.

On the other hand, the power supply device for supplying power to the LED lighting device according to the prior art is the main power supply (SMPS) for supplying a constant voltage. This type of power supply (SMPS) of this constant voltage type is difficult to maintain the constant brightness of the LED because the current is difficult to be constantly supplied from the first module to the last module of the LED, and also the light output compared to the power input to the LED is weak. 15%, 85% of the heat emission problem occurs, causing a problem such as reducing the lifetime of the LED.

In order to solve the heat problem, the LED lighting device which is illuminated with a constant voltage is added with a heat sink or a temperature protection circuit, which is a factor in the increase of the unit price of the product.

In order to solve the problems of the aforementioned constant voltage type power supply (SMPS), a constant current type power supply is used. However, the constant current type power supply has a problem of irregular current caused by load variation and compensation of power according to the ambient temperature, and the unit cost increases due to the complicated circuit configuration, which causes heat generation and efficiency. There is a problem such as falling.

On the other hand, as the prior art, Korean Patent No. 10-0980242 discloses an invention named "switching mode power supply," will be described with reference to FIG.

2 is a circuit diagram showing a power supply (SMPS) according to the prior art.

Referring to FIG. 2, in a power supply device (SMPS) according to the related art, a PWM signal is provided from the oscillation IC 30 to the transformer 10, and the transformer 10 is supplied by the PWM signal of the oscillation IC 30. Induced electromotive force is generated in the secondary winding portion TL2 and the tertiary winding portion TL3, and the AC power output from the tertiary winding portion TL3 of the transformer 10 is generated by the first output rectifier 40. It is converted to DC power.

The feedback circuit unit 50 checks the voltage of the DC power output from the first output rectifying unit 40 and the PWM signal from the oscillation IC 30 by the voltage input from the feedback circuit unit 50 to the oscillation IC 30. By controlling the pulse width, the constant current is output from the tertiary winding portion TL3 of the transformer 10 through the first output rectifier 40 to the LED module 60 regardless of the load variation of the LED module 60. .

In this case, the PFC circuit unit 20 includes inductors L1 and L2 connected by the bridge diode DB1 and a third capacitor C3 connected between the inductors L1 and L2. In the PFC circuit unit 20, the charging current of the second capacitor C3 is limited by the impedance amount of the inductors L1 and L2, so that the conduction angle is widened and the power factor is improved. Here, reference numerals R1 and R2 denote damping resistors, and D6 denotes diodes for surge protection.

In addition, when the input voltage input to the input terminal C is lower than the reference voltage, the oscillation IC 30 outputs a PWM signal having a large pulse width at the output terminal D, thereby increasing the output voltage of the transformer 10. When the input voltage input to the input terminal C is higher than the reference voltage, the output signal D outputs a PWM signal having a small pulse width, thereby lowering the output voltage of the transformer 10.

The first output rectifier 40 includes a diode D4 and a capacitor C11 for converting the AC power transformed by the tertiary winding part TL3 into a DC power source.

The feedback circuit unit 50 includes: a photo coupler (PC1; photo coupler) serving as a dependent current source by changing the magnitude of the current flowing according to the magnitude of the voltage output from the first output rectifier 40; A first zener diode ZD1 for determining a voltage output from the third winding TL3 through the first output rectifier 40; A soft start unit 51 for delaying a current provided to the photocoupler PC1 during an initial operation; A first transistor TR1 whose operation is controlled by the photocoupler PC1 and which controls a voltage provided from the secondary winding TL2 of the transformer 10 to the oscillation IC 30; And a constant current and temperature compensator 52 for controlling the switching of the first transistor.

In addition, the thermistor Th1 having the negative temperature characteristic lowers the bias voltage of the second transistor TR2, thereby lowering the current amplification degree of the constant current second transistor TR2 as the temperature of the second transistor TR2 increases. Reference numeral 70 in FIG. 1 denotes an AC input filter for filtering AC input power input through the fuse F1, and includes a varistor TR1, a first capacitor C1, a line filter LF, and a second capacitor ( C2).

According to the aforementioned power supply device SMPS, the power factor correction circuit 20 is disposed between the bridge diode DB1 rectifying the AC input power and the transformer 10 for transforming the pulse current output from the bridge diode DB1. Thus, the power factor is improved by improving the characteristics of the pulse.

However, the above-described power supply device (SMPS) has a problem in that a photo coupler (PC1) and a secondary side current control circuit are required, and an LED driver IC having a primary side constant current control function is used to eliminate the above problem. Can be.

3 is a general application circuit diagram of an LED driver IC having a primary side constant current control function.

Referring to FIG. 3, a general application of an LED driver IC having a primary side constant current control function includes an LED driver IC 81 having a primary side constant current control function, a bridge diode 82, and a transformer 83, and Rv ( The LED module 85 is driven by the output power set by 84).

The LED driver IC 81 with primary side constant current control is capable of flicker-free phase controlled triac (DIAC) dimming, single PFC and accurate constant current (CC) outputs, a photocoupler and all secondary side current control circuits. As an unnecessary IC, for example, the model name LNK409EG may be used.

The LED driver IC 81 having the primary-side constant current control function maximizes efficiency at 66 kHz oscillation frequency, and enables large-scale SMPS from 8 [W] to 50 [W] in small size and light weight. Minimize noise generation, inrush current, and EMI at the same time.

However, among the existing circuits proposed by the LED driver IC 81, the constant voltage output, constant current output, harmonic limit, inrush current limit, EMI / EMC countermeasure, ripple voltage and ripple current limit, and heat limit should be solved. There is a problem that it is difficult to easily apply the LED driver IC 81 to the field. Accordingly, it is necessary to reinforce the circuit and set the time constant that can satisfy the above conditions.

1) Republic of Korea Patent No. 10-0980242 (application date: October 08, 2009), the title of the invention: "Switching mode power supply" 2) Republic of Korea Patent Publication No. 2010-0098041 (published: September 06, 2010), the title of the invention: "Fixed power control circuit and LED drive circuit using the same" 3) Republic of Korea Patent No. 10-0753665 (application date: October 17, 2006), the title of the invention: "LED constant current drive circuit" 4) Republic of Korea Patent No. 10-0385145 (application date: May 09, 2002), the title of the invention: "Switched mode power supply circuit for light emitting diode drive" 5) Republic of Korea Patent Publication No. 2009-0120225 (published: November 24, 2009), the title of the invention: "Light Emitting Diode Lighting Driving Device"

The technical problem to be solved by the present invention to solve the above problems is, SMPS for LED lighting having a constant current control function to prevent the generation of noise, by preventing the inrush current generation by matching the input voltage using a variable time constant It is to provide.

Another technical problem to be achieved by the present invention is to provide a SMPS for LED lighting having a constant current control function having a sufficient protection function by dualizing an input filter for harmonics removal.

Another technical problem to be achieved by the present invention is to provide an SMPS for LED lighting having a current control function capable of stabilizing the output even in various power supplies.

As a means for achieving the above-described technical problem, the LED lighting power supply (SMPS) with a constant current control function according to the present invention, a switching current-mode LED lighting power supply (Switching-Mode Power Supply: An SMPS comprising: a bridge diode for rectifying an input AC power and converting the input AC power into a DC power; A transformer for boosting or stepping down the DC power output from the bridge diode; An LED driver IC disposed between the bridge diode and the transformer and having a primary side constant current control function of the transformer; An input power matching unit connected to the LED driver IC to match input power through a variable time constant; And a load change adaptive time constant selecting unit connected between the LED driver IC and the input power matching unit to adaptively select a time constant in response to a change in the LED lighting lamp as a load.

The input power matching unit selects a variable time constant by a variable resistor and a capacitor connected to the LED driver IC, and the range of input power matched by the variable time constant is 90 [V] to 235 [V]. Can be.

Here, the reference voltage matching time constant selection unit for selecting a time constant to match the reference voltage for outputting a constant current is connected between the LED driver IC and the secondary winding of the transformer may further include.

Here, the input terminal may further include an input stage filter unit connected to both ends of the AC input power to prevent inrush current generation according to the input of the AC input power.

Here, the harmonic limiting time constant selection unit may be further disposed between the AC input power and the bridge diode to set a time constant for harmonic limitation.

Here, the harmonics are 3rd, 5th, 7th, 9th, and 11th harmonic pie, the harmonic limiting time constant selector is 30% or less of the 3rd harmonic, 10% or less of the 5th harmonic, 7th harmonic 7% or less, 9th harmonic is 5% or less, and 11th harmonic is limited to 3% or less.

Here, the rectified and filtered DC power output from the transformer T1 may further include an automatic constant voltage and current capacity conversion unit for automatically converting the constant voltage and the current capacity according to the variation of the load, such as an LED lamp.

Here, the transformer may further include a transformer time constant selection unit disposed in the secondary winding of the transformer to select a time constant for low heat generation of the transformer.

The line filter disposed between the AC input power and the bridge diode may further include an EMI / EMC reduction unit for removing noise included in the AC power line to reduce EMI / EMC.

According to the present invention, the input voltage is matched using a variable time constant by a passive circuit to prevent noise generation, to prevent inrush current generation of the power supply, and to provide sufficient protection by dualizing an input filter for removing harmonics. have. For example, an operating method may be mounted inside an LED fluorescent lamp configured for two lamps to prevent generation of inrush current and to remove harmonics.

According to the present invention, the output can be stabilized even in a variety of power supplies, for example, it is possible to supply a stable power to the LED light when switching for one lamp.

According to the present invention, it is possible to secure stability in the use of the electronic ballast by simultaneously solving the low heat generation of the transformer and EMI / EMC.

According to the present invention, it is possible to reduce the use of lighting energy at low power, thereby contributing to a low carbon policy and global warming prevention for carbon dioxide reduction.

1 is a view showing a light emitting diode lighting apparatus according to the prior art.
2 is a circuit diagram illustrating a SMPS according to the related art.
3 is a general application circuit diagram of an LED driver IC having a primary side constant current control function.
4 is a view for explaining the operation of the SMPS for LED lighting with a constant current control function according to an embodiment of the present invention.
FIG. 5 is a diagram illustrating a pin configuration of the LED driver IC having the primary side constant current control function shown in FIG. 4.
FIG. 6 is a functional block diagram of an LED driver IC having the primary side constant current control function shown in FIG. 4.
7 is a block diagram of a SMPS for LED lighting having a constant current control function according to an embodiment of the present invention.
8 is a circuit diagram of a SMPS for LED lighting having a constant current control function according to an embodiment of the present invention.
9 is a circuit diagram of a SMPS for LED lighting having a constant current control function according to another embodiment of the present invention.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. 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 the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like parts throughout the specification.

Throughout the specification, when a part is said to "include" a certain component, it means that it can further include other components, without excluding other components unless specifically stated otherwise.

4 is a view for explaining the operation of the SMPS for LED lighting with a constant current control function according to an embodiment of the present invention.

Referring to FIG. 4, the SMPS 100 for LED lighting having a constant current control function according to an embodiment of the present invention includes a bridge diode 110, an LED driver IC 120 having a primary side constant current control function, and a transformer 130. By including the rectifier 160 and the filter 170, the AC power source 200 is input to drive the lamp 300 which is an LED module.

SMPS (100) for LED lighting having a constant current control function according to an embodiment of the present invention, AC-> DC-> switching (oscillation)-> step-up / step-down by transformer winding-> rectification-> filter-> DC Through the process of voltage, the oscillation frequency of 66 kHz or more is used. At this time, the light emitting diode lighting SMPS 100 having the constant current control function uses the LED driver IC 120 having the primary side constant current control function in which a single PFC (power factor correction) and a constant current controller are built in, thereby controlling the secondary side current control. Accurate constant current control without circuitry is possible, which simplifies the secondary circuit.

LED lighting power supply (SMPS) having a constant current control function according to an embodiment of the present invention is SMPS power supply using an LED driver IC (for example, LNK 409EG) having a primary constant current control function for stable power supply As a device, it has a sufficient protection function by duplexing the inrush current prevention part that prevents noise and inrush current of power supply using passive circuit, and the filter for eliminating harmonics, and also includes the function to stabilize the output even in various power supply. .

Low heat generation is possible by resetting the voltage and constant current design, time constant, and transformer's time constant to allow 50W for constant voltage and constant current according to the circuit design and time constant and the number of luminaires used.

Meanwhile, FIG. 5 is a diagram illustrating a pin configuration of the LED driver IC having the primary side constant current control function shown in FIG. 4, and FIG. 6 is a functional block of the LED driver IC having the primary side constant current control function shown in FIG. 4. It is a diagram.

5 and 6, the LED driver IC 120 having the primary-side constant current control function includes DRAIN pin 7 (D), SOURCE 5 pin (S), BYPASS pin 4 (BP), and FEEDBACK 3 Pin (FB), REFERENCE pin 1 (R), and VOLTAGE MONITOR pin 2 (V).

DRAIN pin 7 (D) is a power MOSFET drain connection pin that provides internal operating current for startup and steady-state operation.

SOURCE 5 pin (S) is the power MOSFET source connection pin, which is the ground reference pin for the BYPASS (BP), FEEDBACK (FB), REFERENCE (R), and VOLTAGE MONITOR (V) pins.

BYPASS pin 4 (BP) is the connection point for an internally generated external bypass capacitor for the 5.9V supply, and the output power can be selected by selecting the BYPASS pin (BP) capacitor value.

FEEDBACK pin 3 (FB) is used for output voltage feedback. The current flowing into the FEEDBACK pin is directly proportional to the output voltage. The FEEDBACK pin also contains circuitry to protect the open load and overload output states.

REFERENCE pin 2 (R) is connected to an external precision resistor and is used to select between dimming and non-TRIAC dimming modes of operation.

VOLTAGE MONITOR pin 1 (V) interacts with an external input line peak detector consisting of a rectifier, filter capacitor, and resistor, where the applied current is the stop logic for the input undervoltage (UV) and overvoltage (OV). ) And feed forward for controlling the output current and remote ON / OFF functions.

Specifically, the LED driver IC 120 having a primary side constant current control function is an LED driver IC having a TRIAC dimming function, a single PFC, and a primary side constant current control function, and requires a power factor (PF)> 0.9, a TRIAC dimming function, and high efficiency. The implementation of the LED drive becomes very easy. The use of a single power factor (PF) and constant current controller eliminates the passive circuitry required for power factor correction and electrolytic smoothing capacitors. This primary side control technology eliminates the need for opto-coupler and secondary side current control circuits and enables accurate constant current control. In addition, 725V power MOSFETs, continuous mode PWM controllers, high voltage switching current sources for self-biasing, frequency jittering, cycle-by-cycle current limiting, and hysteresis thermal shutdown circuitry are all integrated into a monolithic IC.

Hereinafter, with reference to FIGS. 7 and 9, the operation and function of the LED two-light power supply device (SMPS) using the LNK 409EG will be described.

On the other hand, Figure 7 is a block diagram of a light emitting diode illumination SMPS with a constant current control function according to an embodiment of the present invention, Figure 8 is a circuit diagram of a light emitting diode illumination SMPS with a constant current control function according to an embodiment of the present invention. .

7 and 8, the SMPS 100 for LED lighting having a constant current control function according to an embodiment of the present invention receives an AC input power 200 and converts it into DC to the LED module 300. And a bridge diode 110, an LED driver IC 120, a transformer 130, and an additional circuit, wherein the additional circuit includes an input power matching unit (variable time constant selection) 141 and an adaptive load change time constant. Selection section 142, reference time matching time constant selection section 143, input stage filter section 144, harmonic limiting time constant selection section 145, automatic constant voltage and current capacity conversion section 146, transformer time constant The selector 147 and the EMI / EMC reduction unit 148 are included.

The bridge diode 110 rectifies and converts AC input power into DC, that is, the bridge diode BD1 rectifies a commercial AC power, for example, AC 220V, to generate a DC power source having a DC voltage. . Here, the voltage value output from the bridge diode BD1 may be appropriately determined according to the AC input voltage value and the number of light emitting diodes. In this case, the DC power output from the bridge diode BD1 may include a DC component and an AC component. It is the included pulse power source.

The transformer 130 boosts the DC voltage provided from the bridge diode 110.

The LED driver IC 120 is an IC having a primary side constant current control function, and may be LNK409EG as described above, and the LNK409EG is an LED driver IC having a primary side constant current control function, and the LED lighting device has a power factor of 0.9 or more with high efficiency. It is a driver IC for LED that can be outputted in the form of a voltage and can input a voltage of 90 [V] to 235 [V] according to the time constant selection.

Specifically, referring to FIG. 8, the REFERENCE 1 pin of the LED driver IC 120 is connected to ground through an external resistor, an internal reference is set according to a selected value, and an operation between dimming and non-dimming operations is performed. The input undervoltage and overvoltage thresholds of the mode and VOLTAGE MONITOR pins are determined, and a 1% resistor is recommended because the resistance tolerance directly affects the output error.

In addition, the switching frequency of the LED driver IC 120 is 66 kHz, so that the switching frequency is jittered by about 1 kHz to further reduce the EMI level.

The fuse F1 provides component fault protection, and the first triac TH1 clamps during the differential input surge, while the LED driver IC 120 is smaller than the rating of the power MOSFET inside the LED driver IC 120. The peak drain voltage of is maintained. The bridge rectifier BD1 rectifies the AC input voltage. In addition, the L1 to L4 coils, C1 capacitors, R2 and R3 resistors provide EMI filtering along with C14 capacitors that bridge the safety isolation barrier between the primary and secondary sides of transformer T1.

At this time, the R2 and R3 resistors operate to damp any resonance formed between the L1 and L2 coils, the C1 capacitor and the AC input impedance. To provide a low impedance source for the primary side switching current, a small smoothing capacitor C3 is required, and the maximum value of the C1 and C3 capacitors is limited to keep the power factor PF greater than 0.9.

In addition, the rectified AC peak to provide peak input voltage information to the LED driver IC 120 charges the C4 capacitor through the D1 diode, and then the VOLTAGE MONITOR of the LED driver IC 120 through the R6 and R7 resistors. The sensing current is supplied to pin 2 (V). The LED driver IC 120 also uses the sensing current to set line input overvoltage and undervoltage protection reference values. At this time, the R5 resistor provides a discharge path to the C4 capacitor with a time constant much longer than the time constant of the rectified AC to prevent the generation of input frequency ripple.

The sensing current on pin 2 of VOLTAGE MONITOR and the current on pin 3 of FEEDBACK are used internally to control the LED current of the average output. For example, for a first TRIAC (TH1) phase dimming application, a resistor R4 is used on REFERENCE pin 1 (R) to provide a linear relationship between input voltage and output current, and to maximize the dimming range, and R6 and R7 A resistor is used on pin 2 of the VOLTAGE MONITOR. In addition, the R4 resistor sets the internal line input undervoltage and overvoltage protection thresholds.

In addition, the D3 diode clamps the drain voltage to a safe level due to the effect of leakage inductance. In addition, diode D3 is required to prevent reverse current from passing through the LED driver IC 120 during the rectified AC input voltage period during which the voltage across C3 drops below the reflect output voltage VOR.

In addition, the D6 diode, C11 capacitor, R14 and R15 resistors make the primary side bias supply at the auxiliary winding of transformer T1. The C10 capacitor provides local decoupling for BYPASS pin 4 (BP) of the LED driver IC 120 corresponding to the supply pin for the internal controller. Accordingly, during startup, the C10 capacitor is charged to a predetermined voltage at an internal high voltage current source connected to pin DRAIN 7 of the LED driver IC 120. Thus, the LED driver IC 120 may begin switching at a point where an operating supply current is provided at the bias supply via the R12 resistor. In addition, the C10 capacitor may select an output power mode.

On the other hand, the bias winding voltage is proportional to the output voltage, i.e., set by the turn ratio between the bias and the secondary winding. Thus, the output voltage can be monitored without the secondary feedback component of the transformer (T1). The resistor R13 converts the bias voltage into a current supplied to the FEEDBACK pin 3 FB of the LED driver IC 120.

In addition, an output overvoltage protection circuit is set by the D7 diode, C13 capacitor, R17 resistor, ZD2 zener diode, C12 capacitor, Q1 transistor, and R16 resistor to limit the output voltage at no load. At this time, when the output load is disconnected, the bias voltage increases until the ZD2 zener diode becomes conductive, and the Q1 transistor is turned on and the current flowing to FEEDBACK pin 3 FB decreases. For example, if this current drops below 20 mA, the LED driver IC 120 enters auto-restart and switching is disabled for 800 ms, for example, so that the output and bias voltages can fall during that time. do.

In addition, the transformer (T1) secondary winding is rectified by the diode and filtered by the C6, C7 and C8 capacitors. At this time, the combined values of the C6, C7, and C8 capacitors are selected to provide peak-to-peak current and LED ripple current. For designs where lower ripple is recommended, you can increase the output capacitance value.

In addition, the LED driver IC 120 applies various aspects of the design according to the requirement to provide output dimming using a low-cost leading-edge phase dimmer based on TRIAC (TH1).

Specifically, the LED-based light consumes much lower power, so the current drawn by the entire lamp is less than the holding current of TRIAC (TH1) in the dimmer. This may result in undesirable behavior, such as limited dimming range and / or flicker, when TRIAC TH1 operates irregularly. For example, when the TRIAC (TH1) is ON due to the relatively large impedance that the LED lamp provides to the line, the ringing can occur largely due to the inrush current charging the input capacitance. In this case, ringing may cause unwanted operation such as the TRIAC (TH1) current goes to zero or becomes OFF.

In the SMPS 100 for LED lighting having a constant current control function according to an embodiment of the present invention, the input power matching unit 141 is set to 90 [V] through a variable time constant in the LED driver IC 120 having the primary side constant current control function. The input power of 235 [V] is matched at V], and the time constant can be selected through the R11 and R19 resistors, the VR1 variable resistor and the C10 capacitor.

The load change adaptive time constant selecting unit 142 adaptively selects a time constant in response to a change in the LED lamp as a load. For example, by turning on the SW1 switch, the time constant selected through the above-described R11 and R19 resistors and the VR1 variable resistor and the C10 capacitor can be selected through the R19 resistor, the VR1 variable resistor and the C10 capacitor.

The time constant selection unit 143 for matching the reference voltage is connected between the FEEDBACK pin 3 of the LED driver IC 120 and the secondary winding of the transformer to select a time constant to match the reference voltage to select a constant current. You can print For example, as described above, to limit the output voltage at no load, the output overvoltage protection circuit is set by the D7 diode, C13 capacitor, R17 resistor, ZD2 zener diode, C12 capacitor, Q1 transistor, and R16 resistor, where R17 and The time constant can be selected by the R16 resistor and the C13 and C12 capacitors.

The input stage filter unit 144 is connected to both ends of the AC input power source and is redundant to prevent inrush current generation. For example, the input stage filter unit 144 may include a second bridge diode BD2, C20, C21 and C22 capacitors, R20 and R21 resistors, D8 and D9 diodes, ZD3 and ZD4 zener diodes, and a relay RY1. Can be.

The harmonic limiting time constant selecting unit 145 is disposed between the AC input power supply and the bridge diode BD1 to set time constants for 3, 5, 7, 9, and 11 harmonic limiting. Here, harmonics refer to other frequencies forming one frequency (for example, fundamental frequency, first harmonic, third harmonic, etc.), and components other than the fundamental frequency, for example, 3, 5, 7, 9 For example, 11 harmonics generate noise, so remove it. The harmonic limiting time constant selector 145 may include, for example, C15 and C16 capacitors, Z1 varistors, C17 capacitors, C1 capacitors, R2 and R3 resistors, and L1 and L2 coils.

The automatic constant voltage and current capacity converting unit 146 is for converting the automatic constant voltage and current capacity according to the variation of the load, which is an LED lamp, and outputs the rectified and filtered DC power output from the transformer T1 coils L5 and L6, C9 and C19 capacitors, R9 resistors, ZD zener diodes and TH2 and TH3 triacs.

The transformer time constant selecting unit 147 selects a time constant by the R18 resistor and the C18 capacitor for low heat generation of the transformer T1.

The EMI / EMC reduction unit 148 is a line filter LF1 disposed between the AC input power and the bridge diode BD1 to reduce EMI / EMC. Here, a filter for removing various noises included in an AC power line is called a line filter, which is a low pass filter composed of a coil and a capacitor.

9 is a circuit diagram of a light emitting diode lighting SMPS having a constant current control function according to another embodiment of the present invention.

Referring to FIG. 9, the light emitting diode lighting SMPS having the constant current control function according to another embodiment of the present invention is compared with the SMPS shown in FIG. 8, the harmonic limiting time constant selecting unit 155 and the EMI. Except that the configuration of the / EMC reduction unit 158 is different, the description of the same parts will be omitted because the other components are substantially the same. That is, the SMPS for LED lighting having a constant current control function according to an embodiment of the present invention, as shown in Figures 8 and 9, respectively, harmonic limiting time constant selection unit (145, 155) and EMI / EMC reduction unit 146 and 158 may be disposed.

In the harmonic limiting time constant selecting unit 155, for example, the harmonic limiting time constant selecting unit 155 is a C1 capacitor, R2 and R3 resistors, L1 and L2 coils are disposed on the AC AC power supply side, C15 and C16 capacitors, Z1 varistors, and C17 capacitors are disposed on the bridge diode BD1 side. At this time, the line filter LF1 which is the EMI / EMC reduction unit 158 is disposed on the bridge diode BD1 side.

On the other hand, the input characteristics of the electrical characteristics of the SMPS for light emitting diode illumination with a constant current control function according to an embodiment of the present invention are as follows. Rated input voltage is single phase 250V / 90V, input voltage range is ㅁ 5%, input frequency range is 50㎐ / 60㎐, input inrush current is 0.2A or less (module unit), efficiency is 85% or more load current The power factor is 90% or more of the load current, the primary inrush current is 0.2A or less, and Vpp is given as less than 3V.

In addition, DC output characteristics among the electrical characteristics of the SMPS for LED lighting having a constant current control function according to an embodiment of the present invention are as follows. Rated output voltage is 24V, operating voltage range is 24V, rated output current is for 0.8A / 1 lamp and 1.6A / 2 lamp, stability for input and load is 1%, secondary inrush current is 0.1A ~ Within 0.2A, the output current is limited within 0.7A to 0.9, and the rectifier module is stopped within 24V to 0.5V for output overvoltage protection.

In addition, the environmental conditions of the electrical characteristics of the SMPS for LED lighting with a constant current control function according to an embodiment of the present invention are as follows. First, in high frequency radio interference (EMI), in the case of three radiation waves (30 MHz to 1,000 MHz), 30 MHz ≤ f ≤ 250 MHz: 10 Hz (30 Hz) or less, and 250 MHz ≤ f ≤ 1,000 MHz: 10 GHz (37 GHz) or less, and in the case of four radiation waves (9 kHz to 300 MHz), 9 kHz ≤ f ≤ 110 MHz: 30 Hz. In addition, for ISO 61000-based harmonics, the 2nd harmonic is below 2%, the 3rd harmonic is below 30% (with power factor 0.9, below 27%), the 5th harmonic is below 10%, and the 7th harmonic is 7%. Hereinafter, the 9th harmonic is 5% or less, and the 11th harmonic is 3% or less. In addition, in operating temperature and humidity, a temperature is given at -30 ° C to + 60 ° C and a humidity is given at 10% to 90%.

As a result, according to the embodiment of the present invention, the input voltage is matched using a variable time constant by a passive circuit to prevent noise generation, to prevent generation of inrush current of the power supply, and to provide sufficient protection by dualizing a filter for removing harmonics. It can have a function. In addition, the output can be stabilized even in various power supplies, for example, stable power can be supplied to LED lights when switching to one lamp, and stability of use of electronic ballasts is solved by simultaneously solving the low heat generation of the transformer and EMI / EMC. Can be secured.

The foregoing description of the present invention is intended for illustration, and it will be understood by those skilled in the art that the present invention may be easily modified in other specific forms without changing the technical spirit or essential features 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 shown by the following claims rather than the above description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included in the scope of the present invention. do.

100: SMPS for LED lighting with primary constant current control
200: AC input power
300: LED module (lighting)
110: bridge diode (BD)
120: LED Driver IC
130: transformer
141: input power matching unit (variable time constant selection)
142: load change adaptive time constant selection unit
143: time constant selection unit for reference voltage matching
144: input stage filter unit
145, 155: Harmonic limit time constant selection unit
146: automatic constant voltage and current capacity conversion unit
147: transformer time constant selection unit
148, 158: EMI / EMC reduction unit

Claims (10)

In the Switching-Mode Power Supply (SMPS) of the constant current type light emitting diode (LED) lighting, A switching diode, Bridge diode (Cridge Diode) for rectifying the input AC power to convert to DC power;
A transformer for boosting or stepping down the DC power output from the bridge diode;
An LED driver IC disposed between the bridge diode and the transformer and having a primary side constant current control function of the transformer;
An input power matching unit connected to the LED driver IC to match input power through a variable time constant; And
Load change adaptive time constant selection unit connected between the LED driver IC and the input power matching unit to adaptively select a time constant in response to a change in the LED lighting lamp as a load
Switching-mode power supply for light emitting diode illumination with a constant current control function comprising a. The method of claim 1,
And the input power matching unit selects a variable time constant by a variable resistor and a capacitor connected to the LED driver IC. The method of claim 2,
And a range of the input power source matched by the variable time constant is 90 [V] to 235 [V]. The method of claim 1,
LED lighting device having a constant current control function further comprising a reference voltage matching time constant selection unit for selecting a time constant to match the reference voltage for outputting a constant current connected between the LED driver IC and the secondary winding of the transformer Switching-mode power supplies. The method of claim 1,
And a constant current control function connected to both ends of the AC input power to prevent an inrush current from being generated according to the input of the AC input power. The method of claim 1,
And a harmonic limiting time constant selector disposed between the AC input power source and the bridge diode to set a time constant for harmonic limiting. The method of claim 6,
The harmonics are 3rd, 5th, 7th, 9th, and 11th harmonics, and the harmonic limiting time constant selector is 30% or less for the 3rd harmonic, 10% or less for the 5th harmonic, and 7% for the 7th harmonic. A switching-mode power supply for a light emitting diode illumination device having a constant current control function, characterized in that the ninth harmonic is limited to 5% or less, and the eleventh harmonic is limited to 3% or less. The method of claim 1,
Switching for light emitting diode lighting having a constant current control function further includes an automatic constant voltage and current capacity conversion unit for automatically converting the constant voltage and current capacity of the DC power outputted from the transformer and rectified and filtered according to the load change such as LED lighting -Mode power supply. The method of claim 1,
Switching-mode power supply for a light emitting diode lighting device having a constant current control function further comprises a transformer time constant selection unit disposed in the secondary winding of the transformer for selecting a low heat generation of the transformer for selecting a time constant. The method of claim 1,
A line filter disposed between the AC input power and the bridge diode, the constant current control function further comprising an EMI / EMC reduction unit for removing noise included in the AC power line to reduce EMI / EMC. Switching-mode power supply for light emitting diode lighting having a.

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