KR101904806B1 - LED Convertor for Constant Power - Google Patents

Abstract

The constant power LED converter according to an exemplary embodiment of the present invention includes a power unit for receiving an AC power and converting the AC power into a DC power and outputting the AC power and a reference voltage for generating an operating voltage and a constant voltage from the DC power according to a predetermined transformer ratio. A PWM (Pulse Width Modulation) signal for controlling the operation of the reactor using an operation voltage, a reference voltage, and a reference current; And a PWM signal is input to a gate of a field effect transistor (FET) to induce the on / off operation of the FET so that when the FET is off, the energy is supplied to the reactor unit And a switching unit for storing the control signal. If the LED module has the same power consumption as the converter, the LEDs constituting the LED module can be applied irrespective of the series or parallel structure, thereby increasing the productivity of the manufacturer and reducing the inventory burden. In addition, the number of LED converters only needs to be replaced, or the LED modules are not restricted by the repairing field, so it is easy for users without electrical knowledge to apply them.

Description

[0001] The present invention relates to a constant power LED converter,

The present invention relates to a converter for supplying stable power to an LED (Light Emitting Diode) module, and more particularly, to a converter for receiving a voltage and a magnitude of a current supplied to an LED module, And more particularly, to an electrostatic power converter incorporated in a lighting apparatus to provide a stable constant electric power to an LED module by reducing an error of electric power using the LED.

LED (Light Emitting Diode) is a widely used light source for various lighting devices. LEDs have lower power consumption, longer lifetime and higher impact resistance than conventional light sources such as fluorescent lamps and incandescent lamps.

Such an LED is driven by a direct current (DC) power source, which utilizes a light emission phenomenon that appears when a voltage is applied to a semiconductor. The device that provides this DC power is commonly referred to as an LED converter.

The LED converters that have been introduced up to this point apply the constant voltage method or the constant current method in order to light one or more LED (hereinafter referred to as "LED module"). In the case of the constant voltage LED converter, the LED module is turned on, the LED voltage can not be compensated slowly due to the heat generated by the LED device, and after the LED is turned on, the power consumption increases until the LED voltage reaches the saturation point, Resulting in poor durability.

In order to stabilize the operation of the LED module, a constant current type LED converter has appeared as an improvement method. However, even if the LED module is driven by the constant current LED converter, there is a problem that the output value of the LED converter must be changed depending on whether the LED elements constituting the LED module are configured in series or in parallel. This lowers productivity in terms of manufacturers of LED luminaires, including LED converters, and is difficult to apply easily to the general user. In addition, if the compatibility between the LED module and the LED converter is incorrect, the performance of the LED module may deteriorate.

Korean Patent No. 10-0373984

SUMMARY OF THE INVENTION It is an object of the present invention to provide an LED converter capable of supplying a constant voltage and current to an LED module.

More particularly, the present invention aims at stably providing driving power of the LED module by comparing the voltage and current supplied to the LED module with a preset reference voltage and a reference current and controlling the voltage and current according to the difference.

The present invention also aims at eliminating the flicker phenomenon of the LED driving voltage and the current by controlling the phase of the input voltage and the current to be as equal as possible.

It is another object of the present invention to provide an LED converter which can be freely used if power consumption is similar regardless of the configuration (serial or parallel, series or parallel combination) of the LED module serving as a load by providing a constant power.

According to an aspect of the present invention, there is provided an electrostatic power LED converter comprising: a power supply for receiving an AC power and converting the AC power into a DC power; A reactor for generating an operating voltage, a reference voltage for generating a constant voltage, a reference current for generating a constant current, and a driving voltage for an LED operation, which is a load, from the DC power supply according to a predetermined transformer ratio; A controller for outputting a PWM signal for controlling the operation of the reactor using the operation voltage, the reference voltage, and the reference current and compensating the power factor; And a switching unit for causing the FET unit to store the energy when the FET is turned off by driving the FET to turn on and off with the PWM signal input to the gate of the FET.

Also, in the constant power LED converter according to the present invention for solving the above-mentioned problems, the control unit includes a reference generator for generating a reference voltage for generating a predetermined constant voltage and a reference current for generating a predetermined constant current; A voltage regulator for outputting a voltage adjustment value obtained by comparing the reference voltage and the operation voltage; A current regulator for outputting a current adjustment value obtained by comparing the reference current with a current flowing through a source of the FET of the switching unit; A power factor compensator for receiving a rectified voltage of the primary side of the reactor unit and a voltage applied to a source of the FET, and outputting a control value proportional to a product of the two values; A first comparator for comparing the voltage adjustment value and the control value; A second comparator for comparing the current control value with the control value; And a switching controller for generating the PWM signal based on an output value, a reference voltage, and a reference current of the first comparator and the second comparator.

Further, in order to solve the above-mentioned problem, in the constant power LED converter according to the present invention, the reactor part includes a rectifying smoothing part for smoothing and outputting the LED driving voltage; And ripple removing means for removing a ripple of the smoothed voltage and current to prevent a flicker phenomenon.

Further, in the constant power LED converter according to the present invention for solving the above-mentioned problems, when the overvoltage or overcurrent is applied to the LED module or the operation temperature of the constant power LED converter exceeds a predetermined reference value, And a protective portion for stopping the stopper.

According to another aspect of the present invention, there is provided an LED converter comprising: a switching control unit for controlling an output current of a light emitting diode .

The constant-current LED converter according to the present invention supplies constant current and voltage to the LED module, so that the durability of the LED device can be improved.

In addition, if the LED module has the same power consumption as the converter, the constant power LED converter according to the present invention can apply the LEDs constituting the LED module irrespective of the series or parallel structure, thereby increasing the productivity of the manufacturer, .

In addition, since the constant power LED converter according to the present invention is not limited by the specification of the LED module in the number of repairing or repairing areas where only an LED converter needs to be replaced, a user without electric knowledge can easily apply it.

Further, the constant power LED converter according to the present invention can increase the reliability because there is no change in power consumption due to the influence of the surroundings (for example, the temperature or the heat dissipation structure of the lamp).

1 is a block diagram of the configuration of an electrostatic power LED converter according to the present invention.
2 is a detailed configuration diagram of the constant power LED converter according to the present invention.
3 is a graph showing a correlation between a reference voltage, a reference current, an output current, an output voltage, and an output power of the constant power LED converter according to the present invention.

The present invention can be variously modified and may have various embodiments, and specific embodiments will be described in detail with reference to the drawings.

It is to be understood, however, that the invention is not to be limited to the specific embodiments, but includes all changes, equivalents, and alternatives falling within the spirit and scope of the invention.

Like reference numerals are used for like elements in describing each drawing. The terms first, second, etc. may be used to describe various elements, but the elements are not limited to these terms. The terms are used only for the purpose of distinguishing one element from another, and are not in any order, and may not be consistent in the description of the invention and claims.

All terms used in the present specification, including technical or scientific terms, have the same meaning as commonly understood and used by those of ordinary skill in the art to which the present invention belongs, unless otherwise defined.

The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present specification, the terms "comprising" or "consisting of" mean that there is a combination of the features, numbers, steps, operations, elements, etc. described in the specification, It is to be understood that the present invention does not preclude the presence or addition of a combination of features, numbers, steps, operations, components, and the like.

It is to be understood that the specific terminology used herein is for the purpose of promoting an understanding of the present invention, and the use of such specific terminology may be embodied in other forms without departing from the spirit of the present invention.

Hereinafter, the constant power LED converter according to the present invention will be described in detail with reference to the drawings.

1 is a block diagram of the configuration of an electrostatic power LED converter.

1, the constant power LED converter according to the present invention includes a power supply unit 110, a reactor unit 120, a switching unit 130, a control unit 140, a rectifying smoothing unit 150, a ripple removal unit 160 ).

By describing each constituent block in detail,

First, the power supply unit 110 receives commercial AC power and converts the AC power into a DC power.

The reactor unit 120 may include a transformer having a predetermined turn ratio. More specifically, the reactor unit 120 may include a DC power source, A reference voltage for generating a constant voltage to generate a constant voltage and a reference current for generating a constant current, and a drive voltage for an LED operation, which is a load, in order to provide a stable constant electric power to the LED module, do.

The controller 140 outputs a PWM signal for controlling the operation of the reactor 120 using the operation voltage, the reference voltage, and the reference current, and compensates the power factor.

The switching unit 130 may be configured to include a FET and induce the on / off operation of the FET using the PWM signal as an input to the gate of the FET. When the FET is off, the switching unit 130 may be connected to the reactor unit 120 Save energy.

The rectifying and smoothing unit 150 rectifies the LED driving voltage induced in the secondary side according to the winding ratio of the transformer of the reactor 120 through the smoothing diode D3 and charges and discharges the energy to the capacitor C3, And outputs it as a voltage source.

The ripple removal unit 160 performs a function of preventing a flicker phenomenon that may occur when the LED module is turned on by removing a ripple of the smoothed voltage and current. The ripple removing unit 160 is not essential in the configuration of the LED converter according to the present invention and is shown in the detailed configuration diagram of FIG. 2 because it can be an optional specification for preventing the flickering phenomenon of the LED module unit 170 It is not.

On the other hand, when the overvoltage or overcurrent is applied to the LED module or the operation temperature of the constant power LED converter exceeds a predetermined reference value, the control unit 140 stops the operation of the switching unit 130 to protect the LED module and the LED converter. On the other hand, the controller 140 lowers the output current value when the operating voltage rises, and increases the output current value when the operating voltage falls, thereby generating a constant output to be supplied to the LED module.

2 is a detailed configuration diagram of the constant power LED converter according to the present invention.

For the sake of simplicity, the description of the elements that are not expected to be difficult to implement the present invention by those skilled in the art will be omitted.

The power supply unit 110 of FIG. 1 receives AC power, converts the DC power to a DC through a full-wave rectification circuit including a bridge diode 210, and outputs the DC power to the primary side of the transformer of the reactor unit 120. A diode D3 and a capacitor C2 are connected to the secondary side of the transformer of the reactor unit 120 so that smoothing and ripple are removed and stable power is supplied to the plurality of LED modules 170. [

Now, the control unit 140 will be described in more detail.

The reference generator 240 receives the operation power supply Vs for internal operation through the resistor R1, the capacitor C1 and the diode D2 and supplies the reference voltage Vref necessary for the voltage adjustment and the reference voltage Vref necessary for the current adjustment Current Iref.

The voltage regulator 241 is a circuit in which the voltage of the LED module connected to the secondary side of the transformer is induced according to the winding ratio of the reactor, and the induced voltage is applied to the operating voltage Vs .

The voltage adjustment unit 241 compares the reference voltage Vref with the operation voltage Vs and outputs the comparison result to the first comparator 244. As a result of comparison between the reference voltage Vref and the operating voltage Vs, different operating voltages are output, and different output values are output according to the smaller operating voltage. This output value of the voltage adjusting unit 241 is an input of the first comparator 244 to inform the state of the voltage source.

The current adjusting unit 242 has one input for the reference current Iref necessary for the current adjustment and the other input has the current applied to the resistor Rcs connected in series with the source terminal of the FET Q1 And outputs it as a signal to the constant current source as the other input.

The current adjusting unit 242 outputs a different output value when the reference voltage Iref required for the current adjustment is larger than the reference voltage Iref as a result of the comparison between the reference voltage Iref and the resistor Rcs. This output value of the current adjustment unit 242 is an input of the second comparator 245 to inform the state of the constant current.

The peak current generated when the primary winding of the transformer constituting the reactor unit 120 is driven by the input power source is divided into R6, which is a resistor connected in series with a half-wave rectified voltage through the diode D2, Lt; RTI ID = 0.0 > R7. ≪ / RTI > And a voltage across the resistor Rcs connected in series with the source of the FET Q1. The waveform of each of these two voltages is monitored in real time, and the power factor is compensated by controlling the sine wave curve from zero to peak line voltage.

The first comparison units PWM1 and 244 compare the output of the power factor correction unit and the signal of the constant voltage source output from the voltage adjustment unit 241 and output the PWM signal to the switching control unit 246 as a PWM signal for constant voltage control.

The second comparison units PWM2 and 245 compare the output of the power factor correction unit and the signal of the constant current source output from the voltage adjustment unit 241 and output the PWM signal to the switching control unit 246 as a constant current control PWM signal.

The protection unit includes an overvoltage protection (OVP) 248, an overcurrent protection (OCP) 249, and an overtemperature protection (OTP) 250. And stops the operation of the switching unit when an overvoltage or an overcurrent is applied to the LED module or an operation temperature of the constant power LED converter exceeds a predetermined reference value. To this end, the overvoltage protection (OVP) 248 outputs to the switching controller 246 a result of comparing the preset reference voltage Vth-ovp with the operating voltage Vs in real time. The overvoltage protection unit 249 may be constituted by a comparator having a reference voltage Vth-ovp and an operation voltage Vs as inputs.

The overcurrent protection unit (OCP) 249 outputs a result of comparing, in real time, the voltage set by the resistor R8 and the voltage across the resistor Rcs connected in series with the source of the FET Q1 to the switching control unit 246 . The overcurrent protection unit 249 may include a comparator having a reference voltage determined by the resistor R8 and a voltage applied to the Rcs stage connected in series with the FET source stage as respective inputs.

And an over-temperature protection (OTP) 250 receives a real-time temperature sensed by an internal temperature sensor (not shown) and outputs it to the switching control unit 246.

The switching controller 246 adjusts the output current value when the operating voltage rises and increases the output current value when the operating voltage falls, so that the gate driving unit 247 controls the constant current source And outputs a trigger voltage having a specific duty to the gate input of Q1 so as to be applied to the module. To this end, the PWM signal for constant voltage control output from the first comparator 244 and the PWM signal for the constant current control output from the second comparator 245 are compared with the reference voltage output from the reference generator 240, And generates a signal that operates in a circle. This signal is written in the logic control block and consequently controls the on / off of the FET by regulating the output to the LED module by generating the signal driving the gate drive.

Describe the process of producing the constant power output. Basically, it is assumed that the reference current Vref for adjusting the voltage of the reference generator 240 is 2.5 V and the reference current Iref for current adjustment is 1 A, in principle. If so, the reference power value of the switching control section 246 becomes 2.5 W (= 2.5 V x 1A). It is assumed that the amount of current applied to the LED module 170 is set to 1 A when the resistance value of Rcs is 0.1 OMEGA. At this time, if the rated voltage of the LED module 170 is 10V, the power applied to the LED module is 10W (= 10V x 1A). However, if the LED module is replaced and the voltage is changed to 20V, the switching controller 246 causes the gate driver 247 to turn on / off Q1 so that the current value becomes 0.5A so as to maintain the reference power value of 2.5W And outputs a PWM signal.

3 is a graph showing a correlation between a reference voltage, a reference current, an output current, an output voltage, and an output power of the constant power LED converter according to the present invention.

Referring to FIG. 3, when the reference voltage Vref for the constant voltage source and the reference current Iref for the constant current source are set, the reference power Pref, which is an area value of the rectangle, is obtained by multiplying the reference voltage Vref and the reference current Iref for the constant current source. In the example of the preceding paragraph, Vref is 2.5V, Iref is 1A, and Pref is 2.5W. If the voltage applied to the LED module becomes V1 (20 V in the above example) which is larger than the reference voltage Vref, I1 having a value smaller than the reference current Iref in order to satisfy the reference power Pref 0.5A), resulting in a constant power supply.

Therefore, the constant power LED converter according to the present invention basically operates as a constant current source, and when a driving voltage applied to the LED module is changed, a constant current is adjusted according to a predetermined reference power value so that a constant power can be supplied .

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. Accordingly, the scope of the present invention is defined by the appended claims, and is not limited by the specific embodiments described herein.

100: constant power LED converter 110: power source part
120: reactor unit 130:
140: control unit 150: rectifying and smoothing unit
160: ripple removal 170: LED module
210: bridge diode 240: reference generator
241: voltage regulator 242: current regulator
243: Power factor protection unit 244:
245: second comparison unit 246: switching control unit
247: Gate driver 248: Overvoltage protection unit
249: overcurrent protection unit 250: overcurrent protection unit

Claims (5)

A power supply unit for receiving an AC power source and switching to a DC power source for output;
A reactor for generating an operating voltage, a reference voltage for generating a constant voltage, a reference current for generating a constant current, and a driving voltage for an LED operation, which is a load, from the DC power supply according to a predetermined transformer ratio;
A controller for outputting a PWM (Pulse Width Modulation) signal for controlling the operation of the reactor using the operation voltage, the reference voltage, and the reference current, and compensating the power factor; And
And a switching unit for inducing the on / off operation of the FET using the PWM signal as an input to a gate of a FET (Field Effect Transistor), thereby storing energy in the reactor unit when the FET is off However,
The control unit
A reference generator for generating a reference voltage for generating a predetermined constant voltage and a reference current for generating a predetermined constant current;
A voltage regulator for outputting a voltage adjustment value obtained by comparing the reference voltage and the operation voltage;
A current regulator for outputting a current adjustment value obtained by comparing the reference current with a current flowing through a source of the FET of the switching unit;
A power factor compensator for receiving a rectified voltage of the primary side of the reactor unit and a voltage applied to a source of the FET, and outputting a control value proportional to a product of the two values;
A first comparator for comparing the voltage adjustment value and the control value;
A second comparator for comparing the current control value with the control value; And
And a switching control unit for generating the PWM signal based on the output value, the reference voltage, and the reference current of the first comparing unit and the second comparing unit,
The switching control unit
Wherein the control unit lowers the output current value when the operating voltage rises, and increases the output current value when the operating voltage falls, so as to be a constant power output.
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