WO2014123255A1 - Light-emitting device driving apparatus and light-emitting device driving method - Google Patents

Light-emitting device driving apparatus and light-emitting device driving method Download PDF

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Publication number
WO2014123255A1
WO2014123255A1 PCT/KR2013/000968 KR2013000968W WO2014123255A1 WO 2014123255 A1 WO2014123255 A1 WO 2014123255A1 KR 2013000968 W KR2013000968 W KR 2013000968W WO 2014123255 A1 WO2014123255 A1 WO 2014123255A1
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Prior art keywords
light emitting
emitting device
unit
current
power supply
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PCT/KR2013/000968
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French (fr)
Korean (ko)
Inventor
김현창
김재하
정덕균
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서울대학교 산학협력단
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Publication of WO2014123255A1 publication Critical patent/WO2014123255A1/en

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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
    • H05B45/40—Details of LED load circuits
    • H05B45/44—Details of LED load circuits with an active control inside an LED matrix
    • H05B45/46—Details of LED load circuits with an active control inside an LED matrix having LEDs disposed in parallel lines
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
    • H05B45/40—Details of LED load circuits
    • H05B45/44—Details of LED load circuits with an active control inside an LED matrix
    • H05B45/48—Details of LED load circuits with an active control inside an LED matrix having LEDs organised in strings and incorporating parallel shunting devices
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
    • H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
    • H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
    • H02M3/158—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load
    • H02M3/1582—Buck-boost converters
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
    • H05B45/30—Driver circuits
    • H05B45/395—Linear regulators
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
    • H05B45/30—Driver circuits
    • H05B45/37—Converter circuits
    • H05B45/3725—Switched mode power supply [SMPS]
    • H05B45/375—Switched mode power supply [SMPS] using buck topology

Definitions

  • the present invention relates to a light emitting element driving apparatus and a light emitting element driving method.
  • LEDs Light emitting diodes
  • GaAs, AlGaAs, GaN, InGaAlP, etc. are a kind of compound semiconductors such as GaAs, AlGaAs, GaN, InGaAlP, etc., and are semiconductor devices that can realize various colors of light by changing materials. These light emitting devices are widely used in various fields such as TV, computer, lighting, and automobiles because of their advantages of excellent monochromatic peak wavelength, excellent light efficiency, miniaturization, eco-friendliness, and low power consumption. Is going out.
  • the converted DC voltage is generally used after converting AC into DC. Convert to level.
  • the light emitting diode has a characteristic that the current increases exponentially with respect to the voltage applied at both ends. Therefore, when there is a deviation between the currents applied to the LED strings, there is a problem in that the amount of light of the light emitting diode is uneven due to the current variation.
  • the human eye is insensitive to the absolute value of the brightness, but sensitive to the relative difference between the two brightnesses, such a variation in the amount of light has a problem that one string is bright, the other string is dark and appears to be stained in the human eye. .
  • the present invention has been made to solve the nonuniformity of the current applied to each string, which is a problem of the above-described current prior art, and an object of the present invention is to provide a light emitting diode driving method and apparatus capable of maintaining a constant current applied to each LED string. There is this.
  • one of the other objects of the present invention is to provide a light emitting diode driving method and apparatus capable of maintaining a constant current applied to each light emitting diode string to uniform the amount of light of the lighting apparatus using the light emitting diode.
  • a light emitting device driving apparatus includes a power supply unit supplying a direct current having a constant ripple, and a light emitting device array, wherein the light emitting device array includes a plurality of unit light emitting device arrays.
  • Each of the unit light emitting device arrays includes a light emitting device string, a switch for supplying or blocking a direct current supplied by the power supply unit to the light emitting device string, and a capacitor for smoothing the direct current supplied by the power supply unit, And a controller configured to control the switch to conduct or cut off the switch, wherein the controller divides the period of the DC current into the plurality of sections n and the number m that is relatively prime. The switch is controlled such that current is sequentially applied to the plurality of unit light emitting device arrays.
  • the number m of each other is one greater or smaller than the plurality n.
  • the power supply unit includes a buck converter that steps down an input voltage.
  • the power supply unit includes a rectifying circuit for rectifying the input AC voltage; And a boost converter for stepping up and outputting the output voltage level of the rectifier circuit.
  • the light emitting device driving apparatus may further include a current sensor configured to sense a current flowing through the plurality of light emitting device arrays, and the controller controls the power supply unit according to a current value detected by the current sensor.
  • the output terminal of the power supply unit is electrically connected to one end of the plurality of unit light emitting device arrays n.
  • the light emitting device string is formed by electrically connecting a plurality of light emitting diodes (LEDs).
  • LEDs light emitting diodes
  • the capacitor includes at least one capacitor, one end of which is connected to the light emitting device string.
  • a method of driving a light emitting device includes: forming a DC current including ripples having a predetermined cycle and applying the formed currents to an array of a plurality of unit light emitting devices; Ripples of the input voltage are divided into a plurality of sections n and a relatively prime number m, and currents of the divided sections are sequentially applied to the plurality of unit light emitting device arrays.
  • the number of mutually stamped m is one larger or smaller than the plurality n, provided that m is equal to or greater than 2, and n is a natural number greater than or equal to 2.
  • the forming of the direct current includes applying an alternating current voltage, rectifying the input alternating voltage, and converting the level of the rectified voltage.
  • a method of driving a light emitting device includes a power supply circuit unit for outputting a DC current including a ripple having a period that can be divided into a predetermined number of sections, and a plurality of unit light emitting device arrays connected to the power supply circuit unit.
  • a light emitting device array wherein the unit light emitting device array is a switch for applying or blocking the current output from the power supply circuit unit, a light emitting device string electrically connected to a plurality of light emitting elements to emit light by receiving the current output from the power supply circuit unit and the light emission And a capacitor for smoothing a current applied to the device string, and controlling the switch so that a section of current applied to the same unit light emitting device array is different for two periods adjacent to each other.
  • the number of unit light emitting device arrays and the number of sections may be relatively prime.
  • the difference between the number of the unit light emitting device arrays and the number of the sections is one.
  • the power supply circuit unit may include a buck converter that steps down an input voltage.
  • the power supply circuit unit may include a rectifying circuit rectifying the input AC voltage; And a boost converter for stepping up and outputting the output voltage level of the rectifier circuit.
  • the light emitting device driving apparatus may further include a current sensor configured to sense a current flowing through the plurality of light emitting device arrays, and the controller controls the power supply unit according to a current value detected by the current sensor.
  • the output terminal of the power supply unit is electrically connected to one end of the plurality of unit light emitting device arrays n.
  • the light emitting device string is formed by electrically connecting a plurality of light emitting diodes (LEDs).
  • LEDs light emitting diodes
  • the capacitor includes at least one capacitor, one end of which is connected to the light emitting device string.
  • the current applied to the plurality of strings of light emitting elements can be made uniform, and the brightness difference can be minimized even when the plurality of strings are used.
  • FIG. 1 and 2 are circuit diagrams of a light emitting device driving apparatus according to an embodiment.
  • 3 is an operation timing diagram of the buck converter 160 included in the power supply unit 100.
  • FIG. 4 is a diagram illustrating dividing one cycle of the output current IL output by the power supply unit into a predetermined section.
  • FIG. 5 is a view showing a comparative example for the embodiment.
  • Fig. 6 is a diagram showing computer simulation test results for the present embodiment.
  • each step may occur differently from the stated order unless the context clearly dictates the specific order. That is, each step may occur in the same order as specified, may be performed substantially simultaneously, or may be performed in the reverse order.
  • a driving device of a light emitting device includes a power supply unit supplying a DC current including a ripple of a predetermined cycle and a light emitting device array, and the light emitting device array includes a plurality of unit light emitting devices.
  • Each unit light emitting device array includes a light emitting device string, a switch for supplying or blocking a direct current supplied from a power supply to the light emitting device string, and a capacitor connected to the light emitting device string at one end thereof, and And a control unit for controlling to cut off, and the control unit divides the period of the DC current into a plurality of sections n and a relatively prime number m, so that the DC currents in each section are arranged in the plurality of unit light emitting device arrays.
  • the switch is controlled to be applied sequentially.
  • the power supply unit 100a includes a switch (SWbuck) for applying or cutting DC power (Vdc), an inductor (Lbuck) connected through a power supply and a switch, and a cathode at a node connected with the switch (SWbuck) and an inductor. ) Is connected, and a diode (Dbuck) is connected to the anode (anode) to the ground potential. Since the light emitting device array 200 connected to the power supply unit is a capacitive load to which capacitors Ca, Cb, and Cc are connected, the power supply unit 100a illustrated in FIG. 1 is in the form of a buck converter.
  • SWbuck switch
  • Lbuck inductor
  • Dbuck diode
  • SWbuck is shown as a P-type metal oxide semiconductor (PMOS) transistor, but this is shown as an example, even if other forms such as N-type (MOS), Bipolar Junction Transistor (BJT) switch, etc. are used. This is also true for the other switches disclosed in the embodiments and drawings to be described below.
  • PMOS P-type metal oxide semiconductor
  • BJT Bipolar Junction Transistor
  • the power supply unit 100b receives a signal output from the rectifier circuit unit 120 and a rectifier circuit unit to rectify the input AC voltage, and steps up to a desired level. It further includes a boost converter (140), and includes a buck converter 160 as in the above-described embodiment.
  • the rectifier circuit unit 120 may be a bridge diode as shown, and in another example not shown, the rectifier circuit unit may be a full wave rectifier circuit. As another example, the rectifying circuit unit may be a half wave rectifier circuit.
  • the power supply unit includes a boost converter connected to the DC power supply and stepping up the level thereof, and a buck converter as in the above-described embodiment.
  • the embodiment further includes a current sensor 400 for branching and sensing the current IL flowing through the light emitting device array.
  • the current sensor may sense the brightness of the light emitting device array 200 by sensing a current IL, which is a branch of the current IL that is the sum of the currents flowing in each unit light emitting device array.
  • the power factor correction circuit 500 for power factor correction in the rectifier circuit part 120 may be further included.
  • the boost converter 140 receives a signal output from the rectifying circuit unit and adjusts the duty ratio of the switch SWboost to step up to a desired level. That is, while the switch SWboost is closed, the current flows through the inductor Lboost through the switch SWboost, but when the switch is opened, it flows through the diode Dboost to accumulate charge in the capacitor C1, so that both ends of the capacitor C1 are closed. In the potential difference is formed.
  • the potential difference formed in the capacitor (C1) is the potential difference across the rectifier circuit 120 and the both ends of the inductor (Lboost) according to Kirchoff's Voltage Law (KVL) Since the potential difference is equal to the sum, the potential difference Vc1 formed across the capacitor C1 is larger than the rectifier circuit potential, and the value can be adjusted according to the duty ratio of the switch.
  • FIG. 3 is an operation timing diagram of the buck converter 160 included in the power supply unit 100.
  • the buck converter 160 is driven by being directly supplied with a direct current DC power supply Vdc or by being converted to direct current Vdc by receiving an alternating current as shown in FIG. 2.
  • the buck converter may be driven by connecting a DC power supply to the boost converter, stepping up, and then connecting the DC power supply to the buck converter. Referring to FIG. 3, it is assumed that energy is not stored in the inductor Lbuck and the light emitting device array serving as the capacitive load at the beginning of the P1 period.
  • the steady state is reached.
  • the both ends of the inductor (Lbuck) are equivalent to a short circuit, but energy is applied to the inductor before the steady state is reached. Is not fully equivalent to the lead and the potential difference of the inductor remains undissipated. Therefore, the potential difference formed across the capacitive load on Kirchhoff's voltage law (KVL) is a value obtained by subtracting the voltage across the inductor (VL) from the power supply voltage (Vdc) as shown in Vo, and thus compared to the power supply voltage (Vdc). Small value.
  • the P2 section when switching occurs in a state where energy is not fully charged in the inductor (Lbuck), when power is not applied to the inductor, the energy stored by the inductor (Lbuck) flows through the diode (Dbuck) in the form of a current. Since the light emitting device array 200 is a capacitive load, the voltage Vo at both ends of the load is continuously maintained due to the characteristics of the capacitive load to be kept constant during the P2 period. If the P2 section is longer, the current IL flowing through the inductor will converge to zero as energy charged in the inductor is depleted, but switching is performed before the current disappears.
  • the inductor Lbuck is connected to the DC power source again through the switch SWbuck to charge the inductor Lbuck.
  • the current IL flowing through the inductor increases from the current value just before switching until the inductor is fully charged with energy.
  • switching is performed before reaching the steady state. Therefore, the voltage Vo formed at both ends of the light emitting device array is always less than or equal to the voltage of the applied DC power, and the current IL applied by the power supply unit 100 to the light emitting device array 200 is determined by the switch SWbuck. It has a predetermined period by switching.
  • the light emitting device array 200 includes a plurality of unit light emitting device arrays, and each of the unit light emitting device arrays 200a, 200b, and 200c respectively represents the light emitting device strings Sa, Sb, Sc, switches SWa, SWb, and SWc for supplying or blocking direct current supplied from the power supply unit to the light emitting device string, and capacitors Ca, Cb and Cc for maintaining the current supplied from the power supply unit uniformly.
  • each of the unit light emitting device arrays 200a, 200b, and 200c respectively represents the light emitting device strings Sa, Sb, Sc, switches SWa, SWb, and SWc for supplying or blocking direct current supplied from the power supply unit to the light emitting device string, and capacitors Ca, Cb and Cc for maintaining the current supplied from the power supply unit uniformly.
  • only three unit light emitting device arrangements are shown in the drawings, but this is purely for easy explanation, easy understanding and simplicity. Therefore, at least two unit light emitting device arrays may be provided.
  • the light emitting device array 200 has a plurality of unit light emitting device arrays 200a, 200b, and 200c connected in parallel.
  • the unit light emitting device arrays may be arranged in a straight line, radial form, or matrix form and used as a lighting fixture.
  • the current IL output by the power supply unit includes a ripple having a predetermined period due to driving characteristics of the power supply unit.
  • the period of the ripple included in the current is divided into a number of sections that are relatively prime with the number of unit light emitting device arrays. For example, if four unit light emitting device arrays are used, the period of the ripple included in the current may be divided into four sections and five sections swept from each other, and may be divided into seven sections or nine sections. As another example, when three unit light emitting device arrangements are used as shown in FIGS. 1 and 2, the ripple period may be divided into three, two, four, five, or seven sections.
  • the ripple period can be divided into four sections.
  • the ripple period may be divided into two sections.
  • a ripple period may be divided into five sections.
  • the period is divided into the number n of the unit light emitting device strings and the predetermined number m of sections, and each unit light emitting device string is sequentially applied to each unit light emitting device string.
  • the current of different sections is applied to each adjacent period.
  • the controller 300 controls the switches SWa, SWb, and SWc to divide current into sections and sequentially apply currents of the sections to the respective unit light emitting device arrays. For example, referring to FIG. 4A, since the number of unit light emitting device arrays is three, one period is divided into four sections. The controller 300 applies the current of the first section T1 to the unit light emitting device string 200a and sequentially applies the current of the second section and the current of the third section to the unit light emitting device string 200b and the unit light emission. After the application to the device string 200c, the switches SWa, SWb, and SWc are controlled to sequentially apply the current of the next section from the unit light emitting device string 200a. In another embodiment, referring to FIG. 4B, one period is divided into two sections.
  • the controller 300 applies the first period of the first period to the unit light emitting device string 200a, and sequentially the unit light emitting device string 200b, the unit light emitting device string 200c, and again for each section of the subsequent period.
  • the switches SWa, SWb, and SWc are controlled to be applied to the unit light emitting device string 200a.
  • one period is divided into five sections.
  • the controller 300 applies an initial section of the initial period to the unit light emitting device string 200a, and sequentially unit light emitting device string 200b, unit light emitting device string 200c, and unit light emitting device for each section of the subsequent period.
  • the switches SWa, SWb, and SWc are controlled to continuously apply to the string 200a.
  • the controller 300 controls the switches SWa, SWb, and SWc as in the above-described embodiment, the brightness difference for each string may be reduced.
  • FIG. 5 which is illustrated as a comparative example, it is assumed that a current including a constant ripple is applied to three unit light emitting device strings through switching. At this time, if one period is divided into three sections and applied to three strings a, b and c, the sections of each period applied to each string a, b and c are the same. When the average current of each section is obtained and shown, the average current Iavg, a in section a, the average current Iavg, b in section b, and average current Iavg, c in section c are different from each other.
  • the control unit 300 controls the switches so that the sections of the currents applied for two periods adjacent to each other with the same unit light emitting device string are different. That is, referring to FIG. 4A, currents of the first section of the first period, the last section, the third section of the second period, and the second section of the third period are applied to the string a. In addition, a current of the second section of the first period T1, the first and last sections of the second period T2, and the third section of the third period T3 is applied to the string b. That is, referring to FIG.
  • the variation of the currents applied to the strings can be reduced. Furthermore, since the capacitors included in each string are averaged and applied to the light emitting device strings, the brightness of each string is increased. The difference can be reduced.
  • the current sensor 400 detects a current flowing through the light emitting element array.
  • a current sensor is mounted for each light emitting device string, but as described above, the controller 300 includes switches SWa, SWb, and SWc included in each unit light emitting device string. Since the strings can be evenly emitted by driving, one current sensor capable of sensing the total amount of current is sufficient in this embodiment.
  • 6A shows a waveform of a current applied to a light emitting element array by a power supply unit. It can be seen that one cycle has 5usec, the average current is about 0.45A, the maximum value is 0.48A, and the minimum value is about 0.42A.
  • 6B illustrates a waveform of a driving pulse in which a controller drives a switch included in each light emitting device string. The controller divides one period into four sections and sequentially switches in the order of SW3, SW2, and SW1.
  • the voltage applied to each string is significantly suppressed in ripple as shown.
  • the average values of the currents flowing through the strings a, b, and c are approximately 151 mA, 150 mA, and 149 mA, and the deviation of the average values is only about 2 mA, which is higher than the current flowing in one string. It can be seen that evenly distributed to suppress the difference in brightness between the strings.

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  • Circuit Arrangement For Electric Light Sources In General (AREA)

Abstract

A light-emitting device driving apparatus according to the one embodiment comprises: a power unit for supplying direct current in which ripples in a constant cycle are included; and a light-emitting device array, wherein the light-emitting device array includes a plurality of unit light-emitting device arrays, and each of the unit light-emitting device arrays comprises: a light-emitting device string; a switch for supplying or cutting off, to the light-emitting device string, direct current supplied by the power unit; and a control unit having a capacitor for smoothing the direct current supplied by the power unit, and controlling the switch so as to be opened or closed. The control unit controls the switch by dividing the cycle of the direct current into a number (m) of intervals, which is relatively prime to a plurality (n) such that the direct current of each interval is consecutively applied to the plurality of unit light-emitting device arrays.

Description

발광 소자 구동 장치 및 발광 소자 구동 방법Light emitting element driving device and light emitting element driving method
본 발명은 발광 소자 구동 장치 및 발광 소자 구동 방법에 관한 것이다.The present invention relates to a light emitting element driving apparatus and a light emitting element driving method.
발광다이오드(LED, Light Emitting Diode)는 GaAs, AlGaAs, GaN, InGaAlP 등의 화합물 반도체(compound semiconductor)의 일종으로, 재료를 변경하여 다양한 색의 빛을 구현할 수 있는 반도체 소자이다. 이러한 발광소자는 우수한 단색성 피크 파장을 가지며 광 효율성이 우수하고 소형화가 가능하다는 장점과 친환경, 저소비전력 등의 이유로 TV, 컴퓨터, 조명, 자동차 등 여러 분야에서 널리 사용되고 있으며, 점차적으로 활용분야를 넓혀 나가고 있다.Light emitting diodes (LEDs) are a kind of compound semiconductors such as GaAs, AlGaAs, GaN, InGaAlP, etc., and are semiconductor devices that can realize various colors of light by changing materials. These light emitting devices are widely used in various fields such as TV, computer, lighting, and automobiles because of their advantages of excellent monochromatic peak wavelength, excellent light efficiency, miniaturization, eco-friendliness, and low power consumption. Is going out.
이러한 발광소자를 광원으로 이용한 조명장치를 가정이나 사무실 또는 옥외 등에서 사용하는 상용 교류(AC) 전원을 이용하여 구동하는 경우에는, 일반적으로 교류를 직류로 변환한 후, 변환된 직류 전압을 목적하는 전압레벨로 변환한다. When driving a lighting device using such a light emitting element as a light source using a commercial AC power source used in homes, offices, or outdoors, the converted DC voltage is generally used after converting AC into DC. Convert to level.
이와 같은 발광 다이오드 등의 구동회로에 관한 선행특허로는 미국 공개특허 2011-0148323호 및 한국 공개특허 제2012-0129633호 등이 있다.Prior patents related to such driving circuits, such as light emitting diodes, include US Patent Publication No. 2011-0148323 and Korean Patent Publication No. 2012-0129633.
발광 다이오드는 양단에 인가된 전압에 대하여 전류가 지수 함수적으로 증가하는 특성을 가진다. 따라서, 발광 다이오드 스트링들에 인가되는 전류들 간에 편차가 있으면 전류의 편차에 의하여 발광 다이오드의 광량이 불균일하게 되는 문제점이 있다. 특히, 사람의 눈은 밝기의 절대값에는 둔감하나, 두 밝기의 상대적인 차이에는 민감하므로, 이와 같은 광량의 편차는 어느 스트링은 밝고, 다른 스트링은 어둡게 인식되어 사람의 눈에는 얼룩진 것처럼 보이는 문제가 있다. The light emitting diode has a characteristic that the current increases exponentially with respect to the voltage applied at both ends. Therefore, when there is a deviation between the currents applied to the LED strings, there is a problem in that the amount of light of the light emitting diode is uneven due to the current variation. In particular, the human eye is insensitive to the absolute value of the brightness, but sensitive to the relative difference between the two brightnesses, such a variation in the amount of light has a problem that one string is bright, the other string is dark and appears to be stained in the human eye. .
본 발명은 상술한 전류 종래 기술의 문제점인 스트링별 인가되는 전류의 불균일성을 해소하기 위하여 안출된 것으로, 각 발광 다이오드 스트링에 인가되는 전류를 일정하게 유지할 수 있는 발광 다이오드 구동 방법 및 장치를 제공하는데 목적이 있다. The present invention has been made to solve the nonuniformity of the current applied to each string, which is a problem of the above-described current prior art, and an object of the present invention is to provide a light emitting diode driving method and apparatus capable of maintaining a constant current applied to each LED string. There is this.
또한, 본 발명의 다른 목적 중 하나는 각 발광 다이오드 스트링에 인가되는 전류를 일정하게 유지하여 발광 다이오드를 이용한 조명장치의 광량을 균일하게 할 수 있는 발광 다이오드 구동 방법 및 장치를 제공하는 것이다.In addition, one of the other objects of the present invention is to provide a light emitting diode driving method and apparatus capable of maintaining a constant current applied to each light emitting diode string to uniform the amount of light of the lighting apparatus using the light emitting diode.
일 실시예에 의한 발광 소자 구동 장치는, 일정한 주기의 리플(ripple)이 포함된 직류 전류를 공급하는 전원부와, 발광 소자 배열을 포함하며, 상기 발광 소자 배열은 복수개의 단위 발광 소자 배열을 포함하고, 각각의 상기 단위 발광소자 배열은 발광 소자 스트링과, 상기 발광 소자 스트링에 상기 전원부가 공급하는 직류를 공급하거나 차단하는 스위치 및 상기 전원부가 공급한 직류 전류를 평활(smoothing)하는 커패시터를 포함하고, 상기 스위치를 도통시키거나 차단하도록 제어하는 제어부를 포함하며, 상기 제어부는 상기 직류 전류의 주기를 상기 복수개(n)와 서로 소(relatively prime)인 개수(m)의 구간으로 분할하여 각 구간의 직류 전류가 상기 복수개의 단위 발광 소자 배열에 순차적으로 인가되도록 상기 스위치를 제어한다.In one embodiment, a light emitting device driving apparatus includes a power supply unit supplying a direct current having a constant ripple, and a light emitting device array, wherein the light emitting device array includes a plurality of unit light emitting device arrays. Each of the unit light emitting device arrays includes a light emitting device string, a switch for supplying or blocking a direct current supplied by the power supply unit to the light emitting device string, and a capacitor for smoothing the direct current supplied by the power supply unit, And a controller configured to control the switch to conduct or cut off the switch, wherein the controller divides the period of the DC current into the plurality of sections n and the number m that is relatively prime. The switch is controlled such that current is sequentially applied to the plurality of unit light emitting device arrays.
일 예로, 상기 서로 소인 개수(m)는 상기 복수개(n) 보다 하나 더 크거나 더 작은 수이다.As an example, the number m of each other is one greater or smaller than the plurality n.
일 예로, 상기 전원부는 입력 전압을 스텝 다운(step down)하는 벅 컨버터를 포함한다.For example, the power supply unit includes a buck converter that steps down an input voltage.
일 예로, 상기 전원부는 입력 교류 전압을 정류하는 정류회로(rectifying circuit); 및 상기 정류회로의 출력 전압 레벨을 스텝 업(step up)하여 출력하는 부스트 컨버터(boost converter)를 더 포함한다.For example, the power supply unit includes a rectifying circuit for rectifying the input AC voltage; And a boost converter for stepping up and outputting the output voltage level of the rectifier circuit.
일 예로, 상기 발광 소자 구동 장치는 상기 복수개 발광 소자 배열에 흐르는 전류를 감지하는 전류 센서를 더 포함하며, 상기 제어부는 상기 전류 센서가 감지한 전류 값에 따라 상기 전원부를 제어한다.For example, the light emitting device driving apparatus may further include a current sensor configured to sense a current flowing through the plurality of light emitting device arrays, and the controller controls the power supply unit according to a current value detected by the current sensor.
일 예로, 전원부의 출력단은 상기 복수개(n)의 단위 발광 소자 배열의 일단과 전기적으로 연결된다.For example, the output terminal of the power supply unit is electrically connected to one end of the plurality of unit light emitting device arrays n.
일 예로, 상기 발광 소자 스트링은 복수개의 발광 다이오드(LED, Light Emitting Diode)들이 전기적으로 연결되어 형성된다.For example, the light emitting device string is formed by electrically connecting a plurality of light emitting diodes (LEDs).
일 예로, 상기 커패시터는, 일단이 상기 발광 소자 스트링에 연결된 적어도 하나의 커패시터를 포함한다.As an example, the capacitor includes at least one capacitor, one end of which is connected to the light emitting device string.
일 실시예에 의한 발광 소자 구동 방법은 일정한 주기의 리플(ripple)이 포함된 직류 전류를 형성하는 단계와, 상기 형성된 전류를 복수개(n)의 단위 발광 소자 배열에 인가하는 단계로, 상기 일정한 주기의 리플이 포함된 입력 전압을 상기 복수개(n)와 서로 소(relatively prime)인 개수(m)의 구간으로 분할하여 분할된 구간의 전류를 상기 복수개의 단위 발광 소자 배열에 순차적으로 인가한다.In one embodiment, a method of driving a light emitting device includes: forming a DC current including ripples having a predetermined cycle and applying the formed currents to an array of a plurality of unit light emitting devices; Ripples of the input voltage are divided into a plurality of sections n and a relatively prime number m, and currents of the divided sections are sequentially applied to the plurality of unit light emitting device arrays.
일 예로, b상기 서로 소인 개수(m)는 상기 복수개(n) 보다 하나 더 크거나 더 작은 수이다(단, m은 2와 같거나 크고, n은 2와 같거나 큰 자연수).As an example, b the number of mutually stamped m is one larger or smaller than the plurality n, provided that m is equal to or greater than 2, and n is a natural number greater than or equal to 2.
일 예로, 상기 직류 전류를 형성하는 단계는, 교류 전압을 인가 받는 단계와상기 입력 교류 전압을 정류하는 단계 및 정류된 전압의 레벨을 변환하는 단계를 포함한다.For example, the forming of the direct current includes applying an alternating current voltage, rectifying the input alternating voltage, and converting the level of the rectified voltage.
일 실시예 따른 발광 소자 구동 방법은 소정 개수의 구간으로 구분될 수 있는 주기를 가지는 리플(ripple)이 포함된 직류 전류를 출력하는 전원 회로부와, 상기 전원 회로부와 연결된 복수개의 단위 발광 소자 배열을 포함하는 발광 소자 배열로, 상기 단위 발광 소자 배열은 전원 회로부가 출력한 전류을 인가하거나 차단하는 스위치와, 전원 회로부가 출력한 전류를 인가받아 발광하는 복수개의 발광 소자들이 전기적으로 연결된 발광 소자 스트링 및 상기 발광 소자 스트링에 인가되는 전류를 평활하는 커패시터를 포함하며, 서로 인접한 두 주기 동안 동일한 단위 발광 소자 배열에 인가되는 전류의 구간이 상이하도록 상기 스위치를 제어한다.A method of driving a light emitting device according to an embodiment includes a power supply circuit unit for outputting a DC current including a ripple having a period that can be divided into a predetermined number of sections, and a plurality of unit light emitting device arrays connected to the power supply circuit unit. A light emitting device array, wherein the unit light emitting device array is a switch for applying or blocking the current output from the power supply circuit unit, a light emitting device string electrically connected to a plurality of light emitting elements to emit light by receiving the current output from the power supply circuit unit and the light emission And a capacitor for smoothing a current applied to the device string, and controlling the switch so that a section of current applied to the same unit light emitting device array is different for two periods adjacent to each other.
일 예로, 단위 발광 소자 배열의 개수와 상기 구간의 개수는 서로 소(relatively prime)이다.As an example, the number of unit light emitting device arrays and the number of sections may be relatively prime.
일 예로, 상기 단위 발광 소자 배열의 개수와 상기 구간의 개수의 차는 1이다.For example, the difference between the number of the unit light emitting device arrays and the number of the sections is one.
일 예로, 상기 전원 회로부는 입력 전압을 스텝 다운(step down)하는 벅 컨버터를 포함한다.For example, the power supply circuit unit may include a buck converter that steps down an input voltage.
일 예로, 상기 전원 회로부는 입력 교류 전압을 정류하는 정류회로(rectifying circuit); 및 상기 정류회로의 출력 전압 레벨을 스텝 업(step up)하여 출력하는 부스트 컨버터(boost converter)를 더 포함한다.For example, the power supply circuit unit may include a rectifying circuit rectifying the input AC voltage; And a boost converter for stepping up and outputting the output voltage level of the rectifier circuit.
일 예로, 상기 발광 소자 구동 장치는 상기 복수개 발광 소자 배열에 흐르는 전류를 감지하는 전류 센서를 더 포함하며, 상기 제어부는 상기 전류 센서가 감지한 전류 값에 따라 상기 전원부를 제어한다.For example, the light emitting device driving apparatus may further include a current sensor configured to sense a current flowing through the plurality of light emitting device arrays, and the controller controls the power supply unit according to a current value detected by the current sensor.
일 예로,전원부의 출력단은 상기 복수개(n)의 단위 발광 소자 배열의 일단과 전기적으로 연결된다.For example, the output terminal of the power supply unit is electrically connected to one end of the plurality of unit light emitting device arrays n.
일 예로, 상기 발광 소자 스트링은 복수개의 발광 다이오드(LED, Light Emitting Diode)들이 전기적으로 연결되어 형성된다.For example, the light emitting device string is formed by electrically connecting a plurality of light emitting diodes (LEDs).
일 예로, 상기 커패시터는 일단이 상기 발광 소자 스트링에 연결된 적어도 하나의 커패시터를 포함한다.For example, the capacitor includes at least one capacitor, one end of which is connected to the light emitting device string.
본 발명에 의한다면 복수개의 발광 소자 스트링에 인가되는 전류를 균일하게 할 수 있어 복수의 스트링을 이용하여도 밝기 차이를 최소화 시킬 수 있다. 또한, 스트링별로 전류 센서를 두지 않고 전체적인 전류를 감지하는 하나의 전류 센서를 이용하므로 경제적인 발광 소자 구동장치를 제공할 수 있다.According to the present invention, the current applied to the plurality of strings of light emitting elements can be made uniform, and the brightness difference can be minimized even when the plurality of strings are used. In addition, it is possible to provide an economical light emitting device driving apparatus by using a single current sensor that senses the entire current without having a current sensor for each string.
도 1 및 도 2는 일 실시예에 따른 발광 소자 구동 장치의 회로도이다. 1 and 2 are circuit diagrams of a light emitting device driving apparatus according to an embodiment.
도 3은 전원부(100)에 포함된 벅 컨버터(160)의 동작 타이밍도이다. 3 is an operation timing diagram of the buck converter 160 included in the power supply unit 100.
도 4는 전원부가 출력하는 출력 전류(IL)의 한 주기를 소정의 구간으로 구분한 것을 도시한 도면이다.4 is a diagram illustrating dividing one cycle of the output current IL output by the power supply unit into a predetermined section.
도 5는 실시예에 대한 일 비교예를 도시한 도면이다.5 is a view showing a comparative example for the embodiment.
도 6은 본 실시예에 대한 컴퓨터 모의 시험 결과를 도시한 도면이다.Fig. 6 is a diagram showing computer simulation test results for the present embodiment.
본 발명에 관한 설명은 구조적 내지 기능적 설명을 위한 실시예에 불과하므로, 본 발명의 권리범위는 본문에 설명된 실시예에 의하여 제한되는 것으로 해석되어서는 아니 된다. 즉, 실시예는 다양한 변경이 가능하고 여러 가지 형태를 가질 수 있으므로 본 발명의 권리범위는 기술적 사상을 실현할 수 있는 균등물들을 포함하는 것으로 이해되어야 한다.Description of the present invention is only an embodiment for structural or functional description, the scope of the present invention should not be construed as limited by the embodiments described in the text. That is, since the embodiments may be variously modified and may have various forms, the scope of the present invention should be understood to include equivalents capable of realizing the technical idea.
한편, 본 출원에서 서술되는 용어의 의미는 다음과 같이 이해되어야 할 것이다.On the other hand, the meaning of the terms described in the present application should be understood as follows.
단수의 표현은 문맥상 명백하게 다르게 뜻하지 않는 한 복수의 표현을 포함하는 것으로 이해되어야 하고, "포함하다" 또는 "가지다" 등의 용어는 설시된 특징, 숫자, 단계, 동작, 구성요소, 부분품 또는 이들을 조합한 것이 존재함을 지정하려는 것이지, 하나 또는 그 이상의 다른 특징들이나 숫자, 단계, 동작, 구성요소, 부분품 또는 이들을 조합한 것들의 존재 또는 부가 가능성을 미리 배제하지 않는 것으로 이해되어야 한다.Singular expressions should be understood to include plural expressions unless the context clearly indicates otherwise, and terms such as "include" or "have" refer to features, numbers, steps, operations, components, parts, or parts thereof described. It is to be understood that the combination is intended to be present, but not to exclude in advance the possibility of the presence or addition of one or more other features or numbers, steps, operations, components, parts or combinations thereof.
각 단계들은 문맥상 명백하게 특정 순서를 기재하지 않은 이상 명기된 순서와 다르게 일어날 수 있다. 즉, 각 단계들은 명기된 순서와 동일하게 일어날 수도 있고 실질적으로 동시에 수행될 수도 있으며 반대의 순서대로 수행될 수도 있다.Each step may occur differently from the stated order unless the context clearly dictates the specific order. That is, each step may occur in the same order as specified, may be performed substantially simultaneously, or may be performed in the reverse order.
여기서 사용되는 모든 용어들은 다르게 정의되지 않는 한, 본 발명이 속하는 분야에서 통상의 지식을 가진 자에 의해 일반적으로 이해되는 것과 동일한 의미를 가진다. 일반적으로 사용되는 사전에 정의되어 있는 것과 같은 용어들은 관련 기술의 문맥상 가지는 의미와 일치하는 것으로 해석되어야 하며, 본 출원에서 명백하게 정의하지 않는 한 이상적이거나 과도하게 형식적인 의미를 지니는 것으로 해석될 수 없다.All terms used herein have the same meaning as commonly understood by one of ordinary skill in the art unless otherwise defined. Terms such as those defined in the commonly used dictionaries should be construed to be consistent with the meanings in the context of the related art and should not be construed as having ideal or overly formal meanings unless expressly defined in this application. .
이하에서는 첨부된 도면을 참조하여 실시예들을 설명한다. 도 1은 일 실시예에 따른 발광 소자 구동 장치의 회로도이다. 도 1을 참조하면, 실시예에 따른 발광 소자의 구동 장치는 일정한 주기의 리플(ripple)이 포함된 직류 전류를 공급하는 전원부와, 발광 소자 배열을 포함하며, 발광 소자 배열은 복수개의 단위 발광 소자 배열을 포함하고, 각각의 단위 발광소자 배열은 발광 소자 스트링과, 발광 소자 스트링에 전원부가 공급하는 직류를 공급하거나 차단하는 스위치 및 일단이 발광 소자 스트링과 연결된 커패시터를 포함하고, 스위치를 도통시키거나 차단하도록 제어하는 제어부를 포함하며, 제어부는 직류 전류의 주기를 복수개(n)와 서로 소(relatively prime)인 개수(m)의 구간으로 분할하여 각 구간의 직류 전류가 복수개의 단위 발광 소자 배열에 순차적으로 인가되도록 스위치를 제어한다.Hereinafter, with reference to the accompanying drawings will be described embodiments. 1 is a circuit diagram of a light emitting device driving apparatus according to an embodiment. Referring to FIG. 1, a driving device of a light emitting device according to an embodiment includes a power supply unit supplying a DC current including a ripple of a predetermined cycle and a light emitting device array, and the light emitting device array includes a plurality of unit light emitting devices. Each unit light emitting device array includes a light emitting device string, a switch for supplying or blocking a direct current supplied from a power supply to the light emitting device string, and a capacitor connected to the light emitting device string at one end thereof, and And a control unit for controlling to cut off, and the control unit divides the period of the DC current into a plurality of sections n and a relatively prime number m, so that the DC currents in each section are arranged in the plurality of unit light emitting device arrays. The switch is controlled to be applied sequentially.
도 1을 참조하면, 전원부(100a)는 직류 전원(Vdc)을 인가하거나 차단하는 스위치(SWbuck), 전원과 스위치를 통하여 연결된 인덕터(Lbuck) 및 스위치(SWbuck)와 인덕터가 연결된 노드에 캐소드(cathode)가 연결되고, 접지전위에 애노드(anode)가 연결된 다이오드(Dbuck)를 포함한다. 전원부와 연결된 발광 소자 배열(200)은 커패시터(Ca, Cb, Cc)가 연결된 용량성 부하(Capacitive load)이므로, 도 1에 도시된 전원부(100a)는 벅 컨버터(buck converter)의 형태이다. 스위치(SWbuck)는 PMOS(P-type Metal Oxide Semiconductor) 트랜지스터로 도시되어 있으나, 이는 일 예로 도시된 것으로, NMOS(N-type MOS), BJT(Bipolar Junction Transistor) 스위치 등과 같이 다른 형태를 이용하여도 무방하며, 이는 이하에서 설명될 실시예 및 도면에 개시된 다른 스위치들에 대하여도 마찬가지이다.Referring to FIG. 1, the power supply unit 100a includes a switch (SWbuck) for applying or cutting DC power (Vdc), an inductor (Lbuck) connected through a power supply and a switch, and a cathode at a node connected with the switch (SWbuck) and an inductor. ) Is connected, and a diode (Dbuck) is connected to the anode (anode) to the ground potential. Since the light emitting device array 200 connected to the power supply unit is a capacitive load to which capacitors Ca, Cb, and Cc are connected, the power supply unit 100a illustrated in FIG. 1 is in the form of a buck converter. The switch (SWbuck) is shown as a P-type metal oxide semiconductor (PMOS) transistor, but this is shown as an example, even if other forms such as N-type (MOS), Bipolar Junction Transistor (BJT) switch, etc. are used. This is also true for the other switches disclosed in the embodiments and drawings to be described below.
도 2를 참조하여 전원부의 다른 실시예을 설명하면, 전원부(100b)는 입력된 교류 전압을 정류하는 정류회로부(120), 정류회로부가 출력한 신호를 입력받아 목적하는 레벨로 스텝 업(step up)하는 부스트 컨버터(boost converter, 140)를 더 포함하며, 상술한 실시예와 같은 벅컨버터(160)를 포함한다. 일 예로, 정류 회로부(120)는 도시된 바와 같이 브릿지 다이오드일 수 있으며, 도시되지 않은 다른 예로, 정류 회로부는 전파 정류 회로(full wave rectifier circuit)일 수 있다. 또 다른 예로, 정류 회로부는 반파 정류 회로(half wave rectifier circuit)일 수 있다. 도시되지 않은 다른 실시예에서, 전원부는 직류 전원과 연결되어 그 레벨을 스텝 업하는 부스트 컨버터와 상술한 실시예와 같은 벅 컨버터를 포함한다. Referring to another embodiment of the power supply unit with reference to FIG. 2, the power supply unit 100b receives a signal output from the rectifier circuit unit 120 and a rectifier circuit unit to rectify the input AC voltage, and steps up to a desired level. It further includes a boost converter (140), and includes a buck converter 160 as in the above-described embodiment. As an example, the rectifier circuit unit 120 may be a bridge diode as shown, and in another example not shown, the rectifier circuit unit may be a full wave rectifier circuit. As another example, the rectifying circuit unit may be a half wave rectifier circuit. In another embodiment not shown, the power supply unit includes a boost converter connected to the DC power supply and stepping up the level thereof, and a buck converter as in the above-described embodiment.
도 1 및 도 2를 참조하면, 실시예는 발광 소자 배열을 흐르는 전류(IL)를 분기하여 감지하는 전류 센서(400)를 더 포함한다. 전류센서는 각각의 단위 발광 소자 배열에 흐르는 전류를 도합한 전류(IL)을 분기한 전류(IL,sense)를 감지하여 발광 소자 배열(200)의 밝기를 감지할 수 있다. 또한, 도 2를 참조하면, 정류회로부(120)에서의 역률보정을 위한 역률보정 회로부(500)를 더 포함할 수 있다.1 and 2, the embodiment further includes a current sensor 400 for branching and sensing the current IL flowing through the light emitting device array. The current sensor may sense the brightness of the light emitting device array 200 by sensing a current IL, which is a branch of the current IL that is the sum of the currents flowing in each unit light emitting device array. In addition, referring to FIG. 2, the power factor correction circuit 500 for power factor correction in the rectifier circuit part 120 may be further included.
부스트 컨버터(boost converter, 140)는 정류 회로부가 출력한 신호를 입력받아 스위치(SWboost)의 듀티비를 조절하여 목적하는 레벨로 스텝 업(step up) 한다. 즉, 스위치(SWboost)가 닫힌 상태에서 전류는 인덕터(Lboost)를 통하여 스위치(SWboost)를 거쳐 흐르나, 스위치가 열리면 다이오드(Dboost)을 통하여 흘러 커패시터(C1)에 전하를 축적하므로 커패시터(C1) 양단에는 전위차가 형성된다. 이러한 과정에서 다이오드(Dboost)가 이상적이라고 가정한다면 커패시터(C1)에 형성되는 전위차는 키르히호프의 전압법칙(Kirchoff's Voltage Law, KVL)에 의하여 정류회로(120) 양단의 전위차와 인덕터(Lboost) 양단의 전위차를 합한 것과 같으므로, 커패시터(C1) 양단에 형성되는 전위차(Vc1)는 정류 회로 전위에 비하여 큰 값이며, 그 값은 스위치의 듀티비에 따라 조절할 수 있다. The boost converter 140 receives a signal output from the rectifying circuit unit and adjusts the duty ratio of the switch SWboost to step up to a desired level. That is, while the switch SWboost is closed, the current flows through the inductor Lboost through the switch SWboost, but when the switch is opened, it flows through the diode Dboost to accumulate charge in the capacitor C1, so that both ends of the capacitor C1 are closed. In the potential difference is formed. Assuming that the diode (Dboost) is ideal in this process, the potential difference formed in the capacitor (C1) is the potential difference across the rectifier circuit 120 and the both ends of the inductor (Lboost) according to Kirchoff's Voltage Law (KVL) Since the potential difference is equal to the sum, the potential difference Vc1 formed across the capacitor C1 is larger than the rectifier circuit potential, and the value can be adjusted according to the duty ratio of the switch.
도 3은 전원부(100)에 포함된 벅 컨버터(160)의 동작 타이밍도이다. 벅 컨버터(160)는 도 1에 도시된 바와 같이 직접 직류전원(Vdc)이 인가되어 구동되거나, 도 2에 도시된 바와 같이 교류를 입력받아 전환된 직류(Vdc)가 인가되어 구동된다. 도시되지는 않았지만, 직류전원을 부스트 컨버터에 연결하여 스텝 업(step up)한 후 이를 벅 컨버터에 연결하여 벅 컨버터를 구동할 수 있다. 도 3을 참조하면, P1 구간 초기에 인덕터(Lbuck)와 용량성 부하인 발광소자 배열에 에너지가 저장되어 있지 않은 상태를 가정한다. 최초로 스위치(SWbuck)가 턴 온되면, 인덕터(Lbuck)의 초기조건에 의하여 인덕터는 개방 회로(open circuit)과 등가(equivalent)로 인덕터를 통하여 흐르는 전류(IL)는 없으며, VL로 도시된 바와 같이 인덕터 양단에 직류전원의 전압(Vdc)이 전부 인가된다. 따라서, Vo로 도시된 바와 같이 발광 소자 배열 양단에는 전압이 인가되지 않는다. 시간이 경과함에 따라 인덕터를 통하여 흐르는 전류가 증가하면서 인덕터 양단에 인가되는 전위(VL)는 감소하며 점차 발광 소자 배열 양단에 전위차(Vo)가 형성된다. 3 is an operation timing diagram of the buck converter 160 included in the power supply unit 100. As illustrated in FIG. 1, the buck converter 160 is driven by being directly supplied with a direct current DC power supply Vdc or by being converted to direct current Vdc by receiving an alternating current as shown in FIG. 2. Although not shown, the buck converter may be driven by connecting a DC power supply to the boost converter, stepping up, and then connecting the DC power supply to the buck converter. Referring to FIG. 3, it is assumed that energy is not stored in the inductor Lbuck and the light emitting device array serving as the capacitive load at the beginning of the P1 period. When the switch SWbuck is turned on for the first time, due to the initial condition of the inductor Lbuck, the inductor is equivalent to the open circuit, and there is no current IL flowing through the inductor, as shown by VL. The voltage Vdc of the DC power supply is applied to both ends of the inductor. Therefore, no voltage is applied across the light emitting element array as shown by Vo. As time passes and the current flowing through the inductor increases, the potential VL applied across the inductor decreases and a potential difference Vo is formed across the light emitting device array.
인덕터와 직류전원이 연결된 후, 상당한 시간이 경과하여 정상 상태(steady state)에 도달하면 인덕터(Lbuck) 양단은 단락회로(short circuit)과 등가(equivalent)이나, 정상상태에 도달하기 전인 인덕터에 에너지가 완전히 충전되지 않은 상태에서는 인덕터가 도선과 등가로 보이지 않으며 인덕터의 전위차가 소멸하지 않고 남아 있다. 따라서, 키르히호프의 전압법칙(KVL)상 용량성 부하 양단에 형성되는 전위차는 Vo에 도시된 바와 같이 전원전압(Vdc)에서 인덕터 양단 전압(VL)을 뺀 값이므로, 전원전압(Vdc)에 비하여 작은 값이다. After a considerable time has elapsed after the inductor and the DC power supply are connected, the steady state is reached. The both ends of the inductor (Lbuck) are equivalent to a short circuit, but energy is applied to the inductor before the steady state is reached. Is not fully equivalent to the lead and the potential difference of the inductor remains undissipated. Therefore, the potential difference formed across the capacitive load on Kirchhoff's voltage law (KVL) is a value obtained by subtracting the voltage across the inductor (VL) from the power supply voltage (Vdc) as shown in Vo, and thus compared to the power supply voltage (Vdc). Small value.
P2 구간을 참조하면, 인덕터(Lbuck)에 에너지가 완전히 충전되지 않은 상태에서 스위칭이 일어나 인덕터에 전원이 인가되지 않으면 인덕터(Lbuck)가 저장한 에너지는 전류의 형태로 다이오드(Dbuck)를 통하여 흐른다. 발광소자 배열(200)은 용량성 부하(capacitive load)이므로, 용량성 부하의 특성상 부하 양단의 전압(Vo)은 연속으로 유지되어 P2 구간동안 일정하게 유지된다. P2 구간이 길어지면 인덕터에 충전된 에너지가 고갈됨에 따라 인덕터를 통하여 흐르는 전류(IL)는 0에 수렴할 것이나, 전류가 소멸되기 이전에 스위칭이 수행된다.Referring to the P2 section, when switching occurs in a state where energy is not fully charged in the inductor (Lbuck), when power is not applied to the inductor, the energy stored by the inductor (Lbuck) flows through the diode (Dbuck) in the form of a current. Since the light emitting device array 200 is a capacitive load, the voltage Vo at both ends of the load is continuously maintained due to the characteristics of the capacitive load to be kept constant during the P2 period. If the P2 section is longer, the current IL flowing through the inductor will converge to zero as energy charged in the inductor is depleted, but switching is performed before the current disappears.
P3 구간에서, 스위치(SWbuck)를 통하여 인덕터(Lbuck)는 다시 직류 전원에 연결되어 인덕터(Lbuck)에 에너지가 충전된다. 인덕터(Lbuck)에 직류 전원이 연결됨에 따라 인덕터를 통하여 흐르는 전류(IL)은 스위칭 직전의 전류값으로부터 인덕터에 에너지가 완전히 충전될 때까지 증가한다. 다만, 상술한 P1 구간과 마찬가지로 정상상태에 도달하기 이전에 스위칭을 수행한다. 따라서 발광 소자 배열 양단에 형성되는 전압(Vo)은 항상 인가된 직류 전원의 전압보다 작거나 같으며, 전원부(100)가 발광소자 배열(200)로 인가하는 전류(IL)는 스위치(SWbuck)의 스위칭에 의한 소정의 주기를 가진다. In the P3 section, the inductor Lbuck is connected to the DC power source again through the switch SWbuck to charge the inductor Lbuck. As the DC power source is connected to the inductor Lbuck, the current IL flowing through the inductor increases from the current value just before switching until the inductor is fully charged with energy. However, like the above-described P1 section, switching is performed before reaching the steady state. Therefore, the voltage Vo formed at both ends of the light emitting device array is always less than or equal to the voltage of the applied DC power, and the current IL applied by the power supply unit 100 to the light emitting device array 200 is determined by the switch SWbuck. It has a predetermined period by switching.
다시 도 1 및 도 2를 참조하면, 발광 소자 배열(200)은 복수개의 단위 발광소자 배열들을 포함하며, 각각의 단위 발광 소자 배열(200a, 200b, 200c)은 각각 발광 소자 스트링(Sa, Sb, Sc)과, 상기 발광 소자 스트링에 상기 전원부가 공급하는 직류를 공급하거나 차단하는 스위치(SWa, SWb, SWc) 및 전원부가 공급한 전류를 균일하게 유지하는 커패시터(Ca, Cb, Cc)을 포함한다. 또한, 도면상에는 단지 세 개의 단위 발광 소자 배열들만이 도시되어 있으나 이는 순전히 쉬운 설명, 용이한 이해와 간명한 도시를 위한 것이다. 따라서 단위 발광 소자 배열들은 적어도 두 개 이상일 수 있다. 발광소자 배열(200)은 복수개의 단위 발광 소자 배열들(200a, 200b, 200c)이 병렬로 연결된 형태이다. 다만, 단위 발광 소자 배열들은 직선형태, 방사형태 또는 매트릭스 형태 등으로 배치되어 조명기구 등으로 사용될 수 있다. Referring back to FIGS. 1 and 2, the light emitting device array 200 includes a plurality of unit light emitting device arrays, and each of the unit light emitting device arrays 200a, 200b, and 200c respectively represents the light emitting device strings Sa, Sb, Sc, switches SWa, SWb, and SWc for supplying or blocking direct current supplied from the power supply unit to the light emitting device string, and capacitors Ca, Cb and Cc for maintaining the current supplied from the power supply unit uniformly. . In addition, only three unit light emitting device arrangements are shown in the drawings, but this is purely for easy explanation, easy understanding and simplicity. Therefore, at least two unit light emitting device arrays may be provided. The light emitting device array 200 has a plurality of unit light emitting device arrays 200a, 200b, and 200c connected in parallel. However, the unit light emitting device arrays may be arranged in a straight line, radial form, or matrix form and used as a lighting fixture.
도 4는 전원부가 출력하는 출력 전류(IL)의 한 주기를 소정의 구간으로 구분한 것을 도시한 도면이다. 도 4를 참조하면, 전원부가 출력한 전류(IL)는 전원부의 구동 특성상 소정의 주기를 가지는 리플(ripple)을 포함한다. 전류에 포함된 리플의 주기를 단위 발광 소자 배열들의 개수와 서로 소(relatively prime)인 개수의 구간으로 분할한다. 일 예로, 단위 발광 소자 배열 4개를 사용한다면, 전류에 포함된 리플의 주기를 4와 서로 소인 5개의 구간으로 나눌 수 있으며, 7개의 구간 또는 9개의 구간 등으로 나눌 수 있다. 다른 예로, 도 1 및 도 2에 도시된 바와 같이 3개의 단위 발광 소자 배열을 사용한다면, 리플의 주기를 3과 서로 소인 2, 4, 5 또는 7개 등의 구간으로 나눌 수 있다. 4 is a diagram illustrating dividing one cycle of the output current IL output by the power supply unit into a predetermined section. Referring to FIG. 4, the current IL output by the power supply unit includes a ripple having a predetermined period due to driving characteristics of the power supply unit. The period of the ripple included in the current is divided into a number of sections that are relatively prime with the number of unit light emitting device arrays. For example, if four unit light emitting device arrays are used, the period of the ripple included in the current may be divided into four sections and five sections swept from each other, and may be divided into seven sections or nine sections. As another example, when three unit light emitting device arrangements are used as shown in FIGS. 1 and 2, the ripple period may be divided into three, two, four, five, or seven sections.
일 실시예로 도 4a를 참조하면, 도 1에 도시된 회로에서, 단위 발광 소자 스트링의 개수는 세 개 이다. 따라서, 리플의 주기를 네 개의 구간으로 구분할 수 있다. 다른 실시예로 도 4b를 참조하면, 단위 발광 소자의 개수는 세 개이므로, 리플의 주기를 두 개의 구간으로 구획할 수 있다. 또 다른 실시예로 도 4c를 참조하면, 리플의 주기를 다섯 구간으로 구분할 수 있다.As an example, referring to FIG. 4A, in the circuit of FIG. 1, the number of unit light emitting device strings is three. Thus, the ripple period can be divided into four sections. As another embodiment, referring to FIG. 4B, since the number of unit light emitting devices is three, the ripple period may be divided into two sections. As another embodiment, referring to FIG. 4C, a ripple period may be divided into five sections.
바람직하게는 단위 발광 소자의 개수를 n이라 하고, 하나의 리플 주기 내에 포함된 구간의 개수를 m이라 한다면, | n - m | = 1인 관계, 즉 n과 m의 차이가 1인 경우가 스위칭 속도 확보의 측면에서 바람직하다. 이와 같이 주기를 단위 발광 소자 스트링의 개수(n)와 서로 소인 소정의 개수(m)의 구간으로 구분하고, 각 구간의 전류를 순차적으로 각각의 단위 발광 소자 스트링에 인가하면 각각의 단위 발광 소자 스트링에는 인접하는 각 주기별로 서로 다른 구간의 전류가 인가된다. Preferably, if the number of unit light emitting elements is n and the number of sections included in one ripple period is m, | n-m | The relationship of = 1, i.e., the difference between n and m is preferably 1 in terms of securing the switching speed. In this way, the period is divided into the number n of the unit light emitting device strings and the predetermined number m of sections, and each unit light emitting device string is sequentially applied to each unit light emitting device string. The current of different sections is applied to each adjacent period.
제어부(300)는 전류를 구간별로 구획하여 각 구간의 전류를 각각의 단위 발광 소자 배열에 순차적으로 인가되도록 각각의 스위치들(SWa, SWb, SWc)을 제어한다. 일 실시예로, 도 4a를 참조하면, 단위 발광소자 배열의 개수가 3개 이므로, 한 주기를 4개의 구간으로 나눈다. 제어부(300)는 첫 주기(T1) 최초 구간의 전류를 단위 발광 소자 스트링(200a)에 인가하고, 두 번째 구간의 전류 및 세 번째 구간의 전류를 순차적으로 단위 발광 소자 스트링(200b) 및 단위 발광 소자 스트링(200c)에 인가한 후, 다음 구간의 전류를 다시 단위 발광 소자 스트링(200a)부터 순차적으로 인가하도록 스위치들(SWa, SWb, SWc)을 제어한다. 다른 실시예로, 도 4b를 참조하면, 한 주기가 2개의 구간으로 구획된다. 제어부(300)는 최초 주기의 최초 구간은 단위 발광 소자 스트링(200a)에 인가하고, 이어지는 주기의 각 구간에 대하여 계속하여 순차적으로 단위 발광 소자 스트링(200b), 단위 발광 소자 스트링(200c) 및 다시 단위 발광 소자 스트링(200a)에 인가하도록 스위치들(SWa, SWb, SWc)을 제어한다. 또 다른 실시예로, 도 4c를 참조하면, 한 주기가 5개의 구간으로 구획된다. 제어부(300)는 최초 주기의 최초 구간은 단위 발광 소자 스트링(200a)에 인가하고, 이어지는 주기의 각 구간에 대하여 순차적으로 단위 발광 소자 스트링(200b), 단위 발광 소자 스트링(200c) 및 단위 발광 소자 스트링(200a)에 계속하여 인가하도록 스위치들(SWa, SWb, SWc)을 제어한다. The controller 300 controls the switches SWa, SWb, and SWc to divide current into sections and sequentially apply currents of the sections to the respective unit light emitting device arrays. For example, referring to FIG. 4A, since the number of unit light emitting device arrays is three, one period is divided into four sections. The controller 300 applies the current of the first section T1 to the unit light emitting device string 200a and sequentially applies the current of the second section and the current of the third section to the unit light emitting device string 200b and the unit light emission. After the application to the device string 200c, the switches SWa, SWb, and SWc are controlled to sequentially apply the current of the next section from the unit light emitting device string 200a. In another embodiment, referring to FIG. 4B, one period is divided into two sections. The controller 300 applies the first period of the first period to the unit light emitting device string 200a, and sequentially the unit light emitting device string 200b, the unit light emitting device string 200c, and again for each section of the subsequent period. The switches SWa, SWb, and SWc are controlled to be applied to the unit light emitting device string 200a. In another embodiment, referring to FIG. 4C, one period is divided into five sections. The controller 300 applies an initial section of the initial period to the unit light emitting device string 200a, and sequentially unit light emitting device string 200b, unit light emitting device string 200c, and unit light emitting device for each section of the subsequent period. The switches SWa, SWb, and SWc are controlled to continuously apply to the string 200a.
제어부(300)가 위에서 설명된 실시예와 같이 스위치들(SWa, SWb, SWc)을 제어함에 따라 스트링별 밝기 차이를 감소시킬 수 있다. 일 비교예로 도시된 도 5를 참조하면, 일정한 주기의 리플이 포함된 전류를 스위칭을 통하여 세 개의 단위 발광 소자 스트링에 인가하는 경우를 가정한다. 이 때 한 주기를 세 개의 구간으로 구획하여 세 개의 스트링(a, b, c)에 인가한다면, 각 스트링(a, b, c)에 인가되는 각 주기의 구간은 동일하다. 각 구간별 평균 전류를 구하여 도시하면 도 5의 점선과 같이 a 구간의 평균전류(Iavg,a), b 구간의 평균전류(Iavg,b) 및 c 구간의 평균 전류(Iavg,c) 값은 서로 다르므로 커패시터를 연결하여 발광 다이오드에 인가되는 전류를 평균화한다 하여도 각각의 스트링으로 인가되는 전류의 평균값이 다를 수 밖에 없어 스트링별 밝기 차이가 존재한다. 따라서, 비교예와 같이 스위칭을 수행하여 발광 소자 스트링을 구동한다면 스트링별 밝기 차이가 존재하여 전체적으로 얼룩이 있는 것처럼 보인다.As the controller 300 controls the switches SWa, SWb, and SWc as in the above-described embodiment, the brightness difference for each string may be reduced. Referring to FIG. 5, which is illustrated as a comparative example, it is assumed that a current including a constant ripple is applied to three unit light emitting device strings through switching. At this time, if one period is divided into three sections and applied to three strings a, b and c, the sections of each period applied to each string a, b and c are the same. When the average current of each section is obtained and shown, the average current Iavg, a in section a, the average current Iavg, b in section b, and average current Iavg, c in section c are different from each other. Therefore, even if the capacitors are connected to average the current applied to the light emitting diode, the average value of the current applied to each string is inevitably different, there is a difference in brightness for each string. Therefore, if the light emitting device string is driven by switching as in the comparative example, there is a difference in brightness for each string, and thus, the entire surface appears to be uneven.
그러나, 본 실시예에 의한다면 제어부(300)는 동일한 단위 발광 소자 스트링으로 서로 인접한 두 주기 동안 인가되는 전류의 구간이 상이하도록 스위치를 제어한다. 즉, 도 4a를 참조하면, 스트링a에는 최초 주기의 최초 구간, 마지막 구간, 두 번째 주기에서 세 번째 구간, 세 번째 주기에서 두 번째 구간의 전류가 인가된다. 또한, 스트링 b에는 최초 주기(T1)의 두 번째 구간, 두 번째 주기(T2)의 최초 및 마지막 구간, 세 번째 주기(T3)의 세 번째 구간의 전류가 인가된다. 즉, 도 4a를 참조하면 a 스트링에는 최초 주기(T1)에서 첫 번째와 네 번째 구간의 전류가, 두 번째 주기에서 세 번째 구간의 전류가 인가되어 서로 인접한 주기에서 서로 다른 구간의 전류가 인가된다. 도 4b에 도시된 실시예에서도 마찬가지로, a 스트링에는 첫 번째 주기의 최초 구간의 전류가, 두 번째 주기에서는 두 번째 구간의 전류가 인가된다. 따라서 비교예와 같이 어느 한 스트링에 계속 동일 구간의 전류가 계속 인가되지 않고, 인접한 주기에서 서로 다른 구간들의 전류가 인가된다.However, according to the present exemplary embodiment, the control unit 300 controls the switches so that the sections of the currents applied for two periods adjacent to each other with the same unit light emitting device string are different. That is, referring to FIG. 4A, currents of the first section of the first period, the last section, the third section of the second period, and the second section of the third period are applied to the string a. In addition, a current of the second section of the first period T1, the first and last sections of the second period T2, and the third section of the third period T3 is applied to the string b. That is, referring to FIG. 4A, currents of the first and fourth sections are applied to the string a in the first period T1, and currents of the third section are applied in the second period, so that currents of different sections are applied in the adjacent periods. . In the embodiment shown in FIG. 4B, the current in the first section of the first period is applied to the string a, and the current in the second section is applied to the second string. Therefore, as in the comparative example, the current in the same section is not continuously applied to any one string, but the current in different sections is applied in the adjacent period.
이와 같이 각각의 스트링에 서로 다른 구간의 전류가 인가되므로 스트링에 인가되는 전류의 편차를 줄일 수 있으며, 나아가 인가된 전류를 각각의 스트링에 포함된 커패시터가 평균화하여 발광 소자 스트링에 인가하므로 스트링별 밝기 차이를 감소시킬 수 있다. As the currents of different sections are applied to each string as described above, the variation of the currents applied to the strings can be reduced. Furthermore, since the capacitors included in each string are averaged and applied to the light emitting device strings, the brightness of each string is increased. The difference can be reduced.
전류 센서(400)는 발광 소자 배열을 통하여 흐르는 전류를 감지한다. 종래에는 각각의 발광 소자 스트링의 밝기 차이를 보상하기 위하여 발광 소자 스트링 별로 전류 센서를 장착하였으나, 제어부(300)가 상술한 바와 같이 각각의 단위 발광 소자 스트링에 포함된 스위치(SWa, SWb, SWc)를 구동하여 스트링들을 고르게 발광시킬 수 있으므로 본 실시예에서는 전체적인 전류의 양을 감지할 수 있는 하나의 전류 센서로 충분하다.The current sensor 400 detects a current flowing through the light emitting element array. Conventionally, in order to compensate for the difference in brightness of each light emitting device string, a current sensor is mounted for each light emitting device string, but as described above, the controller 300 includes switches SWa, SWb, and SWc included in each unit light emitting device string. Since the strings can be evenly emitted by driving, one current sensor capable of sensing the total amount of current is sufficient in this embodiment.
모의시험예Simulation test example
이하는 세 개의 단위 발광 소자 스트링을 구동하는 예에 대한 컴퓨터 모의시험 결과를 나타낸다. 도 6a는 전원부가 발광 소자 배열에 인가하는 전류의 파형을 나타낸 것이다. 한 주기가 5usec이고, 전류의 평균값이 약 0.45A이고, 최대값 0.48A, 최소값이 0.42A 정도로 스윙하는 리플을 포함함을 알 수 있다. 도 6b는 제어부가 각각의 발광 소자 스트링에 포함된 스위치를 구동하는 구동 펄스의 파형을 나타낸 것으로, 한 주기를 4 구간으로 구획하여 SW3, SW2 및 SW1의 순서로 순차적으로 스위칭을 수행한다. The following shows computer simulation results for an example of driving three unit light emitting device strings. 6A shows a waveform of a current applied to a light emitting element array by a power supply unit. It can be seen that one cycle has 5usec, the average current is about 0.45A, the maximum value is 0.48A, and the minimum value is about 0.42A. 6B illustrates a waveform of a driving pulse in which a controller drives a switch included in each light emitting device string. The controller divides one period into four sections and sequentially switches in the order of SW3, SW2, and SW1.
각각의 스트링에 인가되는 전압은 도시된 바와 같이 리플이 상당히 억제되어 있음을 알 수 있다. 또한, 스트링 a, b 및 c에 흐르는 전류의 평균값들은 대략 151mA, 150mA 및 149mA로 평균값들의 편차가 최대 2mA 정도에 불과하여 어느 한 스트링에 흐르는 전류에 비하여 다른 스트링에 흐르는 전류가 높거나 낮지 않고 전체적으로 고르게 분포하여 스트링간 밝기 차이가 억제됨을 알 수 있다. It can be seen that the voltage applied to each string is significantly suppressed in ripple as shown. In addition, the average values of the currents flowing through the strings a, b, and c are approximately 151 mA, 150 mA, and 149 mA, and the deviation of the average values is only about 2 mA, which is higher than the current flowing in one string. It can be seen that evenly distributed to suppress the difference in brightness between the strings.
본 발명에 대한 이해를 돕기 위하여 도면에 도시된 실시 예를 참고로 설명되었으나, 이는 실시를 위한 실시예로, 예시적인 것에 불과하며, 당해 분야에서 통상적 지식을 가진 자라면 이로부터 다양한 변형 및 균등한 타 실시 예가 가능하다는 점을 이해할 것이다. 따라서, 본 발명의 진정한 기술적 보호범위는 첨부된 특허청구범위에 의해 정해져야 할 것이다. Although described with reference to the embodiments shown in the drawings to aid the understanding of the present invention, this is an embodiment for the implementation, it is merely exemplary, those skilled in the art from various modifications and equivalents therefrom It will be appreciated that other embodiments are possible. Therefore, the true technical protection scope of the present invention will be defined by the appended claims.

Claims (20)

  1. 일정한 주기의 리플(ripple)이 포함된 직류 전류를 공급하는 전원부와,A power supply unit supplying a direct current with a constant cycle of ripple,
    발광 소자 배열을 포함하며, 상기 발광 소자 배열은 복수개의 단위 발광 소자 배열을 포함하고, 각각의 상기 단위 발광소자 배열은 발광 소자 스트링과, 상기 발광 소자 스트링에 상기 전원부가 공급하는 직류를 공급하거나 차단하는 스위치 및 상기 전원부가 공급한 직류 전류를 평활(smoothing)하는 커패시터를 포함하고, A light emitting device array, the light emitting device array including a plurality of unit light emitting device arrays, each of the unit light emitting device arrays supplying or blocking a light emitting device string and a direct current supplied by the power supply unit to the light emitting device string; A switch and a capacitor for smoothing a DC current supplied by the power supply unit,
    상기 스위치를 도통시키거나 차단하도록 제어하는 제어부를 포함하며,A control unit for controlling to turn on or off the switch;
    상기 제어부는 상기 직류 전류의 주기를 상기 복수개(n)와 서로 소(relatively prime)인 개수(m)의 구간으로 분할하여 각 구간의 직류 전류가 상기 복수개의 단위 발광 소자 배열에 순차적으로 인가되도록 상기 스위치를 제어하는 발광 소자 구동 장치.The controller divides the period of the DC current into a plurality of sections n and a relatively prime number m, so that the DC currents of the sections are sequentially applied to the plurality of unit light emitting device arrays. A light emitting element drive device for controlling a switch.
  2. 제1항에 있어서, The method of claim 1,
    상기 서로 소인 개수(m)는 상기 복수개(n) 보다 하나 더 크거나 더 작은 수인 발광 소자 구동 장치(단, m은 2와 같거나 크고, n은 2와 같거나 큰 자연수).The number m of each other is m is one or more greater than or smaller than the plurality (n) of the light emitting device driving device (where m is a natural number greater than or equal to 2, n is a natural number greater than or equal to 2).
  3. 제1항에 있어서, The method of claim 1,
    상기 전원부는 입력 전압을 스텝 다운(step down)하는 벅 컨버터를 포함하는 발광 소자 구동 장치.And the power supply unit includes a buck converter for stepping down an input voltage.
  4. 제3항에 있어서, The method of claim 3,
    상기 전원부는 입력 교류 전압을 정류하는 정류회로(rectifying circuit); 및The power supply unit includes a rectifying circuit for rectifying the input AC voltage; And
    상기 정류회로의 출력 전압 레벨을 스텝 업(step up)하여 출력하는 부스트 컨버터(boost converter)를 더 포함하는 발광 소자구동 장치.And a boost converter for stepping up and outputting the output voltage level of the rectifier circuit.
  5. 제1항에 있어서, The method of claim 1,
    상기 발광 소자 구동 장치는The light emitting device driving device
    상기 복수개 발광 소자 배열에 흐르는 전류를 감지하는 전류 센서를 더 포함하며,Further comprising a current sensor for sensing the current flowing in the plurality of light emitting element array,
    상기 제어부는 상기 전류 센서가 감지한 전류 값에 따라 상기 전원부를 제어하는 발광 소자 구동 장치. The control unit is a light emitting device driving apparatus for controlling the power supply in accordance with the current value detected by the current sensor.
  6. 제1항에 있어서, The method of claim 1,
    전원부의 출력단은 상기 복수개(n)의 단위 발광 소자 배열의 일단과 전기적으로 연결된 발광 소자 구동 장치.The output terminal of the power supply unit is a light emitting device driving device electrically connected to one end of the plurality of (n) unit light emitting device array.
  7. 제1항에 있어서, The method of claim 1,
    상기 발광 소자 스트링은 복수개의 발광 다이오드(LED, Light Emitting Diode)들이 전기적으로 연결되어 형성된 발광 소자 구동 장치.The light emitting device string may include a plurality of light emitting diodes (LEDs) electrically connected to each other.
  8. 제1항에 있어서,The method of claim 1,
    상기 커패시터는, The capacitor,
    일단이 상기 발광 소자 스트링에 연결된 적어도 하나의 커패시터를 포함하는 발광 소자 구동 장치.And at least one capacitor, one end of which is connected to the light emitting element string.
  9. 일정한 주기의 리플(ripple)이 포함된 직류 전류를 형성하는 단계와,Forming a direct current with a constant cycle of ripple,
    상기 형성된 전류를 복수개(n)의 단위 발광 소자 배열에 인가하는 단계로, 상기 일정한 주기의 리플이 포함된 입력 전압을 상기 복수개(n)와 서로 소(relatively prime)인 개수(m)의 구간으로 분할하여 분할된 구간의 전류를 상기 복수개의 단위 발광 소자 배열에 순차적으로 인가하는 발광 소자 구동 방법.The step of applying the formed current to the array of a plurality (n) of the unit light emitting device, the input voltage including the ripple of a predetermined period of the plurality of n and the relatively small number of intervals (m) of the interval (m) A method of driving a light emitting device by dividing and applying a current of a divided section sequentially to the plurality of unit light emitting device arrays.
  10. 제9항에 있어서, The method of claim 9,
    상기 서로 소인 개수(m)는 상기 복수개(n) 보다 하나 더 크거나 더 작은 수인 발광 소자 구동 방법(단, m은 2와 같거나 크고, n은 2와 같거나 큰 자연수).The number (m) of each other is a light emitting element driving method is one larger or smaller than the plurality (n) (wherein m is a natural number greater than or equal to 2, n is a natural number greater than or equal to 2).
  11. 제9항에 있어서, The method of claim 9,
    상기 직류 전류를 형성하는 단계는, Forming the direct current,
    교류 전압을 인가 받는 단계와Receiving alternating voltage
    상기 입력 교류 전압을 정류하는 단계 및Rectifying the input alternating voltage; and
    정류된 전압의 레벨을 변환하는 단계를 포함하는 발광 소자 구동 방법.Converting the level of the rectified voltage.
  12. 소정 개수의 구간으로 구분될 수 있는 주기를 가지는 리플(ripple)이 포함된 직류 전류를 출력하는 전원 회로부와,A power supply circuit unit for outputting a DC current including a ripple having a period that can be divided into a predetermined number of sections;
    상기 전원 회로부와 연결된 복수개의 단위 발광 소자 배열을 포함하는 발광 소자 배열로, 상기 단위 발광 소자 배열은 전원 회로부가 출력한 전류을 인가하거나 차단하는 스위치와, 전원 회로부가 출력한 전류를 인가받아 발광하는 복수개의 발광 소자들이 전기적으로 연결된 발광 소자 스트링 및 상기 발광 소자 스트링에 인가되는 전류를 평활하는 커패시터를 포함하며,A light emitting device array including a plurality of unit light emitting device arrays connected to the power supply circuit unit, wherein the unit light emitting device array is a switch for applying or blocking a current output from the power supply circuit unit, a plurality of light emitting by receiving the current output from the power supply circuit unit A light emitting device string electrically connected to the plurality of light emitting devices, and a capacitor for smoothing a current applied to the light emitting device string,
    서로 인접한 두 주기 동안 동일한 단위 발광 소자 배열에 인가되는 전류의 구간이 상이하도록 상기 스위치를 제어하는 제어부를 포함하는 발광 소자 구동 장치.And a controller for controlling the switch such that currents applied to the same unit light emitting device arrays are different during two adjacent periods.
  13. 제12항에 있어서, The method of claim 12,
    단위 발광 소자 배열의 개수와 상기 구간의 개수는 서로 소(relatively prime) 인 발광 소자 구동 장치.And a number of unit light emitting element arrays and a number of sections are relatively prime.
  14. 제12항에 있어서, The method of claim 12,
    상기 단위 발광 소자 배열의 개수와 상기 구간의 개수의 차는 1인 발광 소자 구동 장치.And a difference between the number of the unit light emitting element arrays and the number of the section is one.
  15. 제12항에 있어서, The method of claim 12,
    상기 전원 회로부는 입력 전압을 스텝 다운(step down)하는 벅 컨버터를 포함하는 발광 소자 구동 장치.And the power supply circuit unit includes a buck converter for stepping down an input voltage.
  16. 제15항에 있어서, The method of claim 15,
    상기 전원 회로부는 입력 교류 전압을 정류하는 정류회로(rectifying circuit); 및The power circuit includes a rectifying circuit for rectifying the input AC voltage; And
    상기 정류회로의 출력 전압 레벨을 스텝 업(step up)하여 출력하는 부스트 컨버터(boost converter)를 더 포함하는 발광 소자구동 장치.And a boost converter for stepping up and outputting the output voltage level of the rectifier circuit.
  17. 제12항에 있어서, The method of claim 12,
    상기 발광 소자 구동 장치는The light emitting device driving device
    상기 복수개 발광 소자 배열에 흐르는 전류를 감지하는 전류 센서를 더 포함하며,Further comprising a current sensor for sensing the current flowing in the plurality of light emitting element array,
    상기 제어부는 상기 전류 센서가 감지한 전류 값에 따라 상기 전원부를 제어하는 발광 소자 구동 장치. The control unit is a light emitting device driving apparatus for controlling the power supply in accordance with the current value detected by the current sensor.
  18. 제12항에 있어서, The method of claim 12,
    전원부의 출력단은 상기 복수개(n)의 단위 발광 소자 배열의 일단과 전기적으로 연결된 발광 소자 구동 장치.The output terminal of the power supply unit is a light emitting device driving device electrically connected to one end of the plurality of (n) unit light emitting device array.
  19. 제12항에 있어서, The method of claim 12,
    상기 발광 소자 스트링은 복수개의 발광 다이오드(LED, Light Emitting Diode)들이 전기적으로 연결되어 형성된 발광 소자 구동 장치.The light emitting device string may include a plurality of light emitting diodes (LEDs) electrically connected to each other.
  20. 제12항에 있어서, The method of claim 12,
    상기 커패시터는 일단이 상기 발광 소자 스트링에 연결된 적어도 하나의 커패시터를 포함하는 발광 소자 구동 장치.And the capacitor includes at least one capacitor having one end connected to the light emitting element string.
PCT/KR2013/000968 2013-02-07 2013-02-07 Light-emitting device driving apparatus and light-emitting device driving method WO2014123255A1 (en)

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