KR100469423B1 - Led driving circuit using inverter - Google Patents

Led driving circuit using inverter Download PDF

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Publication number
KR100469423B1
KR100469423B1 KR10-2002-0022288A KR20020022288A KR100469423B1 KR 100469423 B1 KR100469423 B1 KR 100469423B1 KR 20020022288 A KR20020022288 A KR 20020022288A KR 100469423 B1 KR100469423 B1 KR 100469423B1
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South Korea
Prior art keywords
led
voltage
inverter
driving circuit
led driving
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KR10-2002-0022288A
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Korean (ko)
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KR20030083893A (en
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김왕진
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엘지전자 주식회사
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    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/22—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources
    • G09G3/30—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels
    • G09G3/32—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED]
    • 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
    • H02M3/06—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using resistors or capacitors, e.g. potential divider
    • H02M3/07—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using resistors or capacitors, e.g. potential divider using capacitors charged and discharged alternately by semiconductor devices with control electrode, e.g. charge pumps
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2310/00—Command of the display device
    • G09G2310/02—Addressing, scanning or driving the display screen or processing steps related thereto
    • G09G2310/0264—Details of driving circuits

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Computer Hardware Design (AREA)
  • General Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Led Devices (AREA)
  • Dc-Dc Converters (AREA)

Abstract

본 발명은 LED 구동회로에 관한 것으로서, 특히 인버터를 이용하여 LED의 입력전압과 반대 극성을 갖는 전압을 LED의 출력단에 인가함으로써 배터리의 전압을 승압시키지 않고 LED를 구동할 수 있도록 하는 것을 목적으로 한다. 이를 위해 본 발명은 배터리의 전압을 강하시키는 강압부와, 상기 강압부에서 출력된 전압의 극성을 바꾸는 인버터 충전펌프와, 상기 강압부의 출력전압 및 상기 인버터의 출력전압이 양단에 각각 인가되는 복수의 LED를 포함하여 구성된 것을 특징으로 한다.The present invention relates to an LED driving circuit, and in particular, an object of using an inverter to drive a LED without boosting the voltage of the battery by applying a voltage having a polarity opposite to the input voltage of the LED to the output terminal of the LED. . To this end, the present invention provides a plurality of step-down parts for dropping the voltage of the battery, an inverter charge pump for changing the polarity of the voltage output from the step-down part, and output voltages of the step-down part and output voltages of the inverter respectively. Characterized in that configured to include an LED.

Description

인버터를 이용한 ＬＥＤ 구동회로{LED DRIVING CIRCUIT USING INVERTER}LED driving circuit using inverter {LED DRIVING CIRCUIT USING INVERTER}

본 발명은 LED 구동회로에 관한 것으로서, 특히 인버터를 이용하여 LED의 입력전압과 반대 극성을 갖는 전압을 LED의 출력단에 인가함으로써 배터리의 전압을 승압시키지 않고 LED를 구동할 수 있는 인버터를 이용한 LED 구동회로에 관한 것이다.The present invention relates to an LED driving circuit, and in particular, an LED driving circuit using an inverter capable of driving the LED without boosting the voltage of the battery by applying a voltage having a polarity opposite to the input voltage of the LED to the output terminal of the LED using an inverter. It's about the furnace.

현재 이동단말기에 사용 중인 배터리의 전압(3∼4V)은 컬러 LED를 구동하는데 필요한 전압(4V 이상)보다 작기 때문에 컬러 LED를 구동하기 위해서는 배터리의 전압을 승압하여야 한다.Since the voltage (3-4V) of the battery currently used in the mobile terminal is smaller than the voltage (more than 4V) required to drive the color LED, the voltage of the battery must be boosted to drive the color LED.

배터리의 전압을 승압시키는 종래의 기술에는 인덕터를 이용한 스위칭레귤레이터(switching regulator) 방식과 커패시터를 이용한 충전펌프(charge pump) 방식이 있다.Conventional techniques for boosting the voltage of a battery include a switching regulator method using an inductor and a charge pump method using a capacitor.

도 1은 종래의 스위칭레귤레이터 방식을 나타낸다.1 shows a conventional switching regulator method.

도 1에서 승압용 스위칭레귤레이터는 일반적으로 효율이 좋고 일정한 전류를 LED에 공급하여 LED의 밝기가 거의 일정하기 때문에 현재 많은 회로에서 사용 중에 있다.In Figure 1, the boosting regulator is generally in use in many circuits because the efficiency of the LED is generally constant and the LED brightness is almost constant by supplying a constant current to the LED.

그러나, 스위칭레귤레이터 방식은 부하의 개수 즉 LED의 개수에 제한(현재까지는 최대 4개까지 가능함)이 있기 때문에 사용상의 제약이 따르게 된다.However, the switching regulator method has limitations in use because there is a limit on the number of loads, that is, the number of LEDs (to date, up to four).

즉, 예를 들어 서브 LCD의 백라이트 구동을 LED로 하는 경우 메인 LCD와 합쳐 모두 6개의 LED가 필요하기 때문에 스위칭레귤레이터 방식으로는 LED 구동회로를 구현할 수 없다는 문제점이 있다.That is, for example, when the backlight driving of the sub LCD is an LED, since all six LEDs are required in addition to the main LCD, there is a problem in that the LED driving circuit cannot be implemented by the switching regulator method.

또한, 높은 피크 전류(peak current)를 견딜 수 있는 파워 인덕터의 사용에 따른 큰 사이즈(보통 3mm x 3mm 정도 되는 스위칭레귤레이터보다 큰 사이즈)의 스위칭레귤레이터가 필요하기 때문에 공간적 효율성이 떨어지고, 인덕터에서 스위칭시 발생하는 자기장이 다른 회로에 영향을 줄 가능성이 커서 이를 방지하기 위한 인덕터의 적절한 배치 및 자기장의 영향을 최소화할 수 있는 방안을 모색해야 한다는 문제점이 있다.In addition, it requires less switching efficiency due to the large size of the switching regulator (typically larger than the switching regulator of 3mm x 3mm) due to the use of a power inductor capable of withstanding high peak current. Since the generated magnetic field is likely to affect other circuits, there is a problem in that the proper arrangement of the inductor and the method of minimizing the influence of the magnetic field are to be prevented.

도 2는 종래의 충전펌프 방식을 나타낸다.2 shows a conventional charging pump method.

도 2에서 승압용 충전펌프는 도 1에서의 승압용 스위칭레귤레이터에 비해서 효율은 좀 떨어지나 LED의 개수에 제약이 적고 인덕터가 아닌 커패시터를 이용하여 승압을 하기 때문에 상기 인덕터에서 발생하는 문제점을 어느 정도 줄일 수 있다.In FIG. 2, the boosting charge pump is slightly less efficient than the boosting switching regulator in FIG. 1, but the number of LEDs is less limited and the boosting is performed using a capacitor rather than an inductor. Can be.

그러나, 낮은 효율을 갖고 있고 각 LED마다 약간의 전류차가 발생하여 스위칭레귤레이터보다는 밝기의 편차가 크다는 문제점이 있다.However, there is a problem that it has a low efficiency and a slight current difference occurs for each LED, so that the variation in brightness is greater than that of the switching regulator.

또한, 충전펌프에서 출력되는 전압에 리플 또는 노이즈가 발생하기 때문에 이를 제거하기 위한 별도의 부품이 필요하게 된다는 문제점이 있다.In addition, since a ripple or noise is generated in the voltage output from the charge pump, there is a problem that a separate component is required to remove it.

따라서, 본 발명은 상기의 문제점을 해결하기 위하여 안출된 것으로서, 배터리를 승압하지 않고 인버터 충전펌프를 이용함으로써 출력전압의 리플 또는 노이즈를 방지하며 회로의 크기를 줄이고 LED의 개수에 제한을 받지 않는 LED 구동회로를제공하는 것을 목적으로 한다.Accordingly, the present invention has been made to solve the above problems, by using an inverter charge pump without boosting the battery to prevent ripple or noise of the output voltage, reduce the size of the circuit and LED is not limited to the number of LEDs It is an object to provide a driving circuit.

도 1은 종래의 스위칭레귤레이터 방식을 나타내는 예시도.1 is an exemplary view showing a conventional switching regulator method.

도 2는 종래의 충전펌프 방식을 나타내는 예시도.Figure 2 is an exemplary view showing a conventional charge pump method.

도 3은 본 발명에 의한 인버터를 이용한 LED 구동회로의 예시도.Figure 3 is an illustration of an LED drive circuit using an inverter according to the present invention.

도 4는 본 발명에 의한 인버터를 이용한 LED 구동회로를 적용한 예시도.Figure 4 is an exemplary view applying the LED driving circuit using an inverter according to the present invention.

** 도면의 주요부분에 대한 부호설명 **** Explanation of Signs of Major Parts of Drawings **

1 : 배터리 2 : 강압부1: battery 2: step-down part

3 : 인버터 충전펌프3: inverter charge pump

이를 위하여 본 발명은 배터리의 전압을 강하시키는 강압부와, 상기 강압부에서 출력된 전압의 극성을 바꾸는 인버터 충전펌프와, 상기 강압부의 출력전압 및 상기 인버터의 출력전압이 양단에 각각 인가되는 복수의 LED를 포함하여 구성된 것을 특징으로 한다.To this end, the present invention provides a plurality of step-down portions for dropping the voltage of the battery, an inverter charge pump for changing the polarity of the voltage output from the step-down portion, and output voltages of the step-down portion and output voltages of the inverter respectively. Characterized in that configured to include an LED.

이하 첨부된 도면을 참조하여 본 발명을 상세히 설명한다.Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

도 3은 본 발명에 의한 LED 구동회로를 나타낸다.3 shows an LED driving circuit according to the present invention.

도 3에서 도시된 바와 같이, 본 발명에 의한 LED 구동회로는 LDO(Low Drop voltage Output)(2) 및 인버터 충전펌프(3)로 구성되어 있다.As shown in FIG. 3, the LED driving circuit according to the present invention includes a low drop voltage output (LDO) 2 and an inverter charge pump 3.

배터리(1)에서 출력된 전압(3∼4V)은 우선 LDO(2)에 입력되어 예를 들어 2.5V로 강압된다. 여기서 LDO(2)는 현재 이동단말기에서 사용되고 있는 전압강하용 레귤레이터이다.The voltages 3 to 4V output from the battery 1 are first input to the LDO 2 and stepped down, for example, to 2.5V. The LDO 2 is a voltage drop regulator currently used in a mobile terminal.

LDO(2)의 출력단은 병렬로 연결되어 있는 LED의 입력단(a) 및 인버터 충전펌프(3)에 접속된다.The output terminal of the LDO 2 is connected to the input terminal a and the inverter charge pump 3 of the LEDs connected in parallel.

따라서, LDO(2)에서 출력된 전압은 병렬로 연결되어 있는 LED의 입력단(a)의 전압을 이루고, 인버터 충전펌프(3)에 입력된 전압은 반대극성(예를 들어 상기 2.5V 에 대하여 -2.5V 로 바뀜)으로 바뀌어 LED의 출력단(b)에 출력된다.Accordingly, the voltage output from the LDO 2 constitutes the voltage of the input terminal a of the LEDs connected in parallel, and the voltage input to the inverter charge pump 3 is opposite polarity (for example, with respect to 2.5V above). It is changed to 2.5V) and output to the output terminal (b) of the LED.

이와 같이 LED의 입력단(a)의 전위가 2.5V 이고, 출력단(b)의 전위가 -2.5V 이므로 결국 LED에 걸리는 전압이 5V 가 되어(즉, 전압강하가 5V 임) LED를 구동할 수 있는 전압을 얻을 수 있게 된다.Thus, since the potential of the input terminal (a) of the LED is 2.5V and the potential of the output terminal (b) is -2.5V, the voltage applied to the LED eventually becomes 5V (that is, the voltage drop is 5V). The voltage can be obtained.

즉, 본 발명은 LED 구동에 필요한 전압을 얻기 위해서 배터리의 전압을 기존의 방식에 의해 승압시키는 것이 아니라 인버터 충전펌프를 이용하여 LED의 입력전압과 반대극성의 전압을 LED의 출력단에 인가함으로써 결국 LED의 전압강하가 입력전압의 두 배가 되도록 한 것이다. 본 발명의 실시예에서 사용되는 인버터 충전펌프(3)는 하나의 소자로서 생산되고 있으며, 예를 들어 MAXIM의 MAX749 등이 있다.That is, the present invention does not boost the voltage of the battery by a conventional method in order to obtain the voltage required to drive the LED, but instead applies the input voltage of the LED to the output terminal of the LED by using an inverter charge pump to the LED output terminal. The voltage drop at is twice that of the input voltage. Inverter charge pump (3) used in the embodiment of the present invention is produced as a single device, for example MAXIM MAX749 and the like.

도 4는 본 발명의 LED 구동회로의 다른 실시예를 나타낸다.4 shows another embodiment of the LED driving circuit of the present invention.

본 발명에 의한 LED 구동회로는 도 3에서와 같이 단독으로 사용할 수 있으나 상황에 따라 부분적으로 이를 적용할 수도 있다.The LED driving circuit according to the present invention may be used alone as in FIG. 3, but may be partially applied according to circumstances.

즉, 메인 LCD의 백라이트로서 3개의 LED를 사용하고 서브 LCD의 백라이트로서 3개의 LED를 사용하고자 할 때, 도 4에서 도시된 바와 같이, 메인 LCD의 LED인 경우에는 일정한 밝기와 소모전류를 줄이는 것이 필요하기 때문에 높은 효율과 밝기의 편차가 적은 스위칭레귤레이터(4)를 이용하고, 서브 LCD의 LED인경우에는 인디케이터(indicator)로서 잠깐 사용하는 것이므로 본 발명에 의한 LED 구동회로를 이용할 수 있을 것이다.That is, when three LEDs are used as the backlight of the main LCD and three LEDs are used as the backlight of the sub LCD, as shown in FIG. Since it is necessary to use the switching regulator 4 with high efficiency and less variation in brightness, and the LED of the sub LCD is to be used as an indicator for a while, the LED driving circuit according to the present invention can be used.

상기한 바와 같이, 본 발명은 배터리 전압의 승압없이 높은 효율의 인버터 충전펌프를 이용하여 LED를 구동하기 때문에 높은 전압에 의한 리플 또는 노이즈의 발생을 감소시킬 수 있으며, 스위칭레귤레이터 방식에서의 사이즈 증가 및 LED 개수의 제한 문제를 해결할 수 있는 효과가 있다.As described above, the present invention can reduce the occurrence of ripple or noise due to the high voltage because the LED is driven using a high efficiency inverter charge pump without boosting the battery voltage, and the size of the switching regulator method and This can solve the problem of limiting the number of LEDs.

또한, 이동단말기의 입력전원으로 사용되고 있는 기존의 LDO를 이용하기 때문에 본 발명의 LED 구동회로에 부품의 추가가 필요없다는 효과가 있다.In addition, since the existing LDO used as an input power source of the mobile terminal is used, there is an effect that there is no need to add components to the LED driving circuit of the present invention.

Claims (2)

배터리의 전압을 강하시키는 강압부와,A step-down part for lowering the voltage of the battery; 상기 강압부에서 출력된 전압의 극성을 바꾸는 인버터 충전펌프와,Inverter charge pump for changing the polarity of the voltage output from the step-down unit, 상기 강압부의 출력전압 및 상기 인버터의 출력전압이 양단에 각각 인가되는 복수의 LED를 포함하여 구성된 것을 특징으로 하는 인버터를 이용한 LED 구동회로.LED driving circuit using an inverter, characterized in that the output voltage of the step-down portion and the output voltage of the inverter comprises a plurality of LEDs respectively applied to both ends. 제 1항에 있어서,The method of claim 1, 상기 강압부는 LDO인 것을 특징으로 하는 인버터를 이용한 LED 구동회로.LED driving circuit using the inverter, characterized in that the step-down portion is LDO.
KR10-2002-0022288A 2002-04-23 2002-04-23 Led driving circuit using inverter KR100469423B1 (en)

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JP4657799B2 (en) * 2005-05-11 2011-03-23 株式会社リコー Light emitting diode drive circuit

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