KR930000109Y1 - Led printer head electric control circuit - Google Patents
Led printer head electric control circuit Download PDFInfo
- Publication number
- KR930000109Y1 KR930000109Y1 KR2019890002031U KR890002031U KR930000109Y1 KR 930000109 Y1 KR930000109 Y1 KR 930000109Y1 KR 2019890002031 U KR2019890002031 U KR 2019890002031U KR 890002031 U KR890002031 U KR 890002031U KR 930000109 Y1 KR930000109 Y1 KR 930000109Y1
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- led
- current
- fet
- control circuit
- printer head
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- Printers Or Recording Devices Using Electromagnetic And Radiation Means (AREA)
Abstract
내용 없음.No content.
Description
제1도는 LED 프린터헤드의 기능 블럭도.1 is a functional block diagram of an LED printhead.
제2도는 LED 어레이 1개의 칩에 대한 전류제어 회로도.2 is a current control circuit diagram of one chip of an LED array.
제3도는 FET 전류전압 특성도.3 is a characteristic diagram of FET current voltage.
제4도는 본 고안의 전체 블럭도.4 is a block diagram of the present invention.
* 도면의 주요부분에 대한 부호의 설명* Explanation of symbols for main parts of the drawings
1 : LED어레이칩 3, 4 : FET1: LED array chip 3, 4: FET
2, 5, 6 : 저항 7 : LED구동회로2, 5, 6: Resistor 7: LED driving circuit
본 고안은 LED(Light Emitting Diode) 프린터헤드의 전류제어 회로에 관한 것으로, 특히 각 LED어레이칩별로 구동전류를 제어하여 LED 광 출력 편차를 효과적으로 줄이기 위한 회로이다.The present invention relates to a current control circuit of an LED (Light Emitting Diode) printhead, and in particular, a circuit for effectively reducing the LED light output deviation by controlling the driving current for each LED array chip.
종래의 LED프린터헤드의 전류제어 방식은 칩단위가 아닌 LED도트 각각에 대해 전류보정을 하여 줌으로써 각 도트마다 보정 등급 갯수만큼 저항이 필요하여, 실제회로의 제작시에 집적회로에 많은 저항을 넣어야 하는 어려움이 있었다.Conventional current control method of LED printer head requires current resistance for each LED dot instead of chip unit, so each resistor requires as many as the number of correction grades. There was a difficulty.
본 고안은 상기한 문제점을 해결하기 위하여 안출한 것으로, LED 제조 기술이 발달해감에 따라 동일한 칩내에서 각 LED도트사이의 발광 편차가 매우 작아졌다는 점에 착안하여 LED 어레이 칩단위로 전류를 보정하여 줌으로써 구동회로의 간략화로 인하여 구동 집적회로의 제작이 용이한 LED 프린터헤드의 전류제어 회로를 제공하는 것을 그 목적으로 한다.The present invention has been devised to solve the above problems, and as the LED manufacturing technology is developed, the light emission deviation between each LED dot within the same chip is very small, and the current is corrected by the LED array chip unit. It is an object of the present invention to provide a current control circuit of an LED printhead which is easy to manufacture a driving integrated circuit due to the simplification of the driving circuit.
고 밀도의 LED 어레이를 사용하여 광 프린터를 제작할 경우에 LED의 광출력 편차가 인쇄의 질에 영향을 주게된다. 그러나 동일한 칩내에서의 광 출력편차는 매우 작고 다른 칩사이의 편차가 큰점을 고려하여 칩단위로 LED의 구동전류를 FET (Field Effect Transistor)와 저항을 사용하여 전류 제어함으로써 제어회로의 간략화와 더불어 양질의 인쇄 및 고속인쇄가 가능하게 된다.When manufacturing an optical printer using a high density LED array, the variation in the light output of the LEDs affects the quality of the print. However, considering the fact that the optical output deviation in the same chip is very small and the deviation between the different chips is large, the driving current of the LED is controlled by using the FET (Field Effect Transistor) and the resistor in the unit of the chip. Printing and high speed printing are possible.
이하 첨부된 도면을 참조하여 본 고안을 상세히 설명한다.Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.
제1도는 LED프린터헤드를 블럭으로 도시한 것이다.1 is a block diagram of an LED printer head.
LED프린터헤드는 제1도에서와 같이 프린트할 직렬데이타를 쉬프트 레지스터에 저장하고 래치회로(2)에 의해 래치하여 스트로브 신호와 논리곱되어 LED를 각각 온/오프 제어한다. 이때 LED의 제조 특성상 발광량 편차가 나타나며 동일칩 내에서는 LED도트간의 편차는 작고 각기 다른칩 간의 편차는 크게 나타난다. 따라서 칩 LED칩 사이의 발광량 편차를 줄여야 양호한 인쇄의 질을 얻게된다.The LED printhead stores the serial data to be printed in the shift register as shown in FIG. 1 and latches it by the latch circuit 2 to logically multiply with the strobe signal to control the LEDs on and off, respectively. At this time, the variation of emission amount appears due to the manufacturing characteristics of the LED. Within the same chip, the variation between LED dots is small and the variation between different chips is large. Therefore, it is necessary to reduce the light emission variation between the chip LED chip to obtain a good print quality.
제2도는 본 고안의 LED 구동회로도로서, 공급전원(VDD)은 LED 어레이칩(1)에 공급되며 LED(1)의 각 LED는 전류 제한용 저항(2)과 직렬 연결되어 온/오프 제어용 FET(3)게 연결된다.2 is an LED driving circuit diagram of the present invention, the supply power supply (VDD) is supplied to the LED array chip (1) and each LED of the LED (1) is connected in series with the current limiting resistor (2) FET for on / off control (3) is connected.
한편 제1도의 데이타 축력(DO-DN)은 제2도의 FET(3)의 게이트로 각각 인가되어 데이타 축력이 하이레벨이면 FET(3)가 동작되어 LED를 발광시키고, 데이타 출력이 로우레벨이면 FET(3)가 동작되지 않아 LED를 발광시키지 못하게 된다. 또한 LED칩어레이(1)내의 각 LED에 흐르는 전류는 최종적으로 FET(4)에서 제어하게 된다.On the other hand, data storage force (DO-DN) of FIG. 1 is applied to the gate of FET 3 of FIG. (3) does not operate, and LEDs do not emit light. In addition, the current flowing through each LED in the LED chip array 1 is finally controlled by the FET 4.
제3도는 FET의 전류 전압 특성을 도시한 것으로, 드레인(D)에 흐르는 전류 ID는 VDS가 일정할 경우 게이트(G)와 소오스 사이의 전압 VGS가 커짐에 따라 증가한다.FIG. 3 shows the current voltage characteristics of the FET, and the current ID flowing in the drain D increases as the voltage VGS between the gate G and the source increases when the VDS is constant.
결국 전류ID는 LED에 흐르는 전류이므로 VGS를 제어하면 LED의 전류를 제어하게 되어 LED의 발광량을 조절할 수 있게된다.After all, since the current ID is the current flowing through the LED, controlling the VGS controls the current of the LED so that the amount of light emitted from the LED can be adjusted.
본 고안에서는 제2도와 같이 FET(4)의 VGS값을 분압저항(5, 6)에 의해 결정하도록 구성한다. 이를 수식으로 표현하면 VGS=VDDXR6/R6(R5+R6)이다.In the present invention, the VGS value of the FET 4 is determined by the voltage divider resistors 5 and 6 as shown in FIG. Expressed as an expression, VGS = VDDXR6 / R6 (R5 + R6).
이때, R5, R6은 각각 저항(5, 6)의 저항 값이다.At this time, R5 and R6 are resistance values of the resistors 5 and 6, respectively.
한편 전류제어용 FET(4)의 게이트단자는 모두 공통이므로 동일 칩내의 LED전류는 균일하게 제어되며, 제4도의 본 고안 전체 블럭도에서와 같이 LED어레이칩(1)별로 제어하면 LED어레이(1)간의 발광량 편차를 줄일 수 있다.On the other hand, since the gate terminals of the current control FET 4 are all common, the LED current in the same chip is controlled uniformly, and if the LED array chip 1 is controlled for each LED array chip as shown in the overall block diagram of FIG. The variation in the amount of emitted light can be reduced.
또한 LED 어레이칩(1)별로 전류를 제어해주는 분압 저항(5)은 LED 구동회로 (7)내부에 집어 넣어 집적회로화하고 분압저항(6)은 광량 측정후 적절히 조절하여 제4도와 같이 R1-Rm으로 연결하여 발광량의 편차를 보정한 LED 프린터헤드 전류제어 회로를 간단히 구성할 수 있다.In addition, the divided resistor (5) for controlling the current for each LED array chip (1) is integrated into the LED driving circuit (7) into an integrated circuit, and the divided resistor (6) is properly adjusted after measuring the amount of light. It is possible to easily configure the LED printhead current control circuit that compensates for variations in the amount of emitted light by connecting to Rm.
상기한 바와 같이 본 고안에 의하면 LED 어레이칩 간의 발광량 편차를 보정할 수 있는 전류제어 회로를 간단히 구성할 수 있으며, LED 프린터헤드 제작시에 구동 집적회로의 구성이 간단해져 제작상의 어려움을 제거할 수 있고, 또한 전류제어에 의해 LED의 발광량을 균일하게 함으로써 프린터의 속도가 시간 보정방식에 비해 개선되는 효과가 있다.As described above, according to the present invention, it is possible to easily configure a current control circuit capable of correcting the variation in the amount of light emission between the LED array chips, and to simplify the configuration of the driving integrated circuit when manufacturing the LED print head, thus eliminating manufacturing difficulties. In addition, by uniformizing the amount of light emitted from the LED by the current control, the speed of the printer is improved compared to the time correction method.
Claims (1)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
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KR2019890002031U KR930000109Y1 (en) | 1989-02-27 | 1989-02-27 | Led printer head electric control circuit |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
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KR2019890002031U KR930000109Y1 (en) | 1989-02-27 | 1989-02-27 | Led printer head electric control circuit |
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KR930000109Y1 true KR930000109Y1 (en) | 1993-01-09 |
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KR2019890002031U KR930000109Y1 (en) | 1989-02-27 | 1989-02-27 | Led printer head electric control circuit |
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1989
- 1989-02-27 KR KR2019890002031U patent/KR930000109Y1/en not_active IP Right Cessation
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