KR970006986Y1 - Black level correcting circuit - Google Patents

Black level correcting circuit Download PDF

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Publication number
KR970006986Y1
KR970006986Y1 KR92021074U KR920021074U KR970006986Y1 KR 970006986 Y1 KR970006986 Y1 KR 970006986Y1 KR 92021074 U KR92021074 U KR 92021074U KR 920021074 U KR920021074 U KR 920021074U KR 970006986 Y1 KR970006986 Y1 KR 970006986Y1
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South Korea
Prior art keywords
black level
level correction
current
driving transistor
voltage
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KR92021074U
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Korean (ko)
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KR940011352U (en
Inventor
차윤식
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배순훈
대우전자 주식회사
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Priority to KR92021074U priority Critical patent/KR970006986Y1/en
Publication of KR940011352U publication Critical patent/KR940011352U/en
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Publication of KR970006986Y1 publication Critical patent/KR970006986Y1/en

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00—Details of television systems
    • H04N5/14—Picture signal circuitry for video frequency region
    • H04N5/16—Circuitry for reinsertion of dc and slowly varying components of signal; Circuitry for preservation of black or white level
    • H04N5/165—Circuitry for reinsertion of dc and slowly varying components of signal; Circuitry for preservation of black or white level to maintain the black level constant
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/10—Details of semiconductor or other solid state devices to be connected
    • H01L2924/11—Device type
    • H01L2924/12—Passive devices, e.g. 2 terminal devices
    • H01L2924/1203—Rectifying Diode
    • H01L2924/12035—Zener diode

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  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Picture Signal Circuits (AREA)

Abstract

내용없음No content

Description

텔레비젼 수상기의 흑레벨 보정회로Black level correction circuit of TV receiver

제 1 도는 본 고안에 따른 텔레비젼 수상기의 흑레벨 보정회로의 회로도.1 is a circuit diagram of a black level correction circuit of a television receiver according to the present invention.

*도면의 주요부분에 대한 부호의 설명** Description of the symbols for the main parts of the drawings *

R1-R9 : 저항D1-D2 : 다이오드R1-R9: Resistor D1-D2: Diode

ZD1 : 제너다이오드C1 : 콘덴서ZD1: Zener Diode C1: Capacitor

Q1 : 흑레벨 보정용 구동트랜지스터Q1: Drive transistor for black level correction

VR : 흑레벨 가변 저항10 : 흑레벨 보정용 안정부VR: Black level variable resistor 10: Black level correction part

20 : 흑레벨 보정용 구동부20: drive unit for black level correction

본 고안은 TV의 흑레벨 보정회로에 관한 것으로, 특히 TV화면의 밝기가 전류의 변동에 따라 변동하는 흑레벨 변화를 보정할 수 있도록 한 텔레비젼 수상기의 흑레벨 보정회로에 관한 것이다.The present invention relates to a black level correction circuit of a TV, and more particularly, to a black level correction circuit of a television receiver which enables to correct a black level change in which the brightness of a TV screen fluctuates with a change in current.

일반적으로 TV의 흑레벨은 CRT(Cathode-Ray Tube)에서 밝기로 나타내는 명암중 화면상에 전혀 나타나지 않는 레벨 포인터로서, 종래는 TV 화면의 밝기가 비임 전류의 변동에 따라 흑레벨 변화를 보정해주지 못해, 화면의 명암을 충분하게 재생해 주지 못하는 단점이 있었다.In general, the black level of a TV is a level pointer that does not appear at all on the screen of contrast represented by brightness in a CRT (Cathode-Ray Tube). Conventionally, the brightness of a TV screen cannot compensate for a change in the black level due to a change in beam current. However, there was a drawback in not being able to reproduce the contrast of the screen sufficiently.

본 고안은 상기의 단점을 개선하기 위한 것으로서, TV의 전류에 따라 변화하는 흑레벨을 보정할 수 있는 흑레벨 보정용 구동부와 흑레벨 보정용 안정부를 이용하여 좋은 화질을 구현할 수 있는 텔레비젼 수상기의 흑레벨 보정회로를 제공하는 데 그 목적이 있다.The present invention is to improve the above-mentioned disadvantages, the black level of the television receiver capable of realizing good image quality using the black level correction drive unit and the black level correction stabilizer that can correct the black level changes according to the current of the TV. The purpose is to provide a correction circuit.

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

도면은 본 고안의 텔레비젼 수상기의 흑레벨 보정회로의 회로도로써, 텔레비젼 수상기에 있어서, 정전압 제너다이오드에 흐르는 전류에 의해 흑레벨 보정용 구동 트랜지스터를 제어하는 흑레벨 보정용 구동부와, 분압저항에 의해 분압된 전압에 의해 상기 흑레벨 보정용 구동트랜지스터를 안정화시키는 흑레벨 보정용 안정부로 구성된다.Fig. 1 is a circuit diagram of a black level correction circuit of a television receiver according to the present invention, which includes a black level correction driver for controlling a black level correction driving transistor by a current flowing through a constant voltage zener diode, and a voltage divided by a voltage divider resistor. And a black level correction stabilizer for stabilizing the black level correction driving transistor.

이때, 흑레벨 보정용 안정부(10)은 분압저항(R8, R9)와 콘덴서(C1)으로 구성되고, 흑레벨 보정용 구동부(20)은 저항(R4-R7), 정전압 제너다이오드(ZD1)과 다이오드(D2)로 구성된다.At this time, the black level correction stabilizer 10 includes voltage dividers R8 and R9 and a capacitor C1, and the black level correction driver 20 includes resistors R4-R7, a constant voltage zener diode ZD1, and a diode. It consists of (D2).

본 고안의 작용 효과를 상세히 설명하면 다음과 같다.Referring to the effect of the present invention in detail as follows.

B+전원(123V)으로부터 저항(R1)을 통해 인가된 전류(11)는 공지부로부터 출력된 신호와 함께 플라이백 트랜스(Fly-Back Transformer : FBT)측으로 출력되는 바, FBT측으로 출력되는 전류(Ib)가 증가하면 전류(I1)은 역전류 방지용 다이오드(D1)에 의해 흑레벨 제어부측으로 흐르지 못하고, 흑레벨 보정용 구동부(20)의 저항(R4)과 정전압 제너다이오드(ZD1)측으로 감소된 전류(I2)가 흐르게 된다.The current 11 applied from the B + power supply 123V through the resistor R1 is output to the fly-back transformer (FBT) side together with the signal output from the known part, and thus the current Ib is output to the FBT side. ) Increases, the current I2 does not flow to the black level controller side by the reverse current prevention diode D1, and the current I2 decreased to the resistance R4 and the constant voltage zener diode ZD1 side of the black level correction driver 20. ) Flows.

따라서, 전압 법칙(V=IR)에 의해 전압이 떨어진 노드점(C)의 바이어스는 흑레벨 보정용 구동트랜지스터(Q1)의 베이스단에 인가되고, 상기의 베이스단 전류가 흑레벨 보정용 구동 트랜지스터(Q1)의 콜렉터 전류와 함께 감소되어 노드점(D)의 바이어스는 상승하게 된다.Accordingly, the bias of the node point C at which the voltage is dropped by the voltage law (V = IR) is applied to the base end of the black level correction driving transistor Q1, and the base end current is applied to the black level correction driving transistor Q1. Decreases along with the collector current, so that the bias of the node point D rises.

또한, 노드점(C) 바이어스가 흑레벨 보정용 구동트랜지서터(Q1)의 구동전압 이하로 베이스단에 가해지면, 흑레벨 보정용 구동트랜지스터(Q1)는 컷-오프되고, 노드점(D) 바이어스는 흑레벨 보정용 안정부(10)의 저항(R8, R9)를 통해 분할된 전압으로 포화된다.Further, when the node point C bias is applied to the base end below the drive voltage of the black level correction driving transistor Q1, the black level correction driving transistor Q1 is cut off and the node point D bias is applied. Is saturated with the divided voltage through the resistors R8 and R9 of the black level correction stabilizer 10.

따라서, 노드점(D)의 전위상승에 따른 전류(I4)는 감소하고, 결과적으로 노드점(B)의 전위를 상승시킨다.Therefore, the current I4 according to the potential rise of the node point D decreases, and as a result, the potential of the node point B is raised.

이때, 흑레벨 가변저항(VR)을 이용하여 노드점(B)의 기준 전위값을 설정하도록 한다.At this time, the reference potential value of the node point B is set using the black level variable resistor VR.

상기의 전류(Ib)가 증가해서 흑레벨 보정용 구동트랜지스터(Q1)를 컷-오프할 때, 노드점(D) 전위의 포화에 의해 노드점(B)의 전위가 상승하여 안정되는 것이다.When the current Ib increases and the black level correction driving transistor Q1 is cut off, the potential of the node point B rises and stabilizes due to the saturation of the node point D potential.

결과적으로 전류(Ib)가 더욱 증가하면, 흑레벨 제어부로부터 전류(I3)가 역전류 방지용 다이오드(D1)와 저항(R3)을 통해 흐르게 되어, 노드점(B)의 전위가 낮아지게 되는 것이다.As a result, when the current Ib further increases, the current I3 flows from the black level controller through the reverse current prevention diode D1 and the resistor R3, so that the potential of the node point B is lowered.

이와 같이 본 고안은 TV화면은 밝기를 나타내는 흑레벨 설정점보다 낮은 전류가 흐를 때는 낮게 하고, 반대로 설정점보다 높은 전류가 흐를 때는 높게 하여, 어두운 화면에서는 흑레벨을 낮추고, 밝은 화면에서 흑레벨을 올려 화면의 화질을 더욱 좋게 하는 효과가 있다.As such, the present invention lowers the TV screen when the current lower than the black level set point indicating brightness is high, and conversely, increases the current when the current higher than the set point is higher, lowers the black level on a dark screen, and sets the black level on a bright screen. It has the effect of improving the picture quality even better.

Claims (1)

텔레비젼 수상기의 있어서,In the television receiver, 정전압 제너다이오드(ZD1)에 흐르는 전류에 의해 흑레벨 보정용 구동 트랜지스터(Q1)를 제어하는 흑레벨보정용구동부(20)와,A black level correction driver 20 for controlling the black level correction driving transistor Q1 by a current flowing in the constant voltage zener diode ZD1, 분압저항(R8, R9)에 의해 분압된 전압에 의해 상기 흑레벨 보정용 구동트랜지스터(Q1)를 안정화시키는 흑레벨 보정용 안정부(10)로 구성됨을 특징으로 하는 텔레비젼 수상기의 흑레벨 보정회로.And a black level correction stabilizer (10) for stabilizing the black level correction driving transistor (Q1) by the voltage divided by the voltage divider (R8, R9).
KR92021074U 1992-10-30 1992-10-30 Black level correcting circuit KR970006986Y1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
KR92021074U KR970006986Y1 (en) 1992-10-30 1992-10-30 Black level correcting circuit

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Application Number Priority Date Filing Date Title
KR92021074U KR970006986Y1 (en) 1992-10-30 1992-10-30 Black level correcting circuit

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KR940011352U KR940011352U (en) 1994-05-27
KR970006986Y1 true KR970006986Y1 (en) 1997-07-11

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KR92021074U KR970006986Y1 (en) 1992-10-30 1992-10-30 Black level correcting circuit

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