KR920007749Y1 - Automatic bright limiting circuit of tv - Google Patents
Automatic bright limiting circuit of tv Download PDFInfo
- Publication number
- KR920007749Y1 KR920007749Y1 KR2019890007778U KR890007778U KR920007749Y1 KR 920007749 Y1 KR920007749 Y1 KR 920007749Y1 KR 2019890007778 U KR2019890007778 U KR 2019890007778U KR 890007778 U KR890007778 U KR 890007778U KR 920007749 Y1 KR920007749 Y1 KR 920007749Y1
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- South Korea
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- voltage
- overcurrent
- resistor
- limiting circuit
- unit
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N5/00—Details of television systems
- H04N5/44—Receiver circuitry for the reception of television signals according to analogue transmission standards
- H04N5/57—Control of contrast or brightness
- H04N5/59—Control of contrast or brightness in dependence upon beam current of cathode ray tube
Abstract
내용 없음.No content.
Description
제1도는 본 고안에 따른 자동휘도 제한회로도.1 is an automatic luminance limiting circuit diagram according to the present invention.
*도면의 주요부분에 대한 부호의 설명* Explanation of symbols for main parts of the drawings
10 : 수상관 11 : 애노우드10: Winner 11: 11: Anwood
20 : 과전류검출부 30 : 스위칭부20: overcurrent detection unit 30: switching unit
40 : 전압분압수단 50 : 영상증폭부40: voltage divider means 50: video amplifier
본 고안은 자동휘도 제한회로(Automatic Bright Limiting; ABL)에 관한 것으로서, 보다 상세하게는 수상관의 애노우드에 인가되는 전류변화에 따라 영상증폭부의 영상증폭도를 콘트롤하여 수상관의 비임 전류를 제한하는 자동휘도 제한회로에 관한 것이다.The present invention relates to an automatic brightness limiting circuit (ABL), and more particularly, to control the beam amplification of the water pipe by controlling the video amplification of the video amplification unit according to the current change applied to the anode of the water pipe. It relates to an automatic luminance limiting circuit.
일반적으로, 칼라 TV수신기에서는 영상신호의 직류분을 전송하기 위해서 영상증폭부를 직경합하고 있기때문에 휘도 콘트라스트 조절에 의하여 수상관의 비임 전류가 너무 많이 흘러서 수평출력 트랜지스터등이 파괴되는 경우가 있다. 이를 방지하기 위하여 칼라 TV수신에서는 수상관의 비임 전류가 지정된 한도 이상으로 흐르려고하면 즉시 자동적으로 제어하여 지정된 한도상 흐르지 못하도록 해주는 수단이 요구되었다.In general, in a color TV receiver, because the video amplifier unit is combined to transmit the DC portion of the video signal, the beam current of the water pipe flows too much due to the brightness contrast adjustment, which may cause the horizontal output transistor or the like to be destroyed. In order to prevent this, color TV reception required a means for controlling the beam current of the receiving tube to flow more than a specified limit immediately so as not to flow over the specified limit.
따라서 본 고안은 상기와 같은 점에 부응하고자 안출한 것으로서 비임전류가 지정된 한도치 이상으로 흐르지 않도록 제어하는 자동휘도 제한회로를 제공하는데 그 목적을 두고 있다.Therefore, the present invention has been made to meet the above-mentioned point, and an object thereof is to provide an automatic luminance limiting circuit for controlling the beam current not to flow over a specified limit value.
상기의 목적을 달성하기 위하여 본 고안은 수상관(10)의 애노우드단자(11)에 고전압을 인가하는 플라백트랜스(FBT)에 접속되어 상기 애노우드단자(11)에 인가되는 전압에 따른 전류변동이 소정치이상인 가를 검출하는 과전류검출부(20) ; 상기 과전류검출부(20)에서의 검출 결과에 따라 스위칭동작을 하는 스위칭부(30) ; 및 상기 과전류검출부(20)로 부터 과전류의 검출에 의하여 상기 스위칭부(30)가 오프될때 소정의 전압을 분압하여 분압된 전압을 영상증폭부(50)에 공급하기 위한 전압분배수단(40)을 포함하여 단자전압의 변동에 따라 영상증폭도를 제어하는 것을 특징으로 한다.In order to achieve the above object, the present invention is connected to a flyback transformer (FBT) for applying a high voltage to the anode terminal 11 of the water pipe 10 and the current according to the voltage applied to the anode terminal 11. An overcurrent detection unit 20 for detecting whether the variation is more than a predetermined value; A switching unit 30 which performs a switching operation according to the detection result of the overcurrent detecting unit 20; And a voltage divider 40 for supplying the divided voltage to the image amplifier 50 by dividing a predetermined voltage when the switching unit 30 is turned off by the detection of the overcurrent from the overcurrent detector 20. And controlling the image amplification according to the change of the terminal voltage.
이하, 본 고안을 예시된 도면을 참조하여 상세히 설명한다.Hereinafter, the present invention will be described in detail with reference to the illustrated drawings.
제1도에 도시된 도면은 본 고안에 따른 자동휘도 제한회로도로서, 과전류검출부(20)는 수상관(10)의 애노우드 단자(11)에 고전압을 공급하는 플라이백 트랜스(FBT)의 2차측 권선 일측에 연결되어 상기 애노우드 단자(11)에 공급되는 전류가 일정치 이상일때 후술하는 스위칭부(30)를 제어하도록 캐패시터(C1) 및 다이오드(D2)로 구성된 저역필터를 통한 전류에 의하여 전압강하가 결정되는 저항(R1), 저항(R2, R3)에 의해서 바이어스접압이 결정되고 상기 저항(R1)에 의한 전압강하에 따라 스위칭 동작점이 결정되는 트랜지스터(TR) 및 캐패시터(C2)로 구성된다.1 is an automatic luminance limiting circuit diagram according to the present invention, and the overcurrent detection unit 20 is a secondary side of a flyback transformer (FBT) for supplying a high voltage to the anode terminal 11 of the water pipe 10. Connected to one side of the winding, when the current supplied to the anode terminal 11 is a predetermined value or more by a current through a low pass filter composed of a capacitor (C1) and a diode (D2) to control the switching unit 30 to be described later It is composed of a transistor TR and a capacitor C2 in which a bias contact voltage is determined by the resistor R1 and the resistors R2 and R3 in which the drop is determined, and the switching operation point is determined according to the voltage drop by the resistor R1. .
전압분압수단(40)은 저항(R5, R6) 및 콘트라스트 조정용 가변저항(VR)을 직렬연결하여 전원전압(Vcc2)을 분압하여 분압된 전원전압으로 영상증폭부(50)의 영상증폭도를 콘트롤하도록 구성된다.The voltage dividing means 40 connects the resistors R5 and R6 and the variable resistance VR for contrast adjustment in series to divide the power supply voltage Vcc2 to control the image amplification of the image amplification unit 50 with the divided power supply voltage. It is composed.
스위칭부(30)는 상기한 과전류 검출부(20) 내의 트랜지스터(TR)의 에미터단자와 전압분압수단(40)의 저항(R5)과 가변저항(VR)사이의 일점에 다이오드(D3)를 역방향으로 연결하여 구성된다.The switching unit 30 reverses the diode D3 to one point between the emitter terminal of the transistor TR in the overcurrent detecting unit 20 and the resistor R5 and the variable resistor VR of the voltage divider 40. It is composed by connecting.
본 실시예의 자동휘도 제한회로는 상기한 구성을 가지며 그 동작관계는 다음과 같다.The automatic luminance limiting circuit of this embodiment has the above configuration and its operation relationship is as follows.
수상관(10)의 애노우드단자(11)에 인가되는 전압이 일정치 이상일때 과전류검출부(20)내의 저항(R1)에 의한 전업강하가 크기때문에 트랜지스터(TR)의 베이스단자에 인가되는 전압은 콜렉터단자에 공급되어 있는 전압보다 크기 때문에 "온"된다. 트랜지스터(TR)가 "온"되면 스위칭부(30)인 다이오드(D3)의 캐소우드 단자, 즉 Vx점의 전압은 저항(R5)을 통한 전원전압(Vcc2)이 인가된 Vy점의 전압보다 크기때문에 다이오드(D3)는 "오프"상태가 된다.When the voltage applied to the anode terminal 11 of the water pipe 10 is greater than or equal to a predetermined value, the voltage applied to the base terminal of the transistor TR is large because the voltage drop due to the resistance R1 in the overcurrent detecting unit 20 is large. It is "on" because it is greater than the voltage supplied to the collector terminal. When the transistor TR is "on", the cathode terminal of the diode D3, that is, the switching unit 30, that is, the voltage at the point V x is the voltage at the point V y to which the power supply voltage Vcc2 is applied through the resistor R5. Because of its larger size, the diode D3 is turned off.
따라서 영상증폭부(50)에는 저항(R5)과 가변저항(VR) 및 저항(R6)에 의해서 전원전압(Vcc2)을 분압하여 분압된 전압이 인가되어 수상관(10)의 캐소우드전압이 올라가는 결과 애노우드단자(11)에 공급되는 전류는 감소하게되어 휘도를 자동으로 제어한다.Therefore, the divided voltage is applied to the image amplifier 50 by dividing the power supply voltage Vcc2 by the resistor R5, the variable resistor VR and the resistor R6, so that the cathode voltage of the water pipe 10 is increased. As a result, the current supplied to the anode terminal 11 is reduced to automatically control the brightness.
상술한 바와 같이 작동하는 본 고안은 자동휘도 제한회로의 플라이백 트랜스에서 공급되는 수상관의 애노우드 단자전압의 변동에 따라 다이오드의 스위칭특성을 이용하여 영상증폭도를 콘트롤하므로 비용절감 및 동작기능 향상을 도모하게한다.The present invention, which operates as described above, reduces the cost and improves the operation function by controlling the image amplification using the switching characteristic of the diode according to the variation of the anode terminal voltage of the water pipe supplied from the flyback transformer of the automatic luminance limiting circuit. To plan.
Claims (3)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR2019890007778U KR920007749Y1 (en) | 1989-06-03 | 1989-06-03 | Automatic bright limiting circuit of tv |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR2019890007778U KR920007749Y1 (en) | 1989-06-03 | 1989-06-03 | Automatic bright limiting circuit of tv |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| KR910001874U KR910001874U (en) | 1991-01-25 |
| KR920007749Y1 true KR920007749Y1 (en) | 1992-10-17 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| KR2019890007778U KR920007749Y1 (en) | 1989-06-03 | 1989-06-03 | Automatic bright limiting circuit of tv |
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| Country | Link |
|---|---|
| KR (1) | KR920007749Y1 (en) |
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1989
- 1989-06-03 KR KR2019890007778U patent/KR920007749Y1/en not_active IP Right Cessation
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| Publication number | Publication date |
|---|---|
| KR910001874U (en) | 1991-01-25 |
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