KR930006234Y1 - Device for limiting beam current of tv - Google Patents
Device for limiting beam current of tv Download PDFInfo
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- KR930006234Y1 KR930006234Y1 KR2019880010027U KR880010027U KR930006234Y1 KR 930006234 Y1 KR930006234 Y1 KR 930006234Y1 KR 2019880010027 U KR2019880010027 U KR 2019880010027U KR 880010027 U KR880010027 U KR 880010027U KR 930006234 Y1 KR930006234 Y1 KR 930006234Y1
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- beam current
- ray tube
- cathode ray
- transistor
- cathode
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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
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N3/00—Scanning details of television systems; Combination thereof with generation of supply voltages
- H04N3/10—Scanning details of television systems; Combination thereof with generation of supply voltages by means not exclusively optical-mechanical
- H04N3/16—Scanning details of television systems; Combination thereof with generation of supply voltages by means not exclusively optical-mechanical by deflecting electron beam in cathode-ray tube, e.g. scanning corrections
- H04N3/18—Generation of supply voltages, in combination with electron beam deflecting
- H04N3/185—Maintaining dc voltage constant
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- Engineering & Computer Science (AREA)
- Multimedia (AREA)
- Signal Processing (AREA)
- Television Receiver Circuits (AREA)
Abstract
내용 없음.No content.
Description
제1도는 본 고안 장치의 회로도.1 is a circuit diagram of the device of the present invention.
제2도는 종래의 TV수상기의 빔전류 제한장치의 회로도.2 is a circuit diagram of a beam current limiter of a conventional TV receiver.
본 고안은 TV수상기의 빔전류 제한장치에 관한 것으로서 특히, 빔전류량을 검출하는 수단과 빔전류량을 제어하는 수단등을 구비하여 음극선관에 과대한 전류가 흘러 화면이 과도하게 밝아지는 현상을 방지하도록 한 TV수상기의 빔전류 제한 장치에 관한 것이다.The present invention relates to a beam current limiting device of a TV receiver, in particular, having a means for detecting the amount of beam current and a means for controlling the amount of beam current to prevent excessive brightening of the screen by excessive current flow to the cathode ray tube. A beam current limiting device of a TV receiver.
종래에는 제2도에 도시된 바와같이 전원(B2+)이 분배 저항(R3,R4)에 의해 베이스에 인가되는 트랜지스터(Q1)의 콜렉터가 음극선관(1)의 캐소드(K)에 연결됨과 동시에 저항(R6)을 통해 전원(B2+)이 인가되고, 전원(B+1)의 분배저항(R1,R2)에 의해 베이스에 인가됨과 동시에 영상신호(VIDEO)가 베이스에 인가되는 에미터 접지 트랜지스터(Q2)의 콜렉터가 트랜지스터(Q1)의 에미터에 연결되어 구성된 것으로서, 전원(B1+,B2+)이 분배저항(R1과 R2, R3와 R4)에 의해 트랜지스터(Q1,Q2)의 베이스 바이어스를 인가하고 있어 트랜지스터(Q1,Q2)가 동작 증폭회로로 동작하는 것이며, 도면중 미설명 부호 R5, R7은 저항이다.In the related art, as shown in FIG. 2 , the collector of the transistor Q1 to which the power source B 2+ is applied to the base by the distribution resistors R3 and R4 is connected to the cathode K of the cathode ray tube 1, and At the same time, and power (B 2 +) is applied via a resistor (R6), the emitter being soon as applied to the base, the video signal (vIDEO) is applied to the base at the same time by the distribution resistance (R1, R2) of the power source (B + 1) as the collector of the grounded transistor (Q2) is configured is connected to the emitter of the transistor (Q1), power source (B 1 +, B 2 + ) (Q transistor by the distribution resistance (R1 and R 2, R 3 and R4) The base bias of 1 , Q 2 is applied, and the transistors Q 1 and Q 2 operate as an operation amplifier circuit, and reference numerals R5 and R7 in the figure are resistors.
이와같이 트랜지스터(Q2)의 베이스에 영상신호(VIDEO)가 들어오게 되면 분배저항(R1,R2)에 의한 직류 바이어스 전압에 영상신호(VIDEO)가 실려 트랜지스터(Q1,Q2)를 통해 증폭되어 음극선과(1)의 캐소드(K)에 인가됨에 따라 음극선관(1)이 구동되어 영상신호를 재현시키고있으나 빔전류를 제어하는 장치가 있어 과대한 빔전류가 음극선관(1)에 흐르게 되면 화면이 과도하게 밝아져 X선의 방출량이 많아지는 단점이 있다.As such, when the video signal VIDEO enters the base of the transistor Q2, the video signal VIDEO is loaded on the DC bias voltages of the distribution resistors R1 and R2 and amplified through the transistors Q1 and Q2, and the cathode ray ( The cathode ray tube 1 is driven to be applied to the cathode K of 1) to reproduce an image signal. However, there is a device for controlling the beam current, so that when the excessive beam current flows through the cathode ray tube 1, the screen is excessively There is a disadvantage that the amount of emission of X-rays increases.
본 고안은 이와같은 종래의 단점을 해결하기 위하여 빔전류 검출수단과 빔전류 제어수단을 구비하여 플라이백 트랜스(FBT)의 2차코일에 유기되어 음극선관의 애노드에 공급되는 빔전류가 과대하게 공급되는 것을 방지하도록 한 TV수상기의 빔전로 제한장치를 제공하는 것을 목적으로 하며, 이하 첨부된 도면을 참조하면서 본 고안의 구성 및 작용효과를 상세히 설명하면 다음과 같다.The present invention is provided with a beam current detection means and a beam current control means to solve the above-mentioned disadvantages of the present invention is induced in the secondary coil of the flyback transformer (FBT) to supply excessively the beam current supplied to the anode of the cathode ray tube An object of the present invention is to provide a beam converter limiting device for preventing a TV receiver from being described below. Hereinafter, the configuration and operation effects of the present invention will be described in detail with reference to the accompanying drawings.
제1도를 참조하면 본 고안 장치는 플라이백 트랜스(FBT) 2차측에서 음극선관(1)의 애노드(A)로 흐르는 전류량을 검출하는 빔전류 검출수단(3)과, 빔전류랑 검출결과에 따라 영상신호(VIDEO) 증폭율을 제어하여 음극선관(1)의 캐소드(K)로 흐르는 전류량을 가변시키는 빔전류 제어수단(4)을 구비하여 구성된 것으로 상기 빔전류 검출수단(3)은 베이스에 플라이백 트랜스(FBT) 2차측 유기전압이 인가되는 에미터 접지 트랜지스터(Q3)와 바이어스 저항(R9,R10)으로 구성되고 상기 빔전류 제어수단(4)은 발광다이오드(LD1)와 수광트랜지스터(TD1)로 이루어진 광결합기(2)로 구성된 것이다.Referring to FIG. 1, the device of the present invention includes beam current detecting means 3 for detecting an amount of current flowing from the flyback transformer (FBT) secondary side to the anode A of the cathode ray tube 1, and the beam current and the detection result. And a beam current control means (4) for controlling the amount of current flowing to the cathode (K) of the cathode ray tube (1) by controlling the amplification ratio of the video signal (VIDEO). A flyback transformer (FBT) is composed of an emitter ground transistor (Q3) to which a secondary side induced voltage is applied and bias resistors (R9, R10). The beam current control means (4) comprises a light emitting diode (LD1) and a light receiving transistor (TD1). It consists of an optical coupler (2) consisting of.
이와같은 본 고안 장치의 작용효과는 먼저 트랜지스터(Q1,Q2)는 분재저항(R1과 R2,R3와 R4)에 의해 직류 바이어스 전압이 베이스에 인가됨에 따라 트랜지스터(Q1,Q2)증폭회로로 동작하고 있는 상태에서 영상신호(VIDEO)가 트랜지스터(Q2)의 베이스에 인가되면 직류 바이어스 전압에 실려 트랜지스터(Q1,Q2)에 의해 증폭되어 음극선관(1)의 캐소드(K)를 구동시켜 영상을 재현시키게 된다.As described above, the transistor Q1 and Q2 operate as transistor Q1 and Q2 amplifier circuits as a DC bias voltage is applied to the base by the bonsai resistors R1 and R2, R3 and R4. When the video signal VIDEO is applied to the base of the transistor Q2 in the state of being present, it is carried by the DC bias voltage and amplified by the transistors Q1 and Q2 to drive the cathode K of the cathode ray tube 1 to reproduce the image. do.
또한 FBT의 2차 코일에는 1차코일의 스위칭 작용 및 전(B3+)에 의해 고압이 유기되면 이 유기된 고압은 다이오드(D1)를 통해 반파 정류되어 음극선관(1)의 애노드(A)에 인가됨으로서 음극선관(1)의 캐소드(K)와 애노드(A)사이에 빔전류가 흐르게 된다.In addition, when the high pressure is induced by the switching action and pre-B3 + of the primary coil, the induced high pressure is half-wave rectified through the diode D1 and applied to the anode A of the cathode ray tube 1. As a result, a beam current flows between the cathode K and the anode A of the cathode ray tube 1.
따라서 회면이 정상적인 밝기일대에는 트랜지스터(Q3)의 베이스에 정극성 바이어스가 인가되므로서 트랜지스터(Q3)가 동작(온)됨에 따라 광결합기(2)에는 전원(B1+)이 인가되지 않게 된다.Therefore, since the positive bias is applied to the base of the transistor Q3 at the time when the brightness of the normal surface is normal, the power supply B1 + is not applied to the optical coupler 2 as the transistor Q3 is operated (on).
이때 갑자기 과대한 빔전류가 음극선관(1)에 흘러 음극선관(1)이 밝아지게 되면, 트랜지스터(Q3)의 베이스에 인가되는 바이어스 전압이 컷인(Cut in)전압이하로 떨어지게 되어 트랜지스터(Q3)를 오프시키게 된다.At this time, when the excessive beam current suddenly flows through the cathode ray tube 1 and the cathode ray tube 1 becomes bright, the bias voltage applied to the base of the transistor Q3 falls below the cut in voltage and thus the transistor Q3. Will be turned off.
따라서 전원(B1+)이 저항(R10)을 통해 광결합기(2)의 발광다이오드(LD1)에 공급됨에 따라 광결합기(2)의 수광트랜지스터(TD1)가 동작하게 된다.Therefore, as the power supply B1 + is supplied to the light emitting diode LD1 of the optical coupler 2 through the resistor R10, the light receiving transistor TD1 of the optical coupler 2 is operated.
이에따라 트랜지스터(Q2)의 베이스에 인가되는 바이어스 전압이 낮아지게 되므로 트랜지스터(Q1,Q2)의 증폭율이 적어짐에 따라 음극선관(1)의 캐소드(K)에 흐르는 전류가 적어져 음극선관(1)의 애노드(A)와 캐소드(K)에 흐르는 빔전류를 줄이게 된다.Accordingly, since the bias voltage applied to the base of the transistor Q2 is lowered, the amplification rate of the transistors Q1 and Q2 decreases, so that the current flowing in the cathode K of the cathode ray tube 1 decreases, so that the cathode ray tube 1 The beam current flowing through the anode A and the cathode K is reduced.
또한 일정한 빔전류가 음극선관(1)에 흐르게 되면 다시 트랜지스터(Q3)를 온시켜 광결합기(2)가 동작되지 않게 하므로서 정상적인 화면을 재현시키게 된다.In addition, when a constant beam current flows through the cathode ray tube 1, the transistor Q3 is turned on again so that the optical coupler 2 is not operated to reproduce a normal screen.
본 고안은 이와같이 음극선관의 캐소드와 애노드 사이에 흐르는 빔전류를 제한시켜 화면이 과도하게 밝아지는 현상을 방지하고 또한 과대한 빔전류에 의한 X선 방출을 방지한다.The present invention thus restricts the beam current flowing between the cathode and the anode of the cathode ray tube to prevent the screen from being excessively bright and also prevents X-ray emission due to excessive beam current.
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Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR2019880010027U KR930006234Y1 (en) | 1988-06-28 | 1988-06-28 | Device for limiting beam current of tv |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR2019880010027U KR930006234Y1 (en) | 1988-06-28 | 1988-06-28 | Device for limiting beam current of tv |
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| Publication Number | Publication Date |
|---|---|
| KR900001857U KR900001857U (en) | 1990-01-19 |
| KR930006234Y1 true KR930006234Y1 (en) | 1993-09-15 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| KR2019880010027U KR930006234Y1 (en) | 1988-06-28 | 1988-06-28 | Device for limiting beam current of tv |
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| KR (1) | KR930006234Y1 (en) |
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1988
- 1988-06-28 KR KR2019880010027U patent/KR930006234Y1/en not_active IP Right Cessation
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| Publication number | Publication date |
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| KR900001857U (en) | 1990-01-19 |
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