KR970007805B1 - Color level control circuit of television - Google Patents

Abstract

A circuit of controlling the color signal level of TV includes a main processor 10 for combining an input composite video signal, brightness signal and luminance signal, to generate a color signal, a comparison processor 20 configured of first, second and third operational amplifiers, and first, second and third resistors, the comparison processor 20 being constructed in such a manner that the voltage dropped at the first, second and third resistors is applied to the one side of the operational amplifiers and the potential value of the previous stage of the first, second and third resistors is applied to the other side of the operational amplifiers, to generate the voltage difference and send it to the output port of the first, second and third operational amplifiers, an A/D converter 30 for digitalizing the result value of the comparison processor 20, a microcomputer 40 for comparing the result value with a reference value and controlling the DC level of the luminance signal and brightness signal, and a D/A converter 50 for converting the signal automatically corrected by the microcomputer 40 into digital signals.

Description

Color signal level control circuit of TV

1 is a color signal level adjustment circuit diagram of a television of the present invention.

2 is a flowchart showing a process of comparing and adjusting color signal levels according to the present invention.

* Explanation of symbols for main parts of the drawings

10: main processing unit 20: comparison processing unit

30: A / D converter 40: micom

50: D / A converter 60: CRT

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color signal level control circuit of a television. In particular, the microcomputer detects a potential difference that has a fixed resistance to a color signal RGB output to a CRT and causes the microcomputer to compare the current value of the above potential difference with a previously stored reference set value. And a color signal level adjusting circuit of a television which keeps the potential level of the luminance signal constant at all times.

In general, the fading discoloration of the entire screen of the CRT due to the deterioration of the TV over time, the performance of the electronic components deteriorated due to the deterioration of electrical characteristics.

Accordingly, the video detection means and the R.G.B. R.G.B. outputted from the main processor including the color signal output means. Since the potential of the level of the contrast amplitude indicating brightness by changing the color signal into an incorrect signal becomes unstable, the problem of discoloration of the screen has no special countermeasures, which causes a problem of discomfort to the viewer.

Accordingly, the present invention has been made to solve the above problems, and at the same time the user's selection of the test key to perform the comparison logic logic of the microcomputer, R.G.B. Detects the potential level of the color signal output stage and outputs the potential difference of each color signal by means of the potential difference detection means of the associative amplifier, and compares the current value so that the DC potential of the brightness level and the luminance level is kept constant so that the color change of the CRT is always maintained. It is an object of the present invention to provide a color signal level adjusting circuit of a television which enables the phenomenon to be adjusted to an appropriate state.

Hereinafter, with reference to the accompanying drawings the present invention will be described in detail.

As shown in FIG. 1, the color signal level adjusting circuit of the television of the present invention comprises a main processing stage 10 for outputting a color signal by combining a luminance signal of a brightness signal with an input composite video signal, and the first to third operations. amplifier (OP1-OP3), the first to third resistors (R1-R3) is composed of the one end of the operational amplifier ^{(OP1-OP3) (OP1 _} -OP3 _) , the fixed resistance of the first to third A voltage dropped from the resistors R1-R3 is applied, and the first to third resistors R1, which are fixed resistors, are provided at the other end OP1 ⁺ -OP3 ^{+ of} the first to third operational amplifiers OP1-OP3. Comparative processing means 20 for outputting the voltage difference to the output terminals P1-P3 of the first to third operational amplifiers OP1-OP3 by applying the potential values at the front end of the -R3 respectively, and An A / D converter 30 for digitizing the result value from the comparison processing means 20, and a microcomputer for adjusting and outputting the DC level of the brightness signal and the brightness signal by comparing the result value with the reference set value ( 40) and a D / A converter 50 for analogizing the signal automatically corrected from the microcomputer 40.

Based on the above configuration, the operation and effects of the present invention will be described.

R.G.B. output from the main processing stage 10. The color signal is input to the beam output device of the CRT 60 and output as an image signal.

On the one side OP1 ^_ -OP3 ^_ of the first to third operational amplifiers OP1-OP3 of the comparison processing unit 20, a voltage dropped by the first to third resistors R1-R3, which are fixed resistors, is applied. The potential values of the front ends of the first to third resistors R1 to R3, which are fixed resistors, are applied to the other ends OP1 ^{+ to} OP3 ⁺ of the first to third operational amplifiers OP1 to OP3, respectively. The voltage difference is output from the output terminals P1-P3 of the first to third operational amplifiers OP1-OP3.

Wherein the first to third display when the output voltage of the operational amplifier (OP1-OP3) to the formula, V _P1 = V ⁺ -V _{OP1 OP1} ^-, V _P2 = V ⁺ -V _{OP2 OP2} ^-, _P3 V = V _OP3 ⁺ -V _OP3 ^_ respectively, and the above output voltages (V _P1 to V _P3 ) are continuously input in analog form, so that the A / D converter 30 has a digital value obtained from the comparison processing unit 20 above. The output is output to the microcomputer 40 by changing to.

The test key (TEST KEY), which is an external push button key connected to the microcomputer 40 above, is driven by the user's designation, and performs comparison and logic logic inside the microcomputer 40.

Comparison and logic logic are shown in the flowchart of FIG. 2, and it is determined whether the reference set values previously stored in the microcomputer 40 and the detected current value are the same, and the DC level of the constant brightness range and brightness range is always adjusted. And output.

Next, with reference to FIG. 2, the process of comparing microcom and logic logic will be described in detail.

First, the microcomputer 40 checks whether the state of the test key, which is the external push button key, is on (A11), and outputs the output terminals P1- of the first to third operational amplifiers OP1-OP3. The voltage of P3) is checked (A12), and the current of the checked voltage in the step A12 is calculated as a value of the first to third resistors R1-R3, which are fixed resistors (A13), and the above respective outputs. The current values obtained from the terminals P1-P3 are compared with the reference set values stored in the microcomputer 40 respectively (A14), and when the current value above and the previously stored reference set values are the same, the process returns to the step A11. When the current value above and the previously stored reference set value are different from each other, the sizes are compared (A15), and when the current value of each output terminal P1-P3 is larger than the previously stored reference set value, Reduce the magnitude of brightness level and brightness level (A16), and make sure that the current value of each output terminal (P1-P3) is smaller than the previously stored reference setting value. In this case, the magnitudes of the brightness level and the brightness level are raised to a level at a predetermined interval, and then outputted (A17).

As described above, the present invention is a combination of R.G.B. The DC potential level of the color signal is detected, and the potential difference of each color signal is generated by the potential difference detecting means of the first to third operational amplifiers OP1 to OP3 connected together with the voltage drop means of the fixed resistor. By converting the current value into the reference value of the microcomputer, the DC potential level of the luminance signal and the brightness signal can be kept constant so that discoloration of the screen can be prevented and the viewer can be provided with high quality service. There is an effect that can extend the life of TV and CRT.

Claims (1)

The main processing stage 10, the first to third operational amplifiers OP1 to OP3, and the first to third resistors R1 to E3, which combine the brightness signal and the brightness signal with the combined video signal and output the color signals. is, one end of the operational amplifier (OP1-OP3) configuration (OP1 -OP3 ^{_ _)} is the voltage drop across said first through third resistors (R1-R3), wherein the stator is applied, the first to The potentials of the front ends of the first to third resistors R1 to R3, which are fixed resistors, are respectively applied to the other ends OP1 ⁺ -OP3 ⁺ of the operational amplifiers OP1 to OP3, respectively. 3 to the output stages P1-P3 of the operational amplifiers OP1-OP3, the comparison processing means 20 for outputting the voltage difference, and the A / D converter 30 for digitizing the result value from the comparison processing means 20. ), The microcomputer 40 for adjusting and outputting the DC level of the luminance signal and the brightness signal by comparing the result value with the reference set value, and the D / A converter for analogizing the signal automatically corrected from the microcomputer 40. TV consisting of 50, a color signal level adjustment circuit.