KR19990058436A - Contrast Gain Compensator in Large Monitors - Google Patents

Abstract

The present invention relates to a contrast gain compensation device in a large monitor, and in particular, a buffer unit 10 for inverting and outputting the polarity of the signal supplied from the preamplifier; A first buffer 21 for inverting and outputting the signal supplied from the buffer unit 10, a first current amplifier 22 for adjusting current amplification by the operation of the first buffer 21, A first CRT driver (20) comprising a first voltage amplifier (23) for adjusting voltage amplification by the operation of the first current amplifier (22) and a first circuit protection unit (24) for protecting the circuit; The signal supplied through the crosstalk / distortion prevention part 31 and the crosstalk / distortion prevention part 31 which prevent and output crosstalk and distortion of the video signal output by amplifying the first signal by the first CRT driver 20 are output. In operation of the second buffer 32 to invert and output, the second current amplifier 33 to adjust the current amplification by the operation of the second buffer 32, and the second current amplifier 33 And a second CRT driver 30 comprising a second voltage amplifier 34 for adjusting the voltage amplification and a second circuit protection unit 35 for protecting the circuit. By compensating the contrast gain required for large monitors by outputting two stages of CRT drivers to the cathode of the CRT, they can be used together with ordinary monitors and large monitors, and at the same time, the picture quality of large monitors can be clearly realized.

Description

Contrast Gain Compensator in Large Monitors

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contrast gain compensator in a large monitor, and more particularly, to amplify a video signal supplied to a cathode ray tube (hereinafter referred to as a CRT) in two stages with a first and second CRT drivers and sufficiently A contrast gain compensation device in a large monitor that wants to improve the contrast gain by supplying a video signal to the cathode of the CRT.

In general, the conventional CRT driver circuit used for a monitor of 21 inches or less is configured to single stage amplification, and the CRT driver which receives a video signal from a preamplifier (preamplifier) has a single stage amplification of the input video signal. It was then operated to feed the video signal to the cathode of the CRT.

However, if the CRT driver circuit used for 21-inch or smaller monitors is applied to the CRT cathode of a large monitor (29-inch or larger), the contrast gain of the CRT cathode of a large monitor cannot be secured. There was an unclear problem.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems. In particular, the first CRT driver and the second CRT are designed to compensate for the contrast gain required for the large monitor so that the image quality of the large monitor can be maintained clearly. The present invention provides a contrast gain compensation device for a large monitor by amplifying two stages with a driver to compensate and output sufficient contrast gain required for a CRT cathode of a large monitor.

In order to achieve the above object, a contrast gain compensation device in a large-scale monitor according to the present invention includes a buffer unit for inverting and outputting a polarity of a video signal supplied from a preamplifier; A first buffer connected to a signal output terminal of the buffer unit, the first buffer for inverting and outputting a video signal inverted and supplied from the buffer unit, and a first current amplifier for switching by adjusting the amplification by operation of the first buffer; A first circuit, which is connected to a signal output terminal of the first voltage amplifier and a first voltage amplifier which operates as a cascode amplifier and adjusts voltage amplification by an operation of the first current amplifier, and protects the circuit. A first CRT driver comprising a protection unit; A crosstalk / distortion prevention unit for preventing crosstalk and distortion of the video signal output by amplifying the first CRT driver and outputting the second signal; a second buffer for inverting and outputting the video signal supplied through the crosstalk / distortion prevention unit; A second current amplifier for switching by an operation of the second buffer to adjust current amplification; a second voltage amplifier for operating a cascode amplifier to adjust voltage amplification by operation of the second current amplifier; And a second CRT driver connected to the signal output terminal of the second voltage amplifying part and configured to protect the circuit.

1 is a schematic diagram of a contrast gain compensation device in a large monitor of the present invention;

It is a circuit diagram.

<Description of the symbols for the main parts of the drawings>

10: buffer unit 20: first CRT driver

21: first buffer 22: first current amplifier

23: first voltage amplifier 24: first circuit protection unit

30: second CRT driver 31: crosstalk / distortion prevention unit

32: second buffer 33: second current amplifier

34: second voltage amplifier 35: second circuit protection unit

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings, for example, according to an embodiment of the present invention.

<Example>

As shown in FIG. 1, when the first CRT driver 20 performs single stage amplification, the first transistor Q1 of the buffer unit 10 supplied with the video signal output from the preamplifier is supplied. The video signal is inverted and supplied to the second transistor Q2 of the first buffer 21. In the second transistor Q2 of the first buffer 21, the first transistor Q1 of the buffer unit 10 is provided. Inverts the supplied video signal again and supplies the same to the third transistor Q3 of the first current amplifier 22. The third transistor Q3 of the first current amplifier 22 supplies the first signal. The current amplification is adjusted by the operation of the second transistor Q2 of the buffer 21 to be supplied to the fourth transistor Q4 and the fifth transistor Q5 of the first voltage amplifier 23, and the first voltage is supplied. In the amplifier 23, the fourth transistor Q4, the fifth transistor Q5, the second capacitor C2, and the first and second diodes. Is operated as a cascode amplifier by means of resistors D1 and D2 and resistors R10 and R11 to adjust voltage amplification. In the first circuit protection section 24, a third diode D3 and a fourth diode D4 are used. ) And a twelfth resistor R12 to operate stably to protect the circuit.

In addition, the buffer unit 10 includes a first resistor R1, a second resistor R2, and a first transistor Q1, and the first buffer 21 includes a third resistor R3, The fourth resistor R4, the fifth resistor R5, the first capacitor C1, and the second transistor Q2 are configured. The first voltage amplifier 23 includes resistors R6, R7, and R8. R9, R10, and R11, a first diode D1, a second diode D2, a second capacitor C2, a fourth transistor Q4, and a fifth transistor Q5. This embodiment is constituted.

In addition, referring to the configuration of the second CRT driver 30 to which the video signal amplified by the first stage of the first CRT driver 20 is supplied, the third condenser C3 of the crosstalk / distortion prevention unit 31 and In the fourth condenser C4 and the fifth diode D5, crosstalk and distortion of the video signal supplied from the first CRT driver 20 are prevented and supplied to the sixth transistor Q6 of the second buffer 32. The sixth transistor Q6 of the second buffer 32 inverts the supplied video signal and supplies the inverted video signal to the seventh transistor Q7 of the second current amplifier 33. In the seventh transistor Q7 of the third transistor 33, the current amplification is adjusted by the operation of the sixth transistor Q6 of the second buffer 32 to control the eighth transistor Q8 and the eighth transistor of the second voltage amplifier 34. The ninth transistor Q9 is supplied to the ninth transistor Q9, and the second voltage amplifier 34 has an eighth transistor Q8, a ninth transistor Q9, The sixth capacitor C6, the sixth and seventh diodes D6 and D7, and the 20th and 21st resistors R20 and R21 operate as cascode amplifiers to adjust voltage amplification, and the second circuit protection section 35 The eighth diode (D8), the ninth diode (D9), the 22nd resistor (R22), the reactance (L) to protect the circuit, and the first CRT driver 20 and the first 2 is operated by the video signal amplified by the CRT driver 30 to constitute the present embodiment.

In addition, the second buffer 32 includes a thirteenth resistor R13, a fourteenth resistor R14, a fifteenth resistor R15, a fifth capacitor C5, and a sixth transistor Q6. The second voltage amplifier 34 includes resistors R16, R17, R18, R19, R20, and R21, a sixth diode D6, a seventh diode D7, and an eighth transistor Q8. And a ninth transistor Q9 to constitute the present embodiment.

Hereinafter, the operation of the present embodiment configured as described above will be described in detail with reference to the accompanying drawings.

As shown in FIG. 1, the buffer unit 10 including the first resistor R1, the second resistor R2, and the first transistor Q1 is a conventional inverting amplifier, and is a video supplied from a preamplifier. The signal is supplied and inverted, and the inverted signal is supplied to the base of the second transistor Q2 configured in the first buffer 21 of the first CRT driver 20 for single stage amplification. In this case, the second transistor Q2 of the first buffer 21 inverts the signal supplied from the buffer unit 10 again, and outputs a signal, and then generates a third transistor of the first current amplifier 22. In Q3), the voltage gain is close to 1 or 1 with a base common amplifier, and the current amplification is adjusted by the operation of the first buffer 21. In the first voltage amplifier 23, the first gain is adjusted. By operation of the third transistor Q3 configured in the current amplifier 22, the fourth transistor Q4, the fifth transistor Q5, the second capacitor C2, the first diode D1, The second diode D2 and the tenth and eleventh resistors R10 and R11 operate as cascode amplifiers to adjust the voltage amplification of the circuit, and the third circuit of the first circuit protection unit 24. The diode D3 and the fourth diode D4 serve to stably protect the circuit configured in the first CRT driver 20. In one operation, the first CRT driver 20 operates by amplifying the signal supplied from the preamplifier by one stage.

In addition, the signal supplied after the first stage amplification from the first CRT driver 20 is supplied to the third capacitor C3, the fourth capacitor C4, and the fifth diode of the crosstalk / distortion prevention unit 31. After preventing crosstalk and distortion of the signal supplied through D5), the signal is supplied to the sixth transistor Q6 of the second buffer 32, and the crosstalk is performed in the sixth transistor Q6 of the second buffer 32. The signal supplied from the anti-distortion unit 31 is inverted and outputted. In the seventh transistor Q7 of the second current amplifier 33, a voltage gain is close to 1 or 1 with a base common amplifier. The current amplification is adjusted by the operation of the second buffer 32, and the second voltage amplifier 34 is the eighth by the operation of the seventh transistor Q7 of the second current amplifier 33. Transistor Q8, ninth transistor Q9, sixth capacitor C6, sixth diode D6, seventh diode D7, 20th, 21st resistor R2 0, R21 acts as a cascode amplifier to adjust the voltage amplification of the circuit, the eighth diode D8 of the second circuit protection section 35, the ninth diode D9, The 22nd resistor R22 and the reactance L perform a function of stably protecting a circuit configured in the second CRT driver 30, and the first CRT driver 20 and the second CRT driver ( The amplification of 30) compensates the contrast gain required for large monitors and supplies it to the cathode of the CRT to operate. In addition, Vb1 and Vb2 of the first and second CRT drivers 20 and 30 are voltages for determining the lower limit of the overall height of the video signal. Accordingly, the present invention compensates the contrast gain required for a large monitor by outputting the CRT driver by two stages.

As described above, the contrast gain compensator in the large-sized monitor of the present invention, in particular, amplifies the CRT driver by two stages, compensates for the contrast gain required for the large-sized monitor, and outputs the same to the cathodes of the CRT. At the same time, the picture quality of large monitors is clearly displayed.

Claims (1)

A buffer unit for inverting and outputting the polarity of the video signal supplied from the preamplifier; A first buffer connected to a signal output terminal of the buffer unit, the first buffer for inverting and outputting a video signal inverted and supplied from the buffer unit, and a first current amplifier for switching by adjusting the amplification by operation of the first buffer; A first circuit, which is connected to a signal output terminal of the first voltage amplifier and a first voltage amplifier which operates as a cascode amplifier and adjusts voltage amplification by an operation of the first current amplifier, and protects the circuit. A first CRT driver comprising a protection unit; A crosstalk / distortion prevention unit for preventing crosstalk and distortion of the video signal output by amplifying the first CRT driver and outputting the second signal; a second buffer for inverting and outputting the video signal supplied through the crosstalk / distortion prevention unit; A second current amplifier for switching by an operation of the second buffer to adjust current amplification; a second voltage amplifier for operating a cascode amplifier to adjust voltage amplification by operation of the second current amplifier; And a second CRT driver connected to the signal output terminal of the second voltage amplifier and configured to protect the circuit. 2.