KR0137839Y1 - Driving signal output circuit of l.c.d. - Google Patents

Abstract

The present invention selectively outputs a driving signal of a frequency for driving 100,000 and 300,000 pixel display panels. In the conventional driving signal output circuit, the division values of the frequency divider for dividing the driving signals are respectively 1/600 and 1, respectively. It is fixed at / 800 so that only one display panel can be driven without outputting 100,000 pixel display panel and 300,000 pixel display panel as output circuit as one drive signal output circuit. The production cost of the driving signal output circuit of the 100,000 pixels and 300,000 pixels display panel was required.

The present invention includes both 1/600 divider and 1/800 divider, and displays 100,000 pixels as one drive signal output circuit by selectively using 1/600 divider and 1/800 divider according to the selection signal. By selectively outputting the driving signals of the panel and the 300,000 pixel display panel, it is possible to produce both the driving signal output circuit for driving the 100,000 pixels and the 300,000 pixel display panel in one production line, thereby reducing the production equipment cost.

Description

Drive signal output circuit of liquid crystal display device

1 is a driving signal output circuit diagram of a conventional 100,000 pixel liquid crystal display device (LCD).

2 is a driving signal output circuit diagram of a conventional 300,000 pixel liquid crystal display device (LCD).

3 is a drive signal output circuit diagram of the present invention.

* Explanation of symbols for main parts of the drawings

11: phase difference detection unit 12: low pass filter

13: VCO 14: 1/600 minutes

15: 1/800 divider 16: 1st selection unit

17: second selection unit

The present invention relates to a drive signal output circuit of a liquid crystal display (LCD) used as a screen display device in a TV receiver and a LCD monitor using a TFT-LCD (Thin Film Transistor Liquid Crystal Display),

Particularly, a liquid crystal display having one oscillation means and a plurality of distributing means and selectively operating one dispensing means of the plurality of dispensing means to generate drive signals of various frequencies in one drive signal output circuit. A drive signal output circuit of a device (LCD).

For example, an LCD panel with 480 × 240 horizontal and vertical pixels (hereinafter, abbreviated as '100,000 pixel liquid crystal display device (LCD)') and an LCD panel with 640 × 480 (hereinafter, '300,000 pixel liquid crystal display' A liquid crystal display device for selectively outputting a drive signal corresponding to a frequency required by each LCD in a drive signal output circuit including a single oscillation means for driving a drive signal having a frequency for driving the device (LCD); LCD) drive signal output circuit.

The conventional LCD driving signal output circuit is configured to output only one driving signal without selectively outputting driving signals of a 100,000 pixel liquid crystal display (LCD) and a 300,000 pixel liquid crystal display (LCD).

For example, a conventional driving signal output circuit for driving a 100,000 pixel liquid crystal display device (LCD) is shown in FIG.

A phase difference detector (1) for detecting a phase difference between the horizontal synchronization signal (HS) of 15.75 KHz and a comparison signal input as a reference signal, a low pass filter (2) for smoothing the output signal of the phase difference detector (1), and A phase controlled oscillator (VCO) 3 which oscillates according to the output signal of the low pass filter 2 and outputs a driving signal, and divides the output signal of the VCO 3 into 1/600 to provide the phase difference. The 1/600 divider 4 which inputs to the detection part 1 as a comparison signal was comprised.

In the conventional drive signal output circuit configured as described above, the frequency of the drive signal output by the VCO 3 is determined according to the number of horizontal pixels of the liquid crystal display (LCD) to be driven as shown in the following equation, with 100,000 having 480 horizontal pixels. When driving the pixel liquid crystal display device LCD, the frequency of the drive signal is 9.58 MHz.

Frequency of drive signal = number of horizontal pixels / (52.7μsec x 0.95)

= 480 / (52.7 μsec × 0.95)

= 9.58 MHz

In this way, the drive signal output from the VCO 3 is divided into 1/600 by the 1/600 divider 4 and output as a comparison signal having a frequency of about 15.7 KHz, and the output comparison signal and the horizontal synchronization signal of 15.7 KHz. The phase difference detection unit 1 detects the phase difference of (HS) and outputs the phase difference signal, and after the low pass filter 2 smoothes the output phase difference signal to the VCO 3, the VCO 3 starts oscillating. Outputs a drive signal with a frequency of exactly 9.58 MHz.

In the case of driving a 300,000-pixel liquid crystal display (LCD) having 640 horizontal pixels, the frequency of the drive signal output from the VCO 3 is 12.78 MHz as shown in the following equation.

Frequency of drive signal = 640 / (52.7μsec x 0.95) = 12.78MHz

When the 12.78 MHz drive signal is divided by 1/800, the frequency of the horizontal synchronization signal HS is 15.75 KHz. The conventional drive signal output circuit for driving a 300,000 pixel liquid crystal display (LCD) is shown in FIG. 1/800 dividers 5 were used instead of 1/600 dividers 4 as shown.

However, in the conventional drive signal output circuit as described above, the dividing value of the divider for dividing the drive signal is fixed to 1/600 and 1/800, respectively. LCD) and the 300,000 pixel liquid crystal display (LCD) could not be driven, only one liquid crystal display (LCD) could be driven,

In addition, the driving signal output circuit of the 100,000 pixels and 300,000 pixels liquid crystal display (LCD) in each separate production line has to be produced, there is a problem such as a lot of production equipment.

The present invention has been made to solve the above conventional problems,

One oscillating means, a plurality of dispensing means for distributing the output of the oscillating means at different ratios, and means for selectively operating the dispensing means, can freely drive a drive signal of any frequency required for driving an LCD. An object of the present invention is to provide a driving signal output circuit of a liquid crystal display device (LCD) capable of generating and outputting variously,

In particular, it is equipped with both 1/600 frequency divider and 1/800 frequency divider, and selectively using 1/600 frequency divider and 1/800 frequency divider according to the selection signal, 100,000 pixels liquid crystal as one drive signal output circuit It is designed to selectively output drive signals of the display device (LCD) and the 300,000-pixel liquid crystal display (LCD).

This will be described in detail with reference to the accompanying drawings of FIG. 3.

First, referring to FIG. 3, the driving signal output circuit of the liquid crystal display device (LCD) of the present invention is

Oscillation means (11, 12) for receiving the horizontal synchronizing signal (HS) and a signal output from one of the plurality of distributing means, and generating and outputting an LCD driving signal locked to the horizontal synchronizing signal (HS) , 13);

A plurality of distributing means (14, 15) for receiving the output signal of the oscillation means and dividing the output signal at different dispensing ratios and outputting them;

Selecting means (16, 17) for selecting and dispensing one of said plurality of dispensing means from said plurality of dispensing means;

A driving signal output circuit of a liquid crystal display device (LCD) characterized in that the configuration.

The oscillation means,

A phase difference detector 11 for detecting a phase difference between the horizontal synchronization signal HS and the comparison signal, a low pass filter 12 for smoothing the output signal of the phase difference detector 11, and an output of the low pass filter 13; The oscillation frequency was varied according to the signal level, and the voltage controlled oscillator (VCO) 13 oscillated LCD driving signal.

And, the dispensing means,

It consists of a first divider 14 and a second divider 15 for dividing the LCD drive signal which is the output signal of the oscillation means at different division ratios.

Here, the first divider 14 is composed of a 1/600 divider for dividing the LCD driving signal output from the oscillating means to 1/600, the second divider 15 is output from the oscillating means It is executed by 1/800 divider which divides LCD driving signal into 1/800.

And said selection means,

A first selector which inputs the LCD driving signal, which is an output signal of the oscillation means, to only one of the plurality of dispensing means according to a selection signal SC applied from the outside, and blocks the input signal from the other dispensing means; 16) and,

Inputting the divided LCD driving signal output from the selected one division means as a phase difference comparison signal for synchronization to the oscillation means in accordance with the selection signal (SC) applied from the outside, and the output of the remaining division means is cut off It further comprises a second selector 17.

Here, the first selection unit 16,

An inverter IV11 for inverting the selection signal SC applied from the outside, an AND gate AD11 for inputting or blocking the output of the oscillation means to the first divider according to the output signal of the inverter IV11; And an AND gate AD12 for inputting or blocking the output of the oscillation means in a second divider according to the selection signal SC,

The second selection unit,

An inverter IV12 for inverting the selection signal SC applied from the outside, an AND gate AD13 for switching the output signal of the first divider according to the output signal of the inverter IV12, and the second divider Of the AND gate AD14 for switching the output signal in accordance with the selection signal SC and the output signal of the AND gate AD13 and AD14 as the phase difference comparison signal for synchronizing to the oscillation means. Sheave ora gate (EXOR).

The drive signal output circuit of the present invention configured as described above outputs the phase difference signal by detecting the phase difference between the horizontal synchronization signal HS of 15.75 KHz and the comparison signal output from the second selector 17. After the low pass filter 12 smoothes the output phase difference signal, it is applied to the VCO 13. The VCO 13 oscillates at a predetermined frequency and outputs a driving signal according to the input voltage.

At this time, when the selection signal SC is input as the low signal, the AND gate AD12 of the first selection unit 16 continuously outputs the low signal, and the selection signal SC of the low signal is transmitted through the inverter IV11. Since the signal is inverted to the high signal and applied to the AND gate AD11, the driving signal output from the VCO 13 is input to the 1/600 divider 14 through the AND gate AD11 and divided by 1/600.

The AND gate AD14 of the second selector 17 continues to output a low signal by the low signal selection signal SC, and the inverter IV12 outputs a high signal to the AND gate AD13. Therefore, the output signal of the 1/600 divider 14 is inputted as a comparison signal to the phase difference detector 11 through the AND gate AD13 and the exclusive OR gate EXOR, and the VCO 13 is 9.58 MHz. It outputs a driving signal having a frequency of.

On the other hand, when the selection signal SC is input as the high signal, the AND gates AD11 and AD13 to which the inverters IV11 and IV12 both output low signals output the low signals in contrast to the above, and the VCO 13 The output signal of is inputted to the 1/800 divider 15 through the AND gate AD12 and divided by 1/800, and then the phase difference detecting unit 11 is provided through the AND gate AD14 and the exclusive OR gate EXOR. The VCO 13 outputs a driving signal having a frequency of 12.78 MHz because it is input as a comparison signal.

As described in detail above, the present invention includes both 1/600 dividers and 1/800 dividers, and selects 1/600 dividers and 1/800 dividers according to the number of pixels of a liquid crystal display (LCD) to be used. By dividing the output signal of the VCO, it is possible to produce both driving signal output circuits for driving 100,000 pixels and 300,000 pixels liquid crystal display (LCD) in one production line, thereby reducing production equipment costs. There is.

Claims (7)

An oscillating means for receiving the horizontal synchronizing signal HS and a signal output from one of the plurality of dividing means, and generating and outputting an LCD driving signal locked to the horizontal synchronizing signal HS; A plurality of distributing means for receiving the output signal of the oscillating means and dividing the signals at different dispensing ratios and outputting the divided signals; Selecting means for selecting and operating one of the plurality of dispensing means; A drive signal output circuit of a liquid crystal display device (LCD), characterized in that consisting of. The liquid crystal display device according to claim 1, wherein the dispensing means comprises a first divider and a second divider for dividing an LCD driving signal which is an output signal of the oscillation means at different division ratios. (LCD) drive signal output circuit. 3. The LCD of claim 2, wherein the first divider comprises a 1/600 divider for dividing the LCD drive signal output from the oscillation means into 1/600, and the second divider comprises an LCD drive output from the oscillation means. A driving signal output circuit of a liquid crystal display device (LCD), characterized in that consisting of a 1/800 divider for dividing the signal into 1/800. The method of any one of claims 1 to 3, wherein the selecting means divides one of the plurality of dispensing means in accordance with a selection signal SC to which an LCD driving signal which is an output signal of the oscillating means is externally applied. And a first selector for inputting only the means and blocking the other dispensing means from being inputted. 4. The oscillating means according to any one of claims 1 to 3, wherein said selecting means comprises said oscillating means according to a selection signal SC externally applied with a divided LCD driving signal outputted from said selected one dispensing means. And a second selector for inputting a phase difference comparison signal for synchronizing with the signal, and outputting the remaining division means. The method of claim 4, wherein the first selector comprises: an inverter IV11 for inverting the selection signal SC applied from the outside, and outputting the output of the oscillation means in accordance with an output signal of the inverter IV11 for a first minute; And an end gate (AD11) for inputting or blocking in a period and an end gate (AD12) for inputting or blocking the output of the oscillation means in a second divider according to the selection signal (SC). A drive signal output circuit of a liquid crystal display device (LCD). The method of claim 5, wherein the second selection unit, the inverter IV12 for inverting the selection signal (SC) applied from the outside, and the output signal of the first divider in accordance with the output signal of the inverter IV12 The oscillation of the AND gate AD13, the AND gate AD14 for switching the output signal of the second divider according to the selection signal SC, and the output signal of the AND gate AD13 AD14. And an exclusive OR gate (EXOR) for supplying a phase difference comparison signal for synchronization to the means.