KR100623964B1 - Driving apparatus of liquid crystal display - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive device for a liquid crystal display device, wherein a filter for removing high frequency components is provided inside a timing controller. The filter is provided at an output terminal of an RSDS converter that converts and outputs a predetermined signal into an RSDS signal. This removes the high frequency components of the signal and smoothes the distortion of the signal.

Then, the amount of electromagnetic waves generated from the signal applied to the driving drive IC is minimized, and since there is no waveform falling below the reference voltage, the timing margin can be easily designed, so that the reliability of the liquid crystal display device can be improved.

Timing Controllers, RSDS Converters, Filters, Capacitors, Ground

Description

Driving apparatus for liquid crystal display

1 is a block diagram schematically showing a driving device of a liquid crystal display according to the present invention;

2 is a view showing a filter according to the present invention,

3 is a graph comparing waveforms when a filter is formed at an output terminal of the RSDS converter and a waveform when no filter is formed at the output terminal of the RSDS converter.

The present invention relates to a driving device of a liquid crystal display device, and more particularly, to a high frequency component at an output terminal of an RSDS converter for converting a predetermined signal into reduced swing differential signaling (RSDS) in a timing controller. The present invention relates to a driving device of a liquid crystal display device in which a filter to be removed is formed to minimize distortion of a waveform.

BACKGROUND ART Liquid crystal display devices, which have recently been in the spotlight as display products, have a large display unit that displays information using the electrical / optical properties of liquid crystals, and a graphic that is electrically connected to the display unit to generate an initial driving signal required to drive the display unit. It consists of a backlight assembly that guides light to the system and display unit.

The display unit and the graphic system are equipped with a driving circuit unit for driving the liquid crystal display device, the general driving circuit unit is largely divided into the graphic control unit, power supply unit, low voltage differential signaling (LVDS) modulator, LVDS demodulator, timing signal generator and It consists of a drive drive IC. In order to reduce the generation of electromagnetic waves, R, G, B image signals, clock signals (CLK), and synchronization signals (Sync) required for image display in the LVDS modulation section of the driving circuit section having this configuration are referred to as "LVDS signals". After converting the data into the LVDS demodulator, the LVDS demodulator demodulates the drive signal IC by inputting the LVDS signal to demodulate a predetermined signal necessary for driving the drive driver IC, that is, a TTL signal using a CMOS level of 3.3V. The liquid crystal panel is driven.

However, since the TTL signal has a voltage magnitude of 3.3V, a large amount of electromagnetic waves are generated due to high power consumption and high data communication speed. In addition, since the R, G, and B image signals converted from the LVDS demodulator to the TTL signals are transmitted to the drive driver ICs in 6 or 8 bits, respectively, the number of signal lines for transmitting the R, G, and B image signals increases. Therefore, the area of the printed circuit board to which the input side of the driving drive IC is bonded in the display unit becomes large due to many signal lines.

Accordingly, in order to solve this problem, recently developed liquid crystal display modules convert TTL signals into RSDS, which can generate less electromagnetic waves and reduce the number of signal lines, and transmit them to the driving drive IC. Referring to FIG. 1, the driving circuit unit includes a graphic controller, a power supply unit, an LVDS modulator, an LVDS demodulator, a timing signal generator, an RSDS modulator, and a drive driver IC.

The LVDS modulator converts the R, G, and B image signals and clock signals necessary for image display into LVDS signals that are resistant to electromagnetic interference and consume less power, and are then transmitted to the LVDS demodulator. After inputting the LVDS signal, the LVDS demodulator demodulates the signal into a predetermined signal, for example, a TTL signal, and transmits the TTL signal to the RSDS modulator. Then, the RSDS modulator drives the display unit by converting the TTL signal into an RSDS having a low amount of electromagnetic waves and having a low voltage, like the LVDS signal, and transmitting the converted TTL signal to a driving drive IC.

However, even when the TTL level signal is converted to RSDS resistant to electromagnetic interference by using the RSDS converter, distortion is generated as shown in the graph of FIG. 4. As a result, it is difficult to design a timing margin because the reference of the high level and the low level of the data signal and the clock signal, such as the R, G, and B image signals, is ambiguous, and the reliability of the liquid crystal display device is degraded.

In addition, a high frequency component generated by distortion of a signal causes an increase in electromagnetic wave emission.

Accordingly, an object of the present invention is to minimize the distortion of a signal by removing high frequency components from the signal waveform.

Other objects of the present invention will become more apparent from the following detailed description and the accompanying drawings.

In order to achieve the above object, the present invention provides an LVDS receiver for inputting a low voltage differential signal, a TTL signal converter for converting a low voltage differential signal to a TTL level signal, and a driving drive IC to generate a gray voltage and a gate on / off signal. In the timing controller including a control signal generator for generating various control signals and an RSDS converter for converting a TTL level signal to RSDS, which is advantageous in terms of electromagnetic waves, a high frequency component is removed from an output terminal of the RSDS converter to remove distortion of the signal. Install a filter that makes it smooth.

Preferably, the filter consists of a capacitor for filtering the high frequency components and a ground for absorbing the removed high frequency components.

Hereinafter, the driving device of the liquid crystal display according to the present invention will be described with reference to FIGS. 1 to 3.

As shown in FIG. 1, the liquid crystal display device 100 according to the present invention irradiates light to the liquid crystal panel 110 for displaying an image and the driving circuit unit for driving the liquid crystal panel 110 and the liquid crystal panel 110. It consists of a backlight assembly (not shown).

The driving circuit unit is largely comprised of the graphic controller 120, the power supply unit 130, the LVDS transmitter 140, the timing controller 150, and the driving drive IC 180. Among them, the graphic controller 120, the power supply unit 130, and the LVDS transmitter 140 are mounted on a graphic board (not shown), and the timing controller 150 is a source and gate printed on the side of the liquid crystal panel 110. Mounted on the circuit boards 160 and 170, the graphic board and the source printed circuit board 160 are electrically connected by FPC connectors (not shown). The source and gate printed circuit boards 160 and 170 and the liquid crystal panel 110 are electrically connected to each other by the driving drive IC 180.

Here, the graphic controller 120 generates R, G, and B image signals, a clock signal, and a synchronization signal required for image display, and the power supply unit 130 supplies power voltage Vcc necessary to drive the liquid crystal panel 110. Provide a ground potential (GND). The LVDS transmitter 140 receives the R, G, and B image signals, the clock signal, and the synchronization signal from the graphic controller 120, lowers the voltage level of these signals to 1 V or less, and compresses these signals by using a coding technique. Make it an LVDS signal. As such, when the R, G, and B image signals and the clock signals transmitted from the graphic controller 120 are converted into LVDS signals, the number of signal lines for transmitting the LVDS signals from the graphics board to the source printed circuit board 160 is significantly reduced and transmitted. It is possible to minimize the influence of electromagnetic waves generated during the process.

On the other hand, the timing controller 150 converts the low voltage differential signal transmitted from the control board to RSDS and transmits it to the drive drive IC 180, while generating various timing control signals required to drive the liquid crystal panel 110, The LVDS receiver 151, the TTL signal converter 152, the timing signal generator 153, the RSDS converter 154, and the filter 155 are configured.

The LVDS receiver 151 receives the LVDS signal transmitted to the source printed circuit board 160 through the FPC connector, and the TTL signal converter 152 converts the compressed LVDS signal into a 3.3 V TTL level signal. The timing signal generator 153 generates various timing control signals required to drive the liquid crystal panel 110 and transmits R, G, and B image signals and clock signals converted into TTL signals to the RSDS converter.

In addition, the RSDS converter 154 converts a TTL level signal having a voltage magnitude of about 3.3 V into an RSDS signal having a voltage magnitude of about 0.2 V to minimize the influence of electromagnetic waves and minimizes the timing of the electromagnetic waves. The number of signal lines transmitting the RSDS signal from the controller 150 to the driving drive IC 180 is reduced.

Meanwhile, the filter 155 according to the present invention minimizes the signal distortion of the RSDS transmitted from the RSDS converter 154 to the driving drive IC 180 by removing the high frequency component from the RSDS, as shown in FIG. 2. It is formed at the output terminal of the RSDS converter 154 in the timing controller 150. Preferably, the filter 155 includes a capacitor 156 for passing low frequency components and filtering high frequency components in the RSDS transmitted to the drive drive IC 180 and minimizing the effects of electromagnetic waves, and a ground 157 for absorbing the filtered high frequency components. It is composed of Here, since the voltage of the RSDS waveform is small, the capacitance of the capacitor 156 used for the filter 155 is several to several tens of kHz.

As described above, when the filter 155 is installed at the output terminal of the RSDS modulator 154 inside the timing controller 150, the RSDS signal output from the RSDS converter 154 is subjected to a high frequency component by the filter 155. This eliminates the distortion of the RSDS waveform as shown in signal B of FIG.

Therefore, when the high frequency component is removed from the RSDS waveform, since the signal is gentle as shown in the B signal of FIG. 4, there is no section in which a signal falls below the reference voltage level in one data clock. In addition, since the waveform that bounces up to 200 Hz or more in the state converted to RSDS is removed by the capacitor 156 of the filter 155, damage of electromagnetic waves can be minimized.

As described above, the present invention provides a filter for removing a high frequency component inside the timing control. The filter is provided at an output terminal of the RSDS changer that converts and outputs a predetermined signal into an RSDS signal, thereby removing the high frequency component of the signal. Softens the distortion of the signal.

Then, the effect of the electromagnetic wave of the signal applied toward the driving drive IC can be minimized, and since there is no waveform falling below the reference voltage, the design of the timing margin is easy, so that the reliability of the liquid crystal display device can be improved.

Claims (3)

A liquid crystal panel in which a liquid crystal is injected to display image information by electric and optical properties of the liquid crystal; A graphic controller generating an image signal, a clock signal, and a synchronization signal, a power supply unit providing a power supply voltage and a ground potential for driving the liquid crystal panel, and inputting an image signal, a clock signal, and a synchronization signal received from the graphic controller; An LVDS transmitter for converting an image signal and a clock signal into an LVDS signal for transmission to the liquid crystal panel, a timing control for converting the LVDS signal transmitted from the LVDS transmitter into an RSDS signal and generating various timing control signals required to drive the liquid crystal panel; A driving device including a driving drive IC for generating a signal for driving the liquid crystal panel using the RSDS signal and the timing control signal, The timing controller is An LVDS receiving part which receives the LVDS signal transmitted from the LVDS transmitter and converts the LVDS signal into a signal having a TTL level of 3.3V; An RSDS conversion unit converting the TTL signal transmitted from the LVDS receiving part into RSDS resistant to electromagnetic waves; And a filter formed at an output end of the RSDS converter to smooth the waveform of the signal by removing a high frequency component of the RSDS signal output from the RSDS converter. The method of claim 1, wherein the LVDS receiving part An LVDS receiver for receiving the LVDS signal transmitted from the LVDS transmitter; And a TTL signal converter converting the LVDS signal transmitted from the LVDS receiver into the TTL signal. The driving apparatus of claim 2, wherein the filter comprises a capacitor connected between an output terminal of the RSDS converter and a ground.

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