KR20020057026A - Low consumption power operating system of lcd module - Google Patents

Abstract

PURPOSE: A low power consumption driving apparatus of a liquid crystal display module is provided, which reduces power consumption by preventing a rapid current flow by forming a step at a voltage applied between a gate electrode and a source electrode of a thin film transistor. CONSTITUTION: The driving apparatus of a liquid crystal display module drives a liquid crystal cell of a pixel unit by applying a gate electrode to a gate of a thin film transistor arranged in a matrix array type. The first and the second switching device(20a,20b) are complementary each other to apply a B voltage of 1-H period to each gate in common for a gate on driving of the thin film transistor. The first reference voltage generation part(22) applies the first reference voltage to a source of the first switching device. The second reference voltage generation part(24) forms a clamping level as to a potential of a connection node of the first and the second switching device. The driving apparatus generates a gate-source voltage of a step waveform of the thin film transistor.

Description

LOW CONSUMPTION POWER OPERATING SYSTEM OF LCD MODULE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low power consumption driving device for a liquid crystal display module, and more particularly, to reduce power consumption when a large area and high resolution screen is reproduced by adopting a TFT-LCM. A low power consumption driving device of a liquid crystal display module for enabling this.

Currently, a liquid crystal display device, which is noted as a display device for screen reproduction, generally includes a liquid crystal panel in which a liquid crystal is injected between two upper glass substrates and a lower glass substrate, and a driver LSI for driving the liquid crystal panel. It consists of a drive unit having a PCB with integrated circuit elements and a chassis structure including a backlight.

Herein, a thin film transistor formed in the form of a matrix array used to drive a liquid crystal panel serves as a switching element for driving a liquid crystal cell in pixel units. The TFT includes a gate, a source, and a drain. It has a switching function for applying a signal voltage to the pixel electrode.

That is, in order to drive a TFT-LCD having an active matrix structure, a gate voltage must be applied to a TFT gate of a low line, and a data voltage must be applied to a source and a drain of the TFT, and a common electrode formed on the upper glass substrate. The data voltage is alternately applied to the (Com electrode) at a +/- level based on the Vcom voltage.

In order to apply a data voltage to the liquid crystal cell, a channel must be formed in the TFT, and the channel depends on the Vgs level formed between the gate electrode and the source electrode of the corresponding TFT.

In this case, as a high voltage is momentarily applied to the gate of the TFT, a large charging current flows between the gate and the source electrode under the influence of the parasitic capacitance Cgs, resulting in increased power consumption and distortion of the gate voltage. do.

That is, according to the driving method of the conventional liquid crystal display module illustrated in FIG. 1, when the Vgs level is applied to form a channel between the gate and the source of the TFT 10 to which the liquid crystal cell CE is connected to one side ( 2a), a large voltage is instantaneously applied to the gate, resulting in an influence of parasitic capacitance Cgs between the gate and the source, resulting in a large charge current (i = Cgs * dVgs / dt; see FIG. 2b). As it flows, power consumption increases (that is, P = V * i = Vgs * Cgs * dVgs / dt), while distortion in the gate voltage (see “A” in FIG. 2C) occurs. In addition, when the gate voltage is distorted, the charge rate is changed in the liquid crystal cell, and thus the likelihood of generating flicker is considerably increased.

Accordingly, the present invention has been made in view of the above-described state of the art, and forms a step in the voltage applied between the gate electrode and the source electrode of the thin film transistor for driving the liquid crystal display module to prevent rapid current flow. The purpose is to provide a low power consumption driving device of the liquid crystal display module to reduce the power consumption.

In order to achieve the above object, according to a preferred embodiment of the present invention, in the driving device of the liquid crystal display module to apply a gate voltage to the gate of the thin film transistor arranged in the form of a matrix array to drive the liquid crystal cell pixel unit, A first reference voltage is applied to the first and second switching elements, which are complementary to each other, and a source of the first switching element, so that a B voltage of 1-H period is commonly applied to each gate for gate-on driving of the thin film transistor. And a second reference voltage generator for forming a clamping level for the potentials of the connection nodes of the first and second switching elements, and generating a gate-source voltage of the thin film transistor as a step waveform. A low power consumption driving device for a liquid crystal display module is provided.

According to a preferred embodiment of the present invention, the step waveform of the gate-source voltage of the thin film transistor of the first and second switching elements of the first and second switching elements are complementary to the operation of the first and second switching elements The potential of the connection node is formed based on the clock pulse vertical signal.

In addition, according to another application of the present invention, the step waveform of the gate-source voltage of the thin film transistor is complementarily operated by the gate voltages applied by the first and second switching devices. The potential of the connection node of is formed on the basis of the clock pulse vertical signal delayed from the outside, thereby reducing flicker.

According to the low power consumption driving apparatus of the liquid crystal display module according to the present invention having the above-described configuration, the first and second reference voltage generators are applied to the outputs of the first and second switching elements in which the gates are commonly connected in a mutually complementary form. The first and second reference voltages are added to form a gate-source voltage of the thin film transistor in a step waveform so that a large charging current does not flow even when the thin film transistor is gated on, thereby reducing power consumption.

1 is a schematic diagram for explaining a driving method of a conventional liquid crystal display module;

2A to 2C are waveform diagrams for explaining a driving method of the conventional liquid crystal display module shown in FIG. 1;

3 is a view showing the configuration of a low power consumption driving device of a liquid crystal display module according to an embodiment of the present invention;

4A is a circuit diagram illustrating an example of a configuration of a first reference voltage generator shown in FIG. 3;

4B is a circuit diagram showing an example of the configuration of a second reference voltage generator shown in FIG. 3;

5A to 5E are waveform diagrams for explaining the operation of a low power consumption driving device of the liquid crystal display module according to the present invention shown in FIG.

6A to 6C are waveform diagrams for explaining another application example of the present invention.

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

10: thin film transistor (TFT), 20a, 20b: first and second switching elements,

22: the first reference voltage generator, 24: the second reference voltage generator,

224: inverting amplifier.

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

3 shows a configuration of a low power consumption driving device of a liquid crystal display module according to a first embodiment of the present invention.

In the drawing, reference numerals 20a and 20b denote first and second switching elements composed of, for example, MOS FETs, which are complementary to each other, and reference numeral 22 denotes applying a first reference voltage V1 to the first switching element 20a. And a second reference voltage generator 24 for applying a second reference voltage V2 for forming a clamping potential with respect to the voltage appearing at the connection node of the first and second switching elements 20a and 20b. Reference voltage generator.

More specifically, a voltage B is commonly applied to the gate of the first switching element 20a and the active low level gate of the second switching element 20b, and the source of the first switching element 20a is It is connected to the first reference voltage generator 22, and the drain of the second switching element 20b is connected to the ground potential.

The second reference voltage generator 24 is connected to the connection nodes of the first and second switching devices 20a and 20b via a capacitor 26 to obtain a Von voltage.

Referring to FIG. 4A, the first reference voltage generator 22 receives an externally applied Vin1 voltage to the inverting terminal (−) through the resistor 220, and the non-inverting terminal (+) has a ground potential. And an inverting amplifier 224 connected to the inverting terminal (-) and an output terminal thereof, and configured to obtain the first reference voltage V1 at its output side.

In addition, referring to FIG. 4B, the second reference voltage generator 24 is applied to the non-inverting terminal (+) with the external Vin2 voltage divided by the resistors 230 and 232 to convert the second reference voltage. Configured to obtain an amplifier 234.

The voltage Vin1 of the first reference voltage generator 22 is applied in a period of 1-H as shown in FIG. 5A, and the voltage B applied to the gates of the first and second switching devices 20a and 20b is It is applied in the form shown in Fig. 5c.

Accordingly, when the Vin1 voltage is applied to the first reference voltage generator 22 (see FIG. 5A), the second switching device 20b is turned on so that the second reference voltage generator (2) is connected at both ends of the capacitor 26. When the voltage level of only the second reference voltage V2 from 24 is applied, while the first switching device 20a is turned on in the period T1 in the waveform of FIG. 5C, the level of the Von voltage becomes V1 + V2 ( 5b).

In this state, when the CPV signal (i.e., clock pulse vertical signal) shown in FIG. 5D is applied from the gate driver IC (not shown) at time T0 of FIG. 5C, the TFT driving gate pulse Vgs is as shown in FIG. 5D. Similarly, a step waveform is obtained. When the gate electrode of the TFT is driven by the waveform, large current flow is prevented and power consumption is reduced.

Meanwhile, referring to FIG. 6, another application example of the present invention is described. When the CPV signal applied from the gate driver IC is delayed by T1 as shown in FIG. 6B while the Von voltage shown in FIG. 6A is applied, The output waveform of the gate driver IC is obtained with the step waveform of Fig. 6C, thereby reducing the flicker generation caused by the line delay of the gate voltage.

As described above, according to the low power consumption driving apparatus and the driving method thereof of the liquid crystal display module according to the present invention, the step of applying the voltage applied to the gate of the TFT by step waveform is applied to prevent the rapid flow of current, thereby Power consumption can be reduced.

The preferred embodiments of the present invention described above are disclosed for the purpose of illustration, and those skilled in the art will be able to make various modifications, changes, additions, etc. within the spirit and scope of the present invention, and such modifications and changes belong to the following claims Should be seen.

Claims (3)

In the driving device of a liquid crystal display module to drive a liquid crystal cell in pixel units by applying a gate voltage to the gate of the thin film transistor arranged in a matrix array form, First and second switching elements complementary to each other so that a B voltage of 1-H period is commonly applied to each gate for gate-on driving of the thin film transistor; A first reference voltage generator configured to apply a first reference voltage to a source of the first switching device; And a second reference voltage generator for forming a clamping level with respect to the potential of the connection node of the first and second switching elements, so that the gate-source voltage of the thin film transistor is generated in a step waveform. Low power consumption drive of the module. The gate waveform of claim 1, wherein the step waveform of the gate-source voltage of the thin film transistor is connected to the connection node of the first and second switching elements which are complementary to each other by the applied gate voltages of the first and second switching elements. A low power consumption driving device of a liquid crystal display module, characterized in that a potential is formed based on a clock pulse vertical signal. 2. The method of claim 1, wherein the step waveform of the gate-source voltage of the thin film transistor is connected to the connection node of the first and second switching elements that are complementarily operated by the applied gate voltages of the first and second switching elements. A low power consumption driving device of a liquid crystal display module, wherein the electric potential is formed on the basis of a clock pulse vertical signal applied by being delayed from the outside, thereby reducing flicker.