KR100551735B1 - Driving circuit for LCD - Google Patents

Abstract

Even if there is no input data or there is input data, if there is no input data or the input data is the same, the liquid crystal display suitable for minimizing power consumption by forcibly turning off the unnecessary circuit power. The present invention relates to a device driving circuit, wherein the liquid crystal display driving circuit of the present invention forcibly cuts off the power supplied to the LVDS and timing controller including a gate and a source driver IC if there is no data inputted therein, If the data is the same as the previously input data, the previous data is applied to the liquid crystal panel, but when the data is not input by forcibly cutting off the power supplied to the LVDS and the timing controller, or even when the data is input, Unnecessarily large amounts of It is characterized by minimizing power consumption by cutting off power to LVDS and timing controller.

Power Consumption, Timing Controller, LVDS

Description

Liquid crystal display driving circuit {Driving circuit for LCD}

1 is a configuration diagram of a general liquid crystal display device

2 is a configuration diagram of a source driver IC according to a conventional liquid crystal display

3 is a configuration diagram of a liquid crystal display driving circuit according to the present invention;

4 is a configuration diagram of a source driver IC according to an LCD of the present invention.

* Description of the symbols for the main parts of the drawings *

31 liquid crystal panel 33 source driver IC

33a: first shift register 33b: second shift register

33c: Latch 33d: Level Shifter

33e: D / A Converter 33f: Buffer

35: gate driver IC 37: LVDS

39: timing controller 41: data detector

43: power control signal generator 45: power supply

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, wherein a liquid crystal display device driving circuit suitable for interrupting unnecessary power consumption by forcibly turning off the power of a circuit part according to whether data is input or whether previous data is equal to current data It's about the furnace.

In general, a liquid crystal display device is a flat panel display device composed of two glass substrates and a liquid crystal layer enclosed therebetween. In the lower substrate, a gate line and a data line defining a pixel region are intersected and each pixel region is disposed. A thin film transistor is arranged to switch the pixel electrode and the gate line driving signal to apply a signal of the data line to the pixel electrode, and a black matrix is formed on the upper substrate to block light from being transmitted to the region except the pixel electrode. The color filter layer is formed in each pixel region with the black matrix interposed therebetween, and a common electrode is formed on the entire surface.

As shown in FIG. 1, the liquid crystal display device includes a liquid crystal panel in which a plurality of gate lines and a data line cross each other, and a thin film transistor is disposed at a portion where each gate line and the data line intersect to display an image. 11), a source driver IC 13 for applying a driving voltage for driving the data line of the liquid crystal panel 11, and a gate driver for applying a driving voltage for driving the gate line of the liquid crystal panel 11; It consists of IC15.

Although not shown in the drawing, the LVDS unit compresses a plurality of data signals and provides them to the timing controller, and supplies the R, G, and B data signals to the source driver IC 13, and supplies the horizontal synchronizing signal HSYNC and the vertical unit. And a driving circuit such as a timing controller for generating a dot clock and a gate start pulse using the synchronization signal VSYNC to control timing of the source driver IC 13 and the gate driver IC 15.

On the other hand, the source driver IC 13 is to drive the liquid crystal cell by applying data to the liquid crystal panel 11, the basic structure is as shown in FIG.

That is, as shown in FIG. 2, the source driver IC is composed of data voltages of R, G, and B, a power supply for operating a digital circuit, a power supply for driving a liquid crystal cell, and control signals for controlling them. .

Such a source driver IC is composed of a shift register 21, a latch 23, a level shifter 25, a D / A converter 27 and a buffer 29. The latch portion After the TTL (Transistor-Transistor Logic) data voltage input to (23) is shifted in the level shifter section 25, it is converted into an analog voltage in the D / A converter section 27 and finally the liquid crystal through the buffer 29 It is applied to the data line of the panel 11.

According to the conventional LCD configured as described above, in the operation mode, the gate driver IC 15 and the source driver IC 13 together with the peripheral circuits such as the timing controller, including the LVDS, must be supplied with power at all times. 13) and the liquid crystal cell is driven under the control of the gate driver IC 15 so that an image is displayed on the liquid crystal panel 11.

However, the liquid crystal display as described above has a problem in that power is always supplied to the LVDS and the timing controller as well as the gate and source driver ICs even in a power saving mode in which no data is input.

The present invention has been made to solve the above problems of the prior art, it is suitable to minimize the power consumption by forcibly turning off the power of the unnecessary circuit when there is no input data to determine whether data is input or not It is an object of the present invention to provide a liquid crystal display driving circuit.

Another object of the present invention is to compare the current data with the previous data, if the two data are the same mutually forcibly turn off the power supply of unnecessary circuits, and unnecessary power consumption by applying the previous data to the liquid crystal panel It is to provide a liquid crystal display driving circuit suitable for preventing.

The liquid crystal display driving circuit of the present invention for achieving the above object is a LVDS for compressing and outputting a plurality of data, the gate and the source for driving the liquid crystal display using a data signal and a clock signal input from the LVDS A driving circuit for a liquid crystal display device comprising a timing controller for applying various synchronization signals and data signals to a driver IC, comprising: a power supply unit for selectively supplying power to the LVDS, timing controller, gate driver IC, and source driver IC; Connected to the data input terminal of the LVDS to detect the presence or absence of data input to the LVDS and whether the current data is the same as the previously input data, if there is no data input to the LVDS and the control signal for power supply cutoff Output, and even if there is data input to the LVDS before A data detector for outputting a control signal for shutting off the power supply and a shift register control signal for controlling a shift register in the source driver IC if the data is identical to the output data; and receiving a control signal of the LVDS, and supplying a power control signal to the power supply unit. And a power control signal generator for outputting a signal and first and second shift registers, and when a shift register control signal is input from the data detector, transfer previous data stored in the first shift register to the second shift register. And a source driver IC for applying the previous data to the liquid crystal panel.

Here, the power supply unit cuts off the power supplied to the timing controller, the LVDS, the gate and the source driver IC if there is no data input to the LVDS, and if the input data is the same as previously input data, the timing controller and It is desirable to shut off the power to the LVDS.

Hereinafter, a liquid crystal display driving circuit of the present invention will be described with reference to the accompanying drawings.

3 is a block diagram of a liquid crystal display driving circuit according to the present invention.

As shown in FIG. 3, the liquid crystal display driving circuit of the present invention includes a liquid crystal panel 31 in which an image is displayed, a source driver IC 33 for applying a data signal to a data line of the liquid crystal panel 31; A gate driver IC 35 applying a driving voltage for driving the gate line of the liquid crystal panel 31, a low voltage differential signaling (LVDS) 37 providing a plurality of compressed data to a timing controller; The timing controller 39 receives the clock signal and the data from the LVDS 37 and generates the necessary synchronization signal, and provides them to the source driver IC 33 and the gate driver IC 35, and the data input to the LVDS 37. Data detection unit 41 for detecting whether there is an or whether the data currently input to the LVDS 37 is the same as previously input data and the control signal output from the data detection unit 41. In response to the control signal of the power supply control signal generator 43 and the power control signal generator 43 for outputting a control signal to the power supply, the source driver IC 33, the gate driver IC 35, and LVDS And a power supply 45 for supplying power to the timing controller 39.

Here, although not shown in the drawing, the data detector 41 stores a data comparator and previous data for comparing whether data currently input to the LVDS 37 and data previously input to the LVDS 37 are the same. It is configured to include a data memory.

The liquid crystal display driving circuit of the present invention detects whether the data inputted to the LVDS 37 is present by the data sensing unit 41, and if the input data is present, the input data and previously input data are detected. The LVDS 37 and the timing controller 39 are supplied with power only when they are not identical to each other. If the data currently input and the previously input data are the same, the data detector 41 supplies a source. The shift register control signal is output to the driver IC 33 so that previously input data is applied to the liquid crystal panel 31, but the power supply is cut off to the LVDS 37 and the timing controller 39.

In addition, the liquid crystal display driving circuit according to the present invention uses the timing controller 39 and the LVDS to prevent unnecessary power consumption when the data sensing unit 41 does not have data input to the LVDS 37. Forcibly cut off the power of 37).

At this time, the power consumption of the liquid crystal display device is generally about 2W, of which the source driver IC occupies a very small amount of 0.02W, whereas the timing controller 39, the differential amplifier, and the LVDS 37 consume a large amount of power. In consideration of the consumption of the present invention, the present invention which cuts the power supplied to the LVDS 37 and the timing controller 39 according to the presence or absence of data input and whether the current data and the previous data are the same is very effective in reducing power consumption.

In other words, the liquid crystal display driving circuit of the present invention uses the gate and source driver ICs 35 and 33 and the memory when there is no input data and when the current data and the previous data are the same even though there is input data. By forcibly cutting off the power supplied to the timing controller 39 and the LVDS 37, the power consumption may be minimized.

Here, in comparing the current data with the previous data, when the driving method of the liquid crystal display device is a line inversion, the data line is compared with the data line, and the driving method is a dot inversion. ), It is preferable to compare the dots.

For reference, when comparing current data with previous data, it is preferable to always supply power to the gate driver IC 35 and the source driver IC 33. It is also possible to shut off the power applied to the gate driver IC 35 or the source driver IC 33 when there is no input data. However, when comparing current data with previous data, the source driver IC ( 33) stores the previous data in a separate shift register, but if the current data and the previous data are the same, the previous data stored in the separate shift register must be applied to the liquid crystal panel so that the gate and source driver ICs are used. (33) shall continue to be powered.

4 illustrates the structure of the source driver IC according to the liquid crystal display of the present invention, and includes first and second shift registers 33a and 33b, latch 33c, level shifter 33d, and A /. It can be seen that it is composed of the D converter 33e and the buffer 33f.

Here, the shift register control signal is input to the first shift register 33a from the data sensing unit 41, and unless the control signal indicating that the current data and the previous data are not the same, the first shift register ( Data stored in 33a) is transferred to the second shift register 33b.

For reference, the low voltage differential signaling (LVDS) 37 is an interface using a low voltage differential signaling technique. In this environment, since a liquid crystal display generally transmits data using a TTL (Transistor-Transistor Logic) signal having a high frequency, The image signal is affected by the TTL signal, causing the voltage level to fluctuate at a corresponding frequency, causing EMI problems.

Therefore, the method of transmitting data or clock signal by TTL signal requires a large number of transmission lines, and therefore requires a large number of cables and connectors which are configured in the liquid crystal display device. This affects the quality of the screen.

In addition, the number of data transmission bits supported in a graphics controller that is commonly used to realize full color high resolution is limited, and for this reason, low voltage differential signaling technology has been introduced. As defined in P1596.3 ', data transmission at low voltage can be realized.

Hereinafter, the operation of the liquid crystal display driving circuit of the present invention configured as described above will be described.

First, the data detector 41 detects whether or not data is input to the LVDS 37, and if there is no input data, the data control unit 41 outputs a control signal indicating that there is no data currently input to the LVDS 37. Output to (43).

Accordingly, the power control signal generator 43 outputs a power control signal to the power supply 45 so that power is not supplied from the power supply 45 anymore. That is, the power control signal generation unit 43 outputs a power control signal to the power supply unit 45 to supply the timing controller 39, the LVDS 37, the gate driver IC 35, and the source driver IC 33. To force off the power supply so that no more power is applied.

On the other hand, if there is data input to the LVDS 37, the data input to the current LVDS 37 and the previously input data is compared. At this time, the data is compared in a data comparator (not shown), and the data comparator retrieves the data of the data memory storing the data previously input to the LVDS 37 and the data currently input to the LVDS 37. Compare.

As a result of the comparison, when the data currently input to the LVDS 37 and the previously input data are the same, the data detector 41 sends a shift register control signal to the first shift register 33a of the source driver IC 33. Output

Accordingly, data stored in the first shift register 33a (actually previously input data) is transferred to the second shift register 33b to finally latch 33c, level shifter 33d, and D / A converter. It is applied to the liquid crystal panel 11 through the buffer 33f via 33e.

Therefore, if the data inputted to the current LVDS 37 is the same as the previously inputted data, the old data identical to the current data can be used without supplying power to the old LVDS 37 and the timing controller 39. Since it is applied to the panel 11, it is possible to prevent unnecessary power consumption in the timing controller 39 or LVDS 37 that consumes the most power in the liquid crystal display device.

As such, it is clear that the present invention can use various changes, modifications, and equivalents, and that the above embodiments can be appropriately modified and applied in the same manner. Accordingly, the above description does not limit the scope of the invention as defined by the limitations of the following claims.

As described above, the liquid crystal display driving circuit according to the present invention is an example of circuits that do not need to be operated when data is not input or data is input identical to previous data even when data is input. For example, it is possible to forcibly cut off the power supply of peripheral circuits such as LVDS and timing controller to prevent unnecessary power consumption.

Claims (2)

A driving circuit of a liquid crystal display device comprising an LVDS and a timing controller for applying various synchronization signals and data signals to gate and source driver ICs for driving the liquid crystal display device using data signals and clock signals inputted from the LVDS. , A power supply for selectively supplying power to the LVDS, the timing controller, the gate and the source driver IC; It is connected to the data input terminal of the LVDS and detects the presence or absence of data inputted to the LVDS and whether the current input data is the same as previously inputted data. If there is no data inputted to the LVDS, a control signal for power off is outputted. A data detector for outputting a control signal for power off and a shift register control signal for controlling a shift register in the source driver IC if the data input to the LVDS is the same as previously input data; A power control signal generator for receiving a control signal of the LVDS and outputting a power control signal to the power supply unit; And a first shift register and a second shift register, and when a shift register control signal is input from the data detector, transfers previous data stored in the first shift register to the second shift register to apply the previous data to the liquid crystal panel. A drive circuit for a liquid crystal display device comprising a source driver IC. The method of claim 1, wherein the power supply unit, If there is no data input to the LVDS, the power supplied to the timing controller, the LVDS, the gate and the source driver IC is cut off, and if the input data is the same as previously input data, the power supplied to the timing controller and the LVDS is turned off. The driving circuit of the liquid crystal display device characterized in that the cut off.

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