TWI581230B - Source driver - Google Patents

Description

Source driver

The present invention relates to a source driver, particularly a source driver for horizontal n-point (HnDot) inversion.

Liquid crystal displays (LCDs) have the advantages of lightness, low power consumption, and no radiation, so they are commonly used in various electronic products, such as computers, tablets, mobile phones, etc., as output displays. The liquid crystal molecules in the liquid crystal display are mainly controlled by the voltage difference between the pixel electrode and the common voltage to change the intensity of the passing light.

The liquid crystal display includes a source driver controlled by a timing controller for generating a driving signal representing the image data to the pixel electrode. In order to avoid permanent damage of polarization caused by liquid crystal molecules, the source driver needs to periodically change the polarity of the drive signal, called polarity inversion. Commonly used polarity inversion methods include frame inversion, line inversion, or dot inversion.

Since the driving signal does not fall between the positive polarity and the negative polarity in a balanced manner, when a specific pattern appears in the image, for example, when the black image area is adjacent to the white image area, the common voltage is shifted, thereby forming interference. Crosstalk is called the common voltage coupling effect.

Therefore, there is a need to propose a novel mechanism to improve the shortcomings of conventional source drivers.

In view of the above, one of the objects of embodiments of the present invention is to provide a horizontal n-point (HnDot) inverted source driver for avoiding or reducing noise generated by the common voltage coupling effect.

According to an embodiment of the invention, the source driver comprises a drive signal generator and n switch switches. The driving signal generator generates n sets of driving signals related to the column image data, and each group includes a positive driving signal and a negative driving signal. Each switch has two input terminals, and receives two drive signals of the corresponding group, and each switch has two output ends. When horizontal n-point inversion is performed, where n is an integer greater than one, wherein the first output of each switch is connected to one of the first n inversion drive signals among the 2n inversion drive signals, and the second The output terminal is connected to one of the last n inversion driving signals among the 2n inversion driving signals.

The first A diagram and the first B diagram show functional block diagrams of the source driver 100 in which the horizontal n dot or HnDot (n is greater than 1) inversion of the embodiment of the present invention. The first A map and the first B graph are exemplified by horizontal 6 point (H6Dot) inversion, but are not limited thereto.

The source driver 100 of the present embodiment includes a driving signal generator 11 that generates n groups (for example, groups 1 to 6 shown) of the column image data, and each group includes a positive driving signal and a negative electrode. The driving signals are, for example, the positive polarity driving signal A1 of the first group and the negative polarity driving signal B1.

The source driver 100 of this embodiment further includes n switch switches 12. Each switch 12 has two inputs and receives two drive signals of the corresponding group. That is, the first input receives the positive drive signal of the corresponding group, and the second input receives the negative drive signal of the corresponding set. Each switching switch 12 has two outputs, wherein the first output is connected to one of the first n inversion driving signals among the 2n inversion driving signals, and the second output is connected to the 2n inversion driving signals. One of the last n inversion drive signals. Taking the first (topmost) switch 12 of the first A picture as an example, the first output end is connected to one of the first six inversion driving signals (in this example, the first inversion driving signal out1), and the first The two outputs are connected to one of the last six inversion drive signals (in this example, the seventh inversion drive signal out7). The remaining diverter switches 12 are also assigned connections on the same principle, but each inversion drive signal is only assigned to a diverter switch 12.

During the beginning of the frame, each switch 12 is forward-switched, that is, the first output is electrically connected to the first input, and the second output is electrically connected to the second input. . Thereby, as shown in FIG. A, the source driver 100 can generate continuous n positive polarity inversion driving signals (for example, out1~out6), and then successively n negative polarity inversion driving signals (for example, out7~out12). ).

During the next frame, as shown in the first B, each switch 12 is cross-switched, that is, the first output is electrically connected to the second input, and the second output is electrically connected to the second An input. Thereby, as shown in FIG. B, the source driver 100 can generate continuous n negative polarity inversion driving signals (for example, out1~out6), and then successively n positive polarity inversion driving signals (for example, out7~out12). ).

In this embodiment, when a specific image pattern is detected by a timing controller (not shown in the drawing), the source driver 100 is executed to avoid or reduce the noise generated by the common voltage coupling effect. The horizontal n point (HnDot, n is greater than 1) is reversed. When a specific image pattern does not exist, the source driver 100 will resume performing a dot inversion, or may be referred to as H1ot inversion.

2A and 2B show functional block diagrams of the dot-reversed source driver 100 of the embodiment of the present invention. Different from the first A/B diagram, the first output end and the second output end of each switch switch 12 are respectively connected to the corresponding groups of reverse drive signals among the n sets of inverted drive signals. Taking the first (topmost) switch 12 of the second A diagram as an example, the first output terminal is connected to the first inversion driving signal among the first group of reverse driving signals (in this example, the first inversion) The driving signal out1) is connected to the second inversion driving signal (in this example, the second inversion driving signal out2) among the first group of inversion driving signals. The remaining switchers 12 also assign connections in accordance with the same principles.

During the initial frame, each switch 12 is forward-switched, that is, the first output is electrically connected to the first input, and the second output is electrically connected to the second input. Thereby, as shown in FIG. 2A, the source driver 100 can generate an inversion driving signal (for example, out1 to out12) in which the positive polarity and the negative polarity are alternated.

During the next frame, as shown in FIG. 2B, each switch 12 is cross-switched, that is, the first output is electrically connected to the second input, and the second output is electrically connected to the second An input. Thereby, as shown in FIG. 2B, the source driver 100 can generate an inversion driving signal in which the positive polarity and the negative polarity are alternated, but the polarity is opposite to the polarity shown in the second A diagram.

In order to make the switch 12 applicable to both horizontal n-point (HnDot) inversion (first A/B diagram) and point inversion (second A/B diagram), the structure of the switch 12 can be as The third picture shows. Taking the first (topmost) switch 12 of the first A/B diagram and the second A/B diagram as an example, the first switch S1 and the second switch S2 are connected in the forward direction to the corresponding ones of the n sets of inversion drive signals. The group reverses the drive signal. When closed, an inversion drive signal as shown in FIG. 2A is generated. The third switch S3 and the fourth switch S4 are cross-connected to respective groups of inverted driving signals among the n sets of inverted driving signals. When closed, an inversion drive signal as shown in the second B diagram is generated. The fifth switch S5 is connected between the second input terminal and one of the last n inversion driving signals (out7 in this example) among the 2n inversion driving signals. When the first switch S1 and the fifth switch S5 are closed, an inversion driving signal as shown in the first A diagram is generated. The sixth switch S6 is connected between the first input terminal and one of the last n inversion driving signals (out7 in this example) among the 2n inversion driving signals. When the third switch S3 and the sixth switch S6 are closed, an inversion driving signal as shown in the first B diagram is generated.

The above description is only the preferred embodiment of the present invention, and is not intended to limit the scope of the present invention; all other equivalent changes or modifications which are not departing from the spirit of the invention should be included in the following Within the scope of the patent application.

100‧‧‧Source Driver
11‧‧‧Drive signal generator
12‧‧‧Toggle switch
A1~A6‧‧‧Positive drive signal
B1~B6‧‧‧negative driving signal
Out1~out12‧‧‧Reverse drive signal
S1‧‧‧ first switch
S2‧‧‧ second switch
S3‧‧‧ third switch
S4‧‧‧fourth switch
S5‧‧‧ fifth switch
S6‧‧‧ sixth switch

The first A diagram and the first B diagram show functional block diagrams of the horizontal n-dot inversion source driver of the embodiment of the present invention. 2A and 2B show functional block diagrams of the dot-reversed source driver of the embodiment of the present invention. The third figure shows a schematic diagram of the switches of the first A/B diagram and the second A/B diagram.

100‧‧‧Source Driver

11‧‧‧Drive signal generator

12‧‧‧Toggle switch

A1~A6‧‧‧Positive drive signal

B1~B6‧‧‧negative driving signal

Out1~out12‧‧‧Reverse drive signal

Claims (9)

A source driver includes: a driving signal generator that generates n sets of driving signals related to column image data, each set includes a positive driving signal and a negative driving signal; and n switching switches, each switching The switch has two input ends, and receives two driving signals of the corresponding group, each switching switch has two output ends; when performing horizontal n dot inversion, wherein n is an integer greater than one, wherein the first output of each switching switch The terminal is connected to one of the first n inversion driving signals among the 2n inversion driving signals, and the second output terminal is connected to one of the last n inversion driving signals among the 2n inversion driving signals; when the execution level n When the dot is reversed, each switch is switched in the forward direction during the initial frame, whereby the source driver generates continuous n positive polarity inversion driving signals, followed by successive n negative polarity inversion driving Signal; during the next frame, each switch is cross-switched, whereby the source driver generates continuous n negative polarity inversion driving signals, followed by successive n positive polarity inversion driving signals; When the horizontal n-point is reversed, wherein the forward switching of the switching switch electrically connects the first output end to the first input end, and the second output end is electrically connected to the second input end; the cross switching system is first The output end is electrically connected to the second input end, and the second output end is electrically connected to the first input end. The source driver of claim 1, wherein the first input of each of the switches receives a corresponding set of positive polarity drive signals, and the second input receives a corresponding set of negative polarity drive signals. The source driver of claim 1, wherein each of the inversion driving signals is only assigned to one of the switching switches. According to the source driver described in claim 1, the dot inversion is performed. According to the source driver of claim 4, when the dot inversion is performed, the first output end and the second output end of each of the switch switches are respectively connected to the inverse of the corresponding group among the n sets of inverted drive signals. Turn drive signal. According to the source driver described in claim 5, when the dot inversion is performed, each of the switches is forwardly switched during the initial frame, whereby the source driver generates positive and negative electrodes. The alternating reverse driving signal; during the next frame, each switching switch performs cross switching, whereby the source driver generates an inverted driving signal with a negative polarity and a positive polarity, the polarity of which is opposite to the initial drawing The polarity during the frame. According to the source driver of claim 6, when the dot reversal is performed, the forward switching of the switching switch electrically connects the first output end to the first input end, and the second output end is electrically connected. The first output is electrically connected to the second input, and the second output is electrically connected to the first input. The source driver according to claim 1, further comprising a timing controller, wherein when detecting a specific image pattern, the source driver performs horizontal n dot inversion, wherein n is an integer greater than one When the specific image pattern does not exist, the source driver performs dot inversion. A source driver includes: a driving signal generator that generates n sets of driving signals related to column image data, each set includes a positive driving signal and a negative driving signal; and n switching switches, each switching The switch has two input ends, and receives two driving signals of the corresponding group, each switching switch has two output ends; when performing horizontal n dot inversion, wherein n is an integer greater than one, wherein the first output of each switching switch The terminal is connected to one of the first n inversion driving signals among the 2n inversion driving signals, and the second output terminal is connected to one of the last n inversion driving signals among the 2n inversion driving signals; The switch includes: a first switch, a second switch, and a forward driving signal connected to a corresponding group of the n sets of inverted driving signals, when the first switch and the second switch are closed, the source driver Producing a continuous n positive polarity inversion driving signals, followed by n consecutive negative polarity inversion driving signals; the third switch and the fourth switch are cross-connected to respective groups of inversion driving signals of the n sets of inversion driving signals, when When the third switch and the fourth switch are closed, the source driver generates a continuous n negative polarity inversion driving signals, followed by n consecutive positive polarity inversion driving signals; and a fifth switch connected to the second input terminal and Between one of the next n inversion driving signals among the 2n inversion driving signals, when the first switch and the fifth switch are closed, the source driver generates an inversion driving signal with alternating positive polarity and negative polarity; And a sixth switch connected between the first input end and one of the last n inversion driving signals among the 2n inversion driving signals, when the third switch and the sixth switch are closed, the source driver generates Negative polarity Alternating positive polarity inversion driving signal.