KR100542312B1 - Method and circuit for transferring data signal with low Electro Magnetic Interface - Google Patents

Abstract

The present invention relates to a data signal transmission method and circuit for lowering the rate of change of the data signal and reducing the effect of electromagnetic interference by using the case where the data signals of adjacent lines are often the same in the method of transmitting the display data signal.

The present invention compares a current data signal with a previous data signal by using the same probability that the data signals of adjacent lines have the same probability, and transmits the comparison signal of the data signal, and uses the transmitted comparison signal and the previous data signal. Thereby restoring the original data signal, thereby lowering the rate of change of the data signal.

According to an aspect of the present invention, there is provided a data signal transmission circuit for implementing the data signal transmission method, comprising: a controller including a memory for storing a data signal, an encoder configured to compare a current data signal with a previous data signal and output the same; And a source driver comprising a decoder for restoring the original data signal using the output signal.

Description

Method and circuit for transferring data signal with low electro magnetic interface to reduce electromagnetic interference

1 is a block diagram showing a conventional data signal transmission method;

2 is a block diagram showing a data signal transmission method according to an embodiment of the present invention;

3 is a diagram illustrating a control unit for encoding a data signal in a data signal transmission circuit according to an embodiment of the present invention;

4 is a diagram illustrating a source driver for decoding a data signal in a data signal transmission circuit according to an embodiment of the present invention;

(Name of the code for the main part of the drawing)

100: control unit 200: source driving unit

10: memory 20: encoder

30: Decoder 21, 22: D flip flop

XOR1, XOR2: Exclusive OR Gate

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of transmitting data signals of a liquid crystal display (LCD) device. More particularly, the present invention relates to a method of transmitting a data signal between adjacent lines. The present invention relates to a method for lowering an operating frequency according to a change of a data signal and reducing an electromagnetic interference (EMI) by comparing a data signal of the data signal and transmitting the comparison signal of the data signal, and a circuit implementing the method.

Electromagnetic interference is large when the rate of change of the transmitted data signal is high, that is, when the operating frequency for transmitting the data signal is large, and noise is generated by the electromagnetic interference phenomenon, thereby causing malfunction in the circuit. many.

In particular, in recent years, as liquid crystal displays increasingly require larger size and higher resolution, the amount of data signals is increasing, and the operating frequency is increasing in order to process many data signals.

1 illustrates a conventional data signal transmission method. Referring to FIG. 1, in the conventional data signal transmission method, a source drive IC 200 may be applied to a red, green, and blue data signal without any manipulation through the control unit 100. Is sending to. In the above, a case in which the data signals of red (R), green (G), and blue (B) are 6 bits (Bits) are illustrated.

However, when the operating frequency of the data signal increases as described above, malfunctions are often caused in the circuit due to electromagnetic interference. In particular, such malfunctions occur more often as the operating frequency increases.                         

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and provides a data signal transmission method and circuit capable of more stable operation by lowering an operating frequency and reducing electromagnetic interference by using data signals between adjacent lines that are often the same. The purpose is.

In order to achieve the above object, the present invention utilizes a case where the data signals between adjacent lines are often the same, and compares the previous data signal with the current data signal and transmits a comparison signal of the data signals so as to improve the data signal change rate. Lowering the operating frequency.

In order to implement the data signal transmission method, the present invention provides a control unit comprising a memory for storing a data signal, and an encoder for transmitting a comparison value by comparing a previous data signal with a current data signal; And a source driver configured to receive a signal transmitted from the controller and restore a original data signal.

The encoder may generate a comparison signal by comparing a previous data signal with a current data signal using an exclusive OR gate.

The decoder recovers the current data signal by using an exclusive OR gate that takes an output signal of the encoder and a previous data signal fed back from the output terminal to the input terminal.

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

In general, an image data signal has a high probability of having the same data signal between adjacent lines. Thus, when the data signals are the same between adjacent lines, the control unit transmits only one polarity signal through the data transmission channel, and the source driver can restore the original data signal by the signal. Therefore, when there are many identical data signals between adjacent lines, a signal having a low data signal change rate is transmitted through the data transmission channel, thereby reducing electromagnetic interference and noise.

2 shows a data signal transmission circuit according to an embodiment of the present invention. Referring to FIG. 2, after the data signal is stored in the memory 10, the present invention provides a control unit for comparing a previous data signal with a current data signal by the encoder 20 and generating a comparison signal of the data signal. And a source driver 200 including a decoder 30 for receiving the signal transmitted from the controller 100 and restoring the original data signal.

The memory 10 stores a data signal prior to one clock and allows the encoder 20 to compare the current data signal.

3 shows the control unit 100 again. Referring to FIG. 3, the controller 100 receives a first D flip flop 21 that receives a previous data signal R0 (L-1) stored in the memory 10, and a current D flip flop 21. The second D flip-flop 22 having the data signal R0 (L) as an input and the output signals of the first and second D flip-flops 21 and 22 are received and compared with the output signal R0 ( An exclusive OR gate (XOR1) for generating T)) is connected for each data bit.

3 shows first encoding means 23 for encoding the first bit signal R0 of the red data signal R among the internal circuits of the encoder 20. Circuits for comparing data signals are provided for each bit of red, green, and blue data signals to compare the data signals for each bit.

The first D flip-flop 21 and the second D flip-flop 22 are connected to the previous red data signal R0 (L-1) and the current red data signal R0 (L) by a clock signal, respectively. ) Is applied to the exclusive OR gate (XOR1). The exclusive OR gate XOR1 compares two input signals R0 (L-1) and R0 (L), and is low when the two input signals R0 (L-1) and R0 (L) are identical. Generates an output signal R0 (T) and, on the contrary, generates two high output signals R0 (T) when the two input signals R0 (L-1) and R0 (L) are not identical. do.

In order to encode the first data signal, the R0 (L) data signal may be initialized to "0".

In the case of sequentially transmitting image data signals, if the data signals of adjacent lines are the same, the output signals in the low state are all generated by the encoding means connected to each bit of the data signal and transmitted to the source driver 200. Therefore, all data signals transmitted through the data channel have the same polarity, thereby reducing the rate of change of the data signal and reducing electromagnetic interference. The more often the data signals of adjacent lines are the same, the lower the rate of change of the data signal is.

For example, when data signals of red (R), green (G), and blue (B) are transmitted at the values 111111, 000000, and 101010 on one line, respectively, and then the same data signals are transmitted on the next line. If the data signal is transmitted as it is, a frequency of 7 clocks is used for each line. However, in the case of using the data signal transmission method according to the present invention, since the data signals of the adjacent lines are the same, a signal of zero is transmitted in all the second lines of the adjacent lines, so that the rate of change of the data signal becomes zero. Therefore, the driving frequency decreases as the data signals to be transmitted are the same between adjacent lines.

4 shows a first decoding means 31 for receiving the output signal of the encoder 20 at the decoder 30 and restoring the first bit signal R0 of the red data signal R to the original data signal. It is provided for each bit of the data signal of the decoding means 31, and restores the corresponding data bit signal. Referring to FIG. 4, the decoding means 31 receives a second exclusive OR gate for restoring the current data signal R0 (L) by inputting the output signal of the corresponding encoding means 23 and the previous data signal. (XOR2).

When the signal R0 (T) transmitted through the encoder 20 is applied in the low state, the previous data signal R0 (L-1) and the current data signal R0 (L) are the same. The second exclusive OR gate XOR2 may restore the current data signal by outputting the same signal as the input previous data signal. In addition, when the signal R0 (T) transmitted through the encoder 20 is applied in a high state, the previous data signal R0 (L-1) and the current data signal R0 (L) are the same. Otherwise, the second exclusive OR gate XOR2 may recover the current data signal by outputting the inverted signal of the previous data signal.

At this time, by initializing the previous data signal applied to the second exclusive OR gate XOR2 to " 0 ", the decoding function can be normally performed.

In addition, since a shift register is provided inside the source driver 200, it is necessary to restore the original data signal to the address of the corresponding data signal whenever a clock signal is applied. It is possible.

The more the data signals between adjacent lines are the same, the lower the data signal change rate and the less electromagnetic interference.

As described in detail above, according to the data signal transmission method and the circuit implementing the same, a signal obtained by comparing a previous data signal with a current data signal using a large probability that the data signal is the same between adjacent lines is used. By transmitting from the controller to the source driver, the data signal change rate can be lowered and the electromagnetic interference can be reduced.

Hereinafter, this invention can be implemented in various changes in the range which does not deviate from the summary.

Claims (6)

In the method for transmitting the image data signal, Compares the previous data signal with the current data signal using a probability that the data signals between adjacent lines are the same, and transmits a comparison signal indicating whether the two data signals are the same; And comparing the transmitted comparison signal with the previous data signal to restore the original data signal, thereby lowering the rate of change of the data signal transmitted through the data channel. A circuit for comparing a previous data signal with a current data signal and transmitting a data signal by using the comparison signal, A controller including a memory for storing a data signal, an encoder for comparing a current data signal with a previous data signal stored in the memory and outputting a comparison signal; And a source driver including a decoder for receiving a comparison signal output from the encoder and previous data and comparing the two signals to restore the original data signal. The method of claim 2, wherein the encoder Is installed for each data bit, And a plurality of encoding means for comparing the current data signal of the corresponding data bit with the previous data signal to generate a comparison signal. 4. The apparatus of claim 3, wherein the plurality of encoding means A first D flip-flop that takes a previous data signal as input; A second D flip-flop that takes a current data signal as input; And an exclusive OR gate for receiving the output signals of the first and second D flip-flops and outputting a comparison signal between the two input signals. The method of claim 2, wherein the decoder Is installed for each data bit, And a plurality of decoding means for receiving a comparison signal transmitted from an encoder and comparing the comparison signal with a previous data signal to restore an original data signal. 6. The apparatus of claim 5, wherein the plurality of decoding means The comparison signal sent from the encoder is used as one input, And an exclusive OR gate to which the previous data signal output through the output terminal is fed back to the input signal.

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