JP2005345808A - Source driving integrated circuit of lcd module and source driving system using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a source driving integrated circuit of an LCD module that can improve an image quality deterioration problem and decrease the number of components of an LCD module, and to provide a source driving system using the same. <P>SOLUTION: A voltage output section that the source driving integrated circuit includes is equipped with a gamma buffer section that buffers a self-gamma-correction voltage inputted from one side of a gamma correction voltage generation section and outputs the buffering self-gamma-correction voltage to outside the source driving integrated circuit chip, an output D/A converter that inputs a buffering other-gamma-correction voltage as an other-gamma correction voltage outputted from the other side of the gamma correction voltage generation section and the buffering self-gamma correction voltage from outside the source driving integrated circuit chip to convert a digital data signal from a data register into an analog signal and outputs it, and an output driving circuit which converts the analog data signal from the output D/A converter into a driving voltage for source line driving and outputs it. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a liquid crystal display (hereinafter referred to as “LCD”), and more particularly to an LCD module source driving integrated circuit which improves image quality and reduces the number of components, and a source driving system using these. Is.

  In general, an LCD is desired by converting digital data including image information processed by a graphic controller in a PC (Personal Computer), for example, into a liquid crystal driving signal and applying it to a liquid crystal by a column driving integrated circuit. It is a display device showing image information.

  FIG. 1 is a block diagram showing an example of a conventional LCD module. The conventional LCD module includes a source driving system (100), a source PCB (Printed Circuit Board) block (200), a gate driving system (300), a gate PCB block (400), and an LCD panel (500).

  The source PCB block (200) converts a video signal transmitted from a VGA (Video Graphic Adapter) board into various signals and transmits a timing control signal to the source driving system (100) and the gate driving system (300). A timing control unit (210); a power supply unit (220) that is supplied with power from the VGA board and supplies the power to the source driving system (100), the gate driving system (300), and the timing control unit (210); A gamma correction voltage generator (230) that is supplied with power from the unit (220), generates a gamma correction voltage (Vgma), and supplies the gamma correction voltage (Vgma) to the source driving system (100).

  The LCD panel 500 includes a source line, a gate line, and pixels not shown to display a screen.

  The source driving system (100) is electrically connected to the source PCB (200) and the LCD panel (500), and includes a plurality of source driving integrated circuit chips (110-1l to 110-n). ) Source line.

  The gate driving system 300 is electrically connected to the gate PCB block 400 and the LCD panel 500, and includes a plurality of gate driving integrated circuit chips 300-1 to 300-m. 500) source line is driven.

  As shown in FIG. 2, the source driving integrated circuit chip 110-1 includes a data start signal (EIO1, EIO2), a polarity control signal (POL), a load signal (LOAD), and a data clock signal (DCLK). And a control unit (111) that receives the direction signal (Lb / R) and controls the entire source drive integrated circuit chip (110-1), and a shift register that shifts all the bits by one digit every clock cycle. 112, a data register 113 to which a reverse signal (REV1, REV2) and a digital data signal (D00 to D55) are inputted, a two-line latch 114 to which the digital data signal is inputted and outputted, and a voltage It consists of an output unit (118).

  As shown in FIG. 3, the voltage output unit (118) includes a gamma buffer unit (117), an output D / A converter (115), and an output driving circuit (116).

  The gamma buffer unit (117) includes the same gamma buffer (117a, 117b, 117c) and buffers the gamma correction voltage (Vgma) supplied from the gamma correction voltage generation unit (230). Outputs the correction voltage (Vb-gma: Buffering Gamma Correction Voltage).

  The output D / A converter (115) distributes the buffering gamma correction voltage by a distribution resistor (r1 to r63) and outputs a distribution gamma voltage (V0 to V63), and the distribution A switch array unit (115b) having a switch array (115b-1 to 115b-n) for converting the digital data signal into an analog data signal by switching with a gamma voltage.

  The output driving circuit (116) includes a number of output buffers (116-1 to 116-n) having a one-to-one correspondence with the switch array (115b-1 to 115b-n), and receives the analog data signal. Drive voltages (OUT1 to OUTn) are output to the LCD panel (500).

  As shown in FIG. 4, the gamma correction voltage generator (230) external to the source driving system (100) receives four gammas from the first and second input voltages (Vin1, Vin2) from the power source (220). The voltage is distributed by the correction resistors (R1, R2, R3, R4) and the first, second, and third gamma correction voltages (Vgma1, Vgma2, Vgma3) are respectively supplied to the source drive integrated circuit chips (110-1 to 110-n) Common output to That is, the first gamma correction voltage (Vgma1) is a first source driving integrated circuit chip (110-1), a second source driving integrated circuit chip (110-2), and an nth source driving integrated circuit chip (110). -n) is input to the first gamma buffer (117a) in the gamma buffer section (117). The second gamma correction voltage (Vgma2) includes a first source driving integrated circuit chip (110-1), a second source driving integrated circuit chip (110-2), ..., and an nth source driving integrated circuit chip (110-n). ) Is input to the second gamma buffer (117b) in the gamma buffer unit (117). The third gamma correction voltage (Vgma3) includes a first source driving integrated circuit chip (110-1), a second source driving integrated circuit chip (110-2), ..., and an nth source driving integrated circuit chip (110-n). ) In the third gamma buffer (117c) in the gamma buffer unit (117).

  In the conventional LCD module configured as described above, the gamma correction voltage generator (230) sends the gamma correction voltage to the source driving integrated circuit chips (110-1 to 110-n) of the source driving system (100). Supply in parallel. At this time, the value of the gamma correction resistor of the gamma correction voltage generator (230) is appropriately adjusted so that the gamma correction voltage matches the characteristic characteristic of the LCD panel (500).

  The gamma correction voltages are respectively supplied to the gamma buffer units (117) of the source driving integrated circuit chips (110-1 to 110-n) of the source driving system (100) and output from the gamma buffer unit (117). The buffering gamma correction voltages (Vb-gma1, Vb-gma2, and Vb-gma3) are input to the register array (115a). When the register array 115a is an n-bit output D / A converter 115, 2n distributed gamma voltages are supplied to the switch array unit 115b using the input buffering gamma correction voltage. In parallel.

  As shown in FIG. 3, each of the switch arrays 115b-1 to 115b-n of the switch array unit 115b has 2n distributed gamma voltages input from the register array 115a according to input digital data signals. Among them, one selected distribution gamma voltage, that is, an analog data signal is transmitted to the output driving circuit (116). Each of the output buffers (116-1 to 116-n) of the output driving circuit (116) outputs the selected distributed gamma voltage, i.e., the driving voltage (OUT1 to OUTn), to the LCD panel (500). The source line of the LCD panel 500 is driven.

  As shown in FIG. 4, the gamma buffer (117a, 117b, 117c) is built in the source drive integrated circuit chip (110-1 to 110-n) because the gamma correction voltage generator (230) has a gamma The correction resistor (R1, R2, R3, R4) prevents the gamma correction voltage from being changed due to the distribution resistor of the resistor array (115a) of the source driving integrated circuit chip (110-1 to 110-n). It is to do.

  That is, in order to prevent the gamma correction voltage generated from the gamma correction voltage generator (230) from being affected by the resistance of the register array (115a), the output of the gamma correction voltage generator (230). And a gamma buffer unit (117) composed of gamma buffers (117a, 117b, 117c) is inserted between the register array (115a) and the input of the register array (115a).

As described above, when the gamma buffer unit (117) is built in each source driving integrated circuit chip (110-1 to 110-n), the characteristics of the gamma buffer units (117) do not match. That is, the gamma buffer (117a) of the first source driving integrated circuit chip (110-1), the gamma buffer (117a) of the second source driving integrated circuit chip (110-2), and the nth source driving integrated circuit chip. The characteristics between the (110-n) gamma buffers (117a) do not match. Accordingly, the gamma buffer (117a) of the first source driving integrated circuit chip (110-1) and the gamma buffer (117a) of the nth source driving integrated circuit chip (110-n) are connected to the gamma correction voltage generator (230). Even if the same gamma correction voltage is input from, some voltage deviation occurs between the outputs of the gamma buffers (117a). Due to such deviation, the distributed gamma voltages of the first source driving integrated circuit chip (110-1) become V0, V1, V2,..., V63, respectively, while the nth source driving integrated circuit chip (110-n). Can be V0 ′, V1 ′, V2 ′,..., V63 ′ different from V0, V1, V2,. As a result, a drive voltage deviation also occurs between the source drive integrated circuit chips (110-1, 110-n), so that the image quality of the LCD is degraded.
Accordingly, another source driving system has been proposed in order to solve the problem of image quality degradation caused by the LCD using the source driving system 100.

  FIG. 5 is a block diagram showing another configuration of a conventional LCD module. For convenience of explanation, in order to avoid duplication of explanation, differences between the source driving system 120 of FIG. 5 and the source driving system 100 shown in FIGS. 1 to 4 will be mainly described.

  The LCD module illustrated in FIG. 5 is configured such that one gamma buffer unit 127 is commonly connected to the source driving integrated circuit chips 120-1 to 120-n of the source driving system 120. It is arranged in the source PCB block (200) outside the source driving system (120). In addition, the LCD module shown in FIG. 5 is different in that the gamma buffer unit (117) of FIG. 1 is built in each of the source driving integrated circuit chips (110-1 to 110-n) of the source driving system (100). Except for, it has the same structure as the LCD module of FIG.

  That is, in the source driving integrated circuit chip (110-1) illustrated in FIG. 2, the gamma buffer unit (117) is disposed inside the voltage output unit (118), but the source driving integrated circuit chip (110-1) illustrated in FIG. In the integrated circuit chip (120-1), the gamma buffer unit (127) is arranged outside the voltage output unit (128).

  Similarly, the register array 115a of the voltage output unit 118 illustrated in FIG. 3 inputs a buffering gamma correction voltage from the gamma buffer unit 117 disposed in the voltage output unit 118. However, the register array 115a of the voltage output unit 128 shown in FIG. 7 receives the buffering gamma correction voltage from the gamma buffer unit 127 arranged outside the voltage output unit 128. Entered.

  Hereinafter, with respect to the source driving system (120) shown in FIG. 8, only the differences when compared with the source driving system shown in FIG. 4 will be described. The gamma correction voltages (Vgma1, Vgma2, Vgma3) output from the gamma correction voltage generator (230) external to the source driving system (120) are respectively gamma buffer units (external to the source driving system (120)). 127) and the buffering gamma correction voltages (Vb-gma1, Vb-gma2, Vb-gma3) buffered from the gamma buffer unit (127) are respectively source driving integrated circuits of the source driving system (120). Input to the register array (115a) of the chip (120-1 to 120-n). That is, the first, second and third buffering gamma correction voltages are the first source driving integrated circuit chip (120-1), the second source driving integrated circuit chip (120-2), and the nth source driving. The data is input to the register array (115a) provided in the output D / A converter (115) of the integrated circuit chip (120-n).

  In the source driving system 100 shown in FIGS. 1, 2, 3 and 4, a gamma buffer unit 117 having a number of gamma buffers is provided inside the source driving integrated circuit chip 110-1 to 110-n. By incorporating each of them, an output deviation between the source driving integrated circuit chips (110-1 to 110-n), that is, a driving voltage deviation occurs due to the characteristic mismatch of each of the gamma buffers, which causes a problem of image quality degradation. In order to eliminate the image quality degradation problem, the source driving system 120 shown in FIGS. 5, 6, 7 and 8 includes a gamma buffer unit 127 having a large number of gamma buffers. By configuring the components and arranging them outside the source drive integrated circuit chips (120-1 to 120-n), the conventional problems related to image quality degradation have been improved. That is, since it is not affected by the characteristic mismatch between the gamma buffers, for example, if the distributed gamma voltage in the first source driving integrated circuit chip (120-1) is V0, V1, V2,. The distributed gamma voltage in the source drive integrated circuit chip (120-n) is also V0, V1, V2, ..., V63, and no voltage deviation occurs, and between each source drive integrated circuit chip (120-1, 120-n) In addition, there is no drive voltage deviation, so image quality does not deteriorate.

  However, the additional use of separate parts increases the number of assembly process steps, increasing the defect rate and increasing costs.

  Therefore, the present invention improves the image quality degradation problem by using one gamma buffer for one specific gamma correction voltage so as not to cause a drive voltage deviation between source drive integrated circuit chips. With the goal.

  Another object of the present invention is to reduce the number of parts of an LCD module by incorporating a gamma buffer unit including a large number of gamma buffers in a source driving integrated circuit chip.

  The present invention has been made in view of the above-described circumstances, and an LCD module source driving integrated circuit according to the present invention includes a voltage output unit that outputs a driving voltage for driving a source line of an LCD panel. In the source driving integrated circuit chip, the voltage output unit buffers the self-gamma correction voltage input from one side of the gamma correction voltage generation unit, and outputs the buffering self-gamma correction voltage to the outside of the source driving integrated circuit chip. A gamma buffer unit that outputs to the buffer, a buffering other gamma correction voltage corresponding to another gamma correction voltage output from the other side of the gamma correction voltage generation unit, and the buffering self-gamma correction voltage outside the source driving integrated circuit chip Digital data input from the data register. An output D / A converter that converts the analog signal into an analog data signal and outputs the analog data signal input from the output D / A converter into a drive voltage for driving the source line of the LCD panel and outputs the converted voltage Includes an output drive circuit.

  In the source driving integrated circuit of the LCD module, the gamma buffer may include one or more gamma buffers.

  In the source drive integrated circuit of the LCD module, the output D / A converter outputs a distributed gamma voltage by distributing the buffering self-gamma correction voltage and the buffering other gamma correction voltage by a distribution resistor. A switch array unit having a register array and a switch array for converting the digital data signal into the analog data signal by switching the distribution gamma voltage as input may be included.

  In the LCD module source driving integrated circuit, the output driving circuit includes a number of output buffers corresponding to the switch array, and converts the analog data signal input from the switch array into the driving voltage. However, it may be configured to output.

  The source driving system using the source driving integrated circuit of the LCD module according to the present invention includes a first source driving integrated circuit chip and an nth source driving integrated circuit chip having the same internal structure. In the source driving system using a circuit, the first source driving integrated circuit chip buffers a self-gamma correction voltage input from one side of a gamma correction voltage generator, thereby generating a buffering self-gamma correction voltage. (1) A gamma buffer unit that outputs to the outside of the source drive integrated circuit chip, a buffering other gamma correction voltage corresponding to another gamma correction voltage output from the other side of the gamma correction voltage generation unit, and the buffering self-gamma correction voltage By being input from the outside of the first source drive integrated circuit chip. An output D / A converter that converts a digital data signal input from a data register into an analog data signal and outputs the analog data signal; and an analog data signal input from the output D / A converter drives a source line of the LCD panel. A voltage output unit including an output driving circuit that converts the output voltage into a driving voltage for output, and the n-th source driving integrated circuit chip buffers another gamma correction voltage output from the other side of the gamma correction voltage generation unit. A gamma buffer unit for outputting the buffering and other gamma correction voltages to the first source driving integrated circuit chip, a buffering self-gamma correction voltage of the first source driving integrated circuit chip, and an nth source driving integrated circuit chip. To input buffering and other gamma correction voltages output to the outside Accordingly, an output D / A converter that converts a digital data signal input from a data register into an analog data signal and outputs the analog data signal input from the output D / A converter drives a source line of the LCD panel. A voltage output unit including an output drive circuit that converts the output voltage into a drive voltage for output.

  Further, in the source driving system using the source driving integrated circuit of the LCD module, the gamma buffer unit of the first source driving integrated circuit chip has one or more gamma buffers, and the gamma buffer includes the buffering self circuit. It may be configured to output a gamma correction voltage.

  Further, in the source driving system using the source driving integrated circuit of the LCD module, the gamma buffer unit of the nth source driving integrated circuit chip has one or more gamma buffers, and the gamma buffer is the buffer ring or the like. It may be configured to output a gamma correction voltage.

  The source driving system using the source driving integrated circuit of the LCD module of the present invention includes a first source driving integrated circuit chip, a second source driving integrated circuit chip, and an nth source driving integrated circuit chip having the same internal structure. In the source driving system using the source driving integrated circuit of the LCD module including the first source driving integrated circuit chip, the first source driving integrated circuit chip buffers the self-gamma correction voltage input from one side of the gamma correction voltage generator. A gamma buffer unit for outputting a ring self-gamma correction voltage to the outside of the first source driving integrated circuit chip; a buffer ring other gamma correction voltage corresponding to another gamma correction voltage output from the other side of the gamma correction voltage generation unit; The buffering self-gamma correction voltage is applied to the first source driving integrated circuit chip. Output D / A converter that converts a digital data signal input from a data register into an analog data signal and outputs the analog data signal input from the output D / A converter. A voltage output unit including an output drive circuit that converts and outputs a drive voltage for driving a source line of the LCD panel, and the nth source drive integrated circuit chip outputs from the other side of the gamma correction voltage generation unit. A gamma buffer unit that buffers the other gamma correction voltage and outputs the buffering other gamma correction voltage to the first source and the second source driving integrated circuit chip, and the buffering self of the first source driving integrated circuit chip. A gamma correction voltage and a buffer output from the outside of the n-th source driving integrated circuit chip. An output D / A converter that converts a digital data signal input from a data register into an analog data signal by inputting a gamma correction voltage such as uffer ring, and an analog data signal input from the output D / A converter Including a voltage output unit including an output drive circuit that converts and outputs a drive voltage for driving a source line of the LCD panel, and the second source drive integrated circuit chip is a buffer of the first source drive integrated circuit chip By inputting a ring self-gamma correction voltage and a buffer ring or other gamma correction voltage of the nth source driving integrated circuit chip, an output D / A for converting a digital data signal input from a data register into an analog data signal and outputting it Input from the converter and the output D / A converter Is the a voltage output unit comprising an output driver circuit for outputting converted into a drive voltage for driving the source lines of the analog data signal the LCD panel.

  The source driving system using the source driving integrated circuit of the LCD module may include one or more second source driving integrated circuit chips.

  The present invention can improve the image quality degradation problem by using one gamma buffer for one specific gamma correction voltage so as not to cause a drive voltage deviation between the source drive integrated circuit chips, and a large number of them. By incorporating a gamma buffer unit including a plurality of gamma buffers in the source drive integrated circuit chip, the number of parts of the LCD module can be reduced.

Hereinafter, an LCD module source driving integrated circuit and a source driving system using the same will be described in detail with reference to the accompanying drawings. As shown in FIG. 9, the LCD module to which the present invention is applied includes a source driving system (130), a source PCB block (200), a gate driving system (300), a gate PCB block (400), and an LCD panel (500). Consists of.

  The source PCB block (200) includes a timing control unit (210), a power supply unit (220), and a gamma correction voltage generation unit (230). The timing controller 210 converts the video signal transmitted from the VGA board into various signals and transmits a timing control signal to the source driving system 130 and the gate driving system 300. The power supply unit 220 is supplied with power from the VGA board and supplies the power to the source driving system 130, the gate driving system 300, and the timing control unit 210. The gamma correction voltage generator (230) is supplied with power from the power source (220) to generate a gamma correction voltage and supply it to the source driving system (130).

  The LCD panel 500 includes a source line, a gate line, and pixels not shown to display a screen.

  The source driving system 130 is electrically connected to the source PCB block 200 and the LCD panel 500, and has a plurality of source driving integrated circuit chips 130-1 to 130-n having the same internal structure. ) To drive the corresponding source line of the LCD panel (500). The gate driving system 300 is electrically connected to the gate PCB block 400 and the LCD panel 500, and includes a plurality of gate driving integrated circuit chips 300-1 to 300-m. The corresponding gate line of (500) is driven.

  As shown in FIG. 12, the source driving system 130 includes a first source driving integrated circuit chip 130-1 and an nth source driving integrated circuit chip 130-n having the same internal structure. Consists of. The source driving system (130) includes a first source driving integrated circuit chip (130-1), a second source driving integrated circuit chip (130-2), and an nth source driving integrated circuit chip having the same internal structure. (130-n).

  Here, the first source driving integrated circuit chip 130-1 is a gamma correction voltage, that is, the self gamma correction voltage (Vgma2) among the self gamma correction voltage (Vgma2, Vgma3) and the other gamma correction voltage (Vgma1). , Vgma3) is input to output a buffering self-gamma correction voltage (Vb-Vgma2, Vgma3), which is input via the external wiring of the first source driving integrated circuit chip (130-1), and The data is transmitted from the second source driving integrated circuit chip (130-2) to the nth source driving integrated circuit chip (130-n).

The nth source driving integrated circuit chip (130-n) receives the other gamma correction voltage (Vgma1) and outputs a buffering other gamma correction voltage (Vb-gma1), which is output as the nth source. The signal is input through the external wiring of the driving integrated circuit chip (130-n) and transmitted to the first source driving integrated circuit chip (130-1) to the second source driving integrated circuit chip (130-2).
The second source driving integrated circuit chip (130-2) includes a buffering self-gamma correction voltage (Vb-gma2, Vb-gma3) output from the first source driving integrated circuit chip (130-1). The buffering and other gamma correction voltage (Vb-gma1) output from the n-th source driving integrated circuit chip (130-n) is input. Further, one or more source driving integrated circuit chips having the same internal structure and operation as the second source driving integrated circuit chip (130-2) may be provided in the source driving system (130).

  As shown in FIG. 10, the source driving integrated circuit chip 130-1 includes a control unit 111, a shift register 112, a data register 113, a two-line latch 114, and a voltage output unit 138. It is comprised including.

  The control unit (111) receives a data start signal (EIO1, EIO2), a polarity control signal (POL), a load signal (LOAD), a data clock signal (DCLK), and a direction signal (Lb / R) as a source drive The entire integrated circuit chip (130-1) is controlled.

  The shift register (112) shifts all the bits by one digit every clock cycle.

  The data register (113) receives a reverse signal (REV1, REV2) and a digital data signal (D00 to D55).

  The two-line latch 114 receives and outputs the digital data signal.

  The voltage output unit (138) receives the self-gamma correction voltage of the gamma correction voltage generation unit (230) and outputs a buffering self-gamma correction voltage, which is output from the first source driving integrated circuit chip (130-1). ) Through the external wiring, and is input to the output D / A converter (115) and transmitted to the second source driving integrated circuit chip (130-2) to the nth source driving integrated circuit chip (130-n). The voltage output unit 138 receives a buffering and other gamma correction voltage from the nth source driving integrated circuit chip 130-n.

  Accordingly, the voltage output unit 138 receives the buffering self-gamma correction voltage, the buffering other gamma correction voltage, and a digital data signal and outputs a driving voltage (OUT1 to OUTn) as shown in FIG. A source line (not shown) of the LCD panel 500 is driven.

  As shown in FIG. 11, the voltage output unit (138) includes a gamma buffer unit (137), an output D / A converter (115), and an output drive circuit (116). The gamma buffer unit (137) includes a plurality of gamma buffers (117a, 117b) and is supplied with the self-gamma correction voltage (Vgma2, Vgma3) from the gamma correction voltage generation unit (230) for buffering. The buffering self-gamma correction voltage (Vb-gma2, Vb-gma3) is output to the outside of the first source driving integrated circuit chip (130-1). FIG. 11 illustrates the case where the gamma buffer unit 137 includes two gamma buffers 117a and 117b. However, the gamma buffer unit 137 may include one or more gamma buffers. It is possible that the gamma buffer provided is not used. In FIG. 11, the control unit (111), the shift register (112), the data register (113), and the two-line latch (114) of FIG. 10 are not shown for convenience of explanation, but in reality, the first source driving integrated circuit It is obvious that it is arranged on the chip (130-1).

  12 outputs the buffer ring and other gamma correction voltages (Vb-gma1) to the first, second,..., (N-1) source drive integrated circuit chips. To do.

  The output D / A converter (115) includes a register array (115a) and a switch array unit (115b). The register array 115a is a buffering self-gamma correction voltage (Vb-gma2, Vb-gma3) and a buffering other gamma correction voltage inputted through the first source driving integrated circuit chip 130-1 external wiring. By distributing the voltage of (Vb-gma1) by the distribution resistor (rl to r63), the distribution gamma voltage (V0 to V63) is output. The switch array unit 115b receives the distributed gamma voltage V0 to V63 and switches the switch array unit 115b to convert the digital data signal from the two-line latch 114 into an analog data signal. -1 to 115b-n). 11 and 12 exemplify the case where there are 63 distribution resistors, the number of the distribution resistors can be increased or decreased.

  The output driving circuit (116) includes a number of output buffers (116-1 to 116-n) having a one-to-one correspondence with the switch array (115b-1 to 115b-n), and includes the switch array (115b-1). To 115b-n) are converted into driving voltages (OUT1 to OUTn) and output to the source line of the LCD panel (500).

  Hereinafter, the connection relationship of the source driving system 130 will be described with a specific example with reference to FIG. A connection relationship between the first source driving integrated circuit chip (130-1) and the nth source driving integrated circuit chip (130-n) will be described as an example.

In FIG. 12, the control unit (111), the shift register (112), the data register (113), and the two-line latch (114) in FIG. 10 are not shown for convenience of explanation. , n It is obvious that each of the source driving integrated circuit chips (130-1 to 130-n) is arranged, and the gamma correction voltage generator (230) outside the source driving system (130) is a power source (220). ), The first, second and third input voltages (Vin1, Vin2) distributed by the gamma correction resistors (R1, R2, R3, R4) to the first, second and third gamma correction voltages (Vgma1, Vgma2). , Vgma3) is output. Although the case where there are four gamma correction resistors is illustrated, the number of gamma correction resistors can be increased or decreased.

  At this time, the first, second and third gamma correction voltages (Vgma1, Vgma2, Vgma3) are input to the source driving integrated circuit chips (130-1 to 130-n), respectively. That is, the first gamma correction voltage Vgma1 is input to the first gamma buffer 117a in the gamma buffer unit 137 of the nth source driving integrated circuit chip 130-n, and the second gamma correction voltage is input. (Vgma2) is input to the first gamma buffer (117a) in the gamma buffer unit (137) of the first source driving integrated circuit chip (130-1), and the third gamma correction voltage (Vgma3) is the first source driving. The data is input to the second gamma buffer (117b) in the gamma buffer unit (137) of the integrated circuit chip (130-1). Here, the first gamma correction voltage (Vgma1) is another gamma correction voltage, and the second and third gamma correction voltages (Vgma2, Vgma3) are self-gamma correction voltages.

  The first gamma buffer 117a of the n-th source driving integrated circuit chip 130-n buffers the first gamma correction voltage Vgma1 to generate a first buffering gamma correction voltage Vb-gma1. The register array 115a of the first source driving integrated circuit chip 130-1 and the nth source driving integrated circuit chip 130- through the external wiring of the nth source driving integrated circuit chip 130-n. Output to the register array (115a) of n). In addition, the first buffering gamma correction voltage (Vb-gma1) is obtained from the register array 115a of the second source driving integrated circuit chip 130-2 and the registers of the third to n-1 source driving integrated circuit chips. Output to the array.

  The first gamma buffer 117a of the first source driving integrated circuit chip 130-1 buffers the second gamma correction voltage Vgma2 to obtain a second buffering gamma correction voltage Vb-gma2. The register array 115a of the first source driving integrated circuit chip 130-1 and the nth source driving integrated circuit chip 130-n are connected to the first source driving integrated circuit chip 130-1 via the external wiring. ) To the register array (115a). Further, the second buffering gamma correction voltage (Vb-gma2) is obtained from the register array (115a) of the second source driving integrated circuit chip (130-2) and the registers of the third to n-1 source driving integrated circuit chips. Output to the array.

  The second gamma buffer 117b of the first source driving integrated circuit chip 130-1 buffers the third gamma correction voltage Vgma3 to obtain a third buffering gamma correction voltage Vb-gma3. ) Through the external wiring of the first source driving integrated circuit chip (130-1), the register array (115a) of the first source driving integrated circuit chip (130-1) and the nth source driving integrated circuit chip ( 130-n) to the register array (115a). The third buffering gamma correction voltage (Vb-gma3) is generated by register array 115a of second source driving integrated circuit chip 130-2 and register arrays of third to n-1 source driving integrated circuit chips. Is output.

  In addition, the register array 115a of the second source driving integrated circuit chip 130-2 has a second buffering gamma correction from the first gamma buffer 117a of the first source driving integrated circuit chip 130-1. Voltage (Vb-gma2) is input, a third buffering gamma correction voltage (Vb-gma3) is input from the second gamma buffer (117b) of the first source driving integrated circuit chip (130-1), and the first The first buffering gamma correction voltage (Vb-gma1) is input from the first gamma buffer (117a) of the n source driving integrated circuit chip (130-n). Similarly, the register array of the third to (n-1) th source driving integrated circuit chips (not shown) is similar to the register array (115a) of the second source driving integrated circuit chip (130-2). The first, second and third buffering gamma correction voltages (Vb-Vgma1, Vb-Vgma2, Vb-Vgma3) are input. Here, the first buffering gamma correction voltage (Vb-gma1) is a buffering and other gamma correction voltage, and the second and third buffering gamma correction voltages (Vb-gma2, Vb-gma3) are self-buffering. This is a gamma correction voltage.

  Accordingly, the register array 115a of the first to n-th source driving integrated circuit chips 130-1 to 130-n has the first, second and third buffering gamma correction voltages (Vb-Vgma1, The distribution gamma voltage is supplied in parallel to the switch array unit (115b) using Vb-Vgma2, Vb-Vgma3). For example, when the output D / A converter 115 is an n-bit output D / A converter, 2n distributed gamma voltages are supplied to the switch array unit 115b in parallel. At this time, the distributed gamma voltage (V0 to V63) output from the first source driving integrated circuit chip (130-1) and the distributed gamma voltage output from the nth source driving integrated circuit chip (130-n) ( V0 to V63) are the same. Also, the distributed gamma voltages output from the second to (n-1) th source driving integrated circuit chips are the same.

  The switch arrays 115b-1 to 115b-n of the switch array unit 115b have gamma voltages (V0) input from the register array 115a according to digital data signals input from the two-line latch 114. ˜V63), one selected distributed gamma voltage, that is, an analog data signal is output to the output buffer (116-1 to 116-n) of the output drive circuit (116), respectively. Thereafter, the output buffer (116-1 to 116-n) outputs a driving voltage (OUT1 to OUTn) corresponding to the distributed gamma voltage to the LCD panel (500) to drive the source line of the LCD panel (500). To do.

  On the other hand, in the example of the conventional source driving system shown in FIGS. 1, 2, 3 and 4, when a gamma buffer unit is built in each source driving integrated circuit chip, a large number of gamma correction voltages are provided for one gamma correction voltage. By using each gamma buffer for each source drive integrated circuit chip, the characteristics of each gamma buffer do not match, so even if the same gamma correction voltage is input from the gamma correction voltage generator, the output of each gamma buffer In the meantime, some voltage deviation occurs, and there is a problem that the image quality is seriously deteriorated due to the deviation of the driving voltage between the respective source driving integrated circuit chips. However, in the source driving system of the present invention, one gamma buffer is used for one specific gamma correction voltage so that a driving voltage deviation between the driving integrated circuit chips does not occur between the source driving integrated circuit chips. Thus, the image quality degradation problem can be improved.

  As another example of the conventional source driving system described above, the conventional source driving system shown in FIGS. 5, 6, 7, and 8 has been proposed to eliminate the image quality degradation problem due to the driving voltage deviation. In one example, the conventional gamma buffer unit including a large number of gamma buffers is configured as a separate component and provided outside the large number of source driving integrated circuit chips, thereby improving the conventional image quality degradation problem. The use of separate parts increases the number of assembly process steps, increases the defect rate, and increases costs. However, in the source driving system of the present invention, the number of parts of the LCD module can be reduced by incorporating a gamma buffer unit including a large number of gamma buffers in the source driving integrated circuit chip.

  Also, the embodiments according to the present invention are not limited to those described above, and various alternatives, modifications and variations can be implemented within the scope obvious to those having ordinary knowledge in connection with the present invention.

  The present invention has industrial applicability in liquid crystal display devices.

It is the block diagram which showed an example of the conventional LCD (Liquid Crystal Display) module. 2 is a diagram illustrating a source driving integrated circuit chip of the LCD module shown in FIG. FIG. 3 is a detailed circuit diagram showing a voltage output unit of the source driving integrated circuit chip shown in FIG. FIG. 2 is a detailed circuit diagram illustrating a connection relationship between a gamma correction voltage generation unit in FIG. 1 and an example of a source driving system. 6 is a diagram illustrating another configuration of a conventional LCD module. FIG. 6 is a detailed circuit diagram illustrating a source driving integrated circuit chip of the LCD module illustrated in FIG. FIG. 7 is a detailed circuit diagram illustrating a voltage output unit of the source driving integrated circuit chip illustrated in FIG. FIG. 6 is a detailed circuit diagram illustrating a connection relationship between the gamma correction voltage generation unit of FIG. 5 and another example of the source driving system. 3 is a diagram illustrating an LCD module applied to a source driving system according to the present invention. FIG. 10 is a detailed circuit diagram illustrating a source driving integrated circuit chip according to an embodiment of the present invention in the LCD module illustrated in FIG. FIG. 11 is a detailed circuit diagram illustrating a voltage output unit of the source driving integrated circuit chip illustrated in FIG. FIG. 10 is a detailed circuit diagram illustrating a connection relationship between the gamma correction voltage generation unit of FIG. 9 and the source driving system according to the embodiment of the present invention.

Explanation of symbols

130 Source drive system
130-1 to 130-n source drive integrated circuit chip
115 output D / A converter
115a register array
115b Switch array section
116 Output drive circuit
137 Gamma buffer
138 Voltage output section

Claims (9)

In a source driving integrated circuit chip including a voltage output unit that outputs a driving voltage for driving a source line of an LCD panel,
The voltage output unit is
A gamma buffer unit that buffers a self-gamma correction voltage input from one side of the gamma correction voltage generation unit and outputs the buffering self-gamma correction voltage to the outside of the source driving integrated circuit chip;
Buffering other gamma correction voltage corresponding to other gamma correction voltage output from the other side of the gamma correction voltage generator and the buffering self-gamma correction voltage are input from the outside of the source driving integrated circuit chip, An output D / A converter that converts a digital data signal input from a data register into an analog data signal and outputs the analog data signal; and an analog data signal input from the output D / A converter for driving a source line of the LCD panel A source drive integrated circuit for an LCD module, comprising: an output drive circuit for converting into a drive voltage and outputting the drive voltage.   The LCD module source driving integrated circuit of claim 1, wherein the gamma buffer includes one or more gamma buffers. The output D / A converter is
The buffering self-gamma correction voltage and the buffering and other gamma correction voltages are voltage-distributed by a distribution resistor to output a distribution gamma voltage, and the digital data is input by switching the distribution gamma voltage and switched. The source drive integrated circuit of the LCD module according to claim 1, further comprising: a switch array unit having a switch array for respectively converting a signal into the analog data signal.   The output driving circuit includes a plurality of output buffers corresponding to the switch array in one-to-one correspondence, and is configured to convert an analog data signal input from the switch array into the driving voltage and to output the driving voltage. A source driving integrated circuit for an LCD module according to claim 3. In a source driving system using a source driving integrated circuit of an LCD module including a first source driving integrated circuit chip and an nth source driving integrated circuit chip having the same internal structure,
The first source driving integrated circuit chip is:
A gamma buffer unit that buffers the self-gamma correction voltage input from one side of the gamma correction voltage generation unit and outputs the buffering self-gamma correction voltage to the outside of the first source driving integrated circuit chip;
The buffering other gamma correction voltage corresponding to the other gamma correction voltage output from the other side of the gamma correction voltage generator and the buffering self-gamma correction voltage are input from the outside of the first source driving integrated circuit chip. To convert the digital data signal input from the data register into an analog data signal and output the analog data signal, and drive the analog data signal input from the output D / A converter to the source line of the LCD panel. A voltage output unit comprising an output drive circuit that converts and outputs the drive voltage
The nth source driving integrated circuit chip includes:
A gamma buffer unit that buffers another gamma correction voltage output from the other side of the gamma correction voltage generation unit and outputs the buffering other gamma correction voltage to the first source driving integrated circuit chip;
The digital input from the data register by inputting the buffering self-gamma correction voltage of the first source driving integrated circuit chip and the buffering other gamma correction voltage output to the outside of the nth source driving integrated circuit chip. An output D / A converter that converts and outputs a data signal to an analog data signal, and an analog data signal input from the output D / A converter is converted to a drive voltage for driving the source line of the LCD panel and output A source driving system using a source driving integrated circuit of an LCD module, comprising: a voltage output unit including an output driving circuit.   The gamma buffer unit of the first source driving integrated circuit chip includes one or more gamma buffers, and the gamma buffer is configured to output the buffering self-gamma correction voltage. 6. A source driving system using the source driving integrated circuit of the LCD module according to 5.   The gamma buffer unit of the nth source driving integrated circuit chip has one or more gamma buffers, and the gamma buffer is configured to output the buffering and other gamma correction voltages. A source driving system using the source driving integrated circuit of the LCD module according to 5 or 6. In a source driving system using a source driving integrated circuit of an LCD module including a first source driving integrated circuit chip, a second source driving integrated circuit chip, and an nth source driving integrated circuit chip having the same internal structure,
The first source driving integrated circuit chip is:
A gamma buffer unit that buffers the self-gamma correction voltage input from one side of the gamma correction voltage generation unit and outputs the buffering self-gamma correction voltage to the outside of the first source driving integrated circuit chip;
The buffering other gamma correction voltage corresponding to the other gamma correction voltage output from the other side of the gamma correction voltage generator and the buffering self-gamma correction voltage are input from the outside of the first source driving integrated circuit chip. To convert the digital data signal input from the data register into an analog data signal and output the analog data signal, and drive the analog data signal input from the output D / A converter to the source line of the LCD panel. A voltage output unit comprising an output drive circuit that converts and outputs the drive voltage
The nth source driving integrated circuit chip includes:
A gamma buffer unit that buffers another gamma correction voltage output from the other side of the gamma correction voltage generation unit and outputs the buffering other gamma correction voltage to the first source and second source driving integrated circuit chip;
The digital input from the data register by inputting the buffering self-gamma correction voltage of the first source driving integrated circuit chip and the buffering other gamma correction voltage output from the outside of the nth source driving integrated circuit chip. An output D / A converter that converts and outputs a data signal to an analog data signal, and an analog data signal input from the output D / A converter is converted to a drive voltage for driving the source line of the LCD panel and output Including a voltage output unit comprising an output drive circuit,
The second source driving integrated circuit chip is:
By inputting the buffering self-gamma correction voltage of the first source driving integrated circuit chip and the buffering other gamma correction voltage of the nth source driving integrated circuit chip, the digital data signal input from the data register is converted into analog data. An output D / A converter that converts the signal into an output signal; and an output drive circuit that converts an analog data signal input from the output D / A converter into a drive voltage for driving a source line of the LCD panel and outputs the converted signal. A source driving system using a source driving integrated circuit of an LCD module, comprising a voltage output unit. The second source driving integrated circuit chip is:
The source driving system using the source driving integrated circuit of the LCD module according to claim 8, wherein one or more are provided.

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