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Amplifier circuit and display apparatus having the same

A technology for amplifying circuits and amplifying parts, applied in the direction of negative feedback circuit layout, static indicators, instruments, etc., to achieve the effects of preventing errors, improving stability and low power consumption, and reducing power consumption

Inactive Publication Date: 2009-08-12
SHARP KK
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, in an amplifier circuit having multiple amplifiers, since phase delays occur in the amplifiers of each stage, phase compensation is required to prevent oscillation when negative feedback is applied.

Method used

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  • Amplifier circuit and display apparatus having the same
  • Amplifier circuit and display apparatus having the same
  • Amplifier circuit and display apparatus having the same

Examples

Experimental program
Comparison scheme
Effect test

no. 1 Embodiment approach

[0127] figure 1 It is a circuit diagram of an amplifier circuit according to the first embodiment of the present invention. figure 1 In the amplifying circuit 1 shown, a plurality of amplifiers (inverters) connected in cascade are used to amplify the analog input signal AIN, and the amplified signal is used to drive the signal line SL (details will be described later). The amplifier circuit 1 is used, for example, when driving data signal lines of a liquid crystal display device.

[0128] figure 2 It is a block diagram showing the configuration of a liquid crystal display device having an amplifier circuit 1 . figure 2In the illustrated liquid crystal display device, a pixel array 110 , a data signal line driver circuit 120 , and a scanning signal line driver circuit (not shown) are integrally formed on a liquid crystal panel 100 . The pixel array 110 includes a plurality of pixel circuits 111 arranged two-dimensionally, a plurality of data signal lines 112 , and a plural...

no. 2 Embodiment approach

[0166] Figure 10 It is a circuit diagram of an amplifier circuit according to a second embodiment of the present invention. Figure 10 The amplifier circuit 2 shown is the amplifier circuit 1 according to the first embodiment ( figure 1 ), the inverter 13 is replaced by the inverter 16 (including the separation switch 62), and the separation switch 61 and the capacitor 33 are removed. The amplifying circuit 2 is the same as the amplifying circuit 1, and can be used when driving a data signal line of a liquid crystal display device (refer to figure 2 and image 3 ). Among the constituent elements of the present embodiment, the same reference numerals are assigned to the same elements as those of the first embodiment, and description thereof will be omitted.

[0167] In the amplifier circuit 2, switches 21 and 22 functioning as threshold value setting switches are provided corresponding to the respective inverters 11 and 12 other than the final stage. In addition, a capac...

no. 3 Embodiment approach

[0175] Figure 12 It is a circuit diagram of an amplifier circuit according to a third embodiment of the present invention. Figure 12 The amplifier circuit 4 shown is the amplifier circuit 2 according to the second embodiment ( Figure 10 ) is obtained by adding a capacitor 34. The amplifying circuit 4 is the same as the amplifying circuit 1, and can be used when driving the data signal lines of the liquid crystal display device (refer to figure 2 and image 3 ). Among the constituent elements of the present embodiment, the same elements as those in the first or second embodiment are assigned the same reference numerals and description thereof will be omitted.

[0176] One electrode of the capacitor 34 is connected to the input terminal of the inverter 11 and supplies the low-level power supply voltage VSS to the other electrode of the capacitor 34 . The capacitor 34 functions as an input capacitive element, one electrode of which is connected to the input terminal of t...

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Abstract

During an initial setting interval, switches (21-23,71) are rendered conductive, so that the voltage of a signal line (SL) becomes equal to a power supply voltage (VSS) and that the input voltages of inverters (11-13) become equal to a logic threshold voltage. During a write interval, switches (51,61) are rendered conductive, so that the inverters (11-13) function as amplifiers. The inverter (13) in the final stage comprises a P-type transistor (14) and an N-type transistor (15) having a smaller current drive capability. At the beginning of the write interval, a current flowing through the P-type transistor (14) changes the voltage of the signal line (SL), so that even though the N-type transistor (15) has the smaller current drive capability, the change rate of the voltage of the signal line (SL) does not change. On the other hand, since the smaller current drive capability of the N-type transistor (15) causes the inverter (13) to have a larger output resistance, the frequency characteristic of an amplifier circuit (1) has an increased phase margin, resulting in a reduction of the power consumption of the amplifier circuit (1).

Description

technical field [0001] The present invention relates to an amplifying circuit for amplifying an analog input signal and driving a signal line using the amplified signal; and a display device for driving a data signal line using the amplifying circuit. Background technique [0002] In a liquid crystal display device, a method is used to drive a data signal line (also called a source line), that is, a D / A (direct current / alternating current) converter is used to convert a digital video signal into an analog The amplifying circuit (also called amplifier, output circuit, analog buffer, etc.) in the post-stage of the A converter amplifies the analog video signal and uses the amplified signal to drive the data signal line. The reason for using this method is as follows. Since the data signal line has a large capacitive component, the voltage of the data signal line cannot be changed at a sufficient speed only by using the output signal of the D / A converter to drive the data signal...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H03F1/34
CPCG09G2310/027G09G3/3685G09G2310/0297
Inventor 清水新策前田和宏
Owner SHARP KK
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