Gamma reference voltage output circuit of source driver

Abstract

A gamma reference voltage output circuit of a source driver includes a reference voltage generation unit configured to divide power supply voltages by using resistors which are connected in series, and generate a plurality of gamma reference voltages; a gamma buffer unit having a plurality of gamma buffers which selectively output, through internal switching operations, gamma reference voltages needed by a plurality of gamma voltage generation units; and the plurality of gamma voltage generation units configured to divide the gamma reference voltages which are inputted from the gamma buffer unit, by using resistors which are connected in series, in conformity with a required mode and output divided gamma voltages.

Description

technical field [0001] The present invention relates to a technology for outputting a gamma reference voltage in a source driver of a liquid crystal display device, and in particular to a gamma reference voltage output circuit of a source driver. When a gamma reference voltage is output from a gamma buffer, The circuit selectively outputs a gamma reference voltage to an in-plane switching (IPS) gamma voltage generation unit and a twisted nematic (TN) gamma voltage generation unit based on a selected mode. Background technique [0002] Generally speaking, a liquid crystal display device has a source driver integrated circuit, which drives the data lines of the liquid crystal display panel according to R, G and B data input from the outside. [0003] figure 1 A block diagram illustrating a conventional source driver circuit. [0004] refer to figure 1 , the conventional source driver circuit includes a reference voltage generation unit 11, a gamma buffer unit 12, a switch u...

AI Technical Summary

Problems solved by technology

[0015] Due to the fact that there is difficulty in transferring the gamma reference voltage of the target stage because of the voltage drop phenomenon caused by the resistance of the switch

[0016] Considering this situation, when the voltage drop phenomenon is suppressed to some extent by increasing the size of the switch, it will cause a problem that the switch occupies most of the layout

[0017] Furthermore, in the case where the resistance value of the resistance string of the gamma voltage generating unit is designed to be small, it is difficult to generate an accurate gamma voltage value due to the voltage drop.

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