Buffer circuit

Abstract

A buffer circuit comprises an operational amplifier, a first switch circuit and a second switch circuit. The operational amplifier has first and second input terminals and first and second output terminals. The operational amplifier comprises a pre-stage circuit, a first output stage and a second output stage. The pre-stage circuit is coupled to the first input terminal to receive an input signal,and is coupled to the second input terminal to receive a feedback signal and generate an amplified signal. The first output stage is coupled between the pre-stage circuit and the first output end, and generates a first output signal according to the amplification signal to drive the first load. The second output stage is coupled between the pre-stage circuit and the second output end, and generates a second output signal according to the amplification signal to drive a second load. The first switching circuit is coupled between the first output terminal and the second input terminal. The second switching circuit is coupled between the second output terminal and the second input terminal. When the first switch circuit is switched on and the first output stage generates a first output signal to drive the first load, the second switch circuit is switched off and the second output stage is disabled.

Description

technical field [0001] The invention relates to a buffer circuit, in particular to a buffer circuit with high slew rate. Background technique [0002] The panel of the liquid crystal display device includes a plurality of liquid crystal display units (liquid crystal cells). It is currently known that applying a voltage of the same polarity to the liquid crystal layer in the liquid crystal display unit for a long time will cause charged ions to remain at the interface between the liquid crystal layer and the alignment film, thereby generating an internal electric field. This may cause changes in the light penetration properties of the liquid crystal molecules therein, causing irreversible damage to the liquid crystal panel. Therefore, the source driver of the liquid crystal display device usually constantly changes the polarity of the driving voltage applied to the liquid crystal display unit to avoid damage to the liquid crystal molecules due to the continuous application o...

AI Technical Summary

Problems solved by technology

Although this method can meet the requirement of switching the polarity of the driving voltage, because the transmission gate used to switch the polarity of the driving voltage itself has a certain resistance, it will reduce the slew rate of the output buffer circuit (Slew Rate), thereby affecting the pixel capacitance. Charge and discharge speed and characteristics, and reduce the display quality of liquid crystal display devices

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