Patent ID: 8115786
Filing Date: 2012-02-14
Classification: G09G

Abstract:
1. A liquid crystal driving circuit for converting pixel values into driving voltages on a plurality of channels, comprising: a reference voltage generating circuit generating a plurality of grayscale reference voltages, wherein the reference voltage generating circuit is divided into a high voltage generating part and a low voltage generating part according to the medium value of the rail voltage difference that is the difference between a Vcc and a ground voltage; a plurality of buffer amplifiers each corresponding to one of the grayscale voltages, wherein the buffer amplifiers are composed of a plurality of NMOS differential input pair buffer amplifiers each individually corresponding to one of the grayscale voltages from the high voltage generating part and a plurality of PMOS differential input pair buffer amplifiers each individually corresponding to one of the grayscale voltages from the low voltage generating part; an output selection circuit coupling the channels to outputs of the selected buffer amplifiers according to the pixel values; and a plurality of switch circuits coupling inputs of the selected buffer amplifiers to receive the corresponding grayscale reference voltages, and coupling inputs of the unselected buffer amplifiers to receive a supply voltage that is the ground voltage or the Vcc.