Patent ID: 6657619
Filing Date: 2003-12-02
Classification: G09G

Abstract:
A clamping circuit for a liquid crystal display device comprising: a plurality of clamp units for receiving a plurality of input color signals of an input picture signal after deleting a DC bias from each of said input color signals to produce a plurality of clamped color signals, respectively, by adding a predetermined clamping voltage corresponding to a pedestal level of said input picture signal to each of said input color signals; and a plurality of gamma-correction circuits connected to said clamp units for receiving said clamped color signals, respectively, and for performing a predetermined gamma correction and amplification on each of said clamped color signals to produce output color signals, respectively; each of said clamp units being provided with a clamping portion for receiving said input color signal and a clamping voltage generating circuit for supplying a clamping voltage to said clamping portion so as to be controlled in response to an individual first control signal supplied thereto and generates said clamped color signal such that a black level of said clamped color signal coincides with a black level in an input/output characteristic of said gamma-correction circuit, and said clamping portion being supplied with said clamping voltage so as to add said clamping voltage to said pedestal level in a predetermined timing of said input color signal in response to a second control signal supplied thereto.