Patent ID: 7227560
Filing Date: 2007-06-05
Classification: G09G,H03F

Abstract:
1. A display drive circuit for outputting a gray scale voltage according to display data to a display panel, comprising: a generation circuit which generates gray scale voltages of a plurality of levels; and a selection circuit which selects said gray scale voltage according to said display data, among gray scale voltages having said plurality of levels; said display drive circuit having a one-bit mode in which the number of colors to be displayed on said display panel is small and a multi-bit mode in which the number of colors to be displayed on said display panel is large; wherein said generation circuit comprises a first resistor for dividing a reference voltage and a second resistor for further dividing the reference voltage divided by said first resistor to generate said gray scale voltages of a plurality of levels, and a voltage follower circuit coupled between said first resistor and said second resistor; wherein said generation circuit, in said one-bit mode, decreases a current flowing into an internal circuit which generates a gray scale voltage of an intermediate level other than two gray scale voltages of a gray scale voltage of the most lowest level and a gray scale voltage of the most highest level among the gray scale voltages of said plurality of levels, said gray scale voltage of an intermediately level being free from affecting display; and wherein said selection circuit, in said one-bit mode, selects said gray scale voltage according to said display data, from gray scale voltages of a plurality of levels including said lowest level gray scale voltage, said highest level gray scale voltage and said intermediate level gray scale voltage which are generated from said generation circuit.