Patent ID: 7330066

Claim:
A reference voltage generation circuit for generating gamma voltages, the reference voltage generating circuit comprising: a first voltage source; a second voltage source; a variable voltage source, wherein the voltage of the variable voltage source is not fixed, and is modulated between a first voltage value and a second voltage value during positive and negative inversion periods, and the first and second voltage values are between voltage potentials of the first and second voltage sources; a first resistor circuit formed by a plurality of first resistors coupled in series, a first end of the first resistor circuit coupled to the first voltage source and a second end of the first resistor circuit coupled to the variable voltage source; a plurality of first switches each having a first end coupled between two of the first resistors and a second end coupled to a digital-to-analog converter; a plurality of first charge-sharing switches each coupled to a second end of a corresponding first switch; a second resistor circuit formed of a plurality of second resistors coupled in series, a first end of the second resistor circuit coupled to the second voltage source and a second end of the second resistor circuit coupled to the variable voltage source; a plurality of second switches each having a first end coupled between two of the second resistors and a second end coupled to the digital-to-analog converter; a plurality of second charge-sharing switches each coupled to a second end of a corresponding second switch; and a polarity inversion circuit for controlling the first switches and the second switches.