Patent ID: 8217870

Claim:
An apparatus that generates gradation voltages, comprising: a maximum/minimum selection unit configured to output a voltage corresponding to a maximum selection signal as a maximum reference voltage and a voltage corresponding to a minimum selection signal as a minimum reference voltage, from a distribution of voltages ranging from a first source voltage to a second source voltage, wherein the maximum reference voltage is chosen from the first source voltage to a middle voltage of the voltage distribution and the minimum reference voltage is chosen from the middle voltage to the second source voltage of the voltage distribution; a first selector configured to output the maximum reference voltage or the minimum reference voltage as a 1 st gradation voltage, in response to an inversion control signal; a second selector configured to output the minimum reference voltage or the maximum reference voltage as an N th gradation voltage, in response to the inversion control signal, where N is a natural number, wherein when the logic level of the inversion control signal is at a first level, the first selector outputs the maximum reference voltage as the 1 st gradation voltage and the second selector outputs the minimum reference voltage as the N th gradation voltage, and when the logic level of the inversion control signal is at a second level, the first selector outputs the minimum reference voltage as the 1 st gradation voltage and the second selector outputs the maximum reference voltage as the N th gradation voltage; and a gamma control unit configured to: select, from among a plurality of voltages in a voltage distribution between the 1 st gradation voltage and the N th gradation voltage, voltages corresponding to a 1 st gamma selection signal to an M th gamma selection signal, respectively, as a 1 st gamma voltage to an M th gamma voltage, where M is a natural number, and generate a 2 nd gradation voltage to an (N−1) th gradation voltage from the 1 st gamma voltage to the M th gamma voltage, wherein a middle gamma voltage between the 1 st gamma voltage and the M th gamma voltage is used as a symmetric reference voltage, but not used as gradation voltage.