Patent ID: 7511693

Claim:
A display driver adjustable for a gamma specification of a liquid display panel, said display driver comprises: a system interface receiving display data from an external; a memory storing said display data; a grayscale voltage generator generating a plurality of grayscale voltages; a gamma adjusting circuit adjusting said gamma specification; and an output circuit outputting said grayscale voltage in response to said display data from said memory to said liquid display panel, wherein said gamma adjusting circuit includes: a gradient adjustment register controlling variable resistors of a ladder resistor use for said grayscale voltage generator, for adjusting a gradient in middle of a grayscale characteristic for a voltage without changing a dynamic range; an amplitude/reference adjustment register controlling said variable resistor lower side of said ladder resistor used for said grayscale voltage generator, for adjusting an amplitude of said grayscale voltage, and controlling said variable resistor upper side of said ladder resistor used for said grayscale voltage generator, for adjusting a reference of said gradient voltage; and a micro adjustment register controlling each voltage selected by a selector in response to a plurality of voltages generated from said ladder resistor, for making a subtle adjustment of said grayscale voltage, wherein said gradient adjustment register, said amplitude/reference adjustment register and micro adjustment register, are independently set in accordance with red, green and blue, respectively.