Patent ID: 8031148

Claim:
An apparatus for driving a liquid crystal display, comprising: a gray voltage producer generating a plurality of positive gray voltages and a plurality of negative gray voltages based on a plurality of reference voltages including a first reference voltage for positive grays and a second reference voltages for negative grays; a pulse signal producer generating first and second pulse signals with inverted phases; and a reference voltage generator adjusting a voltage level of the first and the second pulse signals from the pulse signal producer to generate the first and the second reference voltages, wherein the reference voltage generator comprises: a switch alternately switching the first and the second pulse signals; a pair of first resistors connected in series between a first predetermined voltage and a second predetermined voltage; a pair of second resistors respectively connected to the first and the second pulse signals, the switch connected to a node between the first resistors and alternately connected to the second resistors; a first amplifier, connected to the node, for amplifying a voltage of the node to produce the first reference voltage; and a second amplifier inverting an output of the first amplifier with respect to a predetermined voltage to produce the second reference voltage.