Patent ID: 7133018

Claim:
A super twist nematic (STN) liquid crystal display (LCD) driver which drives a STN LCD panel, the STN LCD driver comprising: a reference voltage generating unit which generates a reference voltage in response to an external voltage; a voltage boosting unit which generates a boosting voltage by boosting the external voltage; a voltage control unit which generates a first segment voltage and a second segment voltage which drive a segment electrode of the STN LCD panel in response to the reference voltage and the boosting voltage; a first common voltage generating unit which drives a common voltage of the STN LCD panel in response to the external voltage, a ground voltage, and the first segment voltage and generates a first common voltage, the voltage level of which is higher than the voltage level of the first segment voltage, using a predetermined resistance ratio; and a second common voltage generating unit which drives a common voltage of the STN LCD panel in response to the external voltage, the ground voltage, and the first segment voltage and generates a second common voltage, the voltage level of which is lower than the voltage level of the first segment voltage, using a predetermined resistance ratio.