PURPOSE: A driver for a display is provided to perform safe operation by providing a preset drive signal in case of a video signal is abnormal. CONSTITUTION: A frequency detection unit(110) detects difference between the frequency of an inputted video signal and a diverged drive signal. A drive signal generator unit(120) generates the driving signal according to the detection result. The drive signal comprises the frequency synchronized with the frequency of the video signal. In case the detection result is the abnormal operation, a control unit(130) stops the frequency detection operation of the frequency estimator.
