A source driver for driving a display panel includes a sample/hold circuit, a first low voltage amplifier, a second low voltage amplifier, a first multiplexer, a high voltage amplifier, a second multiplexer, and a third multiplexer. The sample/hold circuit outputs a first sampled-held voltage and a second sampled-held voltage. The first and second low voltage amplifiers receives the first and second sampled-held voltages, respectively, and generates a first and second low pixel voltage, respectively. The first multiplexer outputs one of the first and second low pixel voltages according to a polarity signal. The high voltage amplifier ,generates a high pixel voltage. The second and third multiplexers output one of the first low pixel voltage and the high pixel voltage and one of the second low pixel voltage and the high pixel voltage, respectively, to a data line according to the polarity signal.