A power supply module for a driving device of a display system includes a source power unit, for outputting a source high voltage only in a first period and outputting a source low voltage only in a second period according to a power control signal, wherein the source high voltage and the source low voltage are utilized for generating a plurality of data signals of a plurality of pixels in the display system; and a bias power unit, for generating a common voltage, wherein the common voltage is between the source high voltage and the source low voltage; wherein the first period does not overlap the second period.