A lamp driving device has a pulse width modulation circuit, a phase
splitter and several switching circuits. The pulse width modulation
circuit is arranged to generate a pulse width modulation signal. The
phase splitter is coupled to the pulse width modulation circuit and
arranged to split the pulse width modulation signal into several phased
signals having different phases, wherein pulses of each phased signal are
non-overlapping with those of another phased signal. The switching
circuits are coupled to the phase splitter and are arranged to
respectively receive one of the phased signals, wherein each switching
circuit is controlled by the received phased signal.