Abstract: A driving circuit comprises three switch groups, each comprising a first switch, a second switch, a third switch and a fourth switch. The first and the second switches are coupled in series. The third switch is serially coupled to the fourth switch and coupled between the first and the second switches. An ith inductor of a first driving device is coupled between the third and the fourth switches, wherein i ranges between 1˜3. In high speed mode, the first and the third switches of one of the switch groups are turned on, the second and the fourth switches are turned off, the first and the third switches of another of the switch groups are turned off, the second switch is turned on, and the fourth switch is turned on or off to raise voltage of the a driving device.

Abstract: A modulation method is provided. The modulation method includes the steps of receiving multiple sinusoidal signals, obtaining the maximum value of the sinusoidal signals, obtaining the median value of the sinusoidal signals, and obtaining the minimum value of the sinusoidal signals within a period to generate a difference between the maximum value and the minimum value, generating a difference according to an upper limit and a lower limit of a predetermined comparison value, and comparing the two differences to generate an optimized modulation signal.

Abstract: A modulation method is provided. The modulation method includes steps of: receiving multiple sinusoidal signals; obtaining a maximum value, a median value and a minimum value of the sinusoidal signals within a period to generate a first difference between the maximum value and the minimum value; generating a second difference according to an upper limit and a lower limit of a predetermined comparison value; and comparing the first difference with the second difference to generate an optimized modulation signal.

Abstract: A driving circuit comprises three switch groups, each comprising a first switch, a second switch, a third switch and a fourth switch. The first and the second switches are coupled in series. The third switch is serially coupled to the fourth switch and coupled between the first and the second switches. An ith inductor of a first driving device is coupled between the third and the fourth switches, wherein i ranges between 1˜3. In high speed mode, the first and the third switches of one of the switch groups are turned on, the second and the fourth switches are turned off, the first and the third switches of another of the switch groups are turned off, the second switch is turned on, and the fourth switch is turned on or off to raise voltage of the a driving device.