Patent ID: 8427089

Claim:
A motor driving device which drives coil terminals of a three-phase motor to flow three-phase currents, the device comprising: a pulse modulator that generates three-phase modulation pulses, each of the pulses having a duty ratio in accordance with a voltage level to be applied to each coil terminal; a shift amount selection unit that selects a first shift amount from at least two predetermined amounts, according to a pulse width of the longest pulse among the three-phase modulation pulses; a first shift unit that shifts the second-longest pulse among the three-phase modulation pulses backward by the first shift amount to delay timing; a second shift unit that shifts the third-longest pulse among the three-phase modulation pulses backward by a predetermined second shift amount to delay timing; and an inverter that drives each of the coil terminals by switching a driving power supply with the three-phase modulation pulses in which shift results of the first shift unit and the second shift unit are reflected.