| 摘要 |
A phase control circuit for a brushless motor includes a signal output unit that outputs M signals, whose phases differ from each other, in response to a change in the magnetic field resulting from the rotation of magnets placed in a rotor, and a control signal generator that generates two or more different kinds of group of phase control signals, based on at least the M signals, the group of phase control signals being used to control drive voltages, whose phases differ from each other, which are supplied to each phase of an N-phase coil (N being an integer greater than or equal to two). The control signal generator is configured such that a first phase control signal group and a second phase control signal group can be generated. Here, the first phase control signal group controls the drive voltages, which are supplied to each phase of the N-phase coil, in a first drive mode of the brushless motor. The second phase control signal group, whose phase differs from that of the first phase control signal group by a predetermined phase of ± degrees (±>0), controls the drive voltages, which are supplied to each phase of the N-phase coil, in a second drive mode of the brushless motor. |
