| 摘要 |
PROBLEM TO BE SOLVED: To provide a disk unit and a motor that consume less power and produce less noise. SOLUTION: A rotating body mounted with a disk includes a field portion and is rotationally driven by a driving current to a three-phase coil. A switching control portion 22 generates a single switching pulse signal Wp, in response to a supply current to the three-phase coil and a command signal Ac. An excitation portion 31 generates a slew rate switching signal R1 that varies in response to the switching pulse signal, and causes an upper power transistor to perform a follower operation in response to the slew rate switching signal and simultaneously perform a high-frequency switching operation. Thus, a drive voltage for high-frequency switching supplied to the coil is provided with a required voltage gradient to reduce produced switching noise. As a result, the influence of noise on the reproduction signal from the head is reduced, and thus an error in the reproduction signal is significantly reduced. |
