Abstract: Embodiments of the invention avoid erroneous drive current control at the time of a change in the drive waveform for a spindle motor. In one embodiment, a drive current setup section acquires the actual rotational speed from a rotational speed determination section. If the drive waveform is not changed, the feedback system for a first gain determines a drive current. Drive current data corresponding to the drive current is set in a register. If the drive waveform data switches to a curved wave during the next timing cycle, the feedback system does not perform any process, but the same drive current data as for the immediately preceding timing cycle is set in the register. During the next timing cycle, the actual rotational speed is acquired from the rotational speed determination section, and the feedback system for a second gain determines the drive current. When the drive waveform data changes, the feedback system process is skipped once.

Abstract: Embodiments of the invention provide a way to accurately detect the position of a spindle motor. In a spindle motor startup process according to one embodiment, a parameter setup section acquires from a parameter table a sense time value corresponding to an input voltage that is acquired from an ADC. The parameter setup section sets the sense time value in a register. A position determination section, which is within an SPM driver, performs an induced voltage detection process for rotor position detection purposes during the time corresponding to the sense time value that is set in the register. Even when the input voltage is decreased, rotor position detection can be properly achieved by changing the sense time value in accordance with a change in the input voltage.

Abstract: A data storage device includes an enclosure case and a circuit board attached to an outer surface of the enclosure case, the enclosure case containing a spindle motor and a circular movement actuator, the spindle motor being for rotating a storage medium, the circular movement actuator being for controlling a position of a read and write head for reading data from the storage medium and for writing data to the storage medium, the circuit board having an interface cable connector at one end portion thereof for establishing a connection to a host. The circuit board is located between the interface cable connector and the spindle motor, and is attached to the enclosure case by use of a plurality of fastening members. An acceleration sensor is attached to the circuit board next to the fastening members for detecting vibrations applied to the data storage device in a rotation direction in a plane along the circuit board.

Abstract: A hard disk device includes a servo control unit that constitutes a servo loop for a head seek for performing read/write of data from/to a recording medium, a correction signal generation unit for generating a correction signal for correcting a control by the servo control unit based on an output of a predetermined sensor, and a correction signal control unit for estimating an effect of supplying the correction signal to the servo loop and for controlling whether or not the correction signal is to be supplied to the servo loop in response to a result of the estimation. Moreover, the gain of the sensor is dynamically controlled in response to the above estimation result.

Abstract: A system and method for providing rotation control stability within a disk drive. In accordance with the system of the present invention, a disk storage medium on which information is recorded is driven to rotate by a multiphase-phase DC servomotor. An actuator is utilized for loading and unloading the head to and from the disk storage medium. A load/unload controller commands the actuator to load or unload said head. In order to effectively compensate for an abrupt change in load on the servomotor caused by loading the head onto the disk storage medium, a slew rate switching unit is utilized to alter a slew rate of current supplied to the three-phase DC servomotor, based on a loading start command issued by the load/unload controller.