Abstract: A data storage device is disclosed wherein an elevator actuator is controlled to move a head along an axial dimension toward a first disk surface of a first disk while processing a proximity signal generated by a proximity sensor. A first actuator position is detected when the actuator arm is proximate the first disk surface of the first disk based on the proximity signal.

Abstract: The present disclosure generally relates to an electronic circuit and method of operating thereof to back up write cache data on DDR memory in data storage devices during an emergency power off (EPO). The method involves using a power management integrated circuit (PMIC), a combo driver and one MOSFET for regulator output. The method involves detecting a voltage value that is below a predetermined threshold value, retracting a write head away from a hard disk drive (HDD), backing up data, and then resetting the HDD after the backup is complete. The backing up and retraction may occur in parallel or in sequence. The method utilizes the spindle back-electromotive force (BEMF) power to have sufficient power to make the backup. If the power from the spindle BEMF is too low, then the retraction is suspended and a high impedance is present to lighten the load until the BEMF recovers before the power on reset. As such, the back-up data is not reset and volatized by a lack of power.

Abstract: A data storage device is disclosed wherein an elevator actuator is controlled to move a head along an axial dimension toward a first disk surface of a first disk while processing a proximity signal generated by a proximity sensor. A first actuator position is detected when the actuator arm is proximate the first disk surface of the first disk based on the proximity signal.

Abstract: The present disclosure generally relates to an electronic circuit and method of operating thereof to back up write cache data on DDR memory in data storage devices during an emergency power off (EPO). The method involves using a power management integrated circuit (PMIC), a combo driver and one MOSFET for regulator output. The method involves detecting a voltage value that is below a predetermined threshold value, retracting a write head away from a hard disk drive (HDD), backing up data, and then resetting the HDD after the backup is complete. The backing up and retraction may occur in parallel or in sequence. The method utilizes the spindle back-electromotive force (BEMF) power to have sufficient power to make the backup. If the power from the spindle BEMF is too low, then the retraction is suspended and a high impedance is present to lighten the load until the BEMF recovers before the power on reset. As such, the back-up data is not reset and volatized by a lack of power.

Abstract: The present disclosure generally relates to an electronic circuit and method of operating thereof to back up write cache data on DDR memory in data storage devices during an emergency power off (EPO). The method involves using a power management integrated circuit (PMIC), a combo driver and one MOSFET for regulator output. The method involves detecting a voltage value that is below a predetermined threshold value, retracting a write head away from a hard disk drive (HDD), backing up data, and then resetting the HDD after the backup is complete. The backing up and retraction may occur in parallel or in sequence. The method utilizes the spindle back-electromotive force (BEMF) power to have sufficient power to make the backup. If the power from the spindle BEMF is too low, then the retraction is suspended and a high impedance is present to lighten the load until the BEMF recovers before the power on reset. As such, the back-up data is not reset and volatized by a lack of power.

Abstract: A data storage device is disclosed comprising a spindle motor configured to rotate a disk, and a first voice coil motor (VCM) configured to actuate a head over the disk. During at least fifty percent of a seek of the head over the disk, a spindle control signal is generated based on a continuous function of a current flowing through the first VCM, and the spindle control signal is applied to the spindle motor.

Abstract: Embodiments of the present invention provide a magnetic disk drive, in which a disturbance component contained in an output signal from a rotational vibration detector, can be appropriately suppressed irrespective of frequency of the component, and a method of controlling the drive. According to one embodiment, in a magnetic disk drive having a rotational vibration detector for detecting rotational vibration of a drive housing, a main control circuit performs a head moving step of driving a voice coil motor to move a magnetic head on a magnetic disk, a frequency estimation step of estimating a frequency of each disturbance component contained in an output signal from the rotational vibration detector after moving the magnetic head, and a suppressor setting step of setting a notch filter for suppressing the disturbance component based on the estimated frequency.

Abstract: A disk drive uses a hybrid analog-digital acceleration feedforward control system and method for cancellation of rotational disturbances. A rotational vibration (RV) sensor is used with an analog circuit to generate an analog feedforward signal that is summed with the analog actuator control signal from the servo control processor. The analog feedforward signal is also converted to a digital feedforward signal and input to the processor. When the actuator gain deviates from its design value, the processor retrieves the appropriate actuator gain value from a lookup table. The processor uses the actuator gain value and the digital feedforward signal to calculate a modified feedforward signal, which is a fraction of the digital feedforward signal. The processor also calculates a feedback control value from the servo positioning information and a feedback controller.

Abstract: Embodiments of the present invention provide a magnetic disk device including a spindle motor using a fluid dynamic bearing, which can send back READY within a period requested by a host system at the time of starting a magnetic disk device under low temperature and low supply voltage conditions without a particular heating approach. According to one embodiment, the magnetic disk device sets a waiting time in a period from when a spindle motor reaches a rated speed until when an HSA is loaded to a magnetic disk at the time of starting under low temperature and low supply voltage conditions within such a range that the timeout of the host does not occur, and the spindle motor itself is heated by rotation of the spindle motor in the waiting time to lower viscosity of the lubrication fluid to ensure sufficient voltage margin for an SPM driver.

Abstract: Embodiments of the present invention provide a disk drive capable of reducing, by means of simple control, vibrations applied to the drive and vibrations occurring in the drive, and a control method for controlling the disk drive. In one embodiment, a servo system comprises a sensor unit for detecting vibrations, a correction signal generator for, when the sensor unit detects vibrations, generating a correction signal, a position error signal generator for generating a PES signal on the basis of servo data read out from a disk and a target position, a servo controller for generating a servo control signal for controlling a position of a head on the basis of the PES signal, and a servo controller for generating a driving signal on the basis of the correction signal and the servo control signal.

Abstract: Embodiments in accordance with the present invention provide a disk drive that ensures quieter rotational acceleration of a recording disk. Certain embodiments relate to a hard disk drive that detects the vibration of an enclosure by monitoring, via a driver, a counter electromotive voltage generated in a voice coil motor. If the hard disk drive detects a predetermined level of vibration or higher in the enclosure, it switches the status of a drive signal applied to a spindle motor so as to reduce the current level or smooth the waveform. This ensures reduced vibration of the enclosure.

Abstract: Embodiments of the present invention provide a magnetic disk drive, in which a disturbance component contained in an output signal from a rotational vibration detector, can be appropriately suppressed irrespective of frequency of the component, and a method of controlling the drive. According to one embodiment, in a magnetic disk drive having a rotational vibration detector for detecting rotational vibration of a drive housing, a main control circuit performs a head moving step of driving a voice coil motor to move a magnetic head on a magnetic disk, a frequency estimation step of estimating a frequency of each disturbance component contained in an output signal from the rotational vibration detector after moving the magnetic head, and a suppressor setting step of setting a notch filter for suppressing the disturbance component based on the estimated frequency.

Abstract: A disk drive uses a hybrid analog-digital acceleration feedforward control system and method for cancellation of rotational disturbances. A rotational vibration (RV) sensor is used with an analog circuit to generate an analog feedforward signal that is summed with the analog actuator control signal from the servo control processor. The analog feedforward signal is also converted to a digital feedforward signal and input to the processor. When the actuator gain deviates from its design value, the processor retrieves the appropriate actuator gain value from a lookup table. The processor uses the actuator gain value and the digital feedforward signal to calculate a modified feedforward signal, which is a fraction of the digital feedforward signal. The processor also calculates a feedback control value from the servo positioning information and a feedback controller.

Abstract: Embodiments of the present invention provide a magnetic disk device including a spindle motor using a fluid dynamic bearing, which can send back READY within a period requested by a host system at the time of starting a magnetic disk device under low temperature and low supply voltage conditions without particular heating means. According to one embodiment, the magnetic disk device sets a waiting time in a period from when a spindle motor reaches a rated speed until when an HSA is loaded to a magnetic disk at the time of starting under low temperature and low supply voltage conditions within such a range that the timeout of the host does not occur, and the spindle motor itself is heated by rotation of the spindle motor in the waiting time to lower viscosity of the lubrication fluid to ensure sufficient voltage margin for an SPM driver.

Abstract: Embodiments in accordance with the present invention provide a disk drive that ensures quieter rotational acceleration of a recording disk. Certain embodiments relate to a hard disk drive that detects the vibration of an enclosure by monitoring, via a driver, a counter electromotive voltage generated in a voice coil motor. If the hard disk drive detects a predetermined level of vibration or higher in the enclosure, it switches the status of a drive signal applied to a spindle motor so as to reduce the current level or smooth the waveform. This ensures reduced vibration of the enclosure.

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: Embodiments of the present invention provide a disk drive capable of reducing, by means of simple control, vibrations applied to the drive and vibrations occurring in the drive, and a control method for controlling the disk drive. In one embodiment, a servo system comprises a sensor unit for detecting vibrations, a correction signal generator for, when the sensor unit detects vibrations, generating a correction signal, a position error signal generator for generating a PES signal on the basis of servo data read out from a disk and a target position, a servo controller for generating a servo control signal for controlling a position of a head on the basis of the PES signal, and a servo controller for generating a driving signal on the basis of the correction signal and the servo control signal.

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: 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 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.