Abstract: Various illustrative aspects are directed to a data storage device comprising one or more disks, an actuator arm assembly comprising a voice coil motor (VCM), the VCM configured to operate in a first mode and a second, different mode, wherein the first mode corresponds to at least a first and a second setting, and a control circuitry configured to cause the VCM to seek towards a target track in the first mode using the first setting for a first duration, control transition of the VCM from the first to the second setting in the first mode, cause the VCM to seek towards the target track using the second setting for a second duration, and control transition of the VCM from the first to a second mode, wherein controlling the transitioning comprises seeking the VCM toward the target track in the second mode for a third duration.

Abstract: Various illustrative aspects are directed to a data storage device comprising one or more disks, an actuator arm assembly comprising a voice coil motor (VCM), the VCM configured to operate in a first mode and a second, different mode, wherein the first mode corresponds to at least a first and a second setting, and a control circuitry configured to cause the VCM to seek towards a target track in the first mode using the first setting for a first duration, control transition of the VCM from the first to the second setting in the first mode, cause the VCM to seek towards the target track using the second setting for a second duration, and control transition of the VCM from the first to a second mode, wherein controlling the transitioning comprises seeking the VCM toward the target track in the second mode for a third duration.

Abstract: Various illustrative aspects are directed to a data storage device comprising a first spindle motor configured to rotate one or more disks in a first stack of disks, a second spindle motor configured to rotate one or more disks in a second stack of disks, and one or more processing devices configured to detect back electromotive force (BEMF) voltages generated by the first spindle motor and the second spindle motor. In other aspects the one or more processing devices can control speeds of the first spindle motor and the second spindle motor based on the detected BEMF voltages.

Abstract: Various illustrative aspects are directed to a data storage device comprising a disk and a spindle motor configured to rotate the disk wherein the spindle motor is powered by a drive voltage generated in response to a host voltage. The data storage device includes a head configured to be actuated over the disk by a head actuator and control circuitry comprising an isolation field effect transistor (ISOFET) configured to prevent a reverse current from flowing from the drive voltage to the host voltage when the host voltage falls below a threshold. The control circuitry sets a turnoff current level at which the ISOFET is directed to turn off to prevent the reverse current from flowing determines a drain-source on resistance Rdson of the ISOFET, and calculates a voltage turnoff threshold at which the ISOFET is turned off from the turnoff current level and the determined Rdson.

Abstract: A data storage device comprises a lead actuator that actuates a first read-write head over a first disk and a support actuator that actuates a second read-write head over a second disk. A spindle motor rotates the first and second disks. In response to an emergency power off (EPO) event, a processing device retracts and parks the actuators using an internal supply voltage generated from a back electromotive force (BEMF) voltage of the spindle motor, and egresses data from a volatile to a non-volatile semiconductor memory. Egress is throttled before the actuators are retracted and parked when the internal supply voltage falls to or below a first egress throttling threshold voltage. Egress is throttled after the actuators are retracted and parked when the internal supply voltage falls to or below a second egress throttling threshold voltage.

Abstract: Various illustrative aspects are directed to a data storage device comprising one or more disks, an actuator arm assembly comprising one or more disk heads and a voice coil motor (VCM), the VCM configured to operate in a PWM mode and a linear mode, and one or more processing devices configured to: seek the VCM towards a target track in the PWM mode; transition the VCM from the PWM mode to the linear mode, wherein the transitioning comprises switching an offset compensation value from a first offset compensation value to a second compensation offset value to compensate for a transition offset induced while transitioning the VCM from the PWM to the linear mode, wherein the first and the second offset compensation values correspond to the PWM and linear modes, respectively, and seek the VCM towards the target track in the linear mode for a linear mode time.

Abstract: A data storage device comprises a lead actuator that actuates a first read-write head over a first disk and a support actuator that actuates a second read-write head over a second disk. A spindle motor rotates the first and second disks. In response to an emergency power off (EPO) event, a processing device retracts and parks the actuators using an internal supply voltage generated from a back electromotive force (BEMF) voltage of the spindle motor, and brakes the spindle motor. The spindle motor is not braked until both the lead and support actuators have been retracted and parked.

Abstract: Various illustrative aspects are directed to a data storage device comprising a first spindle motor configured to rotate one or more disks in a first stack of disks, a second spindle motor configured to rotate one or more disks in a second stack of disks, and one or more processing devices configured to detect back electromotive force (BEMF) voltages generated by the first spindle motor and the second spindle motor. In other aspects the one or more processing devices can control speeds of the first spindle motor and the second spindle motor based on the detected BEMF voltages.

Abstract: Various illustrative aspects are directed to a data storage device comprising a disk and a spindle motor configured to rotate the disk wherein the spindle motor is powered by a drive voltage generated in response to a host voltage. The data storage device includes a head configured to be actuated over the disk by a head actuator and control circuitry comprising an isolation field effect transistor (ISOFET) configured to prevent a reverse current from flowing from the drive voltage to the host voltage when the host voltage falls below a threshold. The control circuitry sets a turnoff current level at which the ISOFET is directed to turn off to prevent the reverse current from flowing determines a drain-source on resistance Rdson of the ISOFET, and calculates a voltage turnoff threshold at which the ISOFET is turned off from the turnoff current level and the determined Rdson.

Abstract: A perforating apparatus for a cylindrical workpiece, including: a cradle having a groove extending in one direction horizontally from one end to another end; a stopper provided at the one end of the groove; a drill disposed vertically above the groove and movable at least in vertical direction, having a drill bit that extends vertically; and a chuck having a pair of opposing grippers movable toward each other in a horizontal direction perpendicular to the direction in which the groove extends, and symmetrically with respect to a rotation axis of the drill bit, each of the grippers further having a pair of vertically symmetric inclined surfaces expanding upwards and downwards.

Abstract: A data storage device comprises a lead actuator that actuates a first read-write head over a first disk and a support actuator that actuates a second read-write head over a second disk. A spindle motor rotates the first and second disks. In response to an emergency power off (EPO) event, a processing device retracts and parks the actuators using an internal supply voltage generated from a back electromotive force (BEMF) voltage of the spindle motor, and egresses data from a volatile to a non-volatile semiconductor memory. Egress is throttled before the actuators are retracted and parked when the internal supply voltage falls to or below a first egress throttling threshold voltage. Egress is throttled after the actuators are retracted and parked when the internal supply voltage falls to or below a second egress throttling threshold voltage.

Abstract: A data storage device comprises a lead actuator that actuates a first read-write head over a first disk and a support actuator that actuates a second read-write head over a second disk. A spindle motor rotates the first and second disks. In response to an emergency power off (EPO) event, a processing device retracts and parks the actuators using an internal supply voltage generated from a back electromotive force (BEMF) voltage of the spindle motor, and brakes the spindle motor. The spindle motor is not braked until both the lead and support actuators have been retracted and parked.

Abstract: A data storage device comprises a lead actuator that actuates a first read-write head over a first disk and a support actuator that actuates a second read-write head over a second disk. A spindle motor rotates the first and second disks. In response to an emergency power off (EPO) event, a processing device retracts and parks the actuators using an internal supply voltage generated from a back electromotive force (BEMF) voltage of the spindle motor, and brakes the spindle motor. The spindle motor is not braked until both the lead and support actuators have been retracted and parked.

Abstract: Various illustrative aspects are directed to a data storage device comprising one or more disks, an actuator arm assembly comprising one or more disk heads and a voice coil motor (VCM), the VCM configured to operate in a PWM mode and a linear mode, and one or more processing devices configured to: seek the VCM towards a target track in the PWM mode; transition the VCM from the PWM mode to the linear mode, wherein the transitioning comprises switching an offset compensation value from a first offset compensation value to a second compensation offset value to compensate for a transition offset induced while transitioning the VCM from the PWM to the linear mode, wherein the first and the second offset compensation values correspond to the PWM and linear modes, respectively, and seek the VCM towards the target track in the linear mode for a linear mode time.

Abstract: An electronic component protection structure and a switch device capable of protecting an electronic component from static electricity charged on or within a case member are achieved with a simple configuration. An electronic component protection structure includes a circuit board on which an electronic component is mounted, a base member supporting the circuit board, a case member covering the circuit board and fixed to the base member, and a conductive ground member connected to the circuit board. The ground member includes an exposed portion at least a part of which is exposed to the inside of the case member.

Abstract: Various illustrative aspects are directed to a data storage device comprising one or more disks; an actuator arm assembly comprising one or more actuator arms, and configured to position the one or more actuator arms over disk surfaces of the one or more disks; one or more fine actuators, disposed on the one or more actuator arms; and one or more processing devices. The one or more processing devices are configured to: output a driver current to the one or more fine actuators, wherein the one or more processing devices are configured to rate limit a rise of the driver current over time during an activation of the driver current to within a selected rate limit of current rise over time.

Abstract: Various illustrative aspects are directed to a data storage device comprising a first spindle motor configured to rotate one or more disks in a first stack of disks, a second spindle motor configured to rotate one or more disks in a second stack of disks, and one or more processing devices configured to detect back electromotive force (BEMF) voltages generated by the first spindle motor and the second spindle motor. In other aspects the one or more processing devices can control speeds of the first spindle motor and the second spindle motor based on the detected BEMF voltages.

Abstract: A data storage device has a closed loop extended park mode during spin down operation. A data storage device comprises a spindle motor configured to rotate one or more disks, and one or more processing devices. The one or more processing devices are configured to determine a value of current that is discharged from the spindle motor over time during a spin down of the spindle motor, and control a braking duty cycle for braking the spindle motor during the spin down such that the value of current discharged from the spindle motor over time does not exceed a selected current limit.

Abstract: Various illustrative aspects are directed to a data storage device comprising one or more disks; an actuator arm assembly comprising one or more actuator arms, and configured to position the one or more actuator arms over disk surfaces of the one or more disks; one or more fine actuators, disposed on the one or more actuator arms; and one or more processing devices. The one or more processing devices are configured to: output a driver current to the one or more fine actuators, wherein the one or more processing devices are configured to rate limit a rise of the driver current over time during an activation of the driver current to within a selected rate limit of current rise over time.

Abstract: A single-phase brushless DC motor includes a rotor rotatable about a central axis, a stator including salient pole portions, a stator core including a slot between the salient pole portions, and a winding wound around the salient pole portions, the stator opposing the rotor with an air gap interposed therebetween, and a substrate fixed to the stator and including a driver to perform energization control of the winding. The driver includes a Hall element to acquire a timing of the energization control. The substrate includes a Hall IC to detect a circumferential position of the rotor separately from the driver.