Western Digital Technologies, Inc.

Brian Johnson

Robert P Ryan

Naoyuki Kagami

Jaesoo Byoun

Gaku Ikedo

Hideaki Ito

Ryan P Mayo

Shrey Khanna

Peng Huang

Hiroki Watanabe

Yasunori Fukuyama

Christopher B Larsen

Nathaniel Dupler

Ryan Mayo

A data storage device comprises a disk; a head configured to read data from and write data to the disk; and a current balancer configured to receive a first voltage supply having a load limit and to receive a second voltage supply. The current balancer is further configured, to mitigate rotational vibration (RV) noise, to sample a first current Idrawn from the first voltage supply, to maintain a difference between the first current Iand a current balancer threshold parameter Ito be at least twice a minimum peak current minCurrentLimitamount required for turn on of the current balancer (I−I≥2*minCurrentLimit), and to draw a second current from the second voltage supply to satisfy a part of a total load on the first voltage supply that exceeds the load limit.

Data storage device with adaptive control of current balancer to mitigate rotational vibration (RV) noise

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 The spindle motor is not braked until both the lead and support actuators have been retracted and parked.

Data storage device having dual actuators and method for emergency power off retract (EPOR) of dual actuators

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.

VCM PWM to linear mode transition offset optimization to improve PES

A disk drive may include a disk, a head actuated over the disk, a spindle motor comprising a plurality of windings and operable to rotate the disk and coupled to a first and a second spindle driver, the first and the second spindle driver coupled in parallel to the plurality of windings. The disk drive further includes one or more processing devices that are configured to detect a BEMF signal corresponding to a velocity and/or a position of the spindle motor, control, based on detecting the BEMF signal, commutation of the plurality of windings of the spindle motor using the first and the second spindle driver, and wherein the plurality of windings are commutated at or near the same time or in a sequential manner during one or more of a spin up and a spin down routine of the spindle motor.

Enhancing spin up and spin down times for data storage devices

A data storage device or disk drive may include a plurality of regulators, a first voltage rail associated with a first regulator of the plurality of regulators, a second voltage rail associated with a second regulator of the plurality of regulators, wherein a switching frequency of the second regulator is greater than a switching frequency of the first regulator, the first voltage rail is associated with a higher voltage than the second voltage rail, or a combination thereof. The data storage device may include one or more processing devices configured to: determine a minimum switching frequency, identify a start time of a switching cycle for the first regulator, based at least in part on determining the minimum switching frequency; and, at or near the start time of the new switching cycle, couple the first regulator to the second regulator to initiate the switching cycle.

Power improvement for minimum switching frequency operation

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.

Data storage device with closed loop extended park mode during spin down operation

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.

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Laguna Hills, CA, United States of America

Brian Johnson