Western Digital Technologies, Inc.

Peng Huang

Toshihisa Kiyonaga

Masahito Kobayashi

Satoshi Yamamoto

Brian Kenneth Tanner

Kexiu Liu

Brian Johnson

Paolo Capretta

Edward C Sibal

Christopher B Larsen

Hiroaki Sakuma

Junya Takeda

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 is disclosed comprising a voice coil motor (VCM) having a resonance frequency, a first disk surface comprising a first set of servo sectors written at a frequency less than twice the VCM resonance frequency, and a second disk surface comprising a second set of servo sectors circumferentially offset from the first set of servo sectors and written at a frequency less than twice the VCM resonance frequency. An access of the first disk surface is performed by reading at least one of the first set of servo sectors to generate a first position error signal (PES), reading at least one of the second set of servo sectors to generate a second PES, and controlling the VCM based on the first PES and the second PES to position a first head over the first disk surface while accessing the first disk surface.

Data storage device employing staggered servo wedges to increase capacity

A data storage device is disclosed comprising a disk comprising servo data, a spindle motor configured to rotate the disk, and a head actuated over the disk. A position error signal (PES) is generated based on the servo data, and the head is actuated over the disk based on the PES. While swinging a speed of the spindle motor, the swinging is disabled based on the PES.

Data storage device disabling swinging of spindle motor speed based on PES

A data storage device is disclosed comprising a first actuator configured to actuate a first head over a first disk comprising a first plurality of tracks defined by first servo sectors, and a second actuator configured to actuate a second head over a second disk comprising a second plurality of tracks defined by second servo sectors. The first actuator is controlled based on the first servo sectors in order to first write data to the first disk, and the second actuator is controlled based on the second servo sectors in order to second write data to the second disk. The first writing is inhibited when a shock signal generated based on a shock sensor exceeds a first shock threshold, and the second writing is inhibited when the shock signal exceeds a second shock threshold different from the first shock threshold.

Data storage device configuring a write inhibit shock threshold for multiple actuators

A data storage device is disclosed comprising a first voice coil motor (VCM) configured to actuate a first head, and a second VCM configured to actuate a second head. A high priority is assigned to the first VCM and a low priority to the second VCM. A first access command is serviced using the first head by seeking the first VCM using a first high performance seek profile. When seeking the second VCM without seeking the first VCM, a second access command is serviced using the second head using a second high performance seek profile. When concurrently seeking the first VCM and the second VCM, the seeking of the second VCM is with a reduced performance seek profile, wherein the second high performance seek profile decreases a seek time of the second VCM compared to the reduced performance seek profile.

Data storage device seeking multiple voice coil motors using a limited current supply

A data storage device is disclosed wherein multiple voice coil motors (VCMs) are unloaded using a back electromotive force (BEMF) voltage generated by a spindle motor. A velocity and position of each VCM is measured, and a priority assigned to each VCM based on the measured velocity and position. During a delay interval, the BEMF voltage is used to apply a first brake voltage to a high priority VCM and to apply a second brake voltage to a low priority VCM, wherein the second brake voltage is lower than the first brake voltage. After the delay interval, the BEMF voltage is used to apply the first brake voltage to the high priority VCM and to apply a third brake voltage to the low priority VCM, wherein the third brake voltage is higher than the second brake voltage.

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Lake Forest, CA, United States of America

Peng Huang