Hitachi Global Storage Technologies Netherlands B.v.

Western Digital Technologies, Inc.

Bryan Rowan

Masahito Kobayashi

Tetsuo Semba

Amir Hossein Chaghajerdi

Kevin Tzou

Adrian E Cerda

Pushkar Hingwe

Michael Anthony Moser

Gary Allan Herbst

Mantle M Yu

Scott Edwin Heeren

Lee Duyly Nguyentran

Farzin Assar

James Eddy Donaldson

Jeffrey J Dobbek

A data storage device is disclosed comprising a first actuator configured to actuate a first head over a first disk, and a second actuator configured to actuate a second head over a second disk. The first actuator is controlled based on a first feed-forward seek profile to seek the first head over the first disk, and the second actuator is controlled to position the second head over a second data track on the second disk including to process the first feed-forward seek profile to attenuate a coupling disturbance from the first actuator.

Data storage device attenuating multiple actuator coupling disturbance

A data storage device is disclosed comprising a first disk comprising first servo sectors A-Adistributed around a circumference of the first disk, and a second disk comprising second servo sectors B-Bdistributed around a circumference of the second disk, wherein the second servo sectors B-Bare offset circumferentially from the first servo sectors A-A. While the first and second disks are rotating second servo information is transmitted from a second servo channel to a first servo channel. One of the first servo sectors Ai is read to generate first servo information, and a first command value is generated based on the first servo information and the second servo information, wherein a first actuator is controlled based on the first command value.

Data storage device communicating servo information between servo channels of multiple actuators

Voltage regulating systems are provided that adjust their output control signals in response to feed-forward information that is indicative of deterministic changes in the load current. A feed-forward circuit provides a feed-forward signal in response to an input signal generated from a source that is external to the voltage regulating system. The voltage regulator systems can proactively respond to the predictive information by adjusting their output, thereby improving the regulation tolerance to dynamic loading. As an example, the feed-forward information can include signals indicating multiple deterministic events that affect the load. Signals from multiple events can be summed together to generate a feed-forward term. As another example, the voltage regulating systems can be responsive to feedback information and feed-forward information from internal to the regulator, in addition to external deterministic information.

Voltage regulating systems responsive to feed-forward information from deterministic loads

A method of configuring a signal for controlling a voice coil motor (VCM) is disclosed. A voltage at an error amplifier of a VCM driver is accessed. A target value at the error amplifier is accessed. A difference value between the target value and the voltage is determined. An impedance value of the variable compensation coupled with the error amplifier is adjusted, based on the difference value.

Adjustable voice coil motor driver

A magnetic recording disk drive has compensation for both mechanical disturbances and electrical disturbances. The disk drive's servo control system includes mechanical disturbance (MD) feedforward compensation and electrical disturbance (ED) feedforward compensation, of which either or both can be selectively enabled and disabled. In the operation of the disk drive, it is first determined that there is some disturbance that is causing track misregistration (TMR). The system is then tested to determine if the ED is greater than an ED threshold by measuring an averaged ED sensor signal. If ED is greater than the ED threshold, the system is then tested for a reduction in TMR by selectively turning MD compensation and ED compensation on and off, and determining changes in the position error signal (PES). Depending on the test results from the PES measurements, one or both of MD compensation and ED compensation is left on, and maintained on until the TMR falls below the predetermined threshold.

Magnetic recording disk drive with switchable compensation for mechanical and electrical disturbances

A method for compensating for a disturbance in power from a power supply, wherein the disturbance without the compensating would otherwise affect a positioning apparatus coupled to the power supply. The method comprises receiving the disturbance in power from the power supply, deriving a compensation for the disturbance in the power, and transmitting the compensation to a control system for the positioning apparatus.

Power disturbance compensation

Circuitry in a hard disk drive (HDD) senses the supply voltage, normally at power-on, and applies appropriate DC-to-DC conversion (pass-through, step-down, or boost regulation) according to the design requirements of the HDD.

Removable hard disk drive (HDD) that is hot-plug compatible with multiple external power supply voltages

During normal operation of a hard disk drive, control logic controls a plurality of switching elements to provide electrical power to a spindle motor and head motor of the disk drive from a voltage source coupled to first and second voltage supply nodes (e.g., Vcc and ground), the spindle motor has a set of motor windings to which the electric power is applied to rotate the spindle motor, and the control logic is configured to enter a regenerative braking state during normal operation where the switching elements are controlled to isolate the spindle motor from the first voltage supply node and cause regenerative braking of the spindle motor so that kinetic energy due to rotation of the spindle motor is converted to electrical power that is supplied to the head motor by virtue of inductance of one or more motor windings in the set.

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San Jose, CA, United States of America

Bryan Rowan