Matsushita Electric Industrial Co., Ltd.

Western Digital Technologies, Inc.

Kabushiki Kaisha Toshiba

Western Digital Corporation

Samsung Electronics Co., Ltd.

Seagate Technology International

Other

Panasonic Corporation

Toshiba Corporation

Matsushita Electrical Industrial Co., Ltd.

Brian Kenneth Tanner

Ara W Nazarian

James Jinshi Ng

Richard M Ehrlich

Raffi Codilian

Naoyuki Kagami

Gaku Ikedo

David Price Turner

Fred R Hansen

Hiroki Watanabe

Gary L Dunbar

Paolo Capretta

Timothy A Ferris

Thorsten Schmidt

Jaesoo Byoun

Hanan Kupferman

Timothy J Elliott

Richard Koonwai Wong

Yoo H Kim

Debasis Baral

Peng Huang

Toshihisa Kiyonaga

Loc Hoang Nguyen

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.

Write data protection at emergency power off

A data storage device is disclosed comprising a first voice coil motor (VCM) comprising a first voice coil configured to actuate a first head over a first disk, and a second VCM comprising a second voice coil configured to actuate a second head over a second disk. The data storage device further comprises a spindle motor configured to rotate the first and second disk, wherein during a power failure the first and second disks rotating causes the spindle motor to generate a back electromotive force (BEMF) voltage. During the power failure, the BEMF voltage is applied to the first VCM and to the second VCM during a first interval. The BEMF voltage is monitored, and when the BEMF voltage falls below a first threshold, the BEMF voltage is disconnected from the first VCM and the second VCM during a second interval.

Data storage device concurrently disconnecting multiple voice coil motors from spindle motor BEMF voltage during unload

A data storage device is disclosed comprising a first voice coil motor (VCM) comprising a first voice coil configured to actuate a first head over a first disk, a second VCM comprising a second voice coil configured to actuate a second head over a second disk, and a spindle motor configured to rotate the first and second disk, wherein during a power failure the first and second disks rotating causes the spindle motor to generate a back electromotive force (BEMF) voltage. During the power failure the first and second VCMs are unloaded, wherein during a first interval the first voice coil is connected to the BEMF voltage and the second voice coil is disconnected from the BEMF voltage, and during a second interval the second voice coil is connected to the BEMF voltage and the first voice coil is disconnected from the BEMF voltage.

Data storage device employing balanced current drive to unload multiple voice coil motors

A data storage device is disclosed comprising a first voice coil motor (VCM) comprising a first voice coil, and a second VCM comprising a second voice coil. The first VCM and the second VCM are unloaded during a power failure by measuring a first velocity and a first position of the first VCM and measuring a second velocity and a second position of the second VCM. A BEMF voltage generated by a spindle motor is used to generate a first brake voltage based on the first velocity and the first position, and the BEMF voltage is used to generate a second brake voltage based on the second velocity and the second position. The first brake voltage is applied to the first voice coil, and the second brake voltage is applied to the second voice coil.

Data storage device employing smart braking to unload multiple voice coil motors

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.

Data storage device employing delayed braking to unload multiple voice coil motors

A hard disk drive with a voice coil motor coupled to a head. The head is coupled to a disk that is rotated by a spindle motor. The spindle motor generates a back-emf current. The disk drive also includes a drive circuit that causes the voice coil motor to move the head off of the disk. The drive circuit provides at least a portion of the back-emf voltage to the voice coil motor if a head velocity exceeds a first predetermined value and a larger portion of the back-emf voltage if the head velocity exceeds a second predetermined value. For example, a relatively small amount of voltage can be provided if the head velocity falls below a first threshold to accelerate the head and a larger current can be provided if the head velocity falls below a lower threshold to generate a greater head thrust.

Head actuator velocity control for electrical power off in a disk drive

This application discloses a hard disk drive using a self-resonant frequency band of a Voice Coil Motor far above its operational frequency band to predict Rapid Off Track events before its head stack assembly can deliver the disruption to the slider writing a track. A circuit board and/or an integrated circuit are disclosed in various embodiments to predict the ROT events using the self-resonant frequency band and/or to respond to the prediction to suppress the slider writing.

Method and apparatus for detecting rapid off track following and protecting nearby tracks from rapid off track writing in a hard disk drive

Apparatus and methods are disclosed for adaptive control and/or use of a vibration sensor in a hard disk drive (HDD). The HDD, an assembled circuit board and a control circuit are disclosed. The control circuit is configured to electrically couple to piezoelectric devices and includes a sensor interface and a processor. The processor may be configured to receive a sensor reading from the sensor interface and may further be configured to send a gain control signal and/or an input selection signal to the sensor interface. The sensor interface includes pads for electrically coupling to the piezoelectric devices. The sensor interface may respond to the gain control signal by altering a gain of a signal from one pad used and/or may respond to the input selection signal in certain states by disabling one of these signals from affecting the sensor reading. Manufacturing by calibration of the gain control is disclosed.

Method and apparatus for adaptive control and/or use of a vibration sensor in a hard disk drive

A hard disk drive and its circuit board and an integrated circuit are disclosed using two piezoelectric devices each having one terminal used to generate signal. The first signal goes to one input of a differential amplifier. The second signal goes to an amplifier whose gain is controlled to create an amplified second signal for the differential amplifier whose output and the first and second signals create a selected signal received by an A/D converter to create a sampled signal used to create a linear disturbance signal and/or a rotational compensation signal, which in turn are used to control the gain of the amplifier to minimize a PES envelope and/or a harmonic PES envelope either in calibration or normal operation of the hard disk drive.

Method and apparatus for adaptive gain balancing of at least one of two rotational sensors in a hard disk drive

According to one embodiment, a disk drive apparatus includes a sensor to detect mechanical shocks to the disk drive apparatus and to provide a shock output signal representative of such mechanical shocks, a first filter coupled to the sensor to filter the shock output signal to pass signals having a first frequency component, a second filter to independently filter the shock output signal to provide signals having a second frequency component, a detector to inhibit write operations of the disk drive apparatus responsive to the shock output signal from the first filter, and a controller coupled to the second filter to compensate for low frequency mechanical disturbances during write operations to a track on the disk drive apparatus responsive to low frequency component.

Disk drive apparatus having shock adaptive filters

A disk drive system includes a fixed output voltage regulator including an output terminal that provides a substantially fixed output voltage. A pluralities of loads are connected in parallel. A resistor is connected in series between the output terminal of the voltage regulator and the plurality of loads. The resistor causes a voltage provided to the plurality of loads to sag, as compared to the substantially fixed output voltage, when current is pulled, by one or more of the loads, through the resistor.

Systems and methods for reducing power dissipation in a disk drive including a fixed output voltage regulator

A method of determining a correction factor for a voice coil motor of a disk drive device is performed by driving a relatively low current through the voice coil motor during a seek operation. Actuator velocity is then measured. A correction factor is calculated as a function of the actuator velocity to allow estimation of velocity as a function of back EMF.

Voice coil motor effective resistance determination

A disk drive device has a shock sensor that detects mechanical shocks to a disk drive device to provide a shock output signal representative of such mechanical shocks. The shock output signal may be filtered to pass signals having a low frequency component of approximately between 1 and 4 KHz. Low frequency mechanical disturbances may be compensated for during writing to a track on the disk drive as a function of such low frequency component. In one embodiment, higher frequency shocks may be processed on a separate shock channel to inhibit or allow write operations. Different filters may be used on each of the shock channels.

Shock feed forward adaptive filters

A method and device for parking heads of a disk drive device involves receiving a command to immediately park the heads. A first pulse is provided to a voice coil motor causing the heads to move toward a parked position. After the first pulse, the VCM current is reduced substantially (e.g., close to zero) and back EMF in the voice coil motor is measured to determine speed of the heads. The voice coil motor is iteratively pulsed, and back EMF is measured between pulses to track a desired velocity profile to park the heads.

Growing community of inventors

San Jose, CA, United States of America

Brian Kenneth Tanner