Western Digital Technologies, Inc.

Norman D Gardner

Raffi Codilian

Robert P Ryan

Yanning Liu

Charles Royston Patton, Iii

Mingying Gu

Lan V Ngo

A data storage device (DSD) is disclosed comprising a non-volatile memory (NVM), such as a disk or non-volatile semiconductor memory, and control circuitry for detecting a power failure condition. A frequency range of a supply voltage from a first frequency to a second frequency is extracted, wherein the first frequency is greater than ten hertz, the second frequency is higher than the first frequency, and the second frequency is less than one megahertz. The power failure condition is detected in response to the extracted frequency range of the supply voltage.

Data storage device evaluating frequency range of supply voltage to detect power failure

An apparatus and method for regulating an output voltage (V) of a voltage regulator during a brown-out condition is described. The apparatus comprises the voltage regulator, a brown-out protection circuit, a switch, and a first capacitor. The voltage regulator charges the first capacitor to the regulated output voltage V. The brown-out protection circuit is coupled to the voltage regulator and the switch. In operation, the brown-out protection circuit detects the occurrence of an undervoltage condition based on a first undervoltage detection signal received at an undervoltage detection input, the brown-out protection circuit disables the voltage regulator and closes the switch to discharge the first capacitor to below a predetermined voltage level.

Apparatus comprising a brown-out protection circuit for memory devices

A disk drive is disclosed comprising a disk, an actuator arm, a head coupled to a distal end of the actuator arm, a voice coil motor (VCM) operable to actuate the head over the disk in coarse movements by rotating the actuator arm about a pivot, and a microactuator operable to actuate the head over the disk in fine movements. A disk boundary condition is detected by moving the actuator arm toward one of an outer diameter of the disk and an inner diameter of the disk, and monitoring an induced voltage generated by the microactuator. The disk boundary condition is detected when the induced voltage exceeds a threshold.

Disk drive detecting disk boundaries using microactuator

A disk drive comprising a first sensor mounted on a nominally stationary portion of the disk drive and adapted to detect acceleration disturbances of the disk drive. The disk drive further comprising: a dual-function subsystem having a first circuit adapted to provide a write-inhibit signal and a second circuit adapted to provide a feed-forward basis signal, the dual-function subsystem adapted to receive a first sensor signal from the first sensor and to provide (a) the write-inhibit signal based on the received first sensor signal and a first threshold value, and (b) the feed-forward basis signal based on the received first sensor signal.

Acceleration disturbance detection subsystem for use with disk drives

A disk drive is disclosed employing an offset-nulling amplifier for detecting a back EMF voltage of a voice coil motor (VCM) in a velocity mode servo control system. The offset-nulling amplifier comprises a differential amplifier, an input stage for swapping the polarity of the input voltage at a periodic interval, and an output stage comprising a single-ended amplifier having an input switched at the periodic interval between the positive and negative outputs of the differential amplifier.

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Mission Viejo, CA, United States of America

Norman D Gardner