Norman James Gardner

US Patent:

6900959, May 31, 2005

Filed:

Mar 31, 2003

Appl. No.:

10/405013

Inventors:

Norman D. Gardner - Aliso Viejo CA, US
Robert P. Ryan - Mission Viejo CA, US

Assignee:

Western Digital Technologies, Inc. - Lake Forest CA

International Classification:

G11B005/596

US Classification:

360 7804, 360 75

Abstract:

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.

US Patent:

7023640, Apr 4, 2006

Filed:

May 27, 2004

Appl. No.:

10/856400

Inventors:

Raffi Codilian - Irvine CA, US
Lan V. Ngo - Garden Grove CA, US
Norman D. Gardner - Aliso Viejo CA, US

Assignee:

Western Digital Technologies, Inc. - Lake Forest CA

International Classification:

G11B 19/04
G11B 21/02
G11B 19/02

US Classification:

360 60, 360 69, 360 75

Abstract:

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.

US Patent:

8351174, Jan 8, 2013

Filed:

Oct 29, 2009

Appl. No.:

12/608918

Inventors:

Norman D. Gardner - Mission Viejo CA, US
Mingying Gu - Aliso Viejo CA, US

Assignee:

Western Digital Technologies, Inc. - Irvine CA

International Classification:

H02H 3/24

US Classification:

361 92

Abstract:

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.

US Patent:

8498172, Jul 30, 2013

Filed:

Jul 26, 2011

Appl. No.:

13/190533

Inventors:

Norman D. Gardner - Mission Viejo CA, US

Assignee:

Western Digital Technologies, Inc. - Irvine CA

International Classification:

G11C 5/14

US Classification:

365226, 36518907

Abstract:

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.