Timothy A Ferris

Author:

Timothy Ferris

ISBN #:

0060535954

Author:

Timothy Ferris

ISBN #:

0060936487

Author:

Timothy Ferris

ISBN #:

0066211646

Author:

Timothy Ferris

ISBN #:

0316281298

Author:

Timothy Ferris

ISBN #:

0316281336

Author:

Timothy Ferris

ISBN #:

0136937063

Author:

Timothy Ferris

ISBN #:

0517631768

Author:

Timothy Ferris

ISBN #:

0385263260

US Patent:

6493169, Dec 10, 2002

Filed:

Apr 19, 2000

Appl. No.:

09/551925

Inventors:

Timothy A. Ferris - Lake Forest CA
Raffi Codilian - Irvine CA

Assignee:

Western Digital Technologies, Inc. - Lake Forest CA

International Classification:

G11B 1546

US Classification:

360 7303, 360 9807

Abstract:

A disk drive incidentally generates undesirable acoustic noise during an operation mode and includes a spindle motor having windings and a rotor rotatable at an operating spin-rate during the operation mode. A commutation state sequencer includes a sequence of commutation states including a present commutation state and a next commutation state for generating a sequence of control signals. Switching elements are responsive to the sequence of control signals for sequentially applying a voltage across a selected combination of the windings to generate a torque on the rotor in order to maintain the operating spin-rate. A spindle motor control system provides a series of commutation clock pulses having a corresponding series of commutation clock periods to advance the commutation state sequencer from the present commutation state to the next commutation state. At least two of the commutation clock periods each have a systematically introduced variation from a nominal commutation clock period that depends on the operating spin-rate. The systematically introduced variation reduces the acoustic noise in the disk drive.

US Patent:

6788483, Sep 7, 2004

Filed:

Aug 31, 2001

Appl. No.:

09/945076

Inventors:

Timothy A. Ferris - Mission Viejo CA
Robert P. Ryan - Mission Viejo CA

Assignee:

Western Digital Technologies, Inc. - Lake Forest CA

International Classification:

G11B 509

US Classification:

360 46, 360 67

Abstract:

A disk drive comprising a programmable inverting voltage regulator (PIVR) for generating an inverted voltage supply applied to a preamp is disclosed. The PIVR is programmably configured relative to the disk drives mode of operation, including a read mode and a write mode.

US Patent:

6865049, Mar 8, 2005

Filed:

Jun 28, 2002

Appl. No.:

10/184738

Inventors:

Raffi Codilian - Irvine CA, US
Timothy A. Ferris - Mission Viejo CA, US

Assignee:

Western Digital Technologies, Inc. - Lake Forest CA

International Classification:

G11B019/22

US Classification:

360 71, 318376

Abstract:

Methods and devices for converting the kinetic energy of the rotating spindle motor of a disk drive of a rechargeable battery operated mobile host device into electrical energy during braking of the rotating spindle motor. The converted electrical energy is conditioned and used to charge the rechargeable battery of the mobile host device.

US Patent:

6972539, Dec 6, 2005

Filed:

Apr 30, 2003

Appl. No.:

10/427521

Inventors:

Raffi Codilian - Irvine CA, US
Timothy A. Ferris - Mission Viejo CA, US

Assignee:

Western Digital Technologies, Inc. - Lake Forest CA

International Classification:

G05B011/01

US Classification:

318560, 318599, 318811, 318432, 318434, 388911

Abstract:

A disk drive is disclosed comprising a spindle motor comprising a plurality of windings for rotating a disk. The spindle motor is rotated by commutating the windings over a plurality of commutation states, wherein audible noise generated by the disk drive is reduced by phase modulating the commutation interval. Further audible noise reduction is achieved by modulating a current applied to the windings which substantially reduces discontinuities in the torque output of the spindle motor caused by phase modulation of the commutation intervals.

US Patent:

7471483, Dec 30, 2008

Filed:

Sep 19, 2007

Appl. No.:

11/857768

Inventors:

Timothy A. Ferris - Mission Viejo CA, US
Alain Chahwan - Mission Viejo CA, US

Assignee:

Western Digital Technologies, Inc. - Lake Forest CA

International Classification:

G11B 21/02

US Classification:

360 75

Abstract:

A disk drive is disclosed comprising a disk, and a head actuated radially over the disk. A first linear acceleration signal is generated representing a first acceleration disturbance, a second linear acceleration signal is generated representing a second acceleration disturbance, and a third linear acceleration signal is generated representing a thermal popping disturbance. The first linear acceleration signal is combined with the third linear acceleration signal to generate a fourth linear acceleration signal representing a combined physical shock disturbance and thermal popping disturbance.

US Patent:

7852588, Dec 14, 2010

Filed:

Jun 23, 2008

Appl. No.:

12/144015

Inventors:

Timothy A. Ferris - Mission Viejo CA, US
Robert P. Ryan - Mission Viejo CA, US

Assignee:

Western Digital Technologies, Inc. - Lake Forest CA

International Classification:

G11B 19/04

US Classification:

360 60, 360 75

Abstract:

A disk drive is disclosed comprising a disk, a head actuated radially over the disk, and control circuitry including a shock detector. The control circuitry is operable to detect a resonant frequency amplitude (RFA) of the shock detector, adjust the shock detector in response to the RFA, and take protective action in response to the shock detector.

US Patent:

8081395, Dec 20, 2011

Filed:

Dec 15, 2009

Appl. No.:

12/638858

Inventors:

Timothy A. Ferris - Mission Viejo CA, US

Assignee:

Western Digital Technologies, Inc. - Irvine CA

International Classification:

G11B 5/09
G11B 15/18
G11B 21/02

US Classification:

360 39, 360 69, 360 75

Abstract:

A disk drive is disclosed comprising a disk, a head for writing data to the disk, and control circuitry coupled to the head, the control circuitry comprising a signal amplifier outputting a first signal comprising an offset voltage, the control circuitry operable to determine a state signal based on comparing the first signal to a reference signal, increase a M-bit digital count value in response to a first state of the state signal, decrease the M-bit digital count value in response to a second state of the state signal, and determine a first analog signal based on N bits of the digital count value, wherein the first analog signal adjusts the offset voltage and M>N.

US Patent:

8145934, Mar 27, 2012

Filed:

Jul 31, 2009

Appl. No.:

12/534052

Inventors:

Timothy A. Ferris - Mission Viejo CA, US
John R. Agness - Laguna Hills CA, US

Assignee:

Western Digital Technologies, Inc. - Irvine CA

International Classification:

G06F 1/26
G06F 1/14

US Classification:

713330, 713300, 713502

Abstract:

A soft start sequencer is disclosed for starting a plurality of voltage regulators, the soft start sequencer comprising a first clock for clocking a plurality of soft start circuits, wherein each soft start circuit for ramping a reference signal from a first value to a second value over a ramp time after a delay time. Each soft start circuit comprises a divider operable to divide the first clock by an integer N to generate a second clock, a first counter clocked by the first clock, the first counter operable to time the delay time, and a second counter clocked by the second clock, the second counter operable to time the ramp time after the delay time.