Stephen A Jove

US Patent:

6420910, Jul 16, 2002

Filed:

Apr 27, 1999

Appl. No.:

09/300564

Inventors:

John Thomas Contreras - San Jose CA
Paul Wingshing Chung - San Jose CA
Stephen Alan Jove - Watsonville CA
Klaas Berend Klaassen - San Jose CA
Jacobus Cornelis Leonardus Van Peppen - San Jose CA

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

H03K 522

US Classification:

327 77, 327560, 360 67

Abstract:

A method and system for providing a current-sensing preamplifier for use with a magnetoresistive sensor is disclosed. The method includes providing at least one input device coupled with the magnetoresistive sensor, providing a gain stage, and providing a feedback circuit. In a system aspect, the current-sensing preamplifier includes at least one input device. The at least one input device is coupled with the magnetoresistive sensor through an interconnect having a characteristic impedance. The at least one input device provides an input impedance for the current-sensing preamplifier. The current-sensing preamplifier also includes a gain stage coupled with the at least one input device and a feedback circuit coupled with the gain stage and the at least one input device. The feedback circuit provides at least one signal to the at least one input device. The at least one signal controls the input impedance based on at least one error signal.

US Patent:

6822817, Nov 23, 2004

Filed:

Oct 31, 2002

Appl. No.:

10/284811

Inventors:

Paul Wingshing Chung - San Jose CA
John Thomas Contreras - San Jose CA
Stephen Alan Jove - Hollister CA

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G11B 509

US Classification:

360 46, 360 67, 327 52, 330252

Abstract:

Bi-Variant Coupled Pair (BVCP) circuits suitable for use in channel front-end low noise preamplifiers of magnetic storage devices are described. In a magnetic storage device, a BVCP circuit provides a DC bias voltage for a read transducer, low-noise amplification performance, and relatively small AC coupling capacitor values for reducing the cost of an integrated circuit (IC) in which the BVCP circuit may be embodied. The BVCP circuit also has a controllable input impedance for matching a transmission line impedance for high data rate applications.

US Patent:

6847501, Jan 25, 2005

Filed:

Nov 6, 2002

Appl. No.:

10/289076

Inventors:

Wayne Leung Cheung - San Jose CA, US
Stephen Alan Jove - Hollister CA, US
Kevin Roy Vannorsdel - San Jose CA, US

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G11B 509

US Classification:

360 46, 360 66, 360 67, 360 65

Abstract:

A method and apparatus for providing matched differential MR biasing and pre-amplification. Tightly matched and well centered low-level MR bias voltage is provided directly to the sensing element for controlled input-impedance differential pre-amplification without common-mode voltage level control with loops.

US Patent:

6850378, Feb 1, 2005

Filed:

Nov 5, 2002

Appl. No.:

10/288720

Inventors:

John Thomas Conteras - San Jose CA, US
Paul Wingshing Chung - San Jose CA, US
Stephen Alan Jove - Hollister CA, US
Kevin Roy Vannorsdel - San Jose CA, US

Assignee:

Hitachi Global Storage Technologies Netherlands BV

International Classification:

G11B 509

US Classification:

360 46, 360 66, 360 67, 327 55, 330127, 330252

Abstract:

A method and apparatus for providing quadrature biasing for coupled-pair circuits. A QBCP-circuit for quadrature amplifiers provides a new input common-mode sense point that separates the inputs for the differential-and-common mode feedback-control loops. The QBCP circuit biases all four transistors equivalently and reduces the feedback-loop interaction, thereby simplifying the bias control system and improves the voltage-transfer frequency-response performance.

US Patent:

6870696, Mar 22, 2005

Filed:

Jan 7, 2002

Appl. No.:

10/041796

Inventors:

Wayne L. Cheung - San Jose CA, US
Stephen A. Jove - Watsonville CA, US

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G11B005/09

US Classification:

360 46, 360 65, 360 68, 330250, 330253, 330254, 330260

Abstract:

A preamplifier system is provided for use with a magneto-resistive (MR) sensor. Included is an alternating current (AC) coupling module connected to the MR sensor for blocking a direct current (DC) voltage associated with an input signal, and filtering low frequency noise associated with the input signal. Also provided is a gain stage module coupled to the AC coupling module. The gain stage module includes a plurality of cascode field effect transistors (FETs) configured for amplifying the input signal, while reducing intrinsic noise and increasing operational bandwidth. Coupled to the gain stage module is a control circuit for feeding back an output of the gain stage module for bias regulation and disturbance rejection.

US Patent:

20030048559, Mar 13, 2003

Filed:

Sep 6, 2001

Appl. No.:

09/947741

Inventors:

Stephen Alan Jove - San Mateo CA, US
Calvin Shizuo Nomura - San Jose CA, US
Kevin Roy Vannorsdel - San Jose CA, US

International Classification:

G11B005/09

US Classification:

360/046000, 360/067000

Abstract:

Arm electronics (AE) suitable for use in a disk drive are disclosed. The AE has write circuitry configured to operate the AE in a write mode during which a write mode supply current is drawn, and read circuitry configured to operate the AE in a read mode during which a read mode supply current is drawn. The AE uses a decaying current pulse generator that generates a decaying current pulse at the beginning of each write-to-read mode transition. The decaying current pulse has an initial value that is equal to the difference between the write mode supply current and the read mode supply current. This controlled load forces the AE to draw a gradually decreasing supply current for each write-to-read mode transition such that supply voltage transients (otherwise present due to parasitics in cabling between the AE and power supply) are reduced. Thus, the undesirable effects of such transients in the read circuitry are reduced so that write-to-read mode recovery times can be shortened.

US Patent:

52873404, Feb 15, 1994

Filed:

Feb 13, 1992

Appl. No.:

7/835153

Inventors:

Dale B. Chapman - San Jose CA
Michael O. Jenkins - San Jose CA
Stephen A. Jove - Watsonville CA
Jacobus C. L. van Peppen - San Jose CA

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G11B 700
H03F 308

US Classification:

369 4441

Abstract:

An optical data storage system including an amplifier which (i) provides a differential current input having a low impedance over the full range of frequencies for which amplification is required in an optical detector that includes a photodiode that senses the intensity of an optical signal generated by data on the optical storage medium; (ii) reverse biases the photodiode; (iii) amplifies the signal current from both sides of the photodiode to improve signal-to-noise ratio; and (iv) is isolated from and unaffected by power supply noise.

US Patent:

48796107, Nov 7, 1989

Filed:

Sep 28, 1988

Appl. No.:

7/250784

Inventors:

Stephen A. Jove - Watsonville CA
Klaas B. Klaassen - San Jose CA
Calvin S. Nomura - San Jose CA
Jacobus C. L. vanPeppen - San Jose CA

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G11B 502
G11B 5127

US Classification:

360 67

Abstract:

A protective circuit for a magnetoresistive (MR) element having a first and a second terminal in which a first current source is coupled to the first terminal of the MR element to produce a bias current through the MR element and a second current source is coupled to the second terminal of the MR element to produce a reference current. Circuit means coupled across the MR element senses the center potential of the MR element substantially midway between the first and second terminals, and a feedback circuit responsive to the sensed center potential is coupled to adjust the current output of the first current source to maintain the center potential to a selected reference voltage to protect the MR element from short circuits to a conductive area of the magnetic recording medium. A second feedback circuit is provided which comprises a pair of transistors coupled in a differential pair configuration and a transconductance stage which feeds back a signal as a current to the transistors which keeps the dc currents through each of the transistors equal, and the transistors provide an amplified output signal which is a function of the magnetic flux being sensed by the MR element.