Pravin D Patel

US Patent:

7394281, Jul 1, 2008

Filed:

Jan 31, 2008

Appl. No.:

12/023659

Inventors:

Justin P. Bandholz - Cary NC, US
Moises Cases - Austin TX, US
Bradley D. Herman - Cary NC, US
Erdem Matoglu - Austin TX, US
Bhyrav M. Mutnury - Austin TX, US
Thomas D. Pahel - Chapel Hill NC, US
Pravin S. Patel - Cary NC, US
Nam H. Pham - Round Rock TX, US
Christopher C. West - Raleigh NC, US

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

H03K 17/16

US Classification:

326 22, 326 26, 326 83, 326 92

Abstract:

A bi-directional universal serial bus (“USB”) circuit for boosting a signal on a USB bus disclosed. The circuit includes a first stage inverting buffer coupled to a second stage inverting buffer to form a non-inverting buffer circuit. A high pass filter is coupled in series with the non-inverting buffer circuit to provide AC coupling to the USB bus and to allow fast signal edges through the circuit. The booster circuit is arranged to improve signal quality over a USB bus to allow additional USB devices and longer USB busses to be utilized.

US Patent:

7443180, Oct 28, 2008

Filed:

Dec 6, 2006

Appl. No.:

11/567449

Inventors:

Moises Cases - Austin TX, US
Daniel N. de Araujo - Cedar Park TX, US
Bradley D. Herrman - Cary NC, US
Erdem Matoglu - Austin TX, US
Bhyrav M. Mutnury - Austin TX, US
Pravin S. Patel - Cary NC, US
Nam H. Pham - Round Rock TX, US

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G01R 31/02
G01R 31/26

US Classification:

324754, 324765

Abstract:

The invention is directed to an on-chip probing apparatus. In accordance with an embodiment of the present invention, the on-chip probing apparatus includes: a plurality of switches on a chip; a plurality of externally accessible probe points on the chip; and a multiplexer for controlling the plurality of switches to selectively couple an output signal of the chip to one of the plurality of probe points.

US Patent:

7474117, Jan 6, 2009

Filed:

May 27, 2008

Appl. No.:

12/127165

Inventors:

Justin P. Bandholz - Cary NC, US
Moises Cases - Austin TX, US
Bradley D. Herman - Cary NC, US
Erdem Matoglu - Austin TX, US
Bhyrav M. Mutnury - Austin TX, US
Thomas D. Pahel - Chapel Hill NC, US
Pravin S. Patel - Cary NC, US
Nam H. Pham - Round Rock TX, US
Christopher C. West - Raleigh NC, US

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

H03K 17/16

US Classification:

326 22, 326 92

Abstract:

A method of transmitting a signal on a bi-directional universal serial bus (“USB”) circuit for boosting a signal on a USB bus disclosed. The circuit includes a first stage inverting buffer coupled to a second stage inverting buffer to form a non-inverting buffer circuit. A high pass filter is coupled in series with the non-inverting buffer circuit to provide AC coupling to the USB bus and to allow fast signal edges through the circuit. The booster circuit is arranged to improve signal quality over a USB bus to allow additional USB devices and longer USB busses to be utilized.

US Patent:

7525319, Apr 28, 2009

Filed:

Aug 28, 2008

Appl. No.:

12/200208

Inventors:

Rubina Firdaus Ahmed - Cary NC, US
Moises Cases - Austin TX, US
Bradley Donald Herrman - Cary NC, US
Kent Barclay Howieson - Austin TX, US
Bhyrav Murthy Mutnury - Austin TX, US
Pravin Patel - Cary NC, US
Peter Robert Seidel - Cary NC, US

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G01R 31/04
G01R 31/02
G01R 31/28

US Classification:

324538, 324754, 714734

Abstract:

A method of electrically qualifying high speed printed circuit board (PCB) connectors includes mounting a PCB connector on a test card, sending bit patterns through a first portion of the test card, evaluating a waveform on a sense signal on a second portion of the test card for the bit patterns launched on said first portion of the test card to measure common mode noise, and comparing the measured common mode noise of the second portion of the test card to a golden standard performed on a pre-qualified connector. The first portion of the test card comprises connectors to inject bit patterns. The second portion of the test card includes a split plane which induces common mode noise on a sense signal, the sense signal, and a termination pack. If the measured common mode noise on the PCB connector is worse than the golden standard, then the PCB connector is disqualified. If the measured common mode noise on the PCB connector is as good as or better than the golden standard, then the PCB connector is qualified.

US Patent:

7533458, May 19, 2009

Filed:

Jul 17, 2008

Appl. No.:

12/174810

Inventors:

Moises Cases - Austin TX, US
Bradley D. Herrman - Cary NC, US
Kent B. Howieson - Austin TX, US
Erdem Matoglu - Austin TX, US
Bhyrav M. Mutnury - Austin TX, US
Pravin S. Patel - Cary NC, US
Nam H. Pham - Round Rock TX, US
Caleb J. Wesley - Winston Salem NC, US

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

H05K 3/36

US Classification:

29830, 29825, 29832, 29846, 156293

Abstract:

Methods and systems for reducing noise coupling in high-speed digital systems. Exemplary embodiments include a method, including etching a plurality of high speed signal traces onto a core insulating layer, forming trenches on respective sides of the plurality of high speed signal traces, thereby removing insulating material adjacent to the plurality of high speed signal traces and forming pedestals having remaining insulating material, the plurality of high speed signal traces disposed on and coupled to the remaining insulating material, coupling pre-preg material on the high speed signal traces, removing the pre-preg material adjacent the trenches, thereby retaining the pre-preg material aligned with the high speed signal traces, and heating and pressing a core layer to the pre-preg layer, and heating and pressing the pre-preg layer to the core insulating layer.

US Patent:

7667980, Feb 23, 2010

Filed:

Oct 10, 2006

Appl. No.:

11/539990

Inventors:

Brian A. Baker - Raleigh NC, US
James E. Hughes - Apex NC, US
Pravin Patel - Cary NC, US
Challis L. Purrington - Raleigh NC, US
Christopher C. West - Raleigh NC, US

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

H05K 7/00

US Classification:

361782, 174262

Abstract:

Printed circuit boards for countering signal distortion are disclosed that include: a conductive pathway on a printed circuit board between a transmitter and a receiver, the conductive pathway comprised of traces and vias connected together for conductive transfer of a signal from the transmitter to the receiver; a parasitic element on the printed circuit board, the parasitic element having a parasitic effect that distorts the signal; and one or more passive elements mounted adjacent to the conductive pathway without connecting to the conductive pathway, the passive elements having a corrective effect to reduce the distortion from the parasitic effect on the signal.

US Patent:

7701222, Apr 20, 2010

Filed:

Oct 19, 2007

Appl. No.:

11/875001

Inventors:

Moises Cases - Austin TX, US
Bradley Donald Herrman - Cary NC, US
Kent Barclay Howieson - Austin TX, US
Erdem Matoglu - Austin TX, US
Bhyrav Murthy Mutnury - Austin TX, US
Pravin Patel - Cary NC, US
Nam Huu Pham - Round Rock TX, US
Caleb James Wesley - Winston Salem NC, US

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G01K 3/00
G01J 5/00
G01K 17/00
G01R 27/32

US Classification:

324501, 374122, 374137, 702136, 324637

Abstract:

A method for testing a printed circuit board to determining the dielectric loss associated with the circuit board material relative to a standard. Dielectric losses in the material generate heat when a high frequency electronic signal, such as a microwave frequency signal, is communicated through a microstrip that is embedded within the printed circuit board. The temperature or spectrum at the surface of printed circuit board is measured and compared against the temperature or spectrum of the standard to determine whether the material under test is acceptable. While various temperature measurement devices may be used, the temperature is preferably measured without contacting the surface, such as using an infrared radiation probe.

US Patent:

7725783, May 25, 2010

Filed:

Jul 20, 2007

Appl. No.:

11/780505

Inventors:

Moises Cases - Austin TX, US
Daniel N. de Araujo - Cedar Park TX, US
Bradley D. Herrman - Cary NC, US
Erdem Matoglu - Austin TX, US
Bhyrav M. Mutnury - Austin TX, US
Pravin Patel - Cary NC, US
Nam H. Pham - Round Rock TX, US

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G11C 29/00

US Classification:

714718, 714 5, 714 25, 714 42, 714 43, 714 56, 714704, 714712, 365201, 702 38

Abstract:

The present invention assesses memory (DIMM) strength by calculating frequency content of a radiated field which is collected by an apparatus, such as a dipole antenna. Radiated field is created by accelerated charge, which is a function of the slew rate or DIMM strength. Radiated power is directly proportional to the frequency at which bits are driven. By separating the radiated field from the near field or stored field, the DIMM strength content is isolated from other functional DIMM issues, such as tRCD latency, refresh cycles, addressing mode, etc. By examining the radiated power, the disadvantages of the prior art, such as by probing the DIMM's contacts, are avoided.