Sabah Shakir Khesbak

US Patent:

6339361, Jan 15, 2002

Filed:

Jun 9, 1999

Appl. No.:

09/328927

Inventors:

Sabah Khesbak - Irvine CA
Madhukar Reddy - Irvine CA
Pramote Piriyapoksombut - Millbrae CA
Trevor Robinson - Costa Mesa CA

Assignee:

Conexant Systems, Inc. - Newport Beach CA

International Classification:

H03G 310

US Classification:

330285, 330133, 330134, 330279, 330129

Abstract:

A driver system for a power amplifier in a wireless communication handset. The driver system includes a driver and a current source. The driver drives the power amplifier at a level of linearity determined responsive to a variable input bias current provided by the current source. The current source varies the bias current, and thus the degree of linearity provided, responsive to the desired output power of the handset.

US Patent:

6542029, Apr 1, 2003

Filed:

Oct 11, 2000

Appl. No.:

09/686669

Inventors:

Sabah Khesbak - Irvine CA
Madhukar Reddy - Irvine CA

Assignee:

Skyworks Solutions, Inc. - Newport Beach CA

International Classification:

H03G 320

US Classification:

330129, 330130

Abstract:

A system for varying output power of variable-gain amplifiers (VGA) allows for varying the output power transfer function, thus varying the gain, and, hence, the resolution of the output power of the VGA. The preferred embodiment comprises a variable-slope VGA (VSVGA) circuit configured to operate within a closed-loop power-controlled CDMA handset. The VSVGA circuit manipulates the input control voltage of the VGA, thereby, adjusting the gain of the amplifier by varying the slope of a line which models the amplifier output transfer function. Varying gain of the VGA provides for a varying resolution in the VGA amplifier output transfer function. This variation allows for compatibility of a single CDMA handset with different industry standards.

US Patent:

8587377, Nov 19, 2013

Filed:

Dec 1, 2011

Appl. No.:

13/309349

Inventors:

Sabah Khesbak - Irvine CA, US
San Chin - Yorba Linda CA, US

Assignee:

Skyworks Solutions, Inc. - Woburn MA

International Classification:

H03G 3/30

US Classification:

330136

Abstract:

Apparatus and methods for biasing a power amplifier are disclosed. In one embodiment, a power amplifier system includes a power amplifier configured to amplify a radio frequency (RF) signal and a bias control circuit for generating a bias current for the power amplifier. The bias control circuit is configured to receive an envelope of the RF signal and to change an amplitude of the bias current based at least in part on the envelope.

US Patent:

8598950, Dec 3, 2013

Filed:

Dec 12, 2011

Appl. No.:

13/323503

Inventors:

Sabah Khesbak - Irvine CA, US

Assignee:

Skyworks Solutions, Inc. - Woburn MA

International Classification:

H03F 1/14

US Classification:

330 51, 330297, 330 10

Abstract:

Apparatus and methods for capacitive load reduction are disclosed. In one embodiment, a power amplifier system includes a plurality of power amplifiers and an envelope tracking module for generating a supply voltage for the power amplifiers. The power amplifier system further includes a switch and a decoupling capacitor operatively associated with a first power amplifier of the system. The switch is configured to electrically float an end of the decoupling capacitor when the first power amplifier is disabled so as to reduce capacitive loading of the envelope tracker and to operate as a dampening resistor when the power amplifier is enabled so as to improve the stability of the system.

US Patent:

20120200354, Aug 9, 2012

Filed:

Feb 6, 2012

Appl. No.:

13/367190

Inventors:

David Steven Ripley - Marion IA, US
Sabah Khesbak - Irvine CA, US
Benjamin Bartram - Baldock, GB
Kevin Lee Cobley - Cambrideshire, GB
Robert Astle Henshaw - Suffolk, GB
Julian Hildersley - Hertsfoshire, GB
Robert John Thompson - Cedar Rapids IA, US

Assignee:

NUJIRA LTD - Cambridge
SKYWORKS SOLUTIONS, INC. - Wobum MA

International Classification:

H03G 3/20

US Classification:

330131

Abstract:

Apparatus and methods for envelope tracking calibration are provided. In one embodiment, a method of calibrating an envelope tracker having an envelope shaping table generated at a desired gain compression of a power amplifier is provided. The method includes generating a supply voltage for the power amplifier using the envelope tracker, operating the supply voltage of the power amplifier at a first voltage level associated with substantially no gain compression of the power amplifier, and measuring an output power of the power amplifier at the first voltage level. The method further includes decreasing a voltage level of the supply voltage one or more times and measuring the output power at each voltage level, determining a second voltage level of the power amplifier associated with a gain compression equal to about that of the desired gain compression, and calibrating the envelope tracker based on the determination.

US Patent:

20120269240, Oct 25, 2012

Filed:

Apr 20, 2012

Appl. No.:

13/452620

Inventors:

Florinel G. Balteanu - Ottawa, CA
Sabah Khesbak - Irvine CA, US
Yevgeniy A. Tkachenko - Belmont MA, US
David Steven Ripley - Marion IA, US
Robert John Thompson - Cedar Rapids IA, US

Assignee:

SKYWORKS SOLUTIONS, INC. - Woburn MA

International Classification:

H04B 15/00
H04B 1/38
H04B 1/04

US Classification:

375219, 375297

Abstract:

Apparatus and methods for envelope tracking are disclosed. In one embodiment, a power amplifier system including a power amplifier and an envelope tracker is provided. The power amplifier is configured to amplify a radio frequency (RF) signal, and the envelope tracker is configured to control a supply voltage of the power amplifier using an envelope of the RF signal. The envelope tracker includes a buck converter for generating a buck voltage from a battery voltage and a digital-to-analog conversion (DAC) module for adjusting the buck voltage based on the envelope of the RF signal to generate the supply voltage for the power amplifier.

US Patent:

20130116017, May 9, 2013

Filed:

Nov 1, 2012

Appl. No.:

13/666627

Inventors:

Hardik Bhupendra Modi - Irvine CA, US
Sabah Khesbak - Irvine CA, US

Assignee:

SKYWORKS SOLUTIONS, INC. - Woburn MA

International Classification:

H04W 88/02
H03F 3/04

US Classification:

4555757, 330250, 330296

Abstract:

Apparatus and methods for power amplifiers are disclosed. In one embodiment, a power amplifier circuit assembly includes a power amplifier and an impedance matching network. The impedance matching network is operatively associated with the power amplifier and is configured to provide a load line impedance to the power amplifier between about 6 Ω and about 10 Ω. The impedance matching network includes a fundamental matching circuit and one or more termination circuits, and the fundamental matching circuit and each of the of the one or more termination circuits include separate input terminals for coupling to an output of the power amplifier so as to allow the fundamental matching circuit and each of the one or more termination circuits to be separately tuned.

US Patent:

20130217345, Aug 22, 2013

Filed:

Feb 8, 2013

Appl. No.:

13/763410

Inventors:

David Steven Ripley - Marion IA, US
Sabah Khesbak - Irvine CA, US
Jeffrey Gordon Strahler - Greensboro NC, US
Roman Zbigniew Arkiszewski - Oak Ridge NC, US
Yevgeniy A. Tkachenko - Belmont MA, US

Assignee:

SKYWORKS SOLUTIONS, INC. - Woburn MA

International Classification:

H03F 3/193

US Classification:

455 84, 330260

Abstract:

Apparatus and methods for envelope tracking systems are disclosed herein. In certain implementations, an envelope tracking system for generating a power amplifier supply voltage for a power amplifier is provided. The envelope tracking system includes a DC-to-DC converter that generates a regulated voltage from a battery voltage and controls a voltage of the regulated voltage using a low frequency feedback signal. The envelope tracking system further includes an error amplifier that generates an output current using an envelope signal and a high frequency feedback signal. The low frequency feedback signal is based on a low frequency component of the power amplifier supply voltage and the high frequency feedback signal is based on a high frequency component of the power amplifier supply voltage. The error amplifier generates the power amplifier supply voltage by adjusting the magnitude of the regulated voltage using the output current.