Farzad R Sahandiesfanjani

US Patent:

7142047, Nov 28, 2006

Filed:

Nov 29, 2004

Appl. No.:

11/000215

Inventors:

Farzad Sahandiesfanjani - Santa Clara CA, US
Babak Mazda - Mountain View CA, US

Assignee:

Tripath Technology, Inc. - San Jose CA

International Classification:

H03F 1/02

US Classification:

330 9, 327307

Abstract:

A switching circuit is described having an input stage having an input referred offset voltage associated therewith. An output stage has an output offset voltage associated therewith which is due at least in part to the input referred offset associated with the input stage. Offset cancellation circuitry is operable to cancel a portion of the input referred offset voltage before switching of the output stage is enabled thereby resulting in cancellation of the portion of the output offset voltage after switching of the output stage begins. The offset cancellation circuitry is further operable to release the input referred offset voltage after switching of the output stage begins thereby allowing the output offset voltage to drift.

US Patent:

7283001, Oct 16, 2007

Filed:

May 10, 2006

Appl. No.:

11/432291

Inventors:

Babak Mazda - Mountain View CA, US
Farzad Sahandiesfanjani - Santa Clara CA, US
Adya S. Tripathi - San Jose CA, US

Assignee:

Cirrus Logic, Inc. - Austin TX

International Classification:

H03L 7/00

US Classification:

331 1A, 331 25

Abstract:

A generalized amplifier architecture is described which employs noise-shaping feedback, and for which the output waveform closely resembles the input waveform.

US Patent:

7352246, Apr 1, 2008

Filed:

Sep 7, 2007

Appl. No.:

11/852119

Inventors:

Babak Mazda - Los Altos CA, US
Farzad Sahandiesfanjani - Santa Clara CA, US
Adya S. Tripathi - San Jose CA, US

Assignee:

Cirrus Logic, Inc. - Austin TX

International Classification:

H03F 3/04

US Classification:

330310, 330 99

Abstract:

A generalized amplifier architecture is described which employs noise-shaping feedback, and for which the output waveform closely resembles the input waveform.

US Patent:

7466194, Dec 16, 2008

Filed:

Apr 19, 2007

Appl. No.:

11/737616

Inventors:

Babak Mazda - Los Altos CA, US
Rahul Shinkre - Cupertino CA, US
Farzad Sahandiesfanjani - Santa Clara CA, US
Maziar Sayyedi - Mountain View CA, US
Krishna Prasad Sarangapani - Santa Clara CA, US

Assignee:

Cirrus Logic, Inc. - Austin TX

International Classification:

H03F 1/02

US Classification:

330 9, 330 10, 330251, 330207 A

Abstract:

An amplifier is described which includes a first loop including a first amplifier stage having an offset voltage associated therewith. An output stage includes two switching devices in a bridge configuration configured to be coupled between a supply voltage and ground. An output of the bridge configuration is configured to be coupled to a load. The first loop is characterized by a first gain. A decoupling capacitor is configured to be coupled to the load. A second loop which includes the first amplifier stage is configured to charge the decoupling capacitor to a first voltage generated with reference to the offset voltage before operation of the switching devices is enabled. The second loop is characterized by a second gain. The first and second gains are substantially the same such that when operation of the switching devices is enabled a second voltage at the output of the half-bridge configuration is substantially the same as the first voltage.

US Patent:

8616181, Dec 31, 2013

Filed:

Jan 11, 2011

Appl. No.:

13/004839

Inventors:

Farzad Sahandiesfanjani - San Jose CA, US
Chris Hand - Newport Beach CA, US
Mohammad Pirjaberi - San Jose CA, US
Adya S. Tripathi - San Jose CA, US

Assignee:

Tula Technology, Inc. - San Jose CA

International Classification:

F02D 28/00
F02D 17/02
F02D 41/00
G06F 19/00

US Classification:

123350

Abstract:

A variety of methods and arrangements for improving the fuel efficiency of internal combustion engines are described. In some aspects, methods and arrangements are described for operating an engine in a throttled skip fire mode. In other aspects, methods and arrangements are described for controlling the operational state of a variable displacement engine.

US Patent:

20120046853, Feb 23, 2012

Filed:

Aug 18, 2011

Appl. No.:

13/213061

Inventors:

Chester J. Silvestri - Los Gatos CA, US
Adya S. Tripathi - San Jose CA, US
Farzad Sahandiesfanjani - San Jose CA, US

International Classification:

F02D 41/30
F02D 41/26
F02D 28/00

US Classification:

701104

Abstract:

The present invention relates to a compression ignition engine control system and methods for improving fuel efficiency. The system includes a fuel processor which receives instructions for a desired engine output and current operating conditions. The fuel processor generates fueling instructions for a plurality of cylinders. The fueling instructions include a low power skip fire mode of operation and a high power mode of operation. The instructions substantially regulate fuel delivery into to a first group of cylinders at or near optimal efficiency fuel levels during each of their respective working cycles. Likewise, the instructions may either substantially disable fuel injection into to a second grouping of cylinders or regulate fuel injection into to the second grouping of cylinders at an elevated high power fuel to air ratio. The fuel processor may include a synchronizer for synchronizing firing of the cylinders with the engine speed. Likewise, the fuel processor may include a sigma delta control circuit for generating a firing pattern that utilizes predictive adaptive control.

US Patent:

20120109495, May 3, 2012

Filed:

Dec 1, 2011

Appl. No.:

13/309447

Inventors:

Adya S. TRIPATHI - San Jose CA, US
Farzad SAHANDIESFANJANI - San Jose CA, US

Assignee:

TULA TECHNOLOGY, INC. - Santa Clara CA

International Classification:

F02D 28/00

US Classification:

701102

Abstract:

A variety of methods and arrangements for controlling the operation of an internal combustion engine in a skip fire variable displacement mode are described. In one aspect, the working chamber firing that are selected to deliver the desired engine output are determined at least in part based on torque feedback. The torque feedback may be an indication of the torque output of the engine or the torque experienced at some other location in the drive train. In some embodiments, the torque feedback signal is filtered to remove high frequency components of the torque feedback signal in order to help stabilize the system. In another aspect, other operational parameters are used as feedback in the determination of the firing sequence. In yet another aspect, a filter is arranged to filter a feedback signal to provide a filtered feedback signal that is used in the determination of the working chamber firings.

US Patent:

20120143471, Jun 7, 2012

Filed:

Dec 1, 2011

Appl. No.:

13/309460

Inventors:

Adya S. TRIPATHI - San Jose CA, US
Farzad SAHANDIESFANJANI - San Jose CA, US
Biswa R. GHOSH - Los Altos CA, US

Assignee:

TULA TECHNOLOGY, INC. - Santa Clara CA

International Classification:

F02D 17/02
F02D 28/00

US Classification:

701102

Abstract:

A variety of methods and arrangements for controlling the operation of an internal combustion engine in a skip fire variable displacement mode are described. In general, a firing control unit determines working chamber firings during operation of the engine that are suitable for delivering a desired engine output. In one aspect, the firing control unit is arranged to isolate the generation of firing sequences having frequency components in a frequency range of concern and to alter the firing sequence in a manner that reduces the occurrence of frequency components in the frequency range of concern. In another aspect, a filter is arranged to filter a feedback signal to provide a filtered feedback signal that is used in the determination of the working chamber firings. In preferred embodiments, the frequency characteristics of the filter are variable. In various embodiments, the frequency characteristics of the filter vary as a function engine speed and/or a transmission gear ratio.