Patents by Inventor Murari Kejariwal

Murari Kejariwal has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 7808263
    Abstract: An integrated circuit including at least one internal operational block, which includes test control circuitry for initiating a test mode and testing circuitry for verifying an operation of the integrated circuit under a more stringent condition in the test mode as compared to a condition in another operating mode such that proper operation of the integrated circuit is assured in the another operating mode. Pin control circuitry selectively outputs a test signal from a selected pin in the test mode indicative of the operation of the internal block, wherein the selected pin is utilized for exchanging another signal when the integrated circuit is in the another operating mode.
    Type: Grant
    Filed: March 17, 2009
    Date of Patent: October 5, 2010
    Assignee: Cirrus Logic, Inc.
    Inventors: Murari Kejariwal, John Laurence Melanson, Ammisetti V. Prasad, Sherry Xiaohong Wu
  • Patent number: 7643573
    Abstract: A data acquisition system includes a programmable gain amplifier, an analog-to-digital converter, a filter, and control circuitry. The programmable gain amplifier is operatively connected to receive an analog input signal on its input and generates an amplified signal on its output in accordance with gain control signals. The analog-to-digital converter is operatively connected to receive the amplified signal from the amplifier and generates a digitized signal on its output. The filter is operatively connected to receive the digitized signal from the converter and generates a filtered digital signal on its output. The control circuitry is operatively connected to the amplifier and to the converter and is also responsive to the gain control signals for dynamically adjusting power between the amplifier and converter when the gain control signals are changed.
    Type: Grant
    Filed: March 17, 2006
    Date of Patent: January 5, 2010
    Assignee: Cirrus Logic, Inc.
    Inventors: Murari Kejariwal, John R. Coupe, II
  • Patent number: 7639002
    Abstract: A method of testing an integrated circuit including a plurality of test nodes includes initiating a test mode and, during a first time interval of the test mode, stepping a level of a supply current of the integrated circuit to a calibration level. Parameters are observed at the plurality of test nodes to detect errors during a second time interval of the test mode and the level of the supply current selectively stepped in response to a number of errors detected. The level of the supply current is decoded to identify the detected errors.
    Type: Grant
    Filed: April 25, 2006
    Date of Patent: December 29, 2009
    Assignee: Cirrus Logic, Inc.
    Inventors: Murari Kejariwal, Prisad Ammisetti, Axel Thomsen, John Laurence Melanson
  • Publication number: 20090179660
    Abstract: An integrated circuit including at least one internal operational block, which includes test control circuitry for initiating a test mode and testing circuitry for verifying an operation of the integrated circuit under a more stringent condition in the test mode as compared to a condition in another operating mode such that proper operation of the integrated circuit is assured in the another operating mode. Pin control circuitry selectively outputs a test signal from a selected pin in the test mode indicative of the operation of the internal block, wherein the selected pin is utilized for exchanging another signal when the integrated circuit is in the another operating mode.
    Type: Application
    Filed: March 17, 2009
    Publication date: July 16, 2009
    Inventors: Murari Kejariwal, John Laurence Melanson, Ammisetti V. Prasad, Sherry Xiaohong Wu
  • Patent number: 7521951
    Abstract: A method of testing an internal block of an integrated circuit includes initiating a test mode and verifying an operation of the integrated circuit under a more stringent condition in the test mode as compared to a condition in another operating mode such that proper operation of the integrated circuit is assured in the another operating mode. A test signal is selectively output from a selected pin in the test mode indicative of the operation of the internal block, wherein the selected pin is utilized for exchanging another signal when the integrated circuit is in the another operating mode.
    Type: Grant
    Filed: April 12, 2006
    Date of Patent: April 21, 2009
    Assignee: Cirrus Logic, Inc.
    Inventors: Murari Kejariwal, John Laurence Melanson, Ammisetti V. Prasad, Sherry Xiaohong Wu
  • Publication number: 20070217544
    Abstract: A data acquisition system includes a programmable gain amplifier, an analog-to-digital converter, a filter, and control circuitry. The programmable gain amplifier is operatively connected to receive an analog input signal on its input and generates an amplified signal on its output in accordance with gain control signals. The analog-to-digital converter is operatively connected to receive the amplified signal from the amplifier and generates a digitized signal on its output. The filter is operatively connected to receive the digitized signal from the converter and generates a filtered digital signal on its output. The control circuitry is operatively connected to the amplifier and to the converter and is also responsive to the gain control signals for dynamically adjusting power between the amplifier and converter when the gain control signals are changed.
    Type: Application
    Filed: March 17, 2006
    Publication date: September 20, 2007
    Inventors: Murari Kejariwal, John Coupe
  • Patent number: 7262654
    Abstract: An operational amplifier including at least one amplifier stage and chopping circuitry for chopping an input signal to the amplifier stage and an output signal from the chopping signal having a frequency randomly varying within the selected frequency band.
    Type: Grant
    Filed: January 14, 2005
    Date of Patent: August 28, 2007
    Assignee: Cirrus Logic, Inc.
    Inventors: Murari Kejariwal, Gowtham Vemulapalli, John Laurance Melanson
  • Patent number: 7202746
    Abstract: A multiple-stage operational amplifier including a gain stage for amplifying an input signal and implementing a dominant pole producing a frequency response having a gain roll-off with frequency and a unity gain frequency. An intermediate stage is coupled to an output of the gain stage and has a high input impedance and a low output impedance. A high gain amplifier configured as a low gain output stage using resistive feedback and coupled to an output of the intermediate stage drives an output of the operational amplifier and implements a dominant pole at a frequency substantially higher than the unity gain frequency implemented by the dominant pole implemented the gain stage.
    Type: Grant
    Filed: December 14, 2004
    Date of Patent: April 10, 2007
    Assignee: Cirrus Logic, Inc.
    Inventors: Murari Kejariwal, Gowtham Vemulapalli, John Laurance Melanson
  • Publication number: 20060158244
    Abstract: An operational amplifier including at least one amplifier stage and chopping circuitry for chopping an input signal to the amplifier stage and an output signal from the chopping signal having a frequency randomly varying within the selected frequency band.
    Type: Application
    Filed: January 14, 2005
    Publication date: July 20, 2006
    Applicant: Cirrus Logic, Inc.
    Inventors: Murari Kejariwal, Gowtham Vemulapalli, John Melanson
  • Patent number: 6937046
    Abstract: A method of testing an integrated circuit including the steps of observing a selected parameter at a selected test mode to detect an error. The current to the integrated circuit is stepped from a reference level by selected amount.
    Type: Grant
    Filed: December 20, 2001
    Date of Patent: August 30, 2005
    Assignee: Cirrus Logic, Inc.
    Inventors: Murari Kejariwal, Prasad Ammisetti, Axel Thomsen, John Laurence Melanson
  • Patent number: 6885211
    Abstract: A method of testing an integrated circuit includes setting a guardbanded limit for a parameter associated with an embedded node, a deviation from the guardbanded limit under a set of test conditions correlated with a failure of the integrated circuit across a range of operating conditions. A test is performed under the test conditions to detect deviations of the parameter from the guardbanded limit to detect failures of the integrated circuit over the range of operating conditions.
    Type: Grant
    Filed: April 5, 2002
    Date of Patent: April 26, 2005
    Assignee: Cirrus Logic, Inc.
    Inventors: Axel Thomsen, Sherry Wu, Murari Kejariwal, Ammisetti Prasad, John Laurence Melanson
  • Publication number: 20040193977
    Abstract: A method of testing an internal block of an integrated circuit includes testing an internal block under a selected operating condition by setting a selected operating parameter to a value emulating operation of the internal block under another operating condition to detect potential failure of the internal block under the another operating condition.
    Type: Application
    Filed: June 18, 2003
    Publication date: September 30, 2004
    Applicant: Cirrus Logic, Inc.
    Inventors: Murari Kejariwal, John Laurence Melanson, Ammisetti V. Prasad, Xiaohong Sherry Wu
  • Patent number: 6515540
    Abstract: An amplifier is disclosed including multiple integrator stages. The amplifier includes a low-frequency path from a signal input to a signal output and relatively higher-frequency bypass paths around the first integrator stage. The paths converge at a summing node. To prevent instability when the integrators are saturated by large signals, the circuit includes a saturation detector which disables the relatively low-frequency paths during such saturation conditions.
    Type: Grant
    Filed: December 10, 2001
    Date of Patent: February 4, 2003
    Assignee: Cirrus Logic, Inc.
    Inventors: Ammisetti V. Prasad, Murari Kejariwal, Axel Thomsen
  • Patent number: 6466091
    Abstract: Disclosed in this application is the placement of an additional integrator between the first stage integrator output and the input to the attenuator/low pass filter. This approach reduces the input referred offset by a factor equal to the gain of the additional integrator, and the offset of the additional integrator itself will be divided by the gain of the first-stage integrator.
    Type: Grant
    Filed: October 2, 2000
    Date of Patent: October 15, 2002
    Assignee: Cirrus Logic, Inc.
    Inventors: Murari Kejariwal, Prasad Ammisetti, Axel Thomsen
  • Patent number: 6307430
    Abstract: Disclosed is a chopper-stabilized amplifier with current steering used as output switching and to be operated in a low power supply voltage environment.
    Type: Grant
    Filed: October 2, 2000
    Date of Patent: October 23, 2001
    Assignee: Cirrus Logic, Inc.
    Inventors: Axel Thomsen, Murari Kejariwal, Prasad Ammisetti