Patents by Inventor Vikram Varma

Vikram Varma 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: 10615818
    Abstract: A two-step, hybrid analog-to-digital converter (ADC) includes a Delta-Sigma ADC that employs chopping to resolve MSBs, a Nyquist ADC that employs correlated double sampling (CDS) to resolve LSBs, and a combiner that combines the MSBs and the LSBs to generate a digital output signal. The Delta-Sigma ADC has first and second integrators where, after resolving the MSBs, the first integrator is re-configured to function as a reference buffer for the Nyquist ADC and the second integrator is re-configured to function as the Nyquist ADC.
    Type: Grant
    Filed: June 2, 2019
    Date of Patent: April 7, 2020
    Assignee: NXP USA, Inc.
    Inventors: Kamlesh Singh, Vikram Varma
  • Patent number: 9643558
    Abstract: A system for detecting a mismatch between first and second input signals includes first and second analog-to-digital converters, a time-division multiplexing circuit, first and second processors, a time-division de-multiplexing circuit, and a gating circuit. The first processor includes a first sinc filter, a first trimmer, a first infinite impulse response (IIR) filter, and a first high pass filter (HPF). The second processor includes a second sinc filter, a second IIR filter, and a second HPF. A bandwidth of the second IIR filter and the second HPF is greater than a bandwidth of the first IIR filter and the first HPF. A transfer function of the first IIR filter and the first HPF uses floating-point coefficients and a transfer function of the second IIR filter and the second HPF uses coefficients that are an integral power of two.
    Type: Grant
    Filed: February 18, 2015
    Date of Patent: May 9, 2017
    Assignee: FREESCALE SEMICONDUCTOR, INC.
    Inventors: Siddhartha Gopal Krishna, Russell J. Lynch, Vikram Varma
  • Publication number: 20160236637
    Abstract: A system for detecting a mismatch between first and second input signals includes first and second analog-to-digital converters, a time-division multiplexing circuit, first and second processors, a time-division de-multiplexing circuit, and a gating circuit. The first processor includes a first sinc filter, a first trimmer, a first infinite impulse response (IIR) filter, and a first high pass filter (HPF). The second processor includes a second sinc filter, a second IIR filter, and a second HPF. A bandwidth of the second IIR filter and the second HPF is greater than a bandwidth of the first IIR filter and the first HPF. A transfer function of the first IIR filter and the first HPF uses floating-point coefficients and a transfer function of the second IIR filter and the second HPF uses coefficients that are an integral power of two.
    Type: Application
    Filed: February 18, 2015
    Publication date: August 18, 2016
    Inventors: SIDDHARTHA GOPAL KRISHNA, Russell J. Lynch, Vikram Varma
  • Patent number: 9353017
    Abstract: A method of trimming a current source in an IC includes deriving a reference voltage from an external supply, and developing a measurement voltage across an external reference resistance receiving the current to be trimmed. An on-chip ADC is used to provide corresponding digital reference and digital measurement signals. A digital comparator compares the digital signals and provides a digital trim signal, which is used to adjust the current to be trimmed until the digital measurement signal is equal to the digital reference signal within an acceptable tolerance. Gain and offset errors in the ADC cancel and do not affect the calibration of the trim operation.
    Type: Grant
    Filed: June 17, 2014
    Date of Patent: May 31, 2016
    Assignee: FREESCALE SEMICONDUCTOR, INC.
    Inventors: Siddhartha Gopal Krishna, Vikram Varma
  • Publication number: 20150362942
    Abstract: A method of trimming a current source in an IC includes deriving a reference voltage from an external supply, and developing a measurement voltage across an external reference resistance receiving the current to be trimmed. An on-chip ADC is used to provide corresponding digital reference and digital measurement signals. A digital comparator compares the digital signals and provides a digital trim signal, which is used to adjust the current to be trimmed until the digital measurement signal is equal to the digital reference signal within an acceptable tolerance. Gain and offset errors in the ADC cancel and do not affect the calibration of the trim operation.
    Type: Application
    Filed: June 17, 2014
    Publication date: December 17, 2015
    Applicant: Freescale Semiconductor, Inc.
    Inventors: Siddhartha Gopal Krishna, Vikram Varma
  • Patent number: 9157826
    Abstract: A method and system to calibrate temperature and pressure in piezo resistive devices for non-linear sensors having two variables, where a piezo resistive device such as a piezo resistive transducer (PRT) used for example in a pressure sensor system is calibrated to calculate actual/ambient temperature and pressure even though the PRT impedance is unbalanced relative to pressure.
    Type: Grant
    Filed: March 5, 2014
    Date of Patent: October 13, 2015
    Assignee: FREESCALE SEMICONDUCTOR, INC.
    Inventors: Siddhartha Gopal Krishna, Chad S. Dawson, Vikram Varma
  • Patent number: 9071265
    Abstract: A SAR ADC includes capacitors, a comparator, and a SAR logic circuit. The capacitors include a first set of capacitors and an error-detection capacitor. The first set of capacitors generates a first set of voltage signals that are compared with a common-mode voltage signal (VCM) by the comparator during a first set of comparison cycles. The comparator generates a first set of control signals that is used by the SAR logic circuit to successively approximate the first set of voltage signals and generate a first set of bits. An error-detection capacitor generates an error-detection signal that is compared with the common-mode voltage signal VCM by the comparator to generate an error-detection control signal. The SAR logic circuit compensate for an error in the first set of bits based the logic state of the error-detection control signal.
    Type: Grant
    Filed: August 12, 2014
    Date of Patent: June 30, 2015
    Assignee: FREESCALE SEMICONDUCTOR, INC.
    Inventors: Sanjoy K. Dey, Vikram Varma
  • Patent number: 9030346
    Abstract: A single-ended SAR ADC includes an additional capacitor, a self-test engine, and independent control of sample and hold conditions, which allows for quick and accurate testing of the ADC.
    Type: Grant
    Filed: May 24, 2013
    Date of Patent: May 12, 2015
    Assignee: Freescale Semiconductor, Inc.
    Inventors: Sanjoy K. Dey, Michael T. Berens, James R. Feddeler, Vikram Varma
  • Publication number: 20140182353
    Abstract: A method and system to calibrate temperature and pressure in piezo resistive devices for non-linear sensors having two variables, where a piezo resistive device such as a piezo resistive transducer (PRT) used for example in a pressure sensor system is calibrated to calculate actual/ambient temperature and pressure even though the PRT impedance is unbalanced relative to pressure.
    Type: Application
    Filed: March 5, 2014
    Publication date: July 3, 2014
    Inventors: Siddhartha Gopal Krishna, Chad S. Dawson, Vikram Varma
  • Patent number: 8701460
    Abstract: A method and system to calibrate temperature and pressure in piezo resistive devices for non-linear sensors having two variables, where a piezo resistive device such as a piezo resistive transducer (PRT) used for example in a pressure sensor system is calibrated to calculate actual/ambient temperature and pressure even though the PRT impedance is unbalanced relative to pressure.
    Type: Grant
    Filed: March 31, 2011
    Date of Patent: April 22, 2014
    Assignee: Freescale Semiconductor, Inc.
    Inventors: Siddhartha Gopal Krishna, Chad S. Dawson, Vikram Varma
  • Publication number: 20130249723
    Abstract: A single-ended SAR ADC includes an additional capacitor, a self-test engine, and independent control of sample and hold conditions, which allows for quick and accurate testing of the ADC.
    Type: Application
    Filed: May 24, 2013
    Publication date: September 26, 2013
    Inventors: Sanjoy K. Dey, Michael T. Berens, James R. Feddeler, Vikram Varma
  • Patent number: 8477052
    Abstract: A single-ended SAR ADC includes an additional capacitor, a self-test engine, and independent control of sample and hold conditions, which allows for quick and accurate testing of the ADC.
    Type: Grant
    Filed: April 5, 2011
    Date of Patent: July 2, 2013
    Assignee: Freescale Semiconductor, Inc.
    Inventors: Sanjoy K. Dey, Michael T. Berens, James R. Feddeler, Vikram Varma
  • Publication number: 20120256774
    Abstract: A single-ended SAR ADC includes an additional capacitor, a self-test engine, and independent control of sample and hold conditions, which allows for quick and accurate testing of the ADC.
    Type: Application
    Filed: April 5, 2011
    Publication date: October 11, 2012
    Applicant: FREESCALE SEMICONDUCTOR, INC.
    Inventors: Sanjoy K. Dey, Michael T. Berens, James R. Feddeler, Vikram Varma
  • Publication number: 20120247175
    Abstract: A method and system to calibrate temperature and pressure in piezo resistive devices for non-linear sensors having two variables, where a piezo resistive device such as a piezo resistive transducer (PRT) used for example in a pressure sensor system is calibrated to calculate actual/ambient temperature and pressure even though the PRT impedance is unbalanced relative to pressure.
    Type: Application
    Filed: March 31, 2011
    Publication date: October 4, 2012
    Applicant: FREESCALE SEMICONDUCTOR, INC.
    Inventors: Siddhartha Gopal Krishna, Chad S. Dawson, Vikram Varma
  • Patent number: 6958722
    Abstract: An aspect of the invention improves accuracy of digital codes generated at the output of a SAR ADC by using multiple reference voltages. A first reference voltage is used to generate an equivalent voltage corresponding to previous resolved bits and a second reference voltage is used to generate equivalent voltage corresponding to the bits being presently resolved. Another aspect of the present invention provides an ADC with high SNR as well as high throughput performance. Such a feature may be achieved by resolving some of the MSBs of the digital code using a high speed and low SNR DAC and remaining bits of the digital code using a high SNR DAC.
    Type: Grant
    Filed: June 11, 2004
    Date of Patent: October 25, 2005
    Assignee: Texas Instruments Incorporated
    Inventors: Seetharaman Janakiraman, Vikram Varma, Yujendra Mitikiri