Patents by Inventor Vijay K. Chellappa

Vijay K. Chellappa 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: 9154243
    Abstract: Techniques for calibrating a receiver based on a local oscillator (LO) signal from another receiver are disclosed. In an exemplary design, an apparatus (e.g., a wireless device or an integrated circuit) includes first and second local oscillator (LO) generators. The first LO generator generates a first LO signal used by a first receiver for frequency downconversion. The second LO generator generates a second LO signal used by a second receiver for frequency downconversion in a first operating mode. The second LO signal is used to generate a test signal for the first receiver in a second operating mode. The second LO signal may be provided as the test signal or may be amplitude modulated with a modulating signal to generate the test signal. The test signal may be used to calibrate residual sideband (RSB), second order input intercept point (IIP2), receive path gain, etc.
    Type: Grant
    Filed: February 26, 2013
    Date of Patent: October 6, 2015
    Assignee: QUALCOMM Incorporated
    Inventors: Udara C. Fernando, Li-Chung Chang, Vijay K. Chellappa, Frederic Bossu, Ketan Humnabadkar, Gurkanwal Singh Sahota
  • Patent number: 9137757
    Abstract: A wireless communication device includes: an antenna for receiving inbound signals on dual receive channels and transmitting outbound signals on dual transmit channels; a transceiver coupled to the antenna to receive the inbound signals from the antenna and convey the outbound signals; a power controller coupled to the transceiver to control power levels of the outbound signals so a maximum nominal power level of the outbound signals is a first power level; and a processor coupled to the transceiver and the antenna to cause the power controller to control the power levels of the outbound signals so if a power level of a received one of the inbound signals is below a threshold value, then the maximum nominal power level of the outbound signals is a second power level lower than the first power level, wherein the second power level is lower than the first power level.
    Type: Grant
    Filed: February 9, 2011
    Date of Patent: September 15, 2015
    Assignee: QUALCOMM Incorporated
    Inventors: Heechoon Lee, Sharad Deepak Sambhwani, Wesley A. Sampson, Harris S. Simon, Vijay K. Chellappa, Danlu Zhang
  • Patent number: 9041464
    Abstract: Circuitry for reducing power consumption is described. The circuitry includes a power amplifier. The circuitry also includes a predistorter coupled to the power amplifier. The circuitry further includes a power supply coupled to the power amplifier. The circuitry additionally includes a controller coupled to the power amplifier, to the predistorter and to the power supply. The controller captures a transmit signal and a feedback signal concurrently and determines a minimum bias voltage from a set of voltages and a predistortion that enable the power amplifier to produce an amplified transmit signal in accordance with a requirement.
    Type: Grant
    Filed: September 13, 2012
    Date of Patent: May 26, 2015
    Assignee: QUALCOMM Incorporated
    Inventors: Christos Komninakis, Vijay K. Chellappa, Jifeng Geng
  • Patent number: 9031158
    Abstract: A method and apparatus for providing total power from one transmit path. The method provides the steps of: selecting a transmit path and closing a first switch, located after a digital to analog converter. A second switch between the two transmit paths is then closed in order to provide for the use of at least one low-pass filter in each transmit path. The signal is then processed through the at least one low pass filter in each transmit path. The signal is then processed through at least one mixer in each transmit path. After the mixer, the signal is then processed through at least one driver amplifier in each transmit path, and one-half of the total power is allocated to each of two transmission paths. A third switch is then closed after the at least one power amplifier in each transmit path to force the half-power from one transmit path into one output.
    Type: Grant
    Filed: October 8, 2012
    Date of Patent: May 12, 2015
    Assignee: QUALCOMM Incorporated
    Inventors: Prasad Srinivasa Siva Gudem, Vijay K Chellappa, Jeremy Darren Dunworth, Chiewcharn Narathong
  • Publication number: 20140171001
    Abstract: Techniques for calibrating a receiver based on a local oscillator (LO) signal from another receiver are disclosed. In an exemplary design, an apparatus (e.g., a wireless device or an integrated circuit) includes first and second local oscillator (LO) generators. The first LO generator generates a first LO signal used by a first receiver for frequency downconversion. The second LO generator generates a second LO signal used by a second receiver for frequency downconversion in a first operating mode. The second LO signal is used to generate a test signal for the first receiver in a second operating mode. The second LO signal may be provided as the test signal or may be amplitude modulated with a modulating signal to generate the test signal. The test signal may be used to calibrate residual sideband (RSB), second order input intercept point (IIP2), receive path gain, etc.
    Type: Application
    Filed: February 26, 2013
    Publication date: June 19, 2014
    Applicant: QUALCOMM INCORPORATED
    Inventors: Udara C. Fernando, Li-Chung Chang, Vijay K. Chellappa, Frederic Bossu, Ketan Humnabadkar, Gurkanwal Singh Sahota
  • Patent number: 8755456
    Abstract: A wireless device for waveform scaling is disclosed. The wireless device includes a modulator that increases a magnitude of a peak digital code beyond a maximum available digital code for transmit power levels below a transmit power threshold to produce an adjusted digital code. The magnitude of the peak digital code is not increased beyond the maximum available digital code for transmit power levels above the transmit power threshold. The wireless device also includes a digital-to-analog converter that converts the adjusted digital code into an analog signal.
    Type: Grant
    Filed: March 8, 2012
    Date of Patent: June 17, 2014
    Assignee: QUALCOMM Incorporated
    Inventors: Vinod V. Panikkath, Vijay K. Chellappa, Bhushan Shanti Asuri
  • Patent number: 8754706
    Abstract: A power train amplification stage is described. The power train amplification stage includes a power amplifier. The power train amplification stage also includes a switched mode power supply that provides a bias voltage to the power amplifier. The power train amplification stage further includes a pulse density modulator. The power train amplification stage also includes a feedback path from the power amplifier to the pulse density modulator.
    Type: Grant
    Filed: June 7, 2012
    Date of Patent: June 17, 2014
    Assignee: QUALCOMM Incorporated
    Inventors: Prasad Srinivasa Siva Gudem, Ketan Humnabadkar, Vijay K. Chellappa, Sumit Verma
  • Publication number: 20140098906
    Abstract: A method and apparatus for providing total power from one transmit path. The method provides the steps of: selecting a transmit path and closing a first switch, located after a digital to analog converter. A second switch between the two transmit paths is then closed in order to provide for the use of at least one low-pass filter in each transmit path. The signal is then processed through the at least one low pass filter in each transmit path. The signal is then processed through at least one mixer in each transmit path. After the mixer, the signal is then processed through at least one driver amplifier in each transmit path, and one-half of the total power is allocated to each of two transmission paths. A third switch is then closed after the at least one power amplifier in each transmit path to force the half-power from one transmit path into one output.
    Type: Application
    Filed: October 8, 2012
    Publication date: April 10, 2014
    Applicant: QUALCOMM INCORPORATED
    Inventors: Prasad Srinivasa Siva Gudem, Vijay K Chellappa, Jeremy Darren Dunworth, Chiewcharn Narathong
  • Publication number: 20130257529
    Abstract: Circuitry for reducing power consumption is described. The circuitry includes a power amplifier. The circuitry also includes a predistorter coupled to the power amplifier. The circuitry further includes a power supply coupled to the power amplifier. The circuitry additionally includes a controller coupled to the power amplifier, to the predistorter and to the power supply. The controller captures a transmit signal and a feedback signal concurrently and determines a minimum bias voltage from a set of voltages and a predistortion that enable the power amplifier to produce an amplified transmit signal in accordance with a requirement.
    Type: Application
    Filed: September 13, 2012
    Publication date: October 3, 2013
    Applicant: QUALCOMM INCORPORATED
    Inventors: Christos Komninakis, Vijay K. Chellappa, Jifeng Geng
  • Publication number: 20130033314
    Abstract: A power train amplification stage is described. The power train amplification stage includes a power amplifier. The power train amplification stage also includes a switched mode power supply that provides a bias voltage to the power amplifier. The power train amplification stage further includes a pulse density modulator. The power train amplification stage also includes a feedback path from the power amplifier to the pulse density modulator.
    Type: Application
    Filed: June 7, 2012
    Publication date: February 7, 2013
    Applicant: QUALCOMM INCORPORATED
    Inventors: Prasad Srinivasa Siva Gudem, Ketan Humnabadkar, Vijay K. Chellappa, Sumit Verma
  • Publication number: 20120315961
    Abstract: A wireless communication device for deriving a dynamic voltage scaling data profile is described. The wireless communication device includes memory that includes a dynamic voltage scaling voice profile. The wireless communication device also includes a data profile determination module coupled to the memory. The data profile determination module obtains an offset and derives a dynamic voltage scaling data profile by offsetting the dynamic voltage scaling voice profile based on the offset.
    Type: Application
    Filed: May 23, 2012
    Publication date: December 13, 2012
    Applicant: QUALCOMM INCORPORATED
    Inventors: Mei Chen, Vijay K. Chellappa, Sumit Verma, Ketan Humnabadkar, Bhaskar Natarajakumar, Carl Thomas Hardin
  • Patent number: 8275331
    Abstract: Techniques for optimizing the power consumption of existing low cost multi-gain state power amplifiers (PA) to increase the talk time of wireless communication devices are described. In an exemplary embodiment a device, such as a baseband processor, operates to set a multistage PA having at least two gain states for amplifying a transmit signal to a lowest power consuming gain state. The device calculates a transition power level as a function of an identified maximum power reduction (MPR) value and switches the PA to a higher gain state from a lower gain state when a transmission power level is higher than the calculated transition power level.
    Type: Grant
    Filed: December 4, 2009
    Date of Patent: September 25, 2012
    Assignee: QUALCOMM, Incorporated
    Inventors: Sumit Verma, Vijay K. Chellappa, Gurkanwal S. Sahota
  • Publication number: 20120230447
    Abstract: A wireless device for waveform scaling is disclosed. The wireless device includes a modulator that increases a magnitude of a peak digital code beyond a maximum available digital code for transmit power levels below a transmit power threshold to produce an adjusted digital code. The magnitude of the peak digital code is not increased beyond the maximum available digital code for transmit power levels above the transmit power threshold. The wireless device also includes a digital-to-analog converter that converts the adjusted digital code into an analog signal.
    Type: Application
    Filed: March 8, 2012
    Publication date: September 13, 2012
    Applicant: QUALCOMM Incorporated
    Inventors: Vinod V. Panikkath, Vijay K. Chellappa, Bhushan Shanti Asuri
  • Publication number: 20110199949
    Abstract: A wireless communication device includes: an antenna for receiving inbound signals on dual receive channels and transmitting outbound signals on dual transmit channels; a transceiver coupled to the antenna to receive the inbound signals from the antenna and convey the outbound signals; a power controller coupled to the transceiver to control power levels of the outbound signals so a maximum nominal power level of the outbound signals is a first power level; and a processor coupled to the transceiver and the antenna to cause the power controller to control the power levels of the outbound signals so if a power level of a received one of the inbound signals is below a threshold value, then the maximum nominal power level of the outbound signals is a second power level lower than the first power level, wherein the second power level is lower than the first power level.
    Type: Application
    Filed: February 9, 2011
    Publication date: August 18, 2011
    Applicant: QUALCOMM Incorporated
    Inventors: Heechoon Lee, Sharad Deepak Sambhwani, Wesley A. Sampson, Harris S. Simon, Vijay K. Chellappa, Danlu Zhang
  • Publication number: 20110141930
    Abstract: A method for compensating for phase discontinuities on a communication device is described. A communication device may determine a desired output power. The communication device may determine a Digital-to-Analog Converter (DAC) gain corresponding to the desired output power. The communication device may determine a cumulative phase offset based on the DAC gain. The communication device may apply the DAC gain. The communication device may apply a phase compensation to a rotator to adjust for the cumulative phase offset.
    Type: Application
    Filed: August 27, 2010
    Publication date: June 16, 2011
    Applicant: QUALCOMM INCORPORATED
    Inventors: Sumit Verma, Vijay K. Chellappa, Bhushan Shanti Asuri
  • Publication number: 20100308909
    Abstract: Techniques for optimizing the power consumption of existing low cost multi-gain state power amplifiers (PA) to increase the talk time of wireless communication devices are described. In an exemplary embodiment a device, such as a baseband processor, operates to set a multistage PA having at least two gain states for amplifying a transmit signal to a lowest power consuming gain state. The device calculates a transition power level as a function of an identified maximum power reduction (MPR) value and switches the PA to a higher gain state from a lower gain state when a transmission power level is higher than the calculated transition power level.
    Type: Application
    Filed: December 4, 2009
    Publication date: December 9, 2010
    Applicant: QUALCOMM Incorporated
    Inventors: Sumit Verma, Vijay K. Chellappa, Gurkanwal S. Sahota