Patents by Inventor Brett C. Walker

Brett C. Walker 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).

  • Publication number: 20140210482
    Abstract: A method and apparatus that reduce common mode variations experienced by a voltage sensing component. A measurement component such as a BATFET or an external sensing resistor, receives, at its source, a voltage from the top of a battery having a voltage VPH_PWR. A voltage sensing component, such as an ADC, is powered by the voltage from the battery. A power referenced component, such as a power referenced LDO, tracks the voltage from the battery and outputs the tracked voltage minus a predetermined voltage amount to a negative side of the voltage sensing component.
    Type: Application
    Filed: January 28, 2013
    Publication date: July 31, 2014
    Applicant: QUALCOMM Incorporated
    Inventors: Baiying Yu, Brett C. Walker
  • Patent number: 8750324
    Abstract: Embodiments disclosed herein address the need for a single wire bus interface. In one aspect, a device communicates with a second device via a single wire bus using a driver for driving the bus with a write frame comprising a start symbol, a write indicator symbol, an address, and data symbols. In another aspect, the device receives one or more data symbols on the single wire bus during a read frame. In yet another aspect, a device communicates with a second device via a single wire bus using a receiver for receiving a frame on the single wire bus comprising a start symbol, a write indicator symbol, an address, and one or more data symbols, and a driver for driving return read data associated with the address when the write indicator identifies a write frame. Various other aspects are also presented. These aspects provide for communication on a single wire bus, which allows for a reduction in pins, pads, or inter-block connections between devices.
    Type: Grant
    Filed: September 11, 2009
    Date of Patent: June 10, 2014
    Assignee: QUALCOMM Incorporated
    Inventors: David W. Hansquine, Brett C. Walker, Muhammad Asim Muneer
  • Patent number: 8633763
    Abstract: Output circuits using pulse width modulation (PWM) and/or pulse density modulation (PDM) are described. In one aspect, a PWM output circuit includes a PWM modulator that operates based on a square wave signal instead of a sawtooth or triangular wave signal. In another aspect, a PDM output circuit includes a PDM modulator that uses variable reference voltages to reduce variations in switching frequency. In yet another aspect, a dual-mode output circuit supports both PWM and PDM and includes a pulse modulator and a class D amplifier. The pulse modulator performs PWM on an input signal if a PWM mode is selected and performs PDM on the input signal if a PDM mode is selected. The class D amplifier receives a driver signal from the pulse modulator and generates an output signal.
    Type: Grant
    Filed: August 4, 2011
    Date of Patent: January 21, 2014
    Assignee: QUALCOMM Incorporated
    Inventors: Brett C Walker, Song Stone Shi
  • Patent number: 8626099
    Abstract: A direct downconversion receiver architecture having a DC loop to remove DC offset from the signal components, a digital variable gain amplifier (DVGA) to provide a range of gains, an automatic gain control (AGC) loop to provide gain control for the DVGA and RF/analog circuitry, and a serial bus interface (SBI) unit to provide controls for the RF/analog circuitry via a serial bus. The DVGA may be advantageously designed and located as described herein. The operating mode of the VGA loop may be selected based on the operating mode of the DC loop, since these two loops interact with one another. The duration of time the DC loop is operated in an acquisition mode may be selected to be inversely proportional to the DC loop bandwidth in the acquisition mode. The controls for some or all of the RF/analog circuitry may be provided via the serial bus.
    Type: Grant
    Filed: March 14, 2006
    Date of Patent: January 7, 2014
    Assignee: QUALCOMM Incorporated
    Inventors: Tao Li, Christian Holenstein, Inyup Kang, Brett C. Walker, Paul E. Peterzell, Raghu Challa, Matthew L. Severson, Arun Raghupathy, Gilbert Christopher Sih
  • Patent number: 8615212
    Abstract: A direct downconversion receiver architecture having a DC loop to remove DC offset from the signal components, a digital variable gain amplifier (DVGA) to provide a range of gains, an automatic gain control (AGC) loop to provide gain control for the DVGA and RF/analog circuitry, and a serial bus interface (SBI) unit to provide controls for the RF/analog circuitry via a serial bus. The DVGA may be advantageously designed and located as described herein. The operating mode of the VGA loop may be selected based on the operating mode of the DC loop, since these two loops interact with one another. The duration of time the DC loop is operated in an acquisition mode may be selected to be inversely proportional to the DC loop bandwidth in the acquisition mode. The controls for some or all of the RF/analog circuitry may be provided via the serial bus.
    Type: Grant
    Filed: September 27, 2007
    Date of Patent: December 24, 2013
    Assignee: QUALCOMM Incorporated
    Inventors: Tao Li, Christian Holenstein, Inyup Kang, Brett C. Walker, Paul E. Peterzell, Raghu Challa, Matthew L. Severson, Arun Raghupathy, Gilbert Christopher Sih
  • Patent number: 8536938
    Abstract: Output circuits using pulse width modulation (PWM) and/or pulse density modulation (PDM) are described. In one aspect, a PWM output circuit includes a PWM modulator that operates based on a square wave signal instead of a sawtooth or triangular wave signal. In another aspect, a PDM output circuit includes a PDM modulator that uses variable reference voltages to reduce variations in switching frequency. In yet another aspect, a dual-mode output circuit supports both PWM and PDM and includes a pulse modulator and a class D amplifier. The pulse modulator performs PWM on an input signal if a PWM mode is selected and performs PDM on the input signal if a PDM mode is selected. The class D amplifier receives a driver signal from the pulse modulator and generates an output signal.
    Type: Grant
    Filed: August 4, 2011
    Date of Patent: September 17, 2013
    Assignee: QUALCOMM, Incorporated
    Inventors: Brett C Walker, Song Stone Shi
  • Publication number: 20110285463
    Abstract: Output circuits using pulse width modulation (PWM) and/or pulse density modulation (PDM) are described. In one aspect, a PWM output circuit includes a PWM modulator that operates based on a square wave signal instead of a sawtooth or triangular wave signal. In another aspect, a PDM output circuit includes a PDM modulator that uses variable reference voltages to reduce variations in switching frequency. In yet another aspect, a dual-mode output circuit supports both PWM and PDM and includes a pulse modulator and a class D amplifier. The pulse modulator performs PWM on an input signal if a PWM mode is selected and performs PDM on the input signal if a PDM mode is selected. The class D amplifier receives a driver signal from the pulse modulator and generates an output signal.
    Type: Application
    Filed: August 4, 2011
    Publication date: November 24, 2011
    Applicant: QUALCOMM INCORPORATED
    Inventors: Brett C. Walker, Song Stone Shi
  • Publication number: 20110285472
    Abstract: Output circuits using pulse width modulation (PWM) and/or pulse density modulation (PDM) are described. In one aspect, a PWM output circuit includes a PWM modulator that operates based on a square wave signal instead of a sawtooth or triangular wave signal. In another aspect, a PDM output circuit includes a PDM modulator that uses variable reference voltages to reduce variations in switching frequency. In yet another aspect, a dual-mode output circuit supports both PWM and PDM and includes a pulse modulator and a class D amplifier. The pulse modulator performs PWM on an input signal if a PWM mode is selected and performs PDM on the input signal if a PDM mode is selected. The class D amplifier receives a driver signal from the pulse modulator and generates an output signal.
    Type: Application
    Filed: August 4, 2011
    Publication date: November 24, 2011
    Applicant: QUALCOMM INCORPORATED
    Inventors: Brett C. Walker, Song Stone Shi
  • Patent number: 8022756
    Abstract: Output circuits using pulse width modulation (PWM) and/or pulse density modulation (PDM) are described. In one aspect, a PWM output circuit includes a PWM modulator that operates based on a square wave signal instead of a sawtooth or triangular wave signal. In another aspect, a PDM output circuit includes a PDM modulator that uses variable reference voltages to reduce variations in switching frequency. In yet another aspect, a dual-mode output circuit supports both PWM and PDM and includes a pulse modulator and a class D amplifier. The pulse modulator performs PWM on an input signal if a PWM mode is selected and performs PDM on the input signal if a PDM mode is selected. The class D amplifier receives a driver signal from the pulse modulator and generates an output signal.
    Type: Grant
    Filed: May 15, 2007
    Date of Patent: September 20, 2011
    Assignee: QUALCOMM, Incorporated
    Inventors: Brett C. Walker, Song Stone Shi
  • Patent number: 8019301
    Abstract: In one embodiment, this disclosure describes a frequency synthesizer for use in a wireless communication device, or similar device that requires precision frequency synthesis but small amounts of noise. In particular, the frequency synthesizer may include a phase locked loop (PLL) and an integrated voltage controlled oscillator (VCO). The frequency synthesizer may implement one or more calibration techniques to quickly and precisely calibrate the VCO. In this manner, the analog gain of the VCO can be significantly reduced, which may improve performance of the wireless communication device. Also, the initial state of the PLL may be improved to reduce lock time of the PLL, which may enhance performance of the wireless communication device.
    Type: Grant
    Filed: June 17, 2008
    Date of Patent: September 13, 2011
    Assignee: QUALCOMM Incorporated
    Inventors: Jeremy D. Dunworth, Brett C. Walker
  • Patent number: 7974317
    Abstract: A method for controlling the voltage of signals used to control power amplifiers is described. A first multiplexer and a second multiplexer are set to an enabling signal. The first multiplexer is on a first integrated circuit and the second multiplexer is on a second integrated circuit. A command is written to the first multiplexer to set the first multiplexer to one of a plurality of control signals used to control a power amplifier. A command is written to the second multiplexer to select one of the plurality of control signals that maps to the first multiplexer. The second integrated circuit is connected to a power supply.
    Type: Grant
    Filed: June 5, 2008
    Date of Patent: July 5, 2011
    Assignee: QUALCOMM Incorporated
    Inventors: David Maldonado, Puay Hoe See, Bo Sun, Guang Zhang, Brett C. Walker
  • Publication number: 20110105070
    Abstract: A direct downconversion receiver architecture having a DC loop to remove DC offset from the signal components, a digital variable gain amplifier (DVGA) to provide a range of gains, an automatic gain control (AGC) loop to provide gain control for the DVGA and RF/analog circuitry, and a serial bus interface (SBI) unit to provide controls for the RF/analog circuitry via a serial bus. The DVGA may be advantageously designed and located as described herein. The operating mode of the VGA loop may be selected based on the operating mode of the DC loop, since these two loops interact with one another. The duration of time the DC loop is operated in an acquisition mode may be selected to be inversely proportional to the DC loop bandwidth in the acquisition mode. The controls for some or all of the RF/analog circuitry may be provided via the serial bus.
    Type: Application
    Filed: March 14, 2006
    Publication date: May 5, 2011
    Inventors: Tao Li, Christian Holenstein, Inyup Kang, Brett C. Walker, Paul E. Peterzell, Raghu Challa, Matthew L. Severson, Arun Raghupathy, Gilbert Christopher Sih
  • Publication number: 20100064074
    Abstract: Embodiments disclosed herein address the need for a single wire bus interface. In one aspect, a device communicates with a second device via a single wire bus using a driver for driving the bus with a write frame comprising a start symbol, a write indicator symbol, an address, and data symbols. In another aspect, the device receives one or more data symbols on the single wire bus during a read frame. In yet another aspect, a device communicates with a second device via a single wire bus using a receiver for receiving a frame on the single wire bus comprising a start symbol, a write indicator symbol, an address, and one or more data symbols, and a driver for driving return read data associated with the address when the write indicator identifies a write frame. Various other aspects are also presented. These aspects provide for communication on a single wire bus, which allows for a reduction in pins, pads, or inter-block connections between devices.
    Type: Application
    Filed: September 11, 2009
    Publication date: March 11, 2010
    Applicant: QUALCOMM Incorporated
    Inventors: David W. Hansquine, Brett C. Walker, Muhammad Asim Muneer
  • Patent number: 7570925
    Abstract: In one embodiment, this disclosure describes a frequency synthesizer for use in a wireless communication device, or similar device that requires precision frequency synthesis but small amounts of noise. In particular, the frequency synthesizer may include a phase locked loop (PLL) and an integrated voltage controlled oscillator (VCO). The frequency synthesizer may implement one or more amplitude calibration techniques prior to enabling the PLL. For example, an amplitude calibration unit may be used to selectively activate switched unit current sources within a tail current source of the VCO. In this manner, the amplitude the signal generated by the oscillator can be adjusted without requiring closed-loop amplitude monitoring or control.
    Type: Grant
    Filed: May 18, 2006
    Date of Patent: August 4, 2009
    Assignee: QUALCOMM Incorporated
    Inventors: Jeremy D. Dunworth, Brett C. Walker
  • Publication number: 20090161588
    Abstract: A method for controlling the voltage of signals used to control power amplifiers is described. A first multiplexer and a second multiplexer are set to an enabling signal. The first multiplexer is on a first integrated circuit and the second multiplexer is on a second integrated circuit. A command is written to the first multiplexer to set the first multiplexer to one of a plurality of control signals used to control a power amplifier. A command is written to the second multiplexer to select one of the plurality of control signals that maps to the first multiplexer. The second integrated circuit is connected to a power supply.
    Type: Application
    Filed: June 5, 2008
    Publication date: June 25, 2009
    Applicant: QUALCOMM Incorporated
    Inventors: David Maldonado, Puay Hoe See, Bo Sun, Guang Zhang, Brett C. Walker
  • Patent number: 7546097
    Abstract: In one embodiment, this disclosure describes a frequency synthesizer for use in a wireless communication device, or similar device that requires precision frequency synthesis but small amounts of noise. In particular, the frequency synthesizer may include a phase locked loop (PLL) and an integrated voltage controlled oscillator (VCO). The frequency synthesizer may implement one or more calibration techniques to quickly and precisely calibrate the VCO. In this manner, the analog gain of the VCO can be significantly reduced, which may improve performance of the wireless communication device. Also, the initial state of the PLL may be improved to reduce lock time of the PLL, which may enhance performance of the wireless communication device.
    Type: Grant
    Filed: March 6, 2002
    Date of Patent: June 9, 2009
    Assignee: QUALCOMM Incorporated
    Inventors: Jeremy D. Dunworth, Brett C. Walker
  • Publication number: 20080284508
    Abstract: Output circuits using pulse width modulation (PWM) and/or pulse density modulation (PDM) are described. In one aspect, a PWM output circuit includes a PWM modulator that operates based on a square wave signal instead of a sawtooth or triangular wave signal. In another aspect, a PDM output circuit includes a PDM modulator that uses variable reference voltages to reduce variations in switching frequency. In yet another aspect, a dual-mode output circuit supports both PWM and PDM and includes a pulse modulator and a class D amplifier. The pulse modulator performs PWM on an input signal if a PWM mode is selected and performs PDM on the input signal if a PDM mode is selected. The class D amplifier receives a driver signal from the pulse modulator and generates an output signal.
    Type: Application
    Filed: May 15, 2007
    Publication date: November 20, 2008
    Inventors: Brett C. Walker, Song Stone Shi
  • Publication number: 20080248771
    Abstract: In one embodiment, this disclosure describes a frequency synthesizer for use in a wireless communication device, or similar device that requires precision frequency synthesis but small amounts of noise. In particular, the frequency synthesizer may include a phase locked loop (PLL) and an integrated voltage controlled oscillator (VCO). The frequency synthesizer may implement one or more calibration techniques to quickly and precisely calibrate the VCO. In this manner, the analog gain of the VCO can be significantly reduced, which may improve performance of the wireless communication device. Also, the initial state of the PLL may be improved to reduce lock time of the PLL, which may enhance performance of the wireless communication device.
    Type: Application
    Filed: June 17, 2008
    Publication date: October 9, 2008
    Applicant: QUALCOMM INCORPORATED
    Inventors: Jeremy D. Dunworth, Brett C. Walker
  • Patent number: 7174190
    Abstract: A direct downconversion receiver architecture having a DC loop to remove DC offset from the signal components, a digital variable gain amplifier (DVGA) to provide a range of gains, an automatic gain control (AGC) loop to provide gain control for the DVGA and RF/analog circuitry, and a serial bus interface (SBI) unit to provide controls for the RF/analog circuitry via a serial bus. The DVGA may be advantageously designed and located as described herein. The operating mode of the VGA loop may be selected based on the operating mode of the DC loop, since these two loops interact with one another. The duration of time the DC loop is operated in an acquisition mode may be selected to be inversely proportional to the DC loop bandwidth in the acquisition mode. The controls for some or all of the RF/analog circuitry may be provided via the serial bus.
    Type: Grant
    Filed: May 16, 2005
    Date of Patent: February 6, 2007
    Assignee: Qualcomm Inc.
    Inventors: Brett C. Walker, Paul E. Peterzell, Tao Li, Matthew L. Severson
  • Patent number: 7106138
    Abstract: A radio frequency (RF) driver amplifier system and method that provides linear in decibel gain control is provided. The RF driver amplifier system comprises a linear transconductor receiving an input voltage and providing a controlled current based on input voltage received, temperature compensation circuitry for varying current from the linear transconductor according to absolute temperature, an exponential current controller receiving current varied according to temperature and providing an exponential current in response, and an inductive degeneration compensator receiving exponential current and providing a control current to driver amplifier circuitry, thereby compensating for inductive degeneration due to at least one inductor in the driver amplifier circuitry. Control current passes from the inductive degeneration compensator to the driver amplifier circuitry. Output gain from the driver amplifier circuitry varies linearly in decibels with respect to the input voltage.
    Type: Grant
    Filed: June 13, 2005
    Date of Patent: September 12, 2006
    Assignee: Qualcomm Incorporated
    Inventors: Kenneth Barnett, Brett C. Walker, Kevin Gard