Patents by Inventor Alireza Zolfaghari

Alireza Zolfaghari 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: 20130120034
    Abstract: A mobile communication device is provided that has a transceiver including a voltage controlled oscillator (VCO) and a calibration circuit for calibrating the VCO. The calibration circuit includes a logic block configured to estimate a calibration value for a tuning of the VCO to a desired frequency, and an asynchronous counter configured to execute a counting sequence to identify a frequency of the VCO after the tuning of the VCO using the calibration value, where the calibration circuit is configured to determine a tuned calibration value for producing the desired frequency from the counting sequence.
    Type: Application
    Filed: November 16, 2011
    Publication date: May 16, 2013
    Applicant: BROADCOM CORPORATION
    Inventors: Koji Kimura, Alireza Zolfaghari
  • Patent number: 8406692
    Abstract: Various embodiments are disclosed relating to wireless systems, and also relating to transmitter amplifiers, such as, for example, polar transmitter amplifiers with variable output power. According to an example embodiment, a circuit is provided including a plurality of selectable amplifier cells. Each amplifier cell may receive a phase or frequency modulated signal and an amplitude modulated signal. Each amplifier cell may output a signal based upon a combination of the received amplitude modulated signal and the received phase or frequency modulated signal if the amplifier cell is selected. The circuit may provide a variable output current or output power based upon the selection of one or more of the amplifier cells.
    Type: Grant
    Filed: September 13, 2010
    Date of Patent: March 26, 2013
    Assignee: Broadcom Corporation
    Inventor: Alireza Zolfaghari
  • Patent number: 8280322
    Abstract: A phase locked loop (PLL) a phase detector, a charge pump, a loop filter, a controlled oscillator, and a feedback divider. The phase detector is coupled to produce a difference signal based on a difference between phase of a reference oscillation and phase of a feedback oscillation. The charge pump is coupled to convert the difference signal into an up-signal or a down signal. The loop filter coupled to filter the up signal or the down signal to produce a control signal. The controlled oscillator is coupled to generate an output oscillation based on the control signal. The feedback divider is coupled to generate the feedback oscillation from the output oscillation based on a divider value. The loop filter includes a first resistor-capacitor circuit and a second resistor-capacitor circuit. The first resistor-capacitor circuit is calibrated using a first calibration technique and the second resistor-capacitor circuit is calibrated using a second calibration technique.
    Type: Grant
    Filed: February 8, 2010
    Date of Patent: October 2, 2012
    Assignee: Broadcom Corporation
    Inventors: Alireza Zolfaghari, Hooman Darabi
  • Patent number: 8280325
    Abstract: According to an example embodiment, an apparatus may be provided that is configurable to operate in either a separate power amplifier configuration or a combined power amplifier configuration.
    Type: Grant
    Filed: February 27, 2009
    Date of Patent: October 2, 2012
    Assignee: Broadcom Corporation
    Inventor: Alireza Zolfaghari
  • Patent number: 8275332
    Abstract: An apparatus comprising a plurality of switchable full step mixer unit cells, wherein each switchable full step unit cell is configured to, when the full step transceiver mixer unit cell is turned on, increase the gain experienced by an electronic signal by a full step increment, and wherein the step increment is substantially constant regardless of temperature; and at least one switchable partial step mixer unit cell configured to, when the partial step transceiver mixer unit is turned on, increase the gain experienced by the electronic signal by a predetermined step increment less than that of a full step, and wherein the partial step increment is substantially constant regardless of temperature.
    Type: Grant
    Filed: November 22, 2011
    Date of Patent: September 25, 2012
    Assignee: Broadcom Corporation
    Inventors: Ahmad Mirzaei, Alireza Zolfaghari, Hooman Darabi
  • Patent number: 8194785
    Abstract: In an envelope comparison embodiment, a delay calibrator produces a delay signal based on a comparison of a feedback signal and an envelope component of the transmitted signal. A down-converter produces the feedback signal from an outgoing modulated RF signal based on at least one local oscillation. Envelope detectors in the delay calibrator and the envelope signal path are operably coupled to a summing node that produces a delay error signal based on a temporal difference between the two envelopes. One embodiment includes phase detectors to detect and adjust the zero crossings of the feedback signal and the envelope signal path. As the delay mismatch between the envelope signal path and the phase signal path increases, the power spectrum increases in adjacent communication channels. A mask margin measurement technique measures the power level in an adjacent channel and adjusts the envelope path delay accordingly.
    Type: Grant
    Filed: January 19, 2009
    Date of Patent: June 5, 2012
    Assignee: Broadcom Corporation
    Inventors: Alireza Zolfaghari, Henrik T. Jensen, Ahmadreza (Reza) Rofougaran
  • Patent number: 8183932
    Abstract: Aspects of a method and system for processing signals via an integrated low noise amplifier having a configurable input signaling mode are provided. In this regard, one or more circuits comprising an integrated amplifier may be configurable such that, in a first configuration, the one or more circuits are operable to handle a differential input signal, and, in a second mode of operation, the one or more circuits are operable to handle a single-ended input signal. The one or more circuits may output a differential signal when handling a differential input signal and when handling a single-ended input signal. In some instances, whether the one or more circuits are operable to handle a differential input signal or a single-ended input signal may determined by an inductance of a bond wire coupling the integrated amplifier to an integrated circuit package.
    Type: Grant
    Filed: March 5, 2010
    Date of Patent: May 22, 2012
    Assignee: Broadcom Corporation
    Inventor: Alireza Zolfaghari
  • Publication number: 20120112773
    Abstract: According to one disclosed embodiment, an on-chip resistor calibration circuit includes an RC oscillator having a test resistor and a precision capacitor as elements, a counter, and a reference clock. In one embodiment, an RC oscillator generates a waveform having a period dependent upon the resistance of the test resistor and the capacitance of the precision capacitor. In such an embodiment, a counter and a reference clock may be configured to measure the period of the waveform. Using a pre-determined capacitance of the precision capacitor, a resistance of the test resistor may be determined. In another embodiment, an RC oscillator generates first and second waveforms through use of an additional capacitor that can be switched in and out of the RC oscillator circuit. Using a pre-determined capacitance of the precision capacitor, an RC product of the test resistor and the additional capacitor may be determined.
    Type: Application
    Filed: November 10, 2010
    Publication date: May 10, 2012
    Applicant: Broadcom Corporation
    Inventors: Alireza Zolfaghari, Chin-Ming Chien, Bojko Marholev
  • Patent number: 8145146
    Abstract: A radio frequency (RF) transmitter front-end includes a digital to analog conversion module and a power amplifier module. The digital to analog conversion module is coupled to convert amplitude information into analog amplitude adjust signals when a first mode is active and is coupled to convert power level information into analog power level signals when a second mode is active. The power amplifier module is coupled to amplify first phase modulated RF signals in accordance with the analog amplitude adjust signals to produce first outbound RF signals when the first mode is active and is coupled to amplify second phase modulated RF signals in accordance with the analog power level signals to produce second outbound RF signals when the second mode is active.
    Type: Grant
    Filed: May 28, 2010
    Date of Patent: March 27, 2012
    Assignee: Broadcom Corporation
    Inventors: Mohammad Nariman, Alireza Zolfaghari, Hooman Darabi
  • Publication number: 20120071119
    Abstract: An apparatus comprising a plurality of switchable full step mixer unit cells, wherein each switchable full step unit cell is configured to, when the full step transceiver mixer unit cell is turned on, increase the gain experienced by an electronic signal by a full step increment, and wherein the step increment is substantially constant regardless of temperature; and at least one switchable partial step mixer unit cell configured to, when the partial step transceiver mixer unit is turned on, increase the gain experienced by the electronic signal by a predetermined step increment less than that of a full step, and wherein the partial step increment is substantially constant regardless of temperature.
    Type: Application
    Filed: November 22, 2011
    Publication date: March 22, 2012
    Applicant: BROADCOM CORPORATION
    Inventors: Ahmad Mirzaei, Alireza Zolfaghari, Hooman Darabi
  • Patent number: 8126415
    Abstract: Aspects of a method and system for clock synchronization in a GNSS receiver are provided. In this regard, generation of a clock signal in a GNSS receiver may be disabled during a first time interval and enabled during a second time interval, wherein a counter utilized to generate the clock signal may be initialized to a known value during the first time interval via a reset signal synchronized to a reference signal. The reference signal may be generated by a temperature compensated crystal oscillator. Additionally, a counter may be incremented on each active edge of the reference signal that occurs during the first time interval and the value stored in the timer may be utilized to correct time in the GNSS receiver after the first time interval. In this regard, the value stored in the timer may be added to the time at which the first interval began.
    Type: Grant
    Filed: August 15, 2008
    Date of Patent: February 28, 2012
    Assignee: Broadcom Corporation
    Inventor: Alireza Zolfaghari
  • Patent number: 8081937
    Abstract: An apparatus comprising a plurality of switchable full step mixer unit cells, wherein each switchable full step unit cell is configured to, when the full step transceiver mixer unit cell is turned on, increase the gain experienced by an electronic signal by a full step increment, and wherein the step increment is substantially constant regardless of temperature; and at least one switchable partial step mixer unit cell configured to, when the partial step transceiver mixer unit is turned on, increase the gain experienced by the electronic signal by a predetermined step increment less than that of a full step, and wherein the partial step increment is substantially constant regardless of temperature.
    Type: Grant
    Filed: November 29, 2007
    Date of Patent: December 20, 2011
    Assignee: Broadcom Corporation
    Inventors: Ahmad Mirzaei, Alireza Zolfaghari, Hooman Darabi
  • Patent number: 8081929
    Abstract: Methods and systems for optimal frequency planning for an integrated communication system with multiple receivers may include adjusting a center frequency of a low IF signal to reduce interference by a second order interference signal. The center frequency may be adjusted to avoid high power portions of the second order interference signal. The interference level corresponding to a center frequency may be determined by, for example, a SNR of the low IF signal, or by determining a BER for the low IF signal. The center frequency of the low IF signal may be dynamically adjusted to keep second order interference level at an acceptable level. Adjusting the center frequency of the low IF signal may also comprise keeping the low IF signal from being blocked by a DC component of the second order interference signal.
    Type: Grant
    Filed: June 5, 2008
    Date of Patent: December 20, 2011
    Assignee: Broadcom Corporation
    Inventors: Brima Ibrahim, Alireza Zolfaghari, Steven Hall, Kambiz Shoarinejad, Bojko Marholev
  • Patent number: 8073044
    Abstract: A calibration circuit measures the variation in a filter resistor within the analog domain of the envelope path of a polar transmitter and produces a digital value representative of that variation. A digital processor determines a digital control signal from the digital value that is used to compensate, in the digital domain of the envelope path, for the variation in the filter resistor in the analog domain.
    Type: Grant
    Filed: January 2, 2008
    Date of Patent: December 6, 2011
    Assignee: Broadcom Corporation
    Inventors: Alireza Zolfaghari, Hooman Darabi, Henrik T. Jensen
  • Patent number: 8040996
    Abstract: Aspects of a method and system for RF signal generation utilizing a synchronous multi-modulus divider are provided. In this regard, a feedback signal of a PLL may be generated by clocking a counter with an RF signal output by the PLL and toggling the feedback signal each time a determined value of the counter is reached. Moreover, updates of each register in the counter and transitions of the feedback signal may be synchronous with the RF signal output by the PLL. The PLL may be part of a cellular transmitter and/or receiver which may communicate over an EDGE network. A counting sequence of the counter may be determined, at least in part, by an output of a ?? modulator. In this regard, a first counting sequence may be utilized when an output of the ?? modulator may be asserted and a second counting sequence may be utilized when the output of ?? modulator may be de-asserted.
    Type: Grant
    Filed: August 15, 2008
    Date of Patent: October 18, 2011
    Assignee: Broadcom Corporation
    Inventor: Alireza Zolfaghari
  • Patent number: 8018256
    Abstract: Provided are a method and system for providing a power-on reset pulse. The system includes a level detector configured to receive an input signal and produce, at least indirectly, a reset signal when the input signal reaches a predetermined level. The system also includes a counter having counting characteristics and configured to receive the reset signal and a clock signal. The counter produces a delayed signal in accordance with the counting characteristics, the clock signal, and the received reset signal.
    Type: Grant
    Filed: March 9, 2009
    Date of Patent: September 13, 2011
    Assignee: Broadcom Corporation
    Inventor: Alireza Zolfaghari
  • Patent number: 7983632
    Abstract: Amplitude modulation is provided for a polar transmitter that incorporates a translational loop. The input to the polar transmitter and translational loop may be an amplitude modulated signal. The amplitude modulation of the transmitter may be controlled via a closed loop to help ensure that the output of the amplifier accurately corresponds to the modulated input signal. The transmitter may incorporate partially integrated or separate translational and amplitude modulation loops.
    Type: Grant
    Filed: October 15, 2004
    Date of Patent: July 19, 2011
    Assignee: Broadcom Corporation
    Inventor: Alireza Zolfaghari
  • Patent number: 7961812
    Abstract: A polar transmitter includes a digital processor coupled to receive a complex modulated digital signal and a feedback signal produced from the complex modulated digital signal and that is operable to compare the complex modulated digital signal to the feedback signal to determine an error signal indicative of a difference between the complex modulated digital signal and the feedback signal. The digital processor is further operable to produce a correction signal from the error signal and to add the correction signal to the complex modulated digital signal to produce a corrected complex modulated digital signal.
    Type: Grant
    Filed: July 23, 2010
    Date of Patent: June 14, 2011
    Assignee: Broadcom Corporation
    Inventors: Henrik T. Jensen, Hooman Darabi, Alireza Zolfaghari
  • Patent number: 7957704
    Abstract: Methods and systems for reducing AM/PM distortion in a polar amplifier are disclosed and may comprise adding an offset signal to an amplitude signal in the digital domain and removing the offset signal in the analog domain during polar modulation. A sum of an amplitude signal and an offset signal may be mixed with a phase signal in a first differential amplifier to generate a first voltage signal, and the offset signal may be mixed with the phase signal in a second differential amplifier to generate a second voltage signal, which may be subtracted from the first voltage signal. The amplitude and offset signals may be mixed with the phase signal by modulating a current in the differential amplifiers, which may comprise cascode differential amplifiers. The modulated current may be generated using a current source and a current mirror circuit, which may comprise a cascode current mirror.
    Type: Grant
    Filed: March 9, 2007
    Date of Patent: June 7, 2011
    Assignee: Broadcom Corporation
    Inventor: Alireza Zolfaghari
  • Patent number: 7893668
    Abstract: A method for regulating a voltage in an integrated circuit device includes providing a first regulated output based upon a first voltage input range and subsequently receiving the first regulated output and providing a second regulated output based upon a second voltage input range of the first regulated output. A circuit is further provided that operates accordingly. Additionally, a clipper circuit is provided at the input to protect for over voltage conditions that may results, for example, from a charging battery to cause an output voltage of the battery to substantially exceed ordinary output voltage levels.
    Type: Grant
    Filed: June 10, 2008
    Date of Patent: February 22, 2011
    Assignee: Broadcom Corporation
    Inventor: Alireza Zolfaghari