Patents by Inventor Aslamali A. Rafi

Aslamali A. Rafi 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: 10256854
    Abstract: In an embodiment, an apparatus includes: a transmit circuit to upconvert a baseband signal to a first differential radio frequency (RF) signal, the transmit circuit to convert the first differential RF signal to a first single-ended RF signal; a duty cycle correction circuit coupled to the transmit circuit to receive the first single-ended RF signal and compensate for a duty cycle variation in the first single-ended RF signal to output a duty cycle-corrected RF signal; a conversion circuit to convert the duty cycle-corrected RF signal to a second differential RF signal; and an interface circuit to transfer the second differential RF signal from a first ground domain to a second ground domain.
    Type: Grant
    Filed: January 19, 2018
    Date of Patent: April 9, 2019
    Assignee: Silicon Laboratories Inc.
    Inventors: Rangakrishnan Srinivasan, Sriharsha Vasadi, Zhongda Wang, Mustafa H. Koroglu, John M. Khoury, Aslamali A. Rafi, Michael S. Johnson, Francesco Barale, Sherry Xiaohong Wu
  • Publication number: 20180316310
    Abstract: In one embodiment, an apparatus includes a voltage controlled oscillator (VCO) to output an oscillating signal. The VCO may have a tank formed of at least one capacitor coupled in parallel with at least one inductor, and a plurality of transconductors to provide energy to the tank. At least one of the plurality of transconductors can be controllably switched to be coupled to the tank or to be decoupled from the tank.
    Type: Application
    Filed: April 27, 2017
    Publication date: November 1, 2018
    Inventors: Krishna Pentakota, Aslamali Rafi
  • Patent number: 10044383
    Abstract: A technique that reduces or eliminates trading-off power amplifier efficiency and costly external filtering in amplitude and phase modulated sinusoidal signal generation uses multi-phase outphasing and a multi-phase switching mode power amplifier to generate the amplitude and phase modulated sinusoidal signals. The technique combines multiple clock phases with sinusoidally weighted circuits of the switching mode power amplifier to improve amplitude and phase modulated sinusoidal signal generation.
    Type: Grant
    Filed: December 30, 2016
    Date of Patent: August 7, 2018
    Assignee: Silicon Laboratories Inc.
    Inventors: Aaron J. Caffee, Brian G. Drost, Alessandro Piovaccari, Aslamali A. Rafi
  • Publication number: 20180191384
    Abstract: A technique that reduces or eliminates trading-off power amplifier efficiency and costly external filtering in amplitude and phase modulated sinusoidal signal generation uses multi-phase outphasing and a multi-phase switching mode power amplifier to generate the amplitude and phase modulated sinusoidal signals. The technique combines multiple clock phases with sinusoidally weighted circuits of the switching mode power amplifier to improve amplitude and phase modulated sinusoidal signal generation.
    Type: Application
    Filed: December 30, 2016
    Publication date: July 5, 2018
    Inventors: Aaron J. Caffee, Brian G. Drost, Alessandro Piovaccari, Aslamali A. Rafi
  • Patent number: 9979404
    Abstract: A technique that reduces or eliminates trading-off power amplifier efficiency and costly external filtering in amplitude and phase modulated sinusoidal signal generation uses multi-phase outphasing and a multi-phase switching mode power amplifier to generate the amplitude and phase modulated sinusoidal signals. The technique combines multiple clock phases with sinusoidally weighted circuits of the switching mode power amplifier to improve amplitude and phase modulated sinusoidal signal generation.
    Type: Grant
    Filed: December 30, 2016
    Date of Patent: May 22, 2018
    Assignee: Silicon Laboratories Inc.
    Inventors: Brian G. Drost, Aaron J. Caffee, Alessandro Piovaccari, Aslamali A. Rafi
  • Patent number: 9966965
    Abstract: An apparatus includes a signal generator. The signal generator includes a voltage controlled oscillator (VCO) coupled to provide an output signal having a frequency. The signal generator further includes an asymmetric divider coupled to receive the output signal of the VCO and to provide an output signal. The output signal of the asymmetric divider has a frequency that is half the frequency of the output signal of the VCO. The asymmetric divider presents a balanced load to the VCO.
    Type: Grant
    Filed: December 6, 2016
    Date of Patent: May 8, 2018
    Assignee: Silicon Laboratories Inc.
    Inventors: Aslamali A. Rafi, Rangakrishnan Srinivasan, Francesco Barale
  • Patent number: 9948313
    Abstract: Apparatus and methods are disclosed that utilize magnetically differential loop filter capacitor elements that are physically positioned adjacent voltage-controlled oscillator (VCO) inductor/s in the device layout of a phase locked loop (PLL) circuit. Such a PLL circuit may be employed, for example, to produce a PLL output signal for RF receivers, RF transmitters, RF transceivers and any other type of circuit configured to utilize a PLL output signal having a phase that is based on the phase of an input signal.
    Type: Grant
    Filed: December 19, 2016
    Date of Patent: April 17, 2018
    Assignee: Silicon Laboratories Inc.
    Inventor: Aslamali A. Rafi
  • Publication number: 20170359076
    Abstract: An apparatus includes a signal generator. The signal generator includes a voltage controlled oscillator (VCO) coupled to provide an output signal having a frequency. The signal generator further includes an asymmetric divider coupled to receive the output signal of the VCO and to provide an output signal. The output signal of the asymmetric divider has a frequency that is half the frequency of the output signal of the VCO. The asymmetric divider presents a balanced load to the VCO.
    Type: Application
    Filed: December 6, 2016
    Publication date: December 14, 2017
    Inventors: Aslamali A. Rafi, Rangakrishnan Srinivasan, Francesco Barale
  • Patent number: 9712176
    Abstract: An apparatus includes a signal generator. The signal generator includes a voltage controlled oscillator (VCO) coupled to provide an output signal having a frequency. The signal generator further includes an asymmetric divider coupled to receive the output signal of the VCO and to provide an output signal. The output signal of the asymmetric divider has a frequency that is lower than the frequency of the output signal of the VCO. The asymmetric divider presents a balanced load to the VCO.
    Type: Grant
    Filed: June 10, 2016
    Date of Patent: July 18, 2017
    Assignee: Silicon Laboratories Inc.
    Inventors: Aslamali A. Rafi, Mustafa H. Koroglu
  • Patent number: 9496906
    Abstract: A receiver comprises a passive gain stage having an input to receive an in-going radio frequency (RF) signal and a gain control signal to produce an adjusted in-going RF signal, a sliced LNA stage comprising a plurality of LNAs coupled to receive the in-going RF signal. Each LNA includes an adjustable source degeneration circuit for receiving a plurality of gain selection and control signals and an output port to produce an amplified in-going RF signal. A mixer is coupled to receive at least one of the amplified in-going RF signals produced by the sliced LNA stage and is configured to produce a converted signal at another frequency. A PGA is coupled to receive the down-converted signal and produces an amplified in-going signal.
    Type: Grant
    Filed: February 18, 2015
    Date of Patent: November 15, 2016
    Assignee: SILICON LABORATORIES, INC.
    Inventor: Aslamali A. Rafi
  • Patent number: 9490865
    Abstract: A transceiver includes a transmit/receive terminal, a receiver input terminal, a plurality of impedance transformation networks coupled in series, a plurality of power amplifiers, and a controller. Each impedance transformation network has first and second ports. The impedance transformation networks include at least one selectable impedance transformation network having a resonant mode and a termination mode. The power amplifiers have outputs respectively coupled to the second ports of corresponding ones of the impedance transformation networks. In a receive mode, the controller selects the resonant mode for each selectable impedance transformation network and disables all power amplifiers. In a transmit mode, the controller enables a selected power amplifier and selects the resonant mode of any upstream selectable impedance transformation network, and selects the termination mode of a downstream selectable impedance transformation network.
    Type: Grant
    Filed: April 19, 2016
    Date of Patent: November 8, 2016
    Assignee: SILICON LABORATORIES, INC
    Inventors: Aslamali A. Rafi, Ravi Kummaraguntla
  • Publication number: 20160241285
    Abstract: A receiver comprises a passive gain stage having an input to receive an in-going radio frequency (RF) signal and a gain control signal to produce an adjusted in-going RF signal, a sliced LNA stage comprising a plurality of LNAs coupled to receive the in-going RF signal. Each LNA includes an adjustable source degeneration circuit for receiving a plurality of gain selection and control signals and an output port to produce an amplified in-going RF signal. A mixer is coupled to receive at least one of the amplified in-going RF signals produced by the sliced LNA stage and is configured to produce a converted signal at another frequency. A PGA is coupled to receive the down-converted signal and produces an amplified in-going signal.
    Type: Application
    Filed: February 18, 2015
    Publication date: August 18, 2016
    Applicant: SILICON LABORATORIES INC.
    Inventor: Aslamali A. Rafi
  • Publication number: 20160233919
    Abstract: A transceiver includes a transmit/receive terminal, a receiver input terminal, a plurality of impedance transformation networks coupled in series, a plurality of power amplifiers, and a controller. Each impedance transformation network has first and second ports. The impedance transformation networks include at least one selectable impedance transformation network having a resonant mode and a termination mode. The power amplifiers have outputs respectively coupled to the second ports of corresponding ones of the impedance transformation networks. In a receive mode, the controller selects the resonant mode for each selectable impedance transformation network and disables all power amplifiers. In a transmit mode, the controller enables a selected power amplifier and selects the resonant mode of any upstream selectable impedance transformation network, and selects the termination mode of a downstream selectable impedance transformation network.
    Type: Application
    Filed: April 19, 2016
    Publication date: August 11, 2016
    Applicant: Silicon Laboratories Inc.
    Inventors: Aslamali A. Rafi, Ravi Kummaraguntla
  • Publication number: 20160156380
    Abstract: A transceiver comprises a transmit/receive terminal, a receiver input terminal, a scalable impedance network, a plurality of power amplifiers, and a receiver. The scalable impedance network is coupled between the transmit/receive terminal and the receiver input terminal and has a plurality of taps in an order between the transmit/receive terminal and the receiver input terminal, in which an impedance looking into any given tap toward the transmit/receive terminal is smaller than an impedance looking into a subsequent tap toward the transmit/receive terminal, if any, in the order. The plurality of power amplifiers are arranged in an order and have outputs respectively coupled to the plurality of taps of the scalable impedance network. A power of any given power amplifier is higher than a power of a subsequent power amplifier, if any, in the order. The receiver is coupled to the receiver input terminal.
    Type: Application
    Filed: December 2, 2014
    Publication date: June 2, 2016
    Applicant: SILICON LABORATORIES INC.
    Inventors: Aslamali A. Rafi, Ravi Kummaraguntla
  • Patent number: 9350412
    Abstract: A transceiver comprises a transmit/receive terminal, a receiver input terminal, a scalable impedance network, a plurality of power amplifiers, and a receiver. The scalable impedance network is coupled between the transmit/receive terminal and the receiver input terminal and has a plurality of taps in an order between the transmit/receive terminal and the receiver input terminal, in which an impedance looking into any given tap toward the transmit/receive terminal is smaller than an impedance looking into a subsequent tap toward the transmit/receive terminal, if any, in the order. The plurality of power amplifiers are arranged in an order and have outputs respectively coupled to the plurality of taps of the scalable impedance network. A power of any given power amplifier is higher than a power of a subsequent power amplifier, if any, in the order. The receiver is coupled to the receiver input terminal.
    Type: Grant
    Filed: December 2, 2014
    Date of Patent: May 24, 2016
    Assignee: SILICON LABORATORIES INC.
    Inventors: Aslamali A. Rafi, Ravi Kummaraguntla
  • Patent number: 9319027
    Abstract: In an example, apparatus comprises: a low noise amplifier (LNA) including a first transconductor having an input to receive a differential input radio frequency (RF) signal and an output to output a differential amplified RF signal to a RF signal path; and a second transconductor having an input coupled to a first common mode node and a second common mode node to receive a test tone signal and an output to output an amplified test tone signal to the RF signal path.
    Type: Grant
    Filed: December 17, 2014
    Date of Patent: April 19, 2016
    Assignee: Silicon Laboratories Inc.
    Inventor: Aslamali A. Rafi
  • Patent number: 9219512
    Abstract: In one form, an integrated receiver includes a tracking bandpass filter, a tunable lowpass filter, and a mixer formed on a single integrated circuit chip. The tracking bandpass filter has an input for receiving a radio frequency (RF) input signal, and an output, and comprises a variable capacitor having a capacitance that varies in response to a bandpass frequency control signal, in parallel with an integrated inductor. The integrated inductor comprises a plurality of windings formed in a plurality of metal layers. The tunable lowpass filter has an input coupled to the output of the tracking bandpass filter, and an output and having a tuning input for receiving a cutoff frequency signal. The mixer has a signal input coupled to the output of the tunable lowpass filter, a local oscillator input for receiving a local oscillator signal, and a signal output for providing a converted RF signal.
    Type: Grant
    Filed: February 3, 2015
    Date of Patent: December 22, 2015
    Assignee: SILICON LABORATORIES INC.
    Inventors: Ramin Khoini-Poorfard, Alessandro Piovaccari, Aslamali A. Rafi, Mustafa H. Koroglu, David S. Trager, Abdulkerim L. Coban
  • Publication number: 20150147992
    Abstract: In one form, an integrated receiver includes a tracking bandpass filter, a tunable lowpass filter, and a mixer formed on a single integrated circuit chip. The tracking bandpass filter has an input for receiving a radio frequency (RF) input signal, and an output, and comprises a variable capacitor having a capacitance that varies in response to a bandpass frequency control signal, in parallel with an integrated inductor. The integrated inductor comprises a plurality of windings formed in a plurality of metal layers. The tunable lowpass filter has an input coupled to the output of the tracking bandpass filter, and an output and having a tuning input for receiving a cutoff frequency signal. The mixer has a signal input coupled to the output of the tunable lowpass filter, a local oscillator input for receiving a local oscillator signal, and a signal output for providing a converted RF signal.
    Type: Application
    Filed: February 3, 2015
    Publication date: May 28, 2015
    Applicant: SILICON LABORATORIES INC.
    Inventors: Ramin Khoini-Poorfard, Alessandro Piovaccari, Aslamali A. Rafi, Mustafa H. Koroglu, David S. Trager, Abdulkerim L. Coban
  • Patent number: 9002306
    Abstract: A method includes receiving a desired channel indication in a radio tuner, determining a band of operation in which the channel is located, and if the channel is within a first band coupling multiple inductors into a resonant tank, and if the desired channel is within a second band coupling a single inductor into the resonant tank.
    Type: Grant
    Filed: August 5, 2014
    Date of Patent: April 7, 2015
    Assignee: Silicon Laboratories Inc.
    Inventors: Jing Li, Dan B. Kasha, Aslamali Rafi
  • Patent number: 8983419
    Abstract: An integrated receiver includes a first signal processing path, a second signal processing path, and a controller. The first signal processing path has an input and an output for providing a first processed signal, and comprises a first tracking bandpass filter having a first integrated inductor formed with windings in a first number of metal layers of the integrated receiver. The second signal processing path has an input and an output for providing a second processed signal, and comprises a second tracking bandpass filter having a second integrated inductor formed with windings in a second number of metal layers of the integrated receiver. The second number of windings is lower than the first number. The controller enables one of the first and second signal processing paths corresponding to a selected channel of a radio frequency (RF) input signal to provide an output signal.
    Type: Grant
    Filed: March 3, 2014
    Date of Patent: March 17, 2015
    Assignee: Silicon Laboratories Inc.
    Inventors: Ramin Khoini-Poorfard, Alessandro Piovaccari, Aslamali A. Rafi, Mustafa H. Koroglu, David S. Trager, Abdulkerim L. Coban