Patents by Inventor Caiyi Wang

Caiyi Wang 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: 6965761
    Abstract: A method and apparatus for synthesizing high-frequency signals, such as wireless communication signals, includes a phase-locked loop (PLL) frequency synthesizer with a variable capacitance voltage controlled oscillator (VCO) that has a discretely variable capacitance in conjunction with a continuously variable capacitance. The discretely variable capacitance may provide coarse tuning adjustment of the variable capacitance to compensate for capacitor and inductor tolerances and to adjust the output frequency to be near the desired frequency output. The continuously variable capacitance may provide a fine tuning adjustment of the variable capacitance to focus the output frequency to match precisely the desired frequency output. During fine tuning adjustment, the PLL may be controlled by a plurality of analog control signals. The analog control signals may be derived by first generating a plurality of phase shifted signals from a divided version of the VCO output clock.
    Type: Grant
    Filed: February 5, 2003
    Date of Patent: November 15, 2005
    Assignee: Silicon Laboratories, Inc.
    Inventors: David R. Welland, Caiyi Wang
  • Publication number: 20050024509
    Abstract: An image processor system for a charge coupled device (CCD) or CMOS imaging system includes a histogram-based automatic gain control (AGC) circuit which first controls gain by adjusting said CCD system and then for yet a higher gain level makes gain adjustments in said CDSVGA circuit and a digital gain circuit to produce a combined target gain level. A processing system for an imager device includes a camera system for producing an imager signal, a correlated double sample (CDS) circuit for receiving data from an imager, a variable gain amplifier (VGA), an analog-to-digital converter (ADC) coupled to said CDS circuit, a digital gain circuit (DGC) coupled to said ADC, and an automatic gain control (AGC) circuit coupled to said DGC for controlling the CDS circuit and the DGC, as well as shutter timing for shutter gain.
    Type: Application
    Filed: June 7, 2004
    Publication date: February 3, 2005
    Inventors: Nadi Itani, Caiyi Wang, David Welland
  • Publication number: 20040166815
    Abstract: Components of a radio-frequency (RF) apparatus including transceiver circuitry and frequency modification circuitry of a crystal oscillator circuit that generates a reference signal with adjustable frequency may be partitioned in a variety of ways, for example, as one or more separate integrated circuits. The frequency modification circuitry may be implemented as part of a crystal oscillator circuit that includes digitally controlled crystal oscillator (“DCXO”) circuitry and a crystal. The frequency modification circuitry may include at least one variable capacitance device and may be employed to generate a reference signal with adjustable frequency. The adjustable reference signal may be provided to other components of the RF apparatus and/or the RF apparatus may be configured to provide the adjustable reference signal to baseband processor circuitry.
    Type: Application
    Filed: July 31, 2003
    Publication date: August 26, 2004
    Inventors: James Maligeorgos, Augusto M. Marques, Lysander Lim, G. Tyson Tuttle, Aslamali A. Rafi, Tod Paulus, Gregory T. Uehara, Jeffery W. Scott, Richard T. Behrens, Donald A. Kerth, G. Diwakar Vishakhadatta, Vishnu S. Srinivasan, Caiyi Wang
  • Patent number: 6750906
    Abstract: An image processor system for a charge coupled device (CCD) or CMOS imaging system includes a histogram-based automatic gain control (AGC) circuit which first controls gain by adjusting said CCD system and then for yet a higher gain level makes gain adjustments in said CDSVGA circuit and a digital gain circuit to produce a combined target gain level. A processing system for an imager device includes a camera system for producing an imager signal, a correlated double sample (CDS) circuit for receiving data from an imager, a variable gain amplifier (VGA), an analog-to-digital converter (ADC) coupled to said CDS circuit, a digital gain circuit (DGC) coupled to said ADC, and an automatic gain control (AGC) circuit coupled to said DGC for controlling the CDS circuit and the DGC, as well as shutter timing for shutter gain.
    Type: Grant
    Filed: May 8, 1998
    Date of Patent: June 15, 2004
    Assignee: Cirrus Logic, Inc.
    Inventors: Nadi R. Itani, Caiyi Wang, David R. Welland
  • Patent number: 6741846
    Abstract: A method and apparatus for synthesizing high-frequency signals, such as wireless communication signals, includes a phase-locked loop (PLL) frequency synthesizer with a variable capacitance voltage controlled oscillator (VCO) that has a discretely variable capacitance in conjunction with a continuously variable capacitance. The discretely variable capacitance may provide coarse tuning adjustment of the variable capacitance to compensate for capacitor and inductor tolerances and to adjust the output frequency to be near the desired frequency output. The continuously variable capacitance may provide a fine tuning adjustment of the variable capacitance to focus the output frequency to match precisely the desired frequency output. During fine tuning adjustment, the PLL may include an analog control loop in which a phase detector circuit and sample and hold circuit are utilized. The output of the sample and hold circuit may be provided to the PLL VCO as VCO input control signals.
    Type: Grant
    Filed: November 8, 2000
    Date of Patent: May 25, 2004
    Assignee: Silicon Laboratories Inc.
    Inventors: David R. Welland, Caiyi Wang
  • Publication number: 20040075506
    Abstract: A method and apparatus for synthesizing high-frequency signals, such as wireless communication signals, includes a phase-locked loop (PLL) frequency synthesizer with a variable capacitance voltage controlled oscillator (VCO) that has a discretely variable capacitance in conjunction with a continuously variable capacitance. The discretely variable capacitance may provide coarse tuning adjustment of the variable capacitance to compensate for capacitor and inductor tolerances and to adjust the output frequency to be near the desired frequency output. The continuously variable capacitance may provide a fine tuning adjustment of the variable capacitance to focus the output frequency to match precisely the desired frequency output. During fine tuning adjustment, the PLL may include an analog control loop in which a phase detector circuit and sample and hold circuit are utilized. The output of the sample and hold circuit may be provided to the PLL VCO as VCO input control signals.
    Type: Application
    Filed: October 8, 2003
    Publication date: April 22, 2004
    Applicant: Silicon Laboratories Inc.
    Inventors: David R. Welland, Caiyi Wang
  • Publication number: 20040046875
    Abstract: A selectable threshold multimode gain control apparatus and method for a charge coupled device (CCD) or CMOS imaging system includes an automatic gain control (AGC) circuit which continuously controls gain in said CCD system to produce a mutually continuous combined target gain level. A processing system for an imager device includes a camera system for producing an imager signal, a correlated double sample (CDS) circuit for receiving data from an imager, a variable gain amplifier (VGA), an analog-to-digital converter (ADC) coupled to said CDS circuit, a digital gain circuit (DGC) coupled to said ADC, and an automatic gain control (AGC) circuit coupled to said DGC for controlling the CDS circuit and the DGC, as well as shutter timing for shutter gain.
    Type: Application
    Filed: September 10, 2003
    Publication date: March 11, 2004
    Inventors: Nadi R. Itani, Caiyi Wang, David R. Welland
  • Patent number: 6650364
    Abstract: A selectable threshold multimode gain control apparatus and method for a charge coupled device (CCD) or CMOS imaging system includes an automatic gain control (AGC) circuit which continuously controls gain in said CCD system to produce a mutually continuous combined target gain level. A processing system for an imager device includes a camera system for producing an imager signal, a correlated double sample (CDS) circuit for receiving data from an imager, a variable gain amplifier (VGA), an analog-to-digital converter (ADC) coupled to said CDS circuit, a digital gain circuit (DGC) coupled to said ADC, and an automatic gain control (AGC) circuit coupled to said DGC for controlling the CDS circuit and the DGC, as well as shutter timing for shutter gain.
    Type: Grant
    Filed: May 8, 1998
    Date of Patent: November 18, 2003
    Assignee: Cirrus Logic, Inc.
    Inventors: Nadi R. Itani, Caiyi Wang, David R. Welland
  • Publication number: 20030119467
    Abstract: A method and apparatus for synthesizing high-frequency signals, such as wireless communication signals, includes a phase-locked loop (PLL) frequency synthesizer with a variable capacitance voltage controlled oscillator (VCO) that has a discretely variable capacitance in conjunction with a continuously variable capacitance. The discretely variable capacitance may provide coarse tuning adjustment of the variable capacitance to compensate for capacitor and inductor tolerances and to adjust the output frequency to be near the desired frequency output. The continuously variable capacitance may provide a fine tuning adjustment of the variable capacitance to focus the output frequency to match precisely the desired frequency output. During fine tuning adjustment, the PLL may be controlled by a plurality of analog control signals. The analog control signals may be derived by first generating a plurality of phase shifted signals from a divided version of the VCO output clock.
    Type: Application
    Filed: February 5, 2003
    Publication date: June 26, 2003
    Applicant: Silicon Laboratories, Inc.
    Inventors: David R. Welland, Caiyi Wang
  • Patent number: 6574288
    Abstract: A method and apparatus for synthesizing high-frequency signals is disclosed that overcomes integration problem associated with prior implementations while meeting demanding phase noise and other impurity requirements. In one embodiment, a phase-locked loop (PLL) frequency synthesizer is disclosed having a voltage controlled oscillator (VCO) with a variable capacitance that includes a discretely variable capacitance in conjunction with a continuously variable capacitance. The discretely variable capacitance may provide coarse tuning adjustment of the variable capacitance, and the continuously variable capacitance may provide a fine tuning adjustment of the variable capacitance. In a further detail, discrete control circuitry is disclosed that provides a digital control signal to a discretely variable capacitance circuit to control its overall capacitance and that adjusts the digital control signal depending upon feedback from the output frequency.
    Type: Grant
    Filed: May 29, 1998
    Date of Patent: June 3, 2003
    Assignee: Silicon Laboratories Inc.
    Inventors: David R. Welland, Caiyi Wang
  • Patent number: 6549765
    Abstract: A method and apparatus for synthesizing high-frequency signals, such as wireless communication signals, includes a phase-locked loop (PLL) frequency synthesizer with a variable capacitance voltage controlled oscillator (VCO) that has a discretely variable capacitance in conjunction with a continuously variable capacitance. The discretely variable capacitance may provide coarse tuning adjustment of the variable capacitance to compensate for capacitor and inductor tolerances and to adjust the output frequency to be near the desired frequency output. The continuously variable capacitance may provide a fine tuning adjustment of the variable capacitance to focus the output frequency to match precisely the desired frequency output. During fine tuning adjustment, the PLL may be controlled by a plurality of analog control signals. The analog control signals may be derived by first generating a plurality of phase shifted signals from a divided version of the VCO output clock.
    Type: Grant
    Filed: August 20, 2001
    Date of Patent: April 15, 2003
    Assignee: Silicon Laboratories, Inc.
    Inventors: David R. Welland, Caiyi Wang
  • Publication number: 20030003887
    Abstract: A voltage-controlled oscillator (VCO) generates an output signal with adjustable frequency. The VCO circuitry includes a variable capacitor circuitry and a voltage-generator circuitry. In response to a plurality of control signals, the variable capacitor circuitry adjusts the frequency of an output signal of the VCO circuitry. The voltage-generator circuitry generates the plurality of control signals and provides them to the variable capacitor circuitry. The voltage level of each of the plurality of the control signals differs by an offset voltage from the voltage level of the remaining signals in the plurality of signals.
    Type: Application
    Filed: February 13, 2002
    Publication date: January 2, 2003
    Inventors: Lysander Lim, Caiyi Wang, David R. Welland, Donald A. Kerth, Richard T. Behrens, Jeffrey W. Scott, G. Diwakar Vishakhadatta, G. Tyson Tuttle, Vishnu S. Srinivasan
  • Publication number: 20020193084
    Abstract: A radio-frequency (RF) apparatus capable of transmitting RF signals includes transmitter path circuitry. The transmitter path circuitry includes a voltage-controlled oscillator (VCO) circuitry. The VCO circuitry generates a first signal that has a first frequency. A divider circuitry couples to the VCO circuitry and, in response to the first signal, the divider circuitry generates a second signal that has a second frequency. The frequency of the second signal equals the frequency of the first signal divided by a number.
    Type: Application
    Filed: February 13, 2002
    Publication date: December 19, 2002
    Inventors: Lysander Lim, Caiyi Wang, David R. Welland, Donald A. Kerth, Richard T. Behrens, Jeffrey W. Scott, G. Diwakar Vishakhadatta, G. Tyson Tuttle, Vishnu S. Srinivasan
  • Publication number: 20020187763
    Abstract: A radio-frequency (RF) apparatus capable of transmitting RF signals includes transmitter path circuitry. The transmitter path circuitry includes a voltage-controlled oscillator (VCO) that generates an output signal. The frequency of the output signal of the VCO circuitry is adjustable in response to a first control signal and a second control signal. The transmitter path circuitry also includes a first feedback circuitry and a second feedback circuitry that are responsive to the output signal of the VCO circuitry. The first feedback circuitry provides the first control signal to the VCO circuitry. The first control signal coarsely adjusts the frequency of the output signal of the VCO circuitry to a desired frequency. The second feedback circuitry supplies the second control signal to the VCO circuitry. The second control signal fine tunes the frequency of the output signal of the voltage-controlled oscillator circuitry to the desired frequency.
    Type: Application
    Filed: February 13, 2002
    Publication date: December 12, 2002
    Inventors: Lysander Lim, Caiyi Wang, David R. Welland, Donald A. Kerth, Richard T. Behrens, Jeffrey W. Scott, G. Diwakar Vishakhadatta, G. Tyson Tuttle, Vishnu S. Srinivasan
  • Publication number: 20020176009
    Abstract: An image processor system for a charge coupled device (CCD) or CMOS imaging system includes a correlated double sample and variable gain (CDSVGA) circuit for receiving data from a CCD system and an automatic gain control (AGC) circuit which first controls gain by adjusting said CCD system and then for yet a higher gain level makes gain adjustments in said CDSVGA circuit AND a digital gain circuit to produce a combined target gain level. A processing system for an imager device includes a camera system for producing an imager signal, a correlated double sample (CDS) circuit for receiving data from an imager, a variable gain amplifier (VGA), an analog-to-digital converter (ADC) coupled to said CDS circuit, a digital gain circuit (DGC) coupled to said ADC, and an automatic gain control (AGC) circuit coupled to said DGC for controlling the CDS circuit and the DGC.
    Type: Application
    Filed: March 27, 2002
    Publication date: November 28, 2002
    Inventors: Sandra Marie Johnson, Shih-Chung Chao, Nadi Rafik Itani, Caiyi Wang, Brannon Craig Harris, Ash Prabala, Douglas R. Holberg, Alan Wayne Hansford, Syed Khalid Azim, David R. Welland
  • Publication number: 20020009984
    Abstract: A method and apparatus for synthesizing high-frequency signals, such as wireless communication signals, includes a phase-locked loop (PLL) frequency synthesizer with a variable capacitance voltage controlled oscillator (VCO) that has a discretely variable capacitance in conjunction with a continuously variable capacitance. The discretely variable capacitance may provide coarse tuning adjustment of the variable capacitance to compensate for capacitor and inductor tolerances and to adjust the output frequency to be near the desired frequency output. The continuously variable capacitance may provide a fine tuning adjustment of the variable capacitance to focus the output frequency to match precisely the desired frequency output. During fine tuning adjustment, the PLL may be controlled by a plurality of analog control signals. The analog control signals may be derived by first generating a plurality of phase shifted signals from a divided version of the VCO output clock.
    Type: Application
    Filed: August 20, 2001
    Publication date: January 24, 2002
    Applicant: Silicon Laboratories, Inc.
    Inventors: David R. Welland, Caiyi Wang
  • Patent number: 6317006
    Abstract: A method and apparatus for synthesizing high-frequency signals, such as wireless communication signals, includes a phase-locked loop (PLL) frequency synthesizer with a variable capacitance voltage controlled oscillator (VCO) that has a discretely variable capacitance in conjunction with a continuously variable capacitance. The discretely variable capacitance may provide coarse tuning adjustment of the variable capacitance to compensate for capacitor and inductor tolerances and to adjust the output frequency to be near the desired frequency output. The continuously variable capacitance may provide a fine tuning adjustment of the variable capacitance to focus the output frequency to match precisely the desired frequency output. During fine tuning adjustment, the PLL may be controlled by a plurality of analog control signals. The analog control signals may be derived by first generating a plurality of phase shifted signals from a divided version of the VCO output clock by using a shift register.
    Type: Grant
    Filed: July 21, 2000
    Date of Patent: November 13, 2001
    Assignee: Silicon Laboratories, Inc.
    Inventors: David R. Welland, Caiyi Wang
  • Patent number: 6311050
    Abstract: A method and apparatus for synthesizing high-frequency signals is disclosed that overcomes integration problem associated with prior implementations while meeting demanding phase noise and other impurity requirements. In one embodiment, a phase-locked loop (PLL) frequency synthesizer is disclosed having a voltage controlled oscillator (VCO) with a variable capacitance that includes a discretely variable capacitance in conjunction with a continuously variable capacitance. The discretely variable capacitance may provide coarse tuning adjustment of the variable capacitance, and the continuously variable capacitance may provide a fine tuning adjustment of the variable capacitance.
    Type: Grant
    Filed: May 29, 1998
    Date of Patent: October 30, 2001
    Assignee: Silicon Laboratories, Inc.
    Inventors: David R. Welland, Caiyi Wang, Donald A. Kerth
  • Patent number: 6308055
    Abstract: A method and apparatus for synthesizing high-frequency signals, such as wireless communication signals, includes a phase-locked loop (PLL) frequency synthesizer with a variable capacitance voltage controlled oscillator (VCO) that has a discretely variable capacitance in conjunction with a continuously variable capacitance. The discretely variable capacitance may provide coarse tuning adjustment of the variable capacitance to compensate for capacitor and inductor tolerances and to adjust the output frequency to be near the desired frequency output. The continuously variable capacitance may provide a fine tuning adjustment of the variable capacitance to focus the output frequency to match precisely the desired frequency output. During fine tuning adjustment, the PLL may be controlled by a plurality of analog control signals. The analog control signals may be derived by first generating a plurality of phase shifted signals from a divided version of the VCO output clock.
    Type: Grant
    Filed: May 29, 1998
    Date of Patent: October 23, 2001
    Assignee: Silicon Laboratories, Inc.
    Inventors: David R. Welland, Caiyi Wang
  • Patent number: 6167245
    Abstract: A method and apparatus for synthesizing high-frequency signals, such as wireless communication signals, includes a phase-locked loop (PLL) frequency synthesizer with a variable capacitance voltage controlled oscillator (VCO) that has a discretely variable capacitance in conjunction with a continuously variable capacitance. The discretely variable capacitance may provide coarse tuning adjustment of the variable capacitance to compensate for capacitor and inductor tolerances and to adjust the output frequency to be near the desired frequency output. The continuously variable capacitance may provide a fine tuning adjustment of the variable capacitance to focus the output frequency to match precisely the desired frequency output. During fine tuning adjustment, the PLL may include an analog control loop in which a phase detector circuit and sample and hold circuit are utilized. The output of the sample and hold circuit may be provided to the PLL VCO as VCO input control signals.
    Type: Grant
    Filed: May 29, 1998
    Date of Patent: December 26, 2000
    Assignee: Silicon Laboratories, Inc.
    Inventors: David R. Welland, Caiyi Wang