Patents by Inventor Kexin Luo

Kexin Luo 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: 10693463
    Abstract: Example embodiments of the present disclosure relate to a line driver apparatus. In some example embodiments, an apparatus is provided. The apparatus includes a capacitive feed-through module and a driving module. The capacitive feed-through module includes a first pre-driver operable to receive input differential signals and delayed signals of the input differential signals, generate first drive signals from the input differential signals and the delayed signals, and equalize the first drive signals. The capacitive feed-through module also includes a capacitance reducing module arranged between the first pre-driver and transmission lines and operable to reduce parasitic capacitance at the transmission lines in response to the first drive signals. The driving module is coupled to the transmission lines and operable to generate output differential signals from the input differential signals for transmission on the transmission lines.
    Type: Grant
    Filed: April 14, 2017
    Date of Patent: June 23, 2020
    Assignee: LATTICE SEMICONDUCTOR CORPORATION
    Inventor: Kexin Luo
  • Patent number: 10523153
    Abstract: A voltage controlled oscillator (VCO) is disclosed. The VCO includes an amplifier that receives a control signal and a feedback signal and generates an amplified output signal based on the difference between the control signal and the feedback signal. The VCO also includes circuitry to generate an oscillating output signal based on the amplifier output signal. Additionally, the VCO includes a feedback amplifier that generates the feedback signal based on the output of the amplifier. The feedback amplifier includes a first resistor connected in parallel with a second resistor, the second resistor having an adjustable resistance.
    Type: Grant
    Filed: March 9, 2018
    Date of Patent: December 31, 2019
    Assignee: Lattice Semiconductor Corporation
    Inventors: Qiming Wu, Yibin Fu, Yu Shen, Zhi Wu, Kai Lei, Kai Zhou, Kexin Luo, Xiaofeng Wang
  • Patent number: 10250263
    Abstract: Embodiments relate to a voltage oscillator (VCO) that uses a replica bias circuit to generate a cascode bias voltage. The VCO generate an output periodic signal having a frequency and phase that is less or not susceptible to voltage swings by using a bias voltage generated in a replica bias circuit that replicates a voltage-to-current converter in the VOC. The bias voltage is generated and regulated according to a power supply voltage that supplies power to the VCO to account for voltage variations in the power supply voltage.
    Type: Grant
    Filed: May 12, 2015
    Date of Patent: April 2, 2019
    Assignee: Lattice Semiconductor Corporation
    Inventors: Kexin Luo, Rui Yin, Xiaofeng Wang, Jie Yuan, Qiming Wu, Fei Song, Min-Kyu Kim
  • Publication number: 20180198409
    Abstract: A voltage controlled oscillator (VCO) is disclosed. The VCO includes an amplifier that receives a control signal and a feedback signal and generates an amplified output signal based on the difference between the control signal and the feedback signal. The VCO also includes circuitry to generate an oscillating output signal based on the amplifier output signal. Additionally, the VCO includes a feedback amplifier that generates the feedback signal based on the output of the amplifier. The feedback amplifier includes a first resistor connected in parallel with a second resistor, the second resistor having an adjustable resistance.
    Type: Application
    Filed: March 9, 2018
    Publication date: July 12, 2018
    Inventors: Qiming Wu, Yibin Fu, Yu Shen, Zhi Wu, Kai Lei, Kai Zhou, Kexin Luo, Xiaofeng Wang
  • Patent number: 9948234
    Abstract: A voltage controlled oscillator (VCO) is disclosed. The VCO includes an amplifier that receives a control signal and a feedback signal and generates an amplified output signal based on the difference between the control signal and the feedback signal. The VCO also includes circuitry to generate an oscillating output signal based on the amplifier output signal. Additionally, the VCO includes a feedback amplifier that generates the feedback signal based on the output of the amplifier. The feedback amplifier includes a first resistor connected in parallel with a second resistor, the second resistor having an adjustable resistance.
    Type: Grant
    Filed: July 24, 2014
    Date of Patent: April 17, 2018
    Assignee: Lattice Semiconductor Corporation
    Inventors: Qiming Wu, Yibin Fu, Yu Shen, Zhi Wu, Kai Lei, Kai Zhou, Kexin Luo, Xiaofeng Wang
  • Patent number: 9887733
    Abstract: A method that calibrates a device for echo cancellation and a device with calibration for echo cancellation are provided. Devices may be calibrated such that the echo residual error is less than a threshold determined by the calibration accuracy. Non-ideal factors such as mismatch may be eliminated during calibration.
    Type: Grant
    Filed: April 28, 2017
    Date of Patent: February 6, 2018
    Assignee: Lattice Semiconductor Corporation
    Inventors: Kai Zhou, Shinje Tahk, Kai Lei, Qiming Wu, Gijung Ahn, Min-Kyu Kim, Fei Song, Kexin Luo
  • Publication number: 20170302267
    Abstract: Example embodiments of the present disclosure relate to a line driver apparatus. In some example embodiments, an apparatus is provided. The apparatus includes a capacitive feed-through module and a driving module. The capacitive feed-through module includes a first pre-driver operable to receive input differential signals and delayed signals of the input differential signals, generate first drive signals from the input differential signals and the delayed signals, and equalize the first drive signals. The capacitive feed-through module also includes a capacitance reducing module arranged between the first pre-driver and transmission lines and operable to reduce parasitic capacitance at the transmission lines in response to the first drive signals. The driving module is coupled to the transmission lines and operable to generate output differential signals from the input differential signals for transmission on the transmission lines.
    Type: Application
    Filed: April 14, 2017
    Publication date: October 19, 2017
    Inventor: Kexin Luo
  • Publication number: 20170237464
    Abstract: A method that calibrates a device for echo cancellation and a device with calibration for echo cancellation are provided. Devices may be calibrated such that the echo residual error is less than a threshold determined by the calibration accuracy. Non-ideal factors such as mismatch may be eliminated during calibration.
    Type: Application
    Filed: April 28, 2017
    Publication date: August 17, 2017
    Inventors: Kai Zhou, Shinje Tahk, Kai Lei, Qiming Wu, Gijung Ahn, Min-Kyu Kim, Fei Song, Kexin Luo
  • Patent number: 9673959
    Abstract: A method that calibrates a device for echo cancellation and a device with calibration for echo cancellation are provided. Devices may be calibrated such that the echo residual error is less than a threshold determined by the calibration accuracy. Non-ideal factors such as mismatch may be eliminated during calibration.
    Type: Grant
    Filed: September 12, 2014
    Date of Patent: June 6, 2017
    Assignee: Lattice Semiconductor Corporation
    Inventors: Kai Zhou, Shinje Tahk, Kai Lei, Qiming Wu, Gijung Ahn, Min-Kyu Kim, Fei Song, Kexin Luo
  • Publication number: 20170149437
    Abstract: Embodiments relate to a voltage oscillator (VCO) that uses a replica bias circuit to generate a cascode bias voltage. The VCO generate an output periodic signal having a frequency and phase that is less or not susceptible to voltage swings by using a bias voltage generated in a replica bias circuit that replicates a voltage-to-current converter in the VOC. The bias voltage is generated and regulated according to a power supply voltage that supplies power to the VCO to account for voltage variations in the power supply voltage.
    Type: Application
    Filed: May 12, 2015
    Publication date: May 25, 2017
    Applicant: Lattice Semiconductor Corporation
    Inventors: Kexin Luo, Rui Yin, Xiaofeng Wang, Jie Yuan, Qiming Wu, Fei Song, Min-Kyu Kim
  • Patent number: 9559707
    Abstract: Embodiments relate to type-I PLLs that do not lock at a sub-harmonic frequency of a reference clock signal by controlling timing of charging or discharging of one or more capacitors in the PLLs. A phase frequency detector (PFD) of a type-I PLL can prevent sub-harmonic locking by generating a clear output signal to cause a sampling capacitor of PLL's loop filter to discharge only during a time period when the sampling capacitor is not being charged. For example, the PFD can include a gating element to control the time during which the clear output signal is generated. By ensuring that the sampling capacitor is not discharged during a time period while it is being charged, the PLL's voltage-controlled oscillator is controlled to oscillate at an intended frequency rather than at a sub-harmonic of the intended frequency.
    Type: Grant
    Filed: October 23, 2014
    Date of Patent: January 31, 2017
    Assignee: Lattice Semiconductor Corporation
    Inventors: Kexin Luo, Yan Rui, Shaoyong Lu, Rui Yin, Yu Shen
  • Patent number: 9484939
    Abstract: Embodiments describe techniques for utilizing fractional-N phase locked loops (PLL). Some embodiments describe a fractional-divider based fractional-N PLL for a spread spectrum clock (SSC) generator that utilizes phase average techniques to suppress phase interpolator nonlinearity. Some embodiments describe a fractional-N PLL based on fractional dividers with hybrid finite impulse response (FIR) filtering. Some embodiments describe a small size and low power divider for a hybrid FIR fractional-N PLL.
    Type: Grant
    Filed: May 16, 2014
    Date of Patent: November 1, 2016
    Assignee: Lattice Semiconductor Corporation
    Inventors: Kexin Luo, Kai Zhou, Shengguo Cao, Lingfen Yue, Fangquing Chu, Yu Shen, Zhi Wu
  • Patent number: 9477244
    Abstract: Embodiments of the invention are generally directed to a linear regulator with improved power supply ripple rejection. An embodiment of an apparatus includes an linear regulator to receive a system power supply and to generate a regulated power supply; a first voltage reference generator to generate a first voltage reference for the linear regulator; a second voltage reference generator to generate a second voltage reference for the linear regulator; and a voltage reference and power switcher. In some embodiments, the voltage reference and power switcher is to switch a voltage reference for the linear regulator from the first voltage reference to the second voltage reference and is to switch a part of a power supply for the linear regulator from the system power supply to the regulated power supply.
    Type: Grant
    Filed: January 10, 2014
    Date of Patent: October 25, 2016
    Assignee: Lattice Semiconductor Corporation
    Inventors: Kexin Luo, Fangqing Chu, Yu Shen, Zhi Wu, Inyeol Lee
  • Patent number: 9479190
    Abstract: Embodiments relate to successive approximation register (SAR)-based analog-to-digital converters (ADCs) that increase a time frame allocated for the settling of capacitors in a digital-to-analog converter (DAC) capacitor network by feeding a comparator output signal to the DAC to begin DAC capacitor settling before the comparator output is latched by a clock signal at a latching time. The SAR ADC can include a window circuit that provides the comparator output directly from the comparator to the DAC before the latching time of the comparator. After the latching time, the latched version of the comparator output is provided to the DAC capacitor. By providing the capacitor output to the DAC capacitor before latching, DAC capacitor can settle earlier compared to an SAR ADC where DAC capacitor settling begins after the latching time of the comparator.
    Type: Grant
    Filed: October 23, 2014
    Date of Patent: October 25, 2016
    Assignee: Lattice Semiconductor Corporation
    Inventors: Kexin Luo, Xiaozhi Lin, Guofu Peng, Yu Shen, Gijung Ahn
  • Publication number: 20160254818
    Abstract: Embodiments relate to type-I PLLs that do not lock at a sub-harmonic frequency of a reference clock signal by controlling timing of charging or discharging of one or more capacitors in the PLLs. A phase frequency detector (PFD) of a type-I PLL can prevent sub-harmonic locking by generating a clear output signal to cause a sampling capacitor of PLL's loop filter to discharge only during a time period when the sampling capacitor is not being charged. For example, the PFD can include a gating element to control the time during which the clear output signal is generated. By ensuring that the sampling capacitor is not discharged during a time period while it is being charged, the PLL's voltage-controlled oscillator is controlled to oscillate at an intended frequency rather than at a sub-harmonic of the intended frequency.
    Type: Application
    Filed: October 23, 2014
    Publication date: September 1, 2016
    Inventors: Kexin Luo, Yan Rui, Shaoyong Lu, Rui Yin, Yu Shen
  • Publication number: 20160254821
    Abstract: Embodiments relate to successive approximation register (SAR)-based analog-to-digital converters (ADCs) that increase a time frame allocated for the settling of capacitors in a digital-to-analog converter (DAC) capacitor network by feeding a comparator output signal to the DAC to begin DAC capacitor settling before the comparator output is latched by a clock signal at a latching time. The SAR ADC can include a window circuit that provides the comparator output directly from the comparator to the DAC before the latching time of the comparator. After the latching time, the latched version of the comparator output is provided to the DAC capacitor. By providing the capacitor output to the DAC capacitor before latching, DAC capacitor can settle earlier compared to an SAR ADC where DAC capacitor settling begins after the latching time of the comparator.
    Type: Application
    Filed: October 23, 2014
    Publication date: September 1, 2016
    Applicant: Lattice Semiconductor Corporation
    Inventors: Kexin Luo, Xiaozhi Lin, Guofu Peng, Yu Shen, Gijung Ahn
  • Publication number: 20160248376
    Abstract: A voltage controlled oscillator (VCO) is disclosed. The VCO includes an amplifier that receives a control signal and a feedback signal and generates an amplified output signal based on the difference between the control signal and the feedback signal. The VCO also includes circuitry to generate an oscillating output signal based on the amplifier output signal. Additionally, the VCO includes a feedback amplifier that generates the feedback signal based on the output of the amplifier. The feedback amplifier includes a first resistor connected in parallel with a second resistor, the second resistor having an adjustable resistance.
    Type: Application
    Filed: July 24, 2014
    Publication date: August 25, 2016
    Inventors: Qiming Wu, Yibin Fu, Yu Shen, Zhi Wu, Kai Lei, Kai Zhou, Kexin Luo, Xiaofeng Wang
  • Publication number: 20160248574
    Abstract: A method that calibrates a device for echo cancellation and a device with calibration for echo cancellation are provided. Devices may be calibrated such that the echo residual error is less than a threshold determined by the calibration accuracy. Non-ideal factors such as mismatch may be eliminated during calibration.
    Type: Application
    Filed: September 12, 2014
    Publication date: August 25, 2016
    Inventors: Kai Zhou, Shinje Tahk, Kai Lei, Qiming Wu, Gijung Ahn, Min-Kyu Kim, Fei Song, Kexin Luo
  • Publication number: 20160248431
    Abstract: Embodiments describe techniques for utilizing fractional-N phase locked loops (PLL). Some embodiments describe a factional-divider based fractional-N PLL for a spread spectrum clock (SSC) generator that utilizes phase average techniques to suppress phase interpolator nonlinearity. Some embodiments describe a fractional-N PLL based on fractional dividers with hybrid finite impulse response (FIR) filtering. Some embodiments describe a small size and low power divider for a hybrid FIR fractional-N PLL.
    Type: Application
    Filed: May 16, 2014
    Publication date: August 25, 2016
    Inventors: Kexin LUO, Kai ZHOU, Shengguo CAO, Lingfen YUE, Fangquing CHU, Yu SHEN, Zhi WU
  • Patent number: 9344081
    Abstract: Embodiments of the invention are generally directed to a line driver with separate pre-driver for feed-through capacitance. An embodiment of an apparatus includes a differential pair of transistors to generate an output signal on a first output node and a second output node; a pass-through capacitance coupled with the first output node and the second output node; a first pre-driver to drive an input signal for the differential transistors; and a second pre-driver to drive the input signal for the pass-through capacitance.
    Type: Grant
    Filed: March 15, 2013
    Date of Patent: May 17, 2016
    Assignee: Lattice Semiconductor Corporation
    Inventors: Kexin Luo, Fangqing Chu, Huaizhou Yang, Yu Shen, Inyeol Lee