Patents by Inventor Chen Zhai

Chen Zhai 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: 11990913
    Abstract: To increase the operating frequency range of the DLL while decreasing varactor sizes, coarse tuning circuitry may be implemented in a delay-locked loop (DLL). The DLL may include a voltage-controlled delay line (VCDL) including multiple switched capacitors coupled in parallel to each other. An electrical ground may be coupled to the parallel switched capacitors at a first node and a buffer and variable capacitor may be coupled to the parallel switched capacitors at a second node. The coarse tuning circuitry may be electrically coupled to a phase detector and to the multiple switched capacitors of the VCDL, such that the coarse tuning circuitry may receive a signal (e.g., an indication of a phase) from the phase detector and may adjust switched capacitor loading based on the signal received from the phase detector. Such a DLL implementation may increase DLL tuning range and decrease phase noise, among other advantages.
    Type: Grant
    Filed: December 12, 2022
    Date of Patent: May 21, 2024
    Assignee: Apple Inc.
    Inventors: Chen Zhai, Abbas Komijani
  • Publication number: 20240106440
    Abstract: To increase the operating frequency range of the DLL while decreasing varactor sizes, coarse tuning circuitry may be implemented in a delay-locked loop (DLL). The DLL may include a voltage-controlled delay line (VCDL) including multiple switched capacitors coupled in parallel to each other. An electrical ground may be coupled to the parallel switched capacitors at a first node and a buffer and variable capacitor may be coupled to the parallel switched capacitors at a second node. The coarse tuning circuitry may be electrically coupled to a phase detector and to the multiple switched capacitors of the VCDL, such that the coarse tuning circuitry may receive a signal (e.g., an indication of a phase) from the phase detector and may adjust switched capacitor loading based on the signal received from the phase detector. Such a DLL implementation may increase DLL tuning range and decrease phase noise, among other advantages.
    Type: Application
    Filed: December 12, 2022
    Publication date: March 28, 2024
    Inventors: Chen Zhai, Abbas Komijani
  • Patent number: 11742839
    Abstract: Aspects of the disclosure relate to a local oscillator frequency divider for a receiver or transmitter. In this regard a frequency divider has a first frequency input coupled to a first oscillator frequency output, a second frequency input coupled to a complementary second oscillator frequency output, a first in-phase/quadrature (I/Q) divided frequency output, and a complementary second I/Q divided frequency output. The frequency divider further has a first alternating current (AC) coupling capacitor between the first frequency input and the first oscillator frequency output and a second AC coupling capacitor between the second frequency input and the second oscillator frequency output.
    Type: Grant
    Filed: August 16, 2021
    Date of Patent: August 29, 2023
    Assignee: QUALCOMM Incorporated
    Inventors: Chen Zhai, Yung-Chung Lo
  • Publication number: 20230049388
    Abstract: Aspects of the disclosure relate to a local oscillator frequency divider for a receiver or transmitter. In this regard a frequency divider has a first frequency input coupled to a first oscillator frequency output, a second frequency input coupled to a complementary second oscillator frequency output, a first in-phase/quadrature (I/Q) divided frequency output, and a complementary second I/Q divided frequency output. The frequency divider further has a first alternating current (AC) coupling capacitor between the first frequency input and the first oscillator frequency output and a second AC coupling capacitor between the second frequency input and the second oscillator frequency output.
    Type: Application
    Filed: August 16, 2021
    Publication date: February 16, 2023
    Inventors: Chen ZHAI, Yung-Chung LO
  • Patent number: 10700655
    Abstract: An integrated circuit is disclosed for gain-dependent impedance matching and linearity. The integrated circuit includes at least two amplifier branches, an input inductor, and at least two degeneration inductors. Each amplifier branch includes a node, an input transistor, and a cascode stage connected between a drain of the input transistor and the node. Respective nodes of the at least two amplifier branches are connected together and respective gates of the input transistors of the at least two amplifier branches are connected together. The input inductor is connected to the respective gates, and the at least two degeneration inductors are connected between respective sources of the input transistors of the at least two amplifier branches and a ground. The at least two degeneration inductors are configured to establish a magnetic coupling with the input inductor and establish another magnetic coupling between each other.
    Type: Grant
    Filed: November 26, 2018
    Date of Patent: June 30, 2020
    Assignee: QUALCOMM Incorporated
    Inventors: Alaaeldien Mohamed Abdelrazek Medra, David Zixiang Yang, Kevin Hsi Huai Wang, Chen Zhai, Francesco Gatta
  • Publication number: 20190158048
    Abstract: An integrated circuit is disclosed for gain-dependent impedance matching and linearity. The integrated circuit includes at least two amplifier branches, an input inductor, and at least two degeneration inductors. Each amplifier branch includes a node, an input transistor, and a cascode stage connected between a drain of the input transistor and the node. Respective nodes of the at least two amplifier branches are connected together and respective gates of the input transistors of the at least two amplifier branches are connected together. The input inductor is connected to the respective gates, and the at least two degeneration inductors are connected between respective sources of the input transistors of the at least two amplifier branches and a ground. The at least two degeneration inductors are configured to establish a magnetic coupling with the input inductor and establish another magnetic coupling between each other.
    Type: Application
    Filed: November 26, 2018
    Publication date: May 23, 2019
    Inventors: Alaaeldien Mohamed Abdelrazek Medra, David Zixiang Yang, Kevin Hsi Huai Wang, Chen Zhai, Francesco Gatta