Patents by Inventor Chih-Wei Yao

Chih-Wei Yao 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: 20250125998
    Abstract: A wireline transceiver system includes a predriver configured to generate a signal; a source-series termination (SST) driver configured to receive the generated signal; and a replica driver configured to continuously generate bias voltages in real time to modulate current of a push-pull current source of the SST driver based on a voltage of the received signal across a process, voltage, and temperature (PVT) range.
    Type: Application
    Filed: January 2, 2024
    Publication date: April 17, 2025
    Inventors: Minsoo CHOI, Hiep PHAM, Chih-Wei YAO, Hyojun KIM
  • Publication number: 20250125815
    Abstract: A hybrid digital-to-analog converter (DAC) driver is provided. The hybrid DAC driver includes an upper DAC stage configured to receive an upper set of bits of a digital signal, the upper DAC stage comprising an upper set of DAC units, with a first DAC unit in the upper set of DAC units having a different weight than a second DAC unit in the upper set of DAC units; a lower DAC stage configured to receive a lower set of bits of the digital signal, the lower DAC stage comprising a lower set of DAC units formed in an R-2R resistor ladder network; and an output stage for outputting an analog signal from the upper DAC stage and the lower DAC stage.
    Type: Application
    Filed: January 10, 2024
    Publication date: April 17, 2025
    Inventors: Minsoo CHOI, Hiep PHAM, Chih-Wei YAO, Hyojun KIM
  • Patent number: 11431344
    Abstract: An apparatus and method are provided. The apparatus includes a phase locked loop (PLL) configured to generate a reference signal; a sub-sampling PLL (SS-PLL) connected to the PLL and configured to sub-sample the reference signal; and a first pre-charge circuit connected to a sampling device of the SS-PLL and configured to facilitate frequency locking of the SS-PLL.
    Type: Grant
    Filed: June 22, 2021
    Date of Patent: August 30, 2022
    Inventors: Yongrong Zuo, Chih-Wei Yao, Wanghua Wu
  • Patent number: 11233627
    Abstract: An apparatus for providing fast-settling quadrature detection and correction includes: a quadrature correction circuit that receives four quadrature clock signals; a quadrature detector that selects two clock signals among the four quadrature clock signals; and a phase digitizer that generates a digital code indicating a phase difference between the two clock signals. The quadrature correction circuit adjusts a phase between the two clock signals using the digital code.
    Type: Grant
    Filed: October 14, 2020
    Date of Patent: January 25, 2022
    Inventors: Zhiqiang Huang, Hiep Pham, Chih-Wei Yao
  • Patent number: 11175633
    Abstract: A system and method for fast converging gain calibration for phase lock loops (PLL) are herein disclosed. According to one embodiment, a method includes receiving, with a voltage generation circuit, an input value representing a difference between a sampled voltage and a reference voltage, and adjusting, with the voltage generation circuit, the reference voltage by generating a voltage output based on the difference represented by the input value.
    Type: Grant
    Filed: July 22, 2020
    Date of Patent: November 16, 2021
    Inventors: Chih-Wei Yao, Ronghua Ni
  • Publication number: 20210313995
    Abstract: An apparatus and method are provided. The apparatus includes a phase locked loop (PLL) configured to generate a reference signal; a sub-sampling PLL (SS-PLL) connected to the PLL and configured to sub-sample the reference signal; and a first pre-charge circuit connected to a sampling device of the SS-PLL and configured to facilitate frequency locking of the SS-PLL.
    Type: Application
    Filed: June 22, 2021
    Publication date: October 7, 2021
    Inventors: Yongrong ZUO, Chih-Wei Yao, Wanghua Wu
  • Patent number: 11115005
    Abstract: A ring voltage controlled oscillator (VCO) circuit is herein provided. According to one embodiment, a ring VCO circuit includes a plurality of stages connected in series, wherein each stage includes a first inverter, a second inverter, a third inverter and a fourth inverter, the first inverter connected in parallel with the third and fourth inverters and the second inverter connected in parallel with the third and fourth inverters, and a first biasing resistor connected to a first node and coupled to an input of the first inverter. The first biasing resistor includes a first switch configured to set the first biasing resistor to about zero voltage.
    Type: Grant
    Filed: March 31, 2020
    Date of Patent: September 7, 2021
    Inventors: Xiong Liu, Chih-Wei Yao
  • Patent number: 11063599
    Abstract: An apparatus and method are provided. The apparatus includes a phase locked loop (PLL) configured to generate a reference signal; a sub-sampling PLL (SS-PLL) connected to the PLL and configured to sub-sample the reference signal; and a first pre-charge circuit connected to the SS-PLL and configured to allow an output voltage of the SS-PLL to transition to an operating voltage to indicate that a difference between two voltage inputs is zero on average.
    Type: Grant
    Filed: July 19, 2019
    Date of Patent: July 13, 2021
    Inventors: Yongrong Zuo, Chih-Wei Yao, Wanghua Wu
  • Patent number: 11050428
    Abstract: A synchronized I/Q detection circuit is provided. A first subset of input signals and, subsequently, a second subset of input signals are provided by a first multiplexer and received by a first phase detector. Outputs of the first phase detector are receiving, by a first reset and sampling circuit. A second set of input signals are provided by a second multiplexer and received by a second phase detector, from a second multiplexer, while the first multiplexer receives the first and second subsets of input signals. The first subset of input signals has a same phase order as the second set of input signals, and the second subset of input signals has a different phase order than the second set of input signals. Outputs of the second phase detector are received by a second reset and sampling circuit. A comparator outputs a detected phase difference based on the outputs of the first and second reset and sampling circuits.
    Type: Grant
    Filed: September 2, 2020
    Date of Patent: June 29, 2021
    Inventors: Zhiqiang Huang, Chih-Wei Yao, Hiep Pham
  • Patent number: 10996634
    Abstract: A system and method for fast converging gain calibration for phase lock loops (PLL) are herein disclosed. According to one embodiment, a method includes receiving, with a voltage generation circuit, an input value representing a difference between a sampled voltage and a reference voltage, and adjusting, with the voltage generation circuit, the reference voltage by generating a voltage output based on the difference represented by the input value.
    Type: Grant
    Filed: July 20, 2018
    Date of Patent: May 4, 2021
    Inventors: Chih-Wei Yao, Ronghua Ni
  • Patent number: 10965297
    Abstract: Methods and apparatuses are provided for fractional-N frequency synthesis using a phase-locked loop (PLL). A phase detector (PD) of the PLL determines a phase difference between a clock and a feedback clock (CLKFB). A low-pass loop filter of the PLL detects a control voltage based on the phase difference. A voltage-controlled oscillator (VCO) of the PLL generates a periodic signal based on the control voltage. A sigma-delta modulator (SDM) of the PLL generates a division sequence ratio and a selection control signal based on a frequency command word. A multi-modulus divider (MMDIV) generates a first CLKFB and a second CLKFB based on the division sequence ratio and differential inputs of the periodic signal. The MMDIV outputs one of the first CLKFB and the second CLKFB as the CLKFB to the PD based on the selection control signal.
    Type: Grant
    Filed: June 2, 2020
    Date of Patent: March 30, 2021
    Inventors: Wanghua Wu, Chih-Wei Yao
  • Publication number: 20210067145
    Abstract: A ring voltage controlled oscillator (VCO) circuit is herein provided. According to one embodiment, a ring VCO circuit includes a plurality of stages connected in series, wherein each stage includes a first inverter, a second inverter, a third inverter and a fourth inverter, the first inverter connected in parallel with the third and fourth inverters and the second inverter connected in parallel with the third and fourth inverters, and a first biasing resistor connected to a first node and coupled to an input of the first inverter.
    Type: Application
    Filed: March 31, 2020
    Publication date: March 4, 2021
    Inventors: Xiong LIU, Chih-Wei YAO
  • Publication number: 20210067166
    Abstract: A system, method and electronic device are provided. The system includes a shared fractional-N phase-lock loop (PLL), a ring oscillator circuit (OSC), and a multiphase injection pulse generator configured to receive an input signal having a first frequency from the shared fraction-N PLL and generate injection pulses for the OSC based on the input signal.
    Type: Application
    Filed: April 3, 2020
    Publication date: March 4, 2021
    Inventors: Xiong LIU, Chih-Wei YAO
  • Patent number: 10917078
    Abstract: A system and method for fast converging reference clock duty cycle correction for a digital to time converter (DTC) based analog fractional-N phase-locked loop (PLL) are herein disclosed. According to one embodiment, an electronic circuit includes a clock doubler, a comparator that outputs a value representing a difference between a voltage at a voltage-to-current (Gm) circuit and a reference voltage that is adjusted to compensate for an offset of the comparator, and a duty cycle calibration circuit that receives the value output from the comparator and adjusts a duty cycle of the PLL by extracting an error from the value output from the comparator and delaying a clock edge of the duty cycle according to the extracted error.
    Type: Grant
    Filed: February 10, 2020
    Date of Patent: February 9, 2021
    Inventors: Wanghua Wu, Chih-Wei Yao
  • Publication number: 20210028919
    Abstract: An apparatus for providing fast-settling quadrature detection and correction includes: a quadrature correction circuit that receives four quadrature clock signals; a quadrature detector that selects two clock signals among the four quadrature clock signals; and a phase digitizer that generates a digital code indicating a phase difference between the two clock signals. The quadrature correction circuit adjusts a phase between the two clock signals using the digital code.
    Type: Application
    Filed: October 14, 2020
    Publication date: January 28, 2021
    Inventors: Zhiqiang Huang, Hiep Pham, Chih-Wei Yao
  • Publication number: 20200403621
    Abstract: A synchronized I/Q detection circuit is provided. A first subset of input signals and, subsequently, a second subset of input signals are provided by a first multiplexer and received by a first phase detector. Outputs of the first phase detector are receiving, by a first reset and sampling circuit. A second set of input signals are provided by a second multiplexer and received by a second phase detector, from a second multiplexer, while the first multiplexer receives the first and second subsets of input signals. The first subset of input signals has a same phase order as the second set of input signals, and the second subset of input signals has a different phase order than the second set of input signals. Outputs of the second phase detector are received by a second reset and sampling circuit. A comparator outputs a detected phase difference based on the outputs of the first and second reset and sampling circuits.
    Type: Application
    Filed: September 2, 2020
    Publication date: December 24, 2020
    Inventors: Zhiqiang HUANG, Chih-Wei YAO, Hiep PHAM
  • Patent number: 10841072
    Abstract: An apparatus for providing fast-settling quadrature detection and correction includes: a quadrature correction circuit that receives four quadrature clock signals; a quadrature detector that selects two clock signals among the four quadrature clock signals; and a phase digitizer that generates a digital code indicating a phase difference between the two clock signals. The quadrature correction circuit adjusts a phase between the two clock signals using the digital code.
    Type: Grant
    Filed: February 12, 2019
    Date of Patent: November 17, 2020
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Zhiqiang Huang, Hiep Pham, Chih-Wei Yao
  • Publication number: 20200348626
    Abstract: A system and method for fast converging gain calibration for phase lock loops (PLL) are herein disclosed. According to one embodiment, a method includes receiving, with a voltage generation circuit, an input value representing a difference between a sampled voltage and a reference voltage, and adjusting, with the voltage generation circuit, the reference voltage by generating a voltage output based on the difference represented by the input value.
    Type: Application
    Filed: July 22, 2020
    Publication date: November 5, 2020
    Inventors: Chih-Wei YAO, Ronghua NI
  • Publication number: 20200343898
    Abstract: An apparatus and method are provided. The apparatus includes a phase locked loop (PLL) configured to generate a reference signal; a sub-sampling PLL (SS-PLL) connected to the PLL and configured to sub-sample the reference signal; and a first pre-charge circuit connected to the SS-PLL and configured to allow an output voltage of the SS-PLL to transition to an operating voltage to indicate that a difference between two voltage inputs is zero on average.
    Type: Application
    Filed: July 19, 2019
    Publication date: October 29, 2020
    Inventors: Yongrong ZUO, Chih-Wei Yao, Wanghua Wu
  • Patent number: 10812088
    Abstract: A synchronized in-phase/quadrature phase (I/Q) detection circuit and a method of the same are provided. The synchronized I/Q detection circuit includes a first logic circuit; a first filter; a first reset and sampling circuit; a first multiplexer; a second logic circuit; a second filter; a second reset and sampling circuit; a signal generator; and a comparator.
    Type: Grant
    Filed: December 14, 2018
    Date of Patent: October 20, 2020
    Assignee: Samsung Electronics Co., Ltd
    Inventors: Zhiqiang Huang, Chih-Wei Yao, Hiep Pham