Patents by Inventor Lizhi Zhong

Lizhi Zhong 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: 11902059
    Abstract: A receiver circuit including mechanisms for analog channel equalization and channel adaptation is disclosed. The receiver includes a front-end circuit configured to generate a filtered signal by performing filtering of an incoming signal that includes a stream of data symbols. A sample recovery circuit configured to sample an equalized signal, based on the filtered signal, to generate a plurality of recovered data symbols. A decision feedback equalization (DFE) circuit configured to generate the feedback signal based on the plurality of recovered data symbols. A logic circuit is configured to cause adjustment to one or more filters in the front-end circuit based on the plurality of recovered data symbols.
    Type: Grant
    Filed: May 27, 2022
    Date of Patent: February 13, 2024
    Assignee: Apple Inc.
    Inventors: Lizhi Zhong, Vishal Varma, Yu Chen, Wenyi Jin
  • Publication number: 20230388162
    Abstract: A receiver circuit including mechanisms for analog channel equalization and channel adaptation is disclosed. The receiver includes a front-end circuit configured to generate a filtered signal by performing filtering of an incoming signal that includes a stream of data symbols. A sample recovery circuit configured to sample an equalized signal, based on the filtered signal, to generate a plurality of recovered data symbols. A decision feedback equalization (DFE) circuit configured to generate the feedback signal based on the plurality of recovered data symbols. A logic circuit is configured to cause adjustment to one or more filters in the front-end circuit based on the plurality of recovered data symbols.
    Type: Application
    Filed: May 27, 2022
    Publication date: November 30, 2023
    Inventors: Lizhi Zhong, Vishal Varma, Yu Chen, Wenyi Jin
  • Patent number: 11664809
    Abstract: An apparatus includes a receiver buffer, a phase compensation circuit, a data sampler circuit, and an error sampler circuit. The receiver buffer may generate an equalized signal on a signal node using an input signal received via a channel. The phase compensation circuit may, in response to an initiation of a training mode, replace the equalized signal on the signal node with a reference signal. The data sampler circuit may sample, using a data clock signal, the reference signal to generate a plurality of data samples. The error sampler circuit may sample, using an error clock signal, the reference signal to generate a plurality of errors samples. The phase compensation circuit may also adjust a phase difference between the data clock signal and the error clock signal using at least some of the plurality of data samples and at least some of the plurality of error samples.
    Type: Grant
    Filed: April 5, 2021
    Date of Patent: May 30, 2023
    Assignee: Apple Inc.
    Inventors: Jaeduk Han, Wenbo Liu, Wing Liu, Ming-Shuan Chen, Sanjeev K. Maheshwari, Vishal Varma, Sunil Bhosekar, Lizhi Zhong, Gary A. Rogan
  • Publication number: 20210226639
    Abstract: An apparatus includes a receiver buffer, a phase compensation circuit, a data sampler circuit, and an error sampler circuit. The receiver buffer may generate an equalized signal on a signal node using an input signal received via a channel. The phase compensation circuit may, in response to an initiation of a training mode, replace the equalized signal on the signal node with a reference signal. The data sampler circuit may sample, using a data clock signal, the reference signal to generate a plurality of data samples. The error sampler circuit may sample, using an error clock signal, the reference signal to generate a plurality of errors samples. The phase compensation circuit may also adjust a phase difference between the data clock signal and the error clock signal using at least some of the plurality of data samples and at least some of the plurality of error samples.
    Type: Application
    Filed: April 5, 2021
    Publication date: July 22, 2021
    Inventors: Jaeduk Han, Wenbo Liu, Wing Liu, Ming-Shuan Chen, Sanjeev K. Maheshwari, Vishal Varma, Sunil Bhosekar, Lizhi Zhong, Gary A. Rogan
  • Patent number: 10972107
    Abstract: An apparatus includes a receiver buffer, a phase compensation circuit, a data sampler circuit, and an error sampler circuit. The receiver buffer may generate an equalized signal on a signal node using an input signal received via a channel. The phase compensation circuit may, in response to an initiation of a training mode, replace the equalized signal on the signal node with a reference signal. The data sampler circuit may sample, using a data clock signal, the reference signal to generate a plurality of data samples. The error sampler circuit may sample, using an error clock signal, the reference signal to generate a plurality of errors samples. The phase compensation circuit may also adjust a phase difference between the data clock signal and the error clock signal using at least some of the plurality of data samples and at least some of the plurality of error samples.
    Type: Grant
    Filed: July 31, 2019
    Date of Patent: April 6, 2021
    Assignee: Apple Inc.
    Inventors: Jaeduk Han, Wenbo Liu, Wing Liu, Ming-Shuan Chen, Sanjeev K. Maheshwari, Vishal Varma, Sunil Bhosekar, Lizhi Zhong, Gary A. Rogan
  • Publication number: 20210036707
    Abstract: An apparatus includes a receiver buffer, a phase compensation circuit, a data sampler circuit, and an error sampler circuit. The receiver buffer may generate an equalized signal on a signal node using an input signal received via a channel. The phase compensation circuit may, in response to an initiation of a training mode, replace the equalized signal on the signal node with a reference signal. The data sampler circuit may sample, using a data clock signal, the reference signal to generate a plurality of data samples. The error sampler circuit may sample, using an error clock signal, the reference signal to generate a plurality of errors samples. The phase compensation circuit may also adjust a phase difference between the data clock signal and the error clock signal using at least some of the plurality of data samples and at least some of the plurality of error samples.
    Type: Application
    Filed: July 31, 2019
    Publication date: February 4, 2021
    Inventors: Jaeduk Han, Wenbo Liu, Wing Liu, Ming-Shuan Chen, Sanjeev K. Maheshwari, Vishal Varma, Sunil Bhosekar, Lizhi Zhong, Gary A. Rogan
  • Patent number: 10721105
    Abstract: A method and apparatus for adapting, in parallel, two operating parameters associated with an equalizer circuit is disclosed. A control circuit may be configured to initialize a first operating parameter to an initial value, and modify a second operating parameter based upon the initial value of the first parameter. In response to determining a peak amplitude of an output signal of the equalizer circuit is less than a threshold value, the control circuit may be further configured to select a new value for the first operating parameter and adapt, in response to the change in the first operating parameter, the second operating parameter based on a performance metric of the equalizer circuit.
    Type: Grant
    Filed: January 7, 2019
    Date of Patent: July 21, 2020
    Assignee: Apple Inc.
    Inventor: Lizhi Zhong
  • Publication number: 20190140869
    Abstract: A method and apparatus for adapting, in parallel, two operating parameters associated with an equalizer circuit is disclosed. A control circuit may be configured to initialize a first operating parameter to an initial value, and modify a second operating parameter based upon the initial value of the first parameter. In response to determining a peak amplitude of an output signal of the equalizer circuit is less than a threshold value, the control circuit may be further configured to select a new value for the first operating parameter and adapt, in response to the change in the first operating parameter, the second operating parameter based on a performance metric of the equalizer circuit.
    Type: Application
    Filed: January 7, 2019
    Publication date: May 9, 2019
    Inventor: Lizhi Zhong
  • Patent number: 10177945
    Abstract: A method and apparatus for adapting, in parallel, two operating parameters associated with an equalizer circuit is disclosed. A control circuit may be configured to initialize a first operating parameter to an initial value, and modify a second operating parameter based upon the initial value of the first parameter. In response to determining a peak amplitude of an output signal of the equalizer circuit is less than a threshold value, the control circuit may be further configured to select a new value for the first operating parameter and adapt, in response to the change in the first operating parameter, the second operating parameter based on a performance metric of the equalizer circuit.
    Type: Grant
    Filed: July 26, 2017
    Date of Patent: January 8, 2019
    Assignee: Apple Inc.
    Inventor: Lizhi Zhong
  • Patent number: 9787509
    Abstract: An apparatus including a receiver coupled to receive an input signal from a communication link and operable to employ decision feedback equalization to the input signal of the communication link and generate an edge sample signal. The apparatus also includes a timing recovery module coupled to the receiver and operable to receive the edge sample signal and use the edge sample signal to generate a data sampling phase signal, wherein the edge sample signal influences a settling point of the data sampling phase signal.
    Type: Grant
    Filed: January 5, 2016
    Date of Patent: October 10, 2017
    Assignee: Nvidia Corporation
    Inventors: Lizhi Zhong, Vishnu Balan, Arif Al Amin, Sanjeev Maheshwari
  • Patent number: 9762381
    Abstract: A method comprises receiving an input signal at an input of a receiver and retrieving a data sample signal and an error sample signal from the input signal. The method also comprises applying an adaptive procedure to generate a feedback code using the data sample signal and the error sample signal for feeding back into a decision feedback equalization (DFE) module. Further, it comprises converting the feedback code into a corresponding voltage value and assigning the corresponding voltage value as a tap weight for the DFE module. Finally, it comprises generating an edge sample signal by applying DFE to the input signal using the DFE module, wherein the DFE is based on the tap weight.
    Type: Grant
    Filed: July 3, 2013
    Date of Patent: September 12, 2017
    Assignee: NVIDIA CORPORATION
    Inventors: Lizhi Zhong, Vishnu Balan, Gautam Bhatia
  • Publication number: 20160226684
    Abstract: An apparatus including a receiver coupled to receive an input signal from a communication link and operable to employ decision feedback equalization to the input signal of the communication link and generate an edge sample signal. The apparatus also includes a timing recovery module coupled to the receiver and operable to receive the edge sample signal and use the edge sample signal to generate a data sampling phase signal, wherein the edge sample signal influences a settling point of the data sampling phase signal.
    Type: Application
    Filed: January 5, 2016
    Publication date: August 4, 2016
    Inventors: Lizhi Zhong, Vishnu Balan, Arif Al Amin, Sanjeev Maheshwari
  • Patent number: 9246452
    Abstract: An apparatus having a circuit is disclosed. The circuit may be configured to (i) receive an input signal from a communication channel and (ii) generate an intermediate signal by amplifying the input signal (a) by a low-frequency gain in response to an amplitude control signal and (b) by a high-frequency gain in response to a boost control signal.
    Type: Grant
    Filed: February 28, 2013
    Date of Patent: January 26, 2016
    Assignee: Avago Technologies General IP (Singapore) Pte. Ltd.
    Inventors: Lizhi Zhong, Freeman Y. Zhong, Hiroshi Kimura, Eric W. Zhang
  • Patent number: 9231802
    Abstract: An apparatus including a receiver coupled to receive an input signal from a communication link and operable to employ decision feedback equalization to the input signal of the communication link and generate an edge sample signal. The apparatus also includes a timing recovery module coupled to the receiver and operable to receive the edge sample signal and use the edge sample signal to generate a data sampling phase signal, wherein the edge sample signal influences a settling point of the data sampling phase signal.
    Type: Grant
    Filed: December 26, 2012
    Date of Patent: January 5, 2016
    Assignee: NVIDIA CORPORATION
    Inventors: Lizhi Zhong, Vishnu Balan, Arif Al Amin, Sanjeev Maheshwari
  • Patent number: 9166774
    Abstract: An apparatus including a bang-bang clock data recovery module and a decision feedback equalizer. A phase detector of the bang-bang clock and data recovery module may be configured to eliminate coupling between the bang-bang clock and data recovery module and the decision feedback equalizer based upon an error signal of the decision feedback equalizer and a predetermined coefficient.
    Type: Grant
    Filed: December 21, 2010
    Date of Patent: October 20, 2015
    Assignee: Avago Technologies General IP (Singapore) Pte. Ltd.
    Inventor: Lizhi Zhong
  • Patent number: 8964827
    Abstract: An apparatus includes an error sample generating circuit and an adaptation circuit. The error sample generating circuit is generally configured to generate error samples at a plurality of phases. The adaptation circuit may be configured to adjust one or more equalizer settings based upon a data sample and the error samples.
    Type: Grant
    Filed: March 11, 2013
    Date of Patent: February 24, 2015
    Assignee: Avago Technologies General IP (Singapore) Pte. Ltd.
    Inventor: Lizhi Zhong
  • Publication number: 20150010047
    Abstract: A method comprises receiving an input signal at an input of a receiver and retrieving a data sample signal and an error sample signal from the input signal. The method also comprises applying an adaptive procedure to generate a feedback code using the data sample signal and the error sample signal for feeding back into a decision feedback equalization (DFE) module. Further, it comprises converting the feedback code into a corresponding voltage value and assigning the corresponding voltage value as a tap weight for the DFE module. Finally, it comprises generating an edge sample signal by applying DFE to the input signal using the DFE module, wherein the DFE is based on the tap weight.
    Type: Application
    Filed: July 3, 2013
    Publication date: January 8, 2015
    Inventors: Lizhi ZHONG, Vishnu BALAN, Gautam BHATIA
  • Patent number: 8891607
    Abstract: An apparatus including a receiver having a feed forward equalizer (FFE) coupled to a communication channel. The receiver may be configured to adjust the FFE using information based on an estimate of one or more characteristics of the communication channel.
    Type: Grant
    Filed: September 6, 2012
    Date of Patent: November 18, 2014
    Assignee: Avago Technologies General IP (Singapore) Pte. Ltd.
    Inventor: Lizhi Zhong
  • Publication number: 20140314138
    Abstract: A method comprises adapting a first tap weight of an equalizer, wherein a second tap weight of the equalizer is based at least in part on the first tap weight. Adapting the first tap weight further comprises computing a gradient from a data signal, an error signal and a channel pulse response sample. Adapting the first tap weight also comprises filtering the gradient with a loop filter and sending information to a transmitter via a back channel. Adapting the first tap weight further comprises configuring the first tap weight based on the information.
    Type: Application
    Filed: April 22, 2013
    Publication date: October 23, 2014
    Applicant: NVIDIA CORPORATION
    Inventors: Lizhi ZHONG, Vishnu BALAN, Ratnakar DADI, Gautam BHATIA
  • Patent number: 8867604
    Abstract: An apparatus comprising an inter symbol interference (ISI) cancellation circuit and a detector circuit. The inter symbol interference (ISI) cancellation circuit may be configured to minimize ISI at data sampling and crossing sampling points in a symbol interval of an input signal. The detector circuit may be configured to generate data samples and crossing samples at the data sampling and crossing sampling points in the symbol interval of the input signal.
    Type: Grant
    Filed: November 8, 2013
    Date of Patent: October 21, 2014
    Assignee: Avago Technologies General IP (Singapore) Pte. Ltd.
    Inventor: Lizhi Zhong