Patents by Inventor Weiwei Mao

Weiwei Mao 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: 9325537
    Abstract: In described embodiments, process, voltage, temperature (PVT) compensation in a serializer/deserializer (SerDes) device employs a closed loop adaptation compensation that is incorporated into the SerDes receiver adaptation process. A detection method, where the adapted decision feedback equalizer (DFE) target level (e.g., tap H0) is monitored, employs this DFE target level when implementing a closed loop variable gain amplifier adaptation. The DFE target level in conjunction with the VGA level is used to control the PVT setting to maintain target SerDes data path gain by detecting aPVT corner condition. The detected PVT corner condition is employed to generate a control signal to further adjust the LEQ and DFE data path differential pair gain as required by the PVT condition.
    Type: Grant
    Filed: April 3, 2014
    Date of Patent: April 26, 2016
    Assignee: Avago Technologies General IP (Singapore) Pte. Ltd.
    Inventors: Mohammad S. Mobin, Weiwei Mao, Chintan M. Desai, Freeman Y. Zhong, Ye Liu
  • Publication number: 20150263848
    Abstract: Described embodiments provide for, in a clock and data recovery (CDR) circuit, detection of loss of acquisition and CDR restarting with corrective integral accumulator register seeding and gearshift restarting. In described embodiments, a mechanism is employed to cause faster loss of lock condition if the CDR circuit directed on an incorrect acquisition trajectory, actual loss of CDR lock is then detected, and CDR acquisition is recovered with corrective integral accumulator seeding.
    Type: Application
    Filed: April 21, 2014
    Publication date: September 17, 2015
    Applicant: LSI Corporation
    Inventors: Mohammad S. Mobin, Weiwei Mao, Chintan M. Desai, Ye Liu
  • Publication number: 20150249555
    Abstract: In described embodiments, process, voltage, temperature (PVT) compensation in a serializer/deserializer (SerDes) device employs a closed loop adaptation compensation that is incorporated into the SerDes receiver adaptation process. A detection method, where the adapted decision feedback equalizer (DFE) target level (e.g., tap H0) is monitored, employs this DFE target level when implementing a closed loop variable gain amplifier adaptation. The DFE target level in conjunction with the VGA level is used to control the PVT setting to maintain target SerDes data path gain by detecting aPVT corner condition. The detected PVT corner condition is employed to generate a control signal to further adjust the LEQ and DFE data path differential pair gain as required by the PVT condition.
    Type: Application
    Filed: April 3, 2014
    Publication date: September 3, 2015
    Applicant: LSI Corporation
    Inventors: Mohammad S. Mobin, Weiwei Mao, Chintan M. Desai, Freeman Y. Zhong, Ye Liu
  • Patent number: 8867602
    Abstract: A tap coefficient control circuit and a method for controlling a tap coefficient for a decision feedback equalizer are disclosed. The method includes adjusting a correction voltage applied to the tap coefficient based on a first tap quantization and detecting a decision feedback equalizer tap convergence. After the decision feedback equalizer tap convergence is detected, the method adjusts the correction voltage applied to the tap coefficient based on a second tap quantization, wherein the second tap quantization is different from the first tap quantization.
    Type: Grant
    Filed: August 27, 2013
    Date of Patent: October 21, 2014
    Assignee: LSI Corporation
    Inventors: Mohammad S. Mobin, Weiwei Mao, Ye Liu, Brett D. Hardy, Lane A. Smith
  • Patent number: 8143696
    Abstract: An IC inductor structure is provided which includes a first inductor element formed on a semiconductor substrate and at least a second inductor element formed on the semiconductor substrate proximate the first inductor element. The first inductor element has a first effective magnetic field direction associated therewith, and the second inductor element has a second effective magnetic field direction associated therewith. The first and second inductor elements are oriented relative to one another so as to create a non-zero angle between the first and second effective magnetic field directions.
    Type: Grant
    Filed: March 18, 2009
    Date of Patent: March 27, 2012
    Assignee: Agere Systems Inc.
    Inventors: Weiwei Mao, Shahriar Moinian, Kenneth Wade Paist, William B. Wilson
  • Patent number: 8125259
    Abstract: A method and system for modeling and calibrating duty cycle distortion (DCD) of a Serializer and Deserializer (SerDes) device, including first generating a clock DCD signal. Once the clock DCD signal is generated, it is calibrating based upon results obtained from a filtering process of the clock DCD signal. Once the clock DCD signal is calibrated, a data DCD signal is generated and calibrated based upon results obtained from a filtering process of the data DCD signal.
    Type: Grant
    Filed: January 3, 2008
    Date of Patent: February 28, 2012
    Assignee: Agere Systems Inc.
    Inventors: Xingdong Dai, Weiwei Mao, Max J. Olsen, Geoffrey Zhang
  • Patent number: 8044688
    Abstract: Various embodiments of the present invention provide systems and circuits that provide for out of band detection. As one example, an out of band detection circuit is disclosed that includes an input signal, a clock generation circuit, and a sampling circuit. The clock generation circuit receives the input signal and derives therefrom a sampling clock, and the sampling circuit is operable to sample the input signal at a time indicated by the sampling clock.
    Type: Grant
    Filed: February 28, 2008
    Date of Patent: October 25, 2011
    Assignee: Agere Systems Inc.
    Inventors: Mingdeng Chen, Ari Valero-Lopez, Weiwei Mao
  • Publication number: 20100314713
    Abstract: An IC inductor structure is provided which includes a first inductor element formed on a semiconductor substrate and at least a second inductor element formed on the semiconductor substrate proximate the first inductor element. The first inductor element has a first effective magnetic field direction associated therewith, and the second inductor element has a second effective magnetic field direction associated therewith. The first and second inductor elements are oriented relative to one another so as to create a non-zero angle between the first and second effective magnetic field directions.
    Type: Application
    Filed: March 18, 2009
    Publication date: December 16, 2010
    Inventors: Weiwei Mao, Shahriar Moinian, Kenneth Wade Paist, William B. Wilson
  • Patent number: 7777538
    Abstract: Methods and apparatus are provided for controlling at least one of a rise time and a fall time of a signal. A plurality of time shifted clock signals are generated; and a received data signal is sampled using a plurality of parallel data paths, where each of the data paths are controlled by a corresponding one of the plurality of time shifted clock signals. The plurality of time shifted clock signals can be generated, for example, by at least one delay element. The plurality of parallel data paths can be substantially identical and comprise, for example, at least one latch or at least one flip flop. Compensation can optionally be provided for variations in, for example, process corner, supply voltage, aging and operating temperature.
    Type: Grant
    Filed: March 3, 2006
    Date of Patent: August 17, 2010
    Assignee: Agere Systems Inc.
    Inventors: Christopher J. Abel, Weiwei Mao
  • Publication number: 20090219057
    Abstract: Various embodiments of the present invention provide systems and circuits that provide for out of band detection. As one example, an out of band detection circuit is disclosed that includes an input signal, a clock generation circuit, and a sampling circuit. The clock generation circuit receives the input signal and derives therefrom a sampling clock, and the sampling circuit is operable to sample the input signal at a time indicated by the sampling clock.
    Type: Application
    Filed: February 28, 2008
    Publication date: September 3, 2009
    Inventors: Mingdeng Chen, Ari Valero-Lopez, Weiwei Mao
  • Publication number: 20090177457
    Abstract: A method and system for modeling and calibrating duty cycle distortion (DCD) of a Serializer and Deserializer (SerDes) device, including first generating a clock DCD signal. Once the clock DCD signal is generated, it is calibrating based upon results obtained from a filtering process of the clock DCD signal. Once the clock DCD signal is calibrated, a data DCD signal is generated and calibrated based upon results obtained from a filtering process of the data DCD signal.
    Type: Application
    Filed: January 3, 2008
    Publication date: July 9, 2009
    Applicant: Agere Systems Inc.
    Inventors: Xingdong Dai, Weiwei Mao, Max J. Olsen, Geoffrey Zhang
  • Patent number: 7432746
    Abstract: A buffer for interfacing complementary input signals having first logical voltage levels to a circuit operating with second logical voltage levels includes first and second branches outputting first and second complementary output signals, respectively. Each branch includes a PMOS and an NMOS transistor connected in series with a voltage-swing adjusting transistor between a first supply voltage and a second supply voltage. Control terminals of the PMOS and NMOS transistors each receive one of the complementary input signals, and a control terminal of the first voltage-swing adjusting transistor receives a first bias voltage. When the complementary input signal has a first voltage level, the voltage-swing adjusting transistor operates in a linear region and when the first complementary input signal has a second voltage level, current through the voltage-swing adjusting transistor is shut-off. No current flows in either branch when the buffer is in a static state.
    Type: Grant
    Filed: July 31, 2006
    Date of Patent: October 7, 2008
    Assignee: Agere Systems, Inc.
    Inventor: Weiwei Mao
  • Publication number: 20080024177
    Abstract: A buffer for interfacing complementary input signals having first logical voltage levels to a circuit operating with second logical voltage levels includes first and second branches outputting first and second complementary output signals, respectively. Each branch includes a PMOS and an NMOS transistor connected in series with a voltage-swing adjusting transistor between a first supply voltage and a second supply voltage. Control terminals of the PMOS and NMOS transistors each receive one of the complementary input signals, and a control terminal of the first voltage-swing adjusting transistor receives a first bias voltage. When the complementary input signal has a first voltage level, the voltage-swing adjusting transistor operates in a linear region and when the first complementary input signal has a second voltage level, current through the voltage-swing adjusting transistor is shut-off. No current flows in either branch when the buffer is in a static state.
    Type: Application
    Filed: July 31, 2006
    Publication date: January 31, 2008
    Inventor: Weiwei Mao
  • Publication number: 20070210832
    Abstract: Methods and apparatus are provided for controlling at least one of a rise time and a fall time of a signal. A plurality of time shifted clock signals are generated; and a received data signal is sampled using a plurality of parallel data paths, where each of the data paths are controlled by a corresponding one of the plurality of time shifted clock signals. The plurality of time shifted clock signals can be generated, for example, by at least one delay element. The plurality of parallel data paths can be substantially identical and comprise, for example, at least one latch or at least one flip flop. Compensation can optionally be provided for variations in, for example, process corner, supply voltage, aging and operating temperature.
    Type: Application
    Filed: March 3, 2006
    Publication date: September 13, 2007
    Inventors: Christopher Abel, Weiwei Mao
  • Patent number: 5659257
    Abstract: A structure for measuring and testing discrete components interconnected with one or more integrated circuits on a mixed-signal circuit board. Each integrated circuit includes a test cell comprising a plurality of switches connected with a single on-chip bus which is in turn connected with a single circuit board bus. The structure permits a constant current to be supplied to the components over the single bus and voltage measurements to be made to determine the component values with a lower overhead in pins and board area.
    Type: Grant
    Filed: July 5, 1994
    Date of Patent: August 19, 1997
    Assignee: Ford Motor Company
    Inventors: Yunsheng Lu, Weiwei Mao