Patents by Inventor Xujun Liu

Xujun Liu 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: 8908393
    Abstract: An embodiment apparatus comprises a secondary synchronous rectifier and a secondary gate drive controller. The secondary gate drive controller coupled to a transformer winding comprises a secondary synchronous rectifier soft start signal generator configured to generate a plurality of soft start pulses, a pulse width modulation generator configured to generate a forward switch drive signal and a freewheeling switch drive signal based upon a signal across the transformer winding and a soft transition generator configured to generate a soft start freewheeling switch drive signal by gradually releasing the freewheeling switch drive signal during a soft start process.
    Type: Grant
    Filed: October 24, 2011
    Date of Patent: December 9, 2014
    Assignee: Futurewei Technologies, Inc.
    Inventors: Liming Ye, Hengchun Mao, Xujun Liu
  • Publication number: 20140203666
    Abstract: A method and an apparatus for driving a power switch tube. The apparatus includes an input unit, a drive unit, a transformer and a power switch tube. The input unit is connected to the drive unit, which is configured to input a group of drive signals, and the group of drive signals includes four drive signals, where the first drive signal and the second are complementary signals, and a dead time exists; the third drive signal and the fourth are complementary signals, and a dead time exists; the phase difference between the first drive signal and the third is 180 degrees, and the phase difference between the second drive signal and the fourth is 180 degrees; the drive unit is configured to power on a field winding of the transformer; and the transformer provides a drive voltage signal for the power switch tube.
    Type: Application
    Filed: March 25, 2014
    Publication date: July 24, 2014
    Applicant: Huawei Technologies Co., Ltd.
    Inventor: Xujun Liu
  • Patent number: 8744382
    Abstract: A fast tracking power supply device, a fast tracking power supply control method, and communication equipment are provided. The fast tracking power supply device includes: a basic voltage output unit, configured to output a basic voltage; a basic current unit, configured to output a basic current; a linear amplifier, configured to output a compensation current and a compensation voltage, the linear amplifier is connected in parallel with the basic current output unit, and then is connected in series with the basic voltage output unit. The device can output signal with high efficiency and bandwidth.
    Type: Grant
    Filed: December 29, 2010
    Date of Patent: June 3, 2014
    Assignee: Huawei Technologies Co., Ltd.
    Inventors: Zhaozheng Hou, Xujun Liu
  • Patent number: 8564984
    Abstract: A soft switching apparatus comprises an energy recovery channel formed by two diodes in series connection and a resonant tank formed by an inductor and a capacitor. The soft switching apparatus is coupled to the primary side of a bridge converter. An energy transfer process during L-C resonance helps to reduce the amplitude of the current flowing through the inductor in a freewheeling period. Furthermore, the soft switching apparatus can help to reduce the voltage stress across the secondary switching devices as well as the shoot-through currents flowing through the secondary switching devices, and thus enabling the reduction or elimination of dead time in a secondary synchronous rectifier control scheme.
    Type: Grant
    Filed: December 10, 2010
    Date of Patent: October 22, 2013
    Assignee: Futurewei Technologies, Inc.
    Inventors: Hengchun Mao, Dianbo Fu, Zhaozheng Hou, Xujun Liu, Bing Cai
  • Publication number: 20130063185
    Abstract: An embodiment apparatus comprises a first two-piecewise linear approximation generator and a second two-piecewise linear approximation generator coupled to an output of the first two-piece wise linear approximation generator. The second two-piecewise linear approximation generator generates a dead time inversely proportional to the output of the first two-piece wise linear approximation generator. A gate drive generator is configured to generate a primary switch drive signal and an auxiliary switch drive signal complementary to the primary switch drive signal. In addition, the dead time between the primary switch drive signal and the auxiliary switch drive signal is adjustable when the power converter operates in a light load condition.
    Type: Application
    Filed: September 13, 2012
    Publication date: March 14, 2013
    Applicant: FUTUREWEI TECHNOLOGIES, INC.
    Inventors: Liming Ye, Xujun Liu
  • Patent number: 8253487
    Abstract: A tracking power supply, a method for controlling a power supply, and a communication apparatus are disclosed. The tracking power supply includes: a basic voltage output unit, configured to provide a basic voltage; and a compensation voltage output unit, configured to provide a compensation voltage. The compensation voltage output unit and the basic voltage output unit are connected in series so as to provide a voltage which is the sum of the basic voltage and the compensation voltage for a load.
    Type: Grant
    Filed: December 30, 2010
    Date of Patent: August 28, 2012
    Assignee: Huawei Technologies Co., Ltd.
    Inventors: Zhaozheng Hou, Xujun Liu
  • Publication number: 20120147629
    Abstract: A soft switching apparatus comprises an energy recovery channel formed by two diodes in series connection and a resonant tank formed by an inductor and a capacitor. The soft switching apparatus is coupled to the primary side of a bridge converter. An energy transfer process during L-C resonance helps to reduce the amplitude of the current flowing through the inductor in a freewheeling period. Furthermore, the soft switching apparatus can help to reduce the voltage stress across the secondary switching devices as well as the shoot-through currents flowing through the secondary switching devices, and thus enabling the reduction or elimination of dead time in a secondary synchronous rectifier control scheme.
    Type: Application
    Filed: December 10, 2010
    Publication date: June 14, 2012
    Applicant: FutureWei Technologies, Inc.
    Inventors: Hengchun Mao, Dianbo Fu, Zhaozheng Hou, Xujun Liu, Bing Cai
  • Publication number: 20120032509
    Abstract: A voltage transforming device is provided, which includes: a first voltage transforming module, configured to perform a pre-stage voltage transformation on an input DC voltage to output an isolated DC voltage, in which the pre-stage voltage transformation includes a primary transformation that converts the input DC voltage to a to-be-transformed AC voltage, a working period of the primary transformation includes a first half period and a second half period, and a dead time exists when a first half period and a second half period are switched between each other; a capacitor filtering module, configured to perform capacitor filtering compensation on the isolated DC voltage in the dead time to output a stable intermediate DC voltage; and a second voltage transforming module, configured to perform at least two separate post-stage voltage transformations on the intermediate DC voltage to output DC voltages required by at least two loads.
    Type: Application
    Filed: October 13, 2011
    Publication date: February 9, 2012
    Applicant: Huawei Technologies Co., Ltd.
    Inventors: Xiaodong Fan, Xiaming Jing, Zhihua Liu, Xujun Liu
  • Publication number: 20110241424
    Abstract: A voltage transforming device is provided, which includes: a first voltage transforming module, configured to perform a pre-stage voltage transformation on an input DC voltage to output an isolated DC voltage, in which the pre-stage voltage transformation includes a primary transformation that converts the input DC voltage to a to-be-transformed AC voltage; a capacitor filtering module, configured to perform capacitor filtering compensation on the isolated DC voltage in the dead time to output a stable intermediate DC voltage; and a second voltage transforming module, configured to perform at least two separate post-stage voltage transformations on the intermediate DC voltage to output DC voltages required by at least two loads. A voltage transforming method and a power supply system are also provided. Thereby, the decoupling of the pre-stage and post-stage working modes is achieved, and the interference suffered during voltage transformation is reduced.
    Type: Application
    Filed: December 28, 2010
    Publication date: October 6, 2011
    Inventors: Xiaodong Fan, Xiaming Jing, Zhihua Liu, Xujun Liu
  • Patent number: 8027175
    Abstract: A power supply adjusting apparatus includes a primary isolation converting unit, adapted to convert voltage or current of an input power supply signal and output a power supply signal that meets an expected voltage or current requirement. The power supply adjusting apparatus also includes a voltage adjustment controlling unit, adapted to output an adjustment control signal with respect to the output voltage according to an expected output voltage and a tracked signal provided by a powered apparatus. Further, the power supply adjusting apparatus includes a secondary non-isolation adjusting and converting unit, adapted to convert the power supply signal outputted by the primary isolation converting unit to an expected voltage according to the adjustment control signal outputted by the voltage adjustment controlling unit and output the adjusted power supply signal.
    Type: Grant
    Filed: January 19, 2010
    Date of Patent: September 27, 2011
    Assignee: Huawei Technologies Co., Ltd.
    Inventors: Zhihua Liu, Xujun Liu
  • Publication number: 20110193629
    Abstract: A tracking power supply, a method for controlling a power supply, and a communication apparatus are disclosed. The tracking power supply includes: a basic voltage output unit, configured to provide a basic voltage; and a compensation voltage output unit, configured to provide a compensation voltage. The compensation voltage output unit and the basic voltage output unit are connected in series so as to provide a voltage which is the sum of the basic voltage and the compensation voltage for a load.
    Type: Application
    Filed: December 30, 2010
    Publication date: August 11, 2011
    Inventors: Zhaozheng Hou, Xujun LIU
  • Publication number: 20110191606
    Abstract: A fast tracking power supply device, a fast tracking power supply control method, and communication equipment are provided. The fast tracking power supply device includes: a basic voltage output unit, configured to output a basic voltage; a basic current unit, configured to output a basic current; a linear amplifier, configured to output a compensation current and a compensation voltage, the linear amplifier is connected in parallel with the basic current output unit, and then is connected in series with the basic voltage output unit. The device can output signal with high efficiency and bandwidth.
    Type: Application
    Filed: December 29, 2010
    Publication date: August 4, 2011
    Inventors: Zhaozheng HOU, Xujun Liu
  • Publication number: 20100118567
    Abstract: A power supply adjusting apparatus includes a primary isolation converting unit, adapted to convert voltage or current of an input power supply signal and output a power supply signal that meets an expected voltage or current requirement. The power supply adjusting apparatus also includes a voltage adjustment controlling unit, adapted to output an adjustment control signal with respect to the output voltage according to an expected output voltage and a tracked signal provided by a powered apparatus. Further, the power supply adjusting apparatus includes a secondary non-isolation adjusting and converting unit, adapted to convert the power supply signal outputted by the primary isolation converting unit to an expected voltage according to the adjustment control signal outputted by the voltage adjustment controlling unit and output the adjusted power supply signal.
    Type: Application
    Filed: January 19, 2010
    Publication date: May 13, 2010
    Inventors: Zhihua Liu, Xujun Liu