Patents by Inventor Yongxuan Hu

Yongxuan Hu 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: 20150069957
    Abstract: During operation, the DC converter and a DC battery charger controller in a charger circuit transitions from a first error signal to a second error signal for use in charging a battery, wherein the first error signal and the second error signal, respectively, correspond to feedback sources in a plurality of feedback sources with a plurality of feedback sources. Then, the DC converter and a DC battery charger controller selects a gain and an impedance to ground of a damping circuit based on the selected second error signal, where the damping circuit applies the gain and the impedance to ground to the second error signal. Moreover, the DC converter and a DC battery charger controller selects one or more clamping voltages of a voltage-clamping circuit based on the selected second error signal, where the voltage-clamping circuit applies the one or more clamping voltages to an output from the damping circuit.
    Type: Application
    Filed: September 9, 2014
    Publication date: March 12, 2015
    Inventors: Arthur H. Chang, Yongxuan Hu, Shimon Elkayam
  • Publication number: 20150069956
    Abstract: A charger circuit includes an interface connector that may be coupled to a power adapter that provides an input signal having an input voltage, and a buck-boost converter circuit that may be coupled to a battery having a charging voltage. At a given time, the buck-boost converter circuit operates in a mode in a group of modes based on a control signal, where the group of modes may include at least a buck mode and a boost mode. In particular, the charger circuit includes control logic that generates the control signal based on the charging voltage and a charging capability of the power adapter. Thus, if the charging voltage suitably exceeds the input voltage, the buck-boost converter circuit may operate in the boost mode. However, if the charging voltage is approximately less than or equal to the input voltage, the buck-boost converter circuit may operate in the buck mode.
    Type: Application
    Filed: September 9, 2014
    Publication date: March 12, 2015
    Inventors: Yongxuan Hu, Shimon Elkayam, Collin E. Connors, Liyu Yang
  • Publication number: 20150069958
    Abstract: A charging circuit includes an interface connector that may be coupled to a power adapter that provides an input voltage, and a buck-boost charging circuit that receives the input voltage and may be coupled to and may provide an output signal to a battery having a charging voltage. For a given input voltage and a given charging voltage, the buck-boost charging circuit operates in one of a group of modes based on a control signal, where the group of modes comprises: a buck mode, a boost mode and a buck-boost mode. In particular, the charging circuit includes control logic that generates the control signal based on the charging voltage and the input voltage. Thus, the buck-boost charging circuit may operate over a continuous range of input voltages and charging voltages.
    Type: Application
    Filed: September 9, 2014
    Publication date: March 12, 2015
    Inventors: Liyu Yang, Yongxuan Hu, Shimon Elkayam
  • Publication number: 20140268900
    Abstract: A switched-mode power supply with reduced electromagnetic interference (EMI) is described. This switched-mode power supply includes a modulation circuit that continuously frequency modulates a control signal over a bandwidth associated with a spread-spectrum modulation signal. By frequency modulating the control signal in the switched-mode power supply, spectral content associated with a modulated switching signal is spread evenly over the bandwidth, thereby reducing the EMI.
    Type: Application
    Filed: April 1, 2013
    Publication date: September 18, 2014
    Applicant: Apple Inc.
    Inventors: Yongxuan Hu, Keong W. Kam, Shimon Elkayam, Susan R. Schen
  • Publication number: 20140253051
    Abstract: A system and method are described for charging a battery in a portable electronic device wherein the battery is charged using a constant-current, constant-voltage charging process. In described embodiments, a resistance is received for a current loop that includes a charger and the battery. Then, during a constant-current charging phase, a constant current is output from the charger until an output voltage of the charger reaches a target voltage. The target voltage includes a battery target voltage and a compensation voltage based on the received resistance and a charging current. When the output voltage of the charger reaches the target voltage, the charger switches from the constant-current phase to a constant-voltage phase. Then during the constant-voltage phase, the charger outputs the target voltage until the charging current drops below a minimum value at which time the charging process is complete.
    Type: Application
    Filed: March 13, 2013
    Publication date: September 11, 2014
    Applicant: APPLE INC.
    Inventors: Yongxuan Hu, Mao Ye, Shimon Elkayam
  • Publication number: 20140217959
    Abstract: The disclosed embodiments provide a synchronous switching converter that converts a DC input voltage into a DC output voltage. This synchronous switching converter includes a high-side switching MOSFET coupled between an input node and a first node. The converter also includes a low-side switching MOSFET coupled between the first node and a ground node and is in series with the high-side switching MOSFET. This converter additionally includes a bootstrap capacitor coupled to the high-side switching MOSFET to provide turn-on voltage for the high-side switching MOSFET. Furthermore, the converter includes a main refresh circuit coupled to the bootstrap capacitor and is configured to refresh the bootstrap capacitor during a first operating mode of the synchronous switching converter. Moreover, the converter includes an auxiliary refresh circuit coupled to the main refresh circuit and the bootstrap capacitor and is configured to refresh the bootstrap capacitor during a second operating mode of the converter.
    Type: Application
    Filed: March 13, 2013
    Publication date: August 7, 2014
    Applicant: APPLE INC.
    Inventors: Bin Chen, Mao Ye, Yongxuan Hu
  • Publication number: 20140203780
    Abstract: Methods and systems are presented for charging and/or discharging multiple parallel-connected battery packs in portable electronic devices, in which a charging or discharging current of a second battery pack is regulated based at least in part on a charging or discharging current of a first battery pack.
    Type: Application
    Filed: January 24, 2013
    Publication date: July 24, 2014
    Applicant: TEXAS INSTRUMENTS INCORPORATED
    Inventors: Yongxuan Hu, Christopher Lee Betty, J. Randall Cooper
  • Publication number: 20140049238
    Abstract: Methods and apparatus are presented for sensing current flowing in a power transistor of a switch mode converter, in which a voltage is sensed across a first field effect transistor connected in a series circuit branch in parallel with the power transistor, and the sensed voltage is used to generate output signal to indicate the current flowing in the power transistor.
    Type: Application
    Filed: January 30, 2013
    Publication date: February 20, 2014
    Applicant: TEXAS INSTRUMENTS INCORPORATED
    Inventors: Yongxuan Hu, Mohammad Rashedul Hoque