Patents by Inventor Shwu-Liang Hsieh

Shwu-Liang Hsieh 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: 6876190
    Abstract: A current sense apparatus and method comprises a common drain DMOSFET and a MOSFET connected in series between a high voltage and a low voltage to serve as an output stage. The DMOSFET produces a phase output current, a mirror current mirrored from the phase output current, and a sense voltage. A servo amplifier is connected with the mirror current and sense voltage to produce a current sense signal. Due to the mirror current from the DMOSFET proportional to the phase output current, the current sense apparatus senses the phase output current in a temperature independent manner.
    Type: Grant
    Filed: April 9, 2004
    Date of Patent: April 5, 2005
    Assignee: Richtek Technology Corp.
    Inventors: Liang-Pin Tai, Shwu-Liang Hsieh, Hung-I Wang, Jing-Meng Liu
  • Patent number: 6839252
    Abstract: A two-step ripple-free multi-phase buck converter and method thereof comprises a first-stage voltage regulator to convert an input voltage to an intermediate voltage and a second-stage voltage regulator with a phase number not less than two to further convert the intermediate voltage to an output voltage by a split phase control, in which the ratio of the intermediate voltage to the output voltage is intended to the phase number such that the steady state output current of the converter approaches to be ripple-free, and hence the drivers and MOSFETs for the second-stage voltage regulator are lower cost, the efficiency of the second-stage voltage regulator is improved, and a higher slew rate current is obtained for transient driving capabilities.
    Type: Grant
    Filed: May 21, 2003
    Date of Patent: January 4, 2005
    Assignee: Richtek Technology Corp.
    Inventors: Liang-Pin Tai, Shwu-Liang Hsieh, Hung-I Wang, Jing-Meng Liu
  • Patent number: 6801030
    Abstract: A current sense apparatus and method comprises a common drain DMOSFET and a MOSFET connected in series between a high voltage and a low voltage to serve as an output stage. The DMOSFET produces a phase output current, a mirror current mirrored from the phase output current, and a sense voltage. A servo amplifier is connected with the mirror current and sense voltage to produce a current sense signal. Due to the mirror current from the DMOSFET proportional to the phase output current, the current sense apparatus senses the phase output current in a temperature independent manner.
    Type: Grant
    Filed: May 21, 2003
    Date of Patent: October 5, 2004
    Assignee: Richtek Technology Corp.
    Inventors: Liang-Pin Tai, Shwu-Liang Hsieh, Hung-I Wang, Jing-Meng Liu
  • Publication number: 20040189351
    Abstract: A current sense apparatus and method comprises a common drain DMOSFET and a MOSFET connected in series between a high voltage and a low voltage to serve as an output stage. The DMOSFET produces a phase output current, a mirror current mirrored from the phase output current, and a sense voltage. A servo amplifier is connected with the mirror current and sense voltage to produce a current sense signal. Due to the mirror current from the DMOSFET proportional to the phase output current, the current sense apparatus senses the phase output current in a temperature independent manner.
    Type: Application
    Filed: April 9, 2004
    Publication date: September 30, 2004
    Inventors: Liang-Pin Tai, Shwu-Liang Hsieh, Hung-I Wang, Jing-Meng Liu
  • Publication number: 20040008011
    Abstract: To balance the current of individual channel as well as regulate the output voltage for a multi-phase DC-to-DC buck converter, the converter output voltage is sensed and compared with a reference signal to produce a first error signal serving as first control signal for PWM signals of the converter and the channel currents are sensed, summed, averaged and subtracted to produce second error signals that are further modified by saw-tooth wave signal to produce second control signals for the PWM signals. Moreover, the reference signal is controlled by the summed channel currents for adjustable load regulation.
    Type: Application
    Filed: July 12, 2002
    Publication date: January 15, 2004
    Inventors: Hung-I Wang, Shwu-Liang Hsieh, Liang-Pin Tai, Jing-Meng Liu
  • Patent number: 6670794
    Abstract: To balance the current of individual channel as well as regulate the output voltage for a multi-phase DC-to-DC buck converter, the converter output voltage is sensed and compared with a reference signal to produce a first error signal serving as first control signal for PWM signals of the converter and the channel currents are sensed, summed, averaged and subtracted to produce second error signals that are further modified by saw-tooth wave signal to produce second control signals for the PWM signals. Moreover, the reference signal is controlled by the summed channel currents for adjustable load regulation.
    Type: Grant
    Filed: July 12, 2002
    Date of Patent: December 30, 2003
    Assignee: Richtek Technology Corp.
    Inventors: Hung-I Wang, Shwu-Liang Hsieh, Liang-Pin Tai, Jing-Meng Liu
  • Publication number: 20030218893
    Abstract: A two-step ripple-free multi-phase buck converter and method thereof comprises a first-stage voltage regulator to convert an input voltage to an intermediate voltage and a second-stage voltage regulator with a phase number not less than two to further convert the intermediate voltage to an output voltage by a split phase control, in which the ratio of the intermediate voltage to the output voltage is intended to the phase number such that the steady state output current of the converter approaches to be ripple-free, and hence the drivers and MOSFETs for the second-stage voltage regulator are lower cost, the efficiency of the second-stage voltage regulator is improved, and a higher slew rate current is obtained for transient driving capabilities.
    Type: Application
    Filed: May 21, 2003
    Publication date: November 27, 2003
    Inventors: Liang-Pin Tai, Shwu-Liang Hsieh, Hung-I Wang, Jing-Meng Liu
  • Publication number: 20030218455
    Abstract: A current sense apparatus and method comprises a common drain DMOSFET and a MOSFET connected in series between a high voltage and a low voltage to serve as an output stage. The DMOSFET produces a phase output current, a mirror current mirrored from the phase output current, and a sense voltage. A servo amplifier is connected with the mirror current and sense voltage to produce a current sense signal. Due to the mirror current from the DMOSFET proportional to the phase output current, the current sense apparatus senses the phase output current in a temperature independent manner.
    Type: Application
    Filed: May 21, 2003
    Publication date: November 27, 2003
    Inventors: Liang-Pin Tai, Shwu-Liang Hsieh, Hung-I Wang, Jing-Meng Liu