Patents by Inventor David S. C. Liu

David S. C. 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).

  • Publication number: 20240171063
    Abstract: In an embodiment, during an overload or short circuit condition, a current limit circuit of an inverter is utilized in a pulse-by-pulse manner, which in turn causes the AC output of the inverter to operate in a hiccup mode (e.g., pulse-by-pulse based on and off dependent upon the output current) and automatically recover once the operating parameters (e.g., output current) are within the proper ranges. The pulse-by-pulse current limit circuit is configured to protect the switching circuits of the inverter from shorting or device failure during any peak operating voltage conditions by ensuring on/off timing accuracy of the inverter.
    Type: Application
    Filed: November 17, 2022
    Publication date: May 23, 2024
    Inventors: JAMES JIN XIONG ZENG, RAYMOND W. LEI, DAVID S. C. LIU
  • Publication number: 20240171064
    Abstract: A voltage transient protection utilizes Zener diodes, resisters, and a power MOSFET to clamp down the DC spike or surged voltage at the input and prevent damage to the inverter's DC power and control section. The input reverse polarity protection utilizes blocking diodes and a switch to cut off reverse voltage and prevent damage to the DC power and control section of the inverter. Once the surge voltage and/or reverse voltage conditions have been removed, the inverter will automatically recover and power on. In addition, an AC output interlock protection circuit is in place to provide safety protection to the external load. The AC output interlock protection circuit utilizes interlock jumpers on the mating connectors, which when detected (or in response to a control signal), it will activate the internal power relays and enable the AC output voltage to the terminals coupled to the external load.
    Type: Application
    Filed: November 17, 2022
    Publication date: May 23, 2024
    Inventors: JAMES JIN XIONG ZENG, RAYMOND W. LEI, DAVID S. C. LIU
  • Patent number: 7710077
    Abstract: Techniques for high performance inverter charger systems are described herein. In one embodiment, a power supply system includes, but is not limited to, an inverter to generate an AC (alternating current) output based on a DC (direct current) input, a current sensing circuit coupled to the inverter to sense an amount of current drawn from the inverter, and a microcontroller coupled to the inverter and the current sensing circuit to reduce the AC output of the inverter according to a predetermined algorithm stored within the microcontroller, in response to a detection that the amount of current drops below a predetermined threshold. Other methods and apparatuses are also described.
    Type: Grant
    Filed: October 6, 2006
    Date of Patent: May 4, 2010
    Assignee: HDM Systems Corp.
    Inventors: James Jin Xiong Zeng, David S. C. Liu
  • Patent number: 7405571
    Abstract: Methods and apparatuses for determining a battery capacity are described. According to one embodiment, an exemplary method includes generating virtual calibration data of the battery based on one or more characteristics of the battery, determining a virtual open circuit voltage (Voc) of the battery while the battery is being used, and estimating the capacity of the battery based on the determined virtual open circuit voltage of the battery and the virtual calibration data of the battery, while the battery is being used.
    Type: Grant
    Filed: September 13, 2005
    Date of Patent: July 29, 2008
    Assignee: HDM Systems Corporation
    Inventor: David S. C. Liu
  • Patent number: D605589
    Type: Grant
    Filed: October 6, 2006
    Date of Patent: December 8, 2009
    Assignee: HDM Systems Corporation
    Inventors: James Jin Xiong Zeng, David S. C. Liu