Patents Represented by Attorney Emil Oppenheimer Wolff & Donnelly LLP Chang
  • Patent number: 6112022
    Abstract: A method for identifying and selecting pertinent subcircuits from a given circuit design for generating simulation results representative of the given circuit design is disclosed. A large circuit design having a number of input pins and output pins, and one or more clock pins can be simulated by a number of subcircuits where each subcircuit is comprised of circuit information from an input pin to one or more latch devices, an output pin to one or more latch devices, or an output pin to one or more input pins. A latch device can be a flip-flop.
    Type: Grant
    Filed: December 13, 1996
    Date of Patent: August 29, 2000
    Assignee: Legend Design Technology, Inc.
    Inventor: You-Pang Wei
  • Patent number: 6055170
    Abstract: Circuits and methods are provided for operating a transistor as rectifier based upon the detected Vds of the transistor. In sensing the Vds voltage of the SRMOS, during positive conduction, the SRMOS body diode will conduct and the Vds of the SRMOS becomes that of a forward body diode voltage, which may, depending on the type of the device, be approximately -0.6V. If this voltage level is sensed, it may indicates that the SRMOS is turned off too early. During reverse conduction, Vds is non-existent (which is similar to a diode). In this case, the SRMOS may be turned off too late. Thus, by examining Vds, the SRMOS can be operated in such a manner so that it is turned off at an optimal point in time.
    Type: Grant
    Filed: March 13, 1998
    Date of Patent: April 25, 2000
    Assignee: SRMOS, Inc.
    Inventor: H. P. Yee
  • Patent number: 6038150
    Abstract: A secondary subcircuit of a converter circuit is disclosed where a method and circuit for operating a transistor to prevent reverse conduction of the current in the secondary subcircuit is disclosed. The diode in the secondary subcircuits of the prior art is replaced by a transistor and the circuitry for controlling the transistor is made part of the control circuit (ASIC). The secondary converter subcircuit includes a secondary coil for generating a voltage that passes through a first transistor M1, a capacitor, and a second transistor M2, where the output terminal of the subcircuit is across said capacitor. A presently preferred embodiment of a control circuit detects the voltage level at a sync node and the output voltage level at the output terminal and controls transistors M1 and M2 accordingly in generating the desired voltage level at the output terminal.
    Type: Grant
    Filed: March 13, 1998
    Date of Patent: March 14, 2000
    Inventors: Hsian-Pei Yee, Satoru Sawahata, Masaru Wakatabe