Patents by Inventor Ronald Chang

Ronald Chang 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: 20020019060
    Abstract: The present invention provides a cartridge for analyzing a fluid sample. The cartridge provides for the efficient separation of cells or viruses in the sample from the remaining sample fluid, lysis of the cells or viruses to release the analyte (e.g., nucleic acid) therefrom, and optionally chemical reaction and/or detection of the analyte. The cartridge is useful in a variety of diagnostic, life science research, environmental, or forensic applications for determining the presence or absence of one or more analytes in a sample.
    Type: Application
    Filed: October 2, 2001
    Publication date: February 14, 2002
    Applicant: Cepheid
    Inventors: Kurt E. Petersen, Michael T. Taylor, Farzad Pourahmadi, William A. McMillan, Ronald Chang, Stanley H. Sakai, Jesus Ching, Douglas B. Dority, Phillip Belgrader, M. Allen Northrup
  • Patent number: 6340944
    Abstract: An analog-to-digital converter which has a low resolution and high resolution mode. In response to the low resolution mode signal, a switching circuit selects only certain of the digital bit outputs. In one embodiment, the analog-to-digital converter is a pipelined circuit with a number of stages. In response to the low resolution mode, a number of the stages are bypassed, so that only the needed stages for the smaller number of bits are used. The stages that are bypassed are preferably powered down, but not completely. By maintaining a small amount of bias current to the bypassed stages, they can quickly respond when a switch is made back to full resolution mode.
    Type: Grant
    Filed: August 21, 2000
    Date of Patent: January 22, 2002
    Assignee: Exar Corporation
    Inventors: Ronald Chang, Jose A. Salcedo, Raphael Horton
  • Publication number: 20010012612
    Abstract: A method for separating a desired analyte from a fluid sample comprises the steps of introducing the sample into a cartridge having a sample flow path and a lysing chamber in the sample flow path. The lysing chamber contains at least one filter for separating cells or viruses from the sample. The sample is forced to flow through the sample flow path, thereby capturing the cells or viruses with the filter as the sample flows through the chamber. The ratio of the volume of sample forced to flow through the chamber to the volume capacity of the chamber is preferably at least 2:1, and the volume of sample forced to flow through the chamber is preferably at least 100 microliters. The captured cells or viruses are disrupted to release the analyte therefrom, and the analyte is eluted from the chamber.
    Type: Application
    Filed: March 6, 2001
    Publication date: August 9, 2001
    Applicant: Cepheid
    Inventors: Kurt E. Petersen, Michael T. Taylor, Farzad Pourahmadi, William A. McMillan, Ronald Chang, Stanley H. Sakai, Jesus Ching, Douglas B. Dority, Phillip Belgrader, M. Allen Northrup
  • Patent number: 5569235
    Abstract: A valve for a needleless syringe fitting is disclosed. The valve has a receptacle fitting for releasable attachment to the syringe fitting, a valve chamber, a valve seat adjacent the chamber, and elastomeric sealing bowl within the chamber. The bowl is deformed and partially inverted when the syringe fitting is attached to the receptacle fitting, causing the valve to open. Also disclosed is a valved container in which a vial is sealed by a valve of this type.
    Type: Grant
    Filed: June 21, 1994
    Date of Patent: October 29, 1996
    Assignee: Modern Medical Devices
    Inventors: James B. Ross, Ronald Chang
  • Patent number: 5466897
    Abstract: A dispenser apparatus for use in dispensing disposable stethoscope diaphragms for removable attachment to a stethoscope head is disclosed. The apparatus operates by removing a diaphragm from a stack, and presenting it for attachment to a stethoscope, when a dispensing plate is shuttled between retracted and extended positions. Also disclosed is a method for reducing the risk of infection by stethoscope use.
    Type: Grant
    Filed: June 8, 1994
    Date of Patent: November 14, 1995
    Assignee: Modern Medical Devices
    Inventors: James B. Ross, Gary L. Christiansen, Ronald Chang
  • Patent number: 5457418
    Abstract: A track and hold circuit is disclosed which may be used in high speed analog to digital conversions. The circuit includes a control transistor which keeps the circuit's input transistor in a conductive state even when the circuit is in hold mode. As a result, the track and hold circuit achieves a high switching speed while minimizing input voltage spikes.
    Type: Grant
    Filed: December 5, 1994
    Date of Patent: October 10, 1995
    Assignee: National Semiconductor Corporation
    Inventor: Ronald Chang