Patents by Inventor David J. Knobbe

David J. Knobbe 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).

  • Apparatus and method for sensitive circuit protection with set-scan testing
    Patent number: 5357572
    Abstract: A set/scan test capability is provided for a circuit that includes sensitive subcircuits, but that can be latched out to prevent reverse engineering the sensitive elements. A mechanism to inhibit set/scan test access to at least some of the sensitive subcircuits is selectively actuated by a control circuit to override a normal set/scan test and inhibit set/scan access to the sensitive subcircuits. Various implementations are possible, such as fusible-link PROMs for irreversibly inhibiting set/scan access to the sensitive subcircuits after an initial non-inhibited test period, the use of encryption codes to enable repeated set/scan access to the sensitive subcircuits, and an erasable/reprogrammable mechanism for inhibiting set/scan access to programmed sets of subcircuits.
    Type: Grant
    Filed: September 22, 1992
    Date of Patent: October 18, 1994
    Assignee: Hughes Aircraft Company
    Inventors: Mark E. Bianco, Douglas A. Dwyer, David J. Knobbe, James P. Baukus, Allan R. Kramer, Faik S. Ozdemir