Patents Represented by Attorney Brian L. Brown Rudnick Freed & Gesmer, PC Michaelis, Esq.
  • Patent number: 6138195
    Abstract: A method and apparatus for hot-plugging circuit boards having lower voltage logic devices into a higher voltage backplane in a manner that minimizes overvoltage stress during system power-up, or during a lower voltage power failure. The method and apparatus ensures that the lower voltage device(s') power input reaches at least a nominal input level before any other inputs of the device are driven to a level greater than or equal to an expected input level. Dedicated output pins on lower voltage logic device(s) are configured to issue a control output signal for enabling higher voltage devices. Output enable terminals for the higher voltage parts, which are connected to respective control outputs from a lower voltage device, are normally in a disabled state as a function of pull-up or pull-down circuitry.
    Type: Grant
    Filed: March 20, 1998
    Date of Patent: October 24, 2000
    Assignee: EMC Corporation
    Inventors: Michael Bermingham, Christopher S. MacLellan, John K. Walton