Patents by Inventor Sergio D. Camerlo

Sergio D. Camerlo 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).

  • Patent number: 6204712
    Abstract: A method and apparatus for drastically reducing timing uncertainties in clocked digital circuits simply, at virtually no cost, and using only standard clock drivers and simple, inexpensive electrical components is described. The method includes the steps of minimizing timing uncertainties by controlling both clock skew and clock jitter. Intrinsic clock skew is eliminated by ganging the outputs of a multi-line clock together onto a capacitive metal island disposed on a printed circuit board (PCB). Extrinsic clock skew is controlled through the use of wide, relatively high-capacitance traces of matched length and disposed on a single, common signal layer of the PCB, each leading to a respective receiver circuit and terminated identically. Clock jitter is controlled by electrically isolating a region of the PCB, disposing the clock driver in the region in such a way as to minimize noise, and providing quiet local power and ground to the region.
    Type: Grant
    Filed: November 12, 1999
    Date of Patent: March 20, 2001
    Assignee: Cisco Technology, Inc.
    Inventor: Sergio D. Camerlo
  • Patent number: 6157251
    Abstract: A method and apparatus for drastically reducing timing uncertainties in clocked digital circuits simply, at virtually no cost, and using only standard clock drivers and simple, inexpensive electrical components is described. The method includes the steps of minimizing timing uncertainties by controlling both clock skew and clock jitter. Intrinsic clock skew is eliminated by ganging the outputs of a multi-line clock together onto a capacitive metal island disposed on a printed circuit board (PCB). Extrinsic clock skew is controlled through the use of wide, relatively high-capacitance traces of matched length and disposed on a single, common signal layer of the PCB, each leading to a respective receiver circuit and terminated identically. Clock jitter is controlled by electrically isolating a region of the PCB, disposing the clock driver in the region in such a way as to minimize noise, and providing quiet local power and ground to the region.
    Type: Grant
    Filed: November 12, 1999
    Date of Patent: December 5, 2000
    Assignee: Cisco Technology, Inc.
    Inventor: Sergio D. Camerlo
  • Patent number: 6157250
    Abstract: A method and apparatus for drastically reducing timing uncertainties in clocked digital circuits simply, at virtually no cost, and using only standard clock drivers and simple, inexpensive electrical components is described. The method includes the steps of minimizing timing uncertainties by controlling both clock skew and clock jitter. Intrinsic clock skew is eliminated by ganging the outputs of a multi-line clock together onto a capacitive metal island disposed on a printed circuit board (PCB). Extrinsic clock skew is controlled through the use of wide, relatively high-capacitance traces of matched length and disposed on a single, common signal layer of the PCB, each leading to a respective receiver circuit and terminated identically. Clock jitter is controlled by electrically isolating a region of the PCB, disposing the clock driver in the region in such a way as to minimize noise, and providing quiet local power and ground to the region.
    Type: Grant
    Filed: July 23, 1999
    Date of Patent: December 5, 2000
    Assignee: Cisco Technology, Inc.
    Inventor: Sergio D. Camerlo
  • Patent number: 6081106
    Abstract: A precision voltage regulator comprises a three terminal regulator coupled to a voltage divider. The voltage divider has two composite resistors, each of which comprises a plurality of matched value resistors fabricated on a common substrate, mixed in series and parallel configurations. The resultant voltage divider produces a wide range of divider ratios, while preserving a divider ratio which is independent of temperature and tolerance effects.
    Type: Grant
    Filed: August 21, 1998
    Date of Patent: June 27, 2000
    Assignee: Cisco Technology, Inc.
    Inventor: Sergio D. Camerlo
  • Patent number: 6069539
    Abstract: A system for the distribution of VTT termination voltage for a GTL bus system includes a plurality of GTL signal lines, a plurality of first termination resistors, and a plurality of second termination resistors. The GTL signal lines have a first end and a second end. The resistors have a signal end and a VTT end. The first end of the signal line is connected to the signal end of the first resistor. The second end of the signal line is connected to the signal end of the first resistor. A plurality of nodes are formed from the VTT ends of the first and second resistors. These nodes may be formed in many different ways, and in many different numbers. The nodes are each driven with a separate VTT supply, and the nodes are interconnected such that a failure in the power supply furnishing power to one node does not affect the other nodes, and does not affect the operation of the system consuming this VTT voltage.
    Type: Grant
    Filed: May 27, 1999
    Date of Patent: May 30, 2000
    Assignee: Cisco Technology, Inc.
    Inventors: David K. Sanders, Sergio D. Camerlo
  • Patent number: 6052012
    Abstract: A method and apparatus for drastically reducing timing uncertainties in clocked digital circuits simply, at virtually no cost, and using only standard clock drivers and simple, inexpensive electrical components is described. The method includes the steps of minimizing timing uncertainties by controlling both clock skew and clock jitter. Intrinsic clock skew is eliminated by ganging the outputs of a multi-line clock together onto a capacitive metal island disposed on a printed circuit board (PCB). Extrinsic clock skew is controlled through the use of wide, relatively high-capacitance traces of matched length and disposed on a single, common signal layer of the PCB, each leading to a respective receiver circuit and terminated identically. Clock jitter is controlled by electrically isolating a region of the PCB, disposing the clock driver in the region in such a way as to minimize noise, and providing quiet local power and ground to the region.
    Type: Grant
    Filed: June 29, 1998
    Date of Patent: April 18, 2000
    Assignee: Cisco Technology, Inc.
    Inventor: Sergio D. Camerlo