Patents by Inventor John W. Fernandes

John W. Fernandes 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).

  • Sub-ranging A/D converter with flash converter having balanced input
    Patent number: 4814767
    Abstract: A 12-bit sub-ranging A/D converter which operates through four successive sub-ranging cycles with an 8:1 gain change between the cycles. The residue signal for each cycle is directed to a four-bit flash converter the output of which sets the latches for corresponding bit-current-sources of a DAC. The flash converter input circuit comprises identical residue and reference amplifiers driving symmetrical residue and reference networks for controlling the flash converter comparators. The DAC output for each cycle is compared with the analog input signal to produce a corresponding new residue signal. There are 15 bit-current-sources, three for the first cycle, and four for each of the last three cycles. The MSB of each group of four bit-current sources is an overlap bit having the same current weighting as the LSB of the preceding group.
    Type: Grant
    Filed: October 8, 1987
    Date of Patent: March 21, 1989
    Assignee: Analog Devices, Inc.
    Inventors: John W. Fernandes, Gerald A. Miller, Andrew M. Mallinson
  • Sub-ranging A/D converter with improved error correction
    Patent number: 4804960
    Abstract: A 12-bit sub-ranging A/D converter which operates through four successive sub-ranging cycles with an 8:1 gain change between the cycles. The residue signal for each cycle is directed to a four-bit flash converter the output of which sets the latches for corresponding bit-current-sources of a DAC. The flash converter input circuit comprises identical residue and reference amplifiers driving symmetrical residue and reference networks for controlling the flash converter comparators. The DAC output for each cycle is compared with the analog input signal to produce a corresponding new residue signal. There are 15 bit-current-sources, three for the first cycle, and four for each of the last three cycles. The MSB of each group of four bit-current sources is an overlap bit having the same current weighting as the LSB of the preceding group.
    Type: Grant
    Filed: October 8, 1987
    Date of Patent: February 14, 1989
    Assignee: Analog Deivces, Incorporated
    Inventors: John W. Fernandes, Gerald A. Miller, Andrew M. Mallinson, Stephen R. Lewis