Patents Assigned to VTC Incorporated
  • Patent number: 4638187
    Abstract: A CMOS output buffer provides high drive current without sacrificing speed and with minimum output signal distortion due to internal chip ground bounce or output signal ringing. The output buffer includes a pull-up circuit and a pull-down circuit which distribute switching current spikes over time. The pull-up circuit includes a P-channel FET and an N-channel FET connected in parallel between an output terminal and supply terminal V.sub.DD, with an inverter connected between the gates of the N-channel and P-channel FETs to provide the proper phase for the P-channel FET as well as delaying turn-on of the P-channel FET with respect to turn-on of the N-channel FET. The pull-down circuit includes a pair of N-channel FETs connected in parallel between the output terminal and ground, and a delay resistance connected between their gates so that turn-on of one of the N-channel FETs is delayed with respect to the other.
    Type: Grant
    Filed: October 1, 1985
    Date of Patent: January 20, 1987
    Assignee: VTC Incorporated
    Inventors: Clifford H. Boler, William W. Leake, Surinder S. Rai, Gene B. Zemske