Patents by Inventor Bob Thelen

Bob Thelen 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: 5287070
    Abstract: A biasing system for a CMOS differential comparator includes a unity gain amplifier for developing a reference voltage corresponding to the trip point of an output inverter. The reference voltage is applied to a voltage to current converter for developing a reference current proportional to the reference voltage. The reference current biases the output inverters at their trip points when the input voltages to the differential comparator are at the same potential. The biasing system includes a reference inverter having characteristics substantially identical to the output inverters. The output and input of the reference inverter are connected together so that a reference voltage is established at the inverter output which is always at the switch point of the inverter. A differential transistor stage includes resistive loads matched in process characteristics and sized to each pass one-half the value of the reference current to reduce the load capacitance at the differential stage.
    Type: Grant
    Filed: September 2, 1992
    Date of Patent: February 15, 1994
    Assignee: NCR Corporation
    Inventors: Bob Thelen, Donald M. Bartlett