Patents by Inventor James A. Littlefield

James A. Littlefield 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).

  • A/D converter system with interface and passive voltage reference source
    Patent number: 5359327
    Abstract: An A/D circuit to convert an analog signal to a digital signal. The circuit includes a low noise analog-to-digital conversion chip and a precision voltage reference source. The voltage reference source includes a diode with two terminals and a passive attenuation circuit. The attenuation circuit and the diode are coupled in parallel between the two terminals to provide a voltage reference signal for use by the analog to digital conversion chip. The analog to digital chip uses the voltage reference signal to set the full scale input range for the signal conversion, and the voltage reference signal is attenuated to correspond to the full scale range of the analog signal.
    Type: Grant
    Filed: May 28, 1993
    Date of Patent: October 25, 1994
    Inventors: Eric W. Brown, James A. Littlefield