Patents by Inventor Karl E. Sundstrom

Karl E. Sundstrom 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).

  • Current control circuit with particular application in bipolar constant current control of step motors
    Patent number: 4450517
    Abstract: The present invention is a switch mode current control circuit which is particulary useful with step motors. The circuit has a first transistor, a coil and a first resistor connected in a series with a first voltage source. An optocoupler having a light emitting diode and a second transistor therein has the light emitting diode connected across the first resistor and the second transistor is connected across the base emitter junction of the first transistor. A second resistor is connected to the base of the first transistor and to the second voltage source. A diode is connected across the coil.
    Type: Grant
    Filed: January 16, 1981
    Date of Patent: May 22, 1984
    Inventor: Karl E. Sundstrom