Patents by Inventor Wei-Zen Shen

Wei-Zen Shen 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).

  • Variable frequency LC oscillator using variable impedance and negative impedance circuits
    Patent number: 5486794
    Abstract: A variable frequency oscillator which can be implemented entirely in a semiconductor chip, which is variable over a broad frequency range and which has relatively low phase noise, includes a variable impedance circuit, a reactive load connected to an output terminal pair of the variable impedance circuit, and a negative impedance circuit having an output terminal pair connected to the output terminal pair of the variable impedance circuit. In one embodiment, the negative impedance circuit has an input terminal pair connected to an input terminal pair of the variable impedance circuit to serve as a positive feedback path for the variable impedance circuit. In another embodiment, the negative impedance circuit includes a pair of level shifters which ensure that the variable impedance circuit is properly biased and works in a forward active region.
    Type: Grant
    Filed: December 15, 1994
    Date of Patent: January 23, 1996
    Assignee: National Science Council of R.O.C.
    Inventors: Jieh-Tsong Wu, Wei-Zen Shen