The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 07, 2003
Filed:
Feb. 18, 1998
Fujitsu Limited, Kawasaki, JP;
Abstract
A voltage controlled oscillation circuit with an oscillation frequency thereof controlled in accordance with an external voltage is disclosed. An odd number of inversion circuit elements such as inverters for inverting output signals thereof with respect to input signals thereto are connected in series with each other. An output side of the last-stage one of the odd number of the inversion circuit elements is connected to an input side of the first-stage one of the inversion circuit elements to thereby cause an oscillation. A plurality of oscillation frequency variable control units such as variable resistor circuit elements for changing an oscillation frequency in accordance with an external voltage are each inserted between each set of adjacent inversion circuit elements. A plurality of fixed resistor circuit elements each having a fixed resistance value are connected in parallel with a plurality of the oscillation frequency variable control units, respectively. The functions of both the variable resistor circuit elements and the fixed resistor circuit elements can be carried out at the same time by the use of a depletion type transistor or a transistor of a short channel type.