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:
Aug. 15, 2006
Filed:
Jun. 08, 2004
Masashi Takamatsu, Tokyo, JP;
Masashi Takamatsu, Tokyo, JP;
Seiko NPC Corporation, Tokyo, JP;
Abstract
The present invention provides a MOS-type variable capacitance element which can obtain a sufficient capacitance valuable width and, at the same time, can eliminate restrictions imposed on a control voltage range. A MOS-type variable capacitance element includes a MOS transistor in which an N well having polarity opposite to polarity of the P type is formed on a P type semiconductor substrate, a pair of source and drain regions are formed in the inside of the N well, an N-type high-concentration region is formed in the inside of the N well, a gate oxide film is formed on the N well, and a gate electrode is formed on the gate oxide film, a first electrode which connects the source and drain regions to a reference potential, a second electrode which is connected to the gate electrode, and a third electrode which is connected to the N well and applies a control voltage having polarity equal to polarity of the P type to the N well using the reference potential as a reference, wherein a variable capacitance element is provided between the second electrode and the third electrode.