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:
Sep. 14, 2004
Filed:
Mar. 10, 2003
Hiroshi Komurasaki, Hyogo, JP;
Hisayasu Satoh, Hyogo, JP;
Kinya Hosoda, Saitama, JP;
Akira Hyogo, Chiba, JP;
Keitaro Sekine, Tokyo, JP;
Renesas Technology Corp., Tokyo, JP;
Abstract
A variable gain amplifier is configured of an amplification circuit and a control circuit controlling a gain of the amplification circuit. The amplification circuit has first and second MOS transistors identical in characteristics and having respective sources connected to a first fixed potential. The amplification circuit has a differential gain proportional to a square root of a ratio between a current flowing through the first MOS transistor and a current flowing through the second MOS transistor. The control circuit applies a potential corresponding to a constant voltage plus a control voltage to a gate of the first MOS transistor and a potential corresponding to the constant voltage minus the control voltage to a gate of the second MOS transistor.