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:
May. 10, 2005
Filed:
Jul. 10, 2002
Kazuhiro Fujimura, Kanagawa, JP;
Shinichi Tanabe, Kanagawa, JP;
Kazuhiro Fujimura, Kanagawa, JP;
Shinichi Tanabe, Kanagawa, JP;
Sony Corporation, Tokyo, JP;
Abstract
The present invention provides systems and methods related to a variable gain amplifier. The variable gain amplifier includes a first differential amplifier, a second differential amplifier, a combining circuit, and a current control circuit. The first differential amplifier circuit and the second differential amplifier circuit share a common input signal and have different amplification degrees. Each of the first and second differential amplifier circuits includes a first transistor and a second transistor that form a differential pair. The first transistor and the second transistor of each differential amplifier circuit have bases that are supplied with the input signal, and collectors that output signals to the combining circuit. The current control circuit changes a ratio between a bias current of the first differential amplifier circuit and a bias current of said second differential amplifier circuit based on a gain control signal.