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:
Dec. 31, 2013
Filed:
Jan. 27, 2012
Masakazu Mizokami, Kanagawa, JP;
Kazuaki Hori, Kanagawa, JP;
Masakazu Mizokami, Kanagawa, JP;
Kazuaki Hori, Kanagawa, JP;
Renesas Electronics Corporation, Kanagawa, JP;
Abstract
A variable gain amplifier circuit includes output nodes, a plurality of amplifiers, and a detection circuit. The amplifiers are coupled in parallel with each other between the output nodes and a reference node and selectively assume an operating state in accordance with a control signal. The detection circuit outputs a detection signal according to the magnitude of an input signal to each amplifier. Each amplifier includes a first transistor, a second transistor, and a bias circuit. The first transistor receives, at its control electrode, the input signal or a signal proportional to the input signal. The second transistor is series-coupled to the first transistor between the first reference node and an output node. The bias circuit applies a DC voltage of a magnitude according to the detection signal to a control electrode of the second transistor.