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. 26, 2014
Filed:
Jul. 12, 2011
Differential amplifier with function of variable gain and optical receiver implemented with the same
Applicants:
Yoshiyuki Sugimoto, Yokohama, JP;
Sosaku Sawada, Yokohama, JP;
Taizo Tatsumi, Yokohama, JP;
Inventors:
Assignee:
Sumitomo Electric Industries, Ltd., Osaka, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H03F 3/45 (2006.01);
U.S. Cl.
CPC ...
Abstract
A differential circuit with a function of a variable gain without shifting the output cross point is disclosed. The differential circuit includes an amplifying stage and a control stage. The amplifying stage includes three units each having a pair of transistors, a pair of load resistors, and a pair of current sources. The second and third units each put between the first unit and the load resistor to bypass the current. The control stage includes two units and two current sources to compensate the current bypassed by the second or third unit to keep the DC output level substantially in constant.