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. 29, 2009
Filed:
Dec. 19, 2005
Applicant:
Kazuhisa Ishiguro, Gunma, JP;
Inventor:
Kazuhisa Ishiguro, Gunma, JP;
Assignee:
Ricoh Co., Ltd., Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H03F 3/04 (2006.01);
U.S. Cl.
CPC ...
Abstract
A first MOS transistor (M) and a second MOS transistor (M) constitute a cascode amplifier. The second MOS transistor (M) is in a differential connection with a gain control MOS transistor (M), which has its gate supplied with an AGC control voltage (VAGC), and it is arranged that the device area ratio of the second MOS transistor (M) to the gain control MOS transistor (M) is one to N (where N≧1). In this way, even in a region where the AGC control voltage (VAGC) is small, abrupt variations of the gain can be suppressed, while the drain current of the first MOS transistor (M) can be kept constant independently of the gain control.