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:
Apr. 06, 2004
Filed:
Jul. 03, 2002
Takaya Maruyama, Tokyo, JP;
Hisayasu Satoh, Tokyo, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
A differential amplifier of an exponentially-changing current producing circuit has a pair of transistors of which bases are connected to each other through a differential base resistor of a resistance value R, a control current of a value K ×T−(K ×K ×T×V /K ) produced from a gain control current (K ·V ), a gain reference current (K ) and a bias current (K ·T) is fed to the base of one transistor, and an exponentially-changing current is output. V denotes a gain control voltage, K , K and K are constant, and T denotes an absolute temperature. An input signal is amplified in a variable gain cell at a gain corresponding to the exponentially-changing current, and an amplified signal is output. Therefore, the gain in the variable gain cell is controlled according to the exponentially-changing current.