Ladas & Parry
Variable gain amplification circuit having a circuit for controlling a bias current
 A variable gain amplification circuit can increase a dynamic range without increasing an offset voltage. The variable gain amplification circuit amplifies an input signal by a desired gain. An amplification circuit amplifies the input signal by a predetermined gain based on a bias current. A bias current control circuit controls the bias current based on a level of the input signal. The bias current supplied to the amplification circuit can be reduced when there is no input signal, and the bias current increases as the level of the input signal increases. Thus, an offset voltage can be decreased while a sufficient dynamic range is maintained. 
Mitsumi Electric Co., Ltd.
H
H03G
inventional
Masaru Yukihiro
Takeuchi Terada