| 摘要 |
<p>The driving current of a current source (30; 30b to 30n) of a differential-pair control variable gain amplifier is adjusted according to the gain. Specifically, according to a control voltage (VCR) generated by a variable voltage source (25) for determining the gain of differential stage (20, 21) for generating an output signal in accordance with an input signal, the driving current of a current source transistor (Q2) of the differential stage is decreased as the gain decreased. Only the current corresponding to the gain is consumed, and therefore the current consumption is reduced without any distortion of the signal.</p> |
