Patent ID: 6333675
Filing Date: 2001-12-25
Classification: H03G

Abstract:
A variable gain amplifier, comprising:a plurality of series connected unit variable gain amplifiers including a front stage amplifier and a back stage amplifier, for amplifying an input signal in accordance with respective gains and generating a multi-stage amplified signal; anda gain control circuit, connected to the plurality of unit variable gain amplifiers, for generating control signals which control the respective gains of the unit variable gain amplifiers in accordance with a gain control input signal so that the gain of the front stage amplifier is greater than that of the back stage amplifier, wherein the gain control circuit includes,a control voltage branch circuit for causing the voltage of the gain control input signal to branch at a plurality of branch voltage corresponding to the unit variable gain amplifiers, each of the branch voltage having a gradient, anda plurality of voltage gradient regulating circuits, connected to the control voltage branch circuit, for regulating the gradients of the plurality of branch voltages to generate the control signals.