Patent ID: 7667541
Filing Date: 2010-02-23
Classification: H03G

Abstract:
1. An amplifier circuit comprising: a current conversion circuit that receives a high frequency signal and produces a signal current according to the high frequency signal; a gain control circuit that includes a control signal input for receiving a control signal, a first output, and a second output, and produces the signal current from said first output or said second output according to the control signal; an impedance circuit that includes a first node connected to said first output, a second node connected to said second output, and a third node, said impedance circuit presenting a predetermined impedance between said nodes; a switch circuit that is inserted between said first output and said first node; and a load impedance unit that is connected to said first output and produces a gain signal representing an amplified high frequency signal, wherein the amplifier circuit changes a level of the gain signal according to the control signal.