Patent ID: 6600377
Filing Date: 2003-07-29
Classification: H03G

Abstract:
A gain control amplifier comprising:a first transistor having a first input point and a first output circuit, an a third transistor having a third output circuit; a load connected to the output circuit of the first transistor; a second transistor having a second output circuit connected between the first output circuit of said first transistor and said load; a connecting point located between said load and said second transistor; said first transistor for amplifying a signal received at said first input point, and for outputting the amplified signal at the connecting point; a control bias connected to said third transistor; switch means for turning on and off the control bias; and said third output circuit of the third transistor connected in parallel with a series circuit of the output circuit of said second transistor and said load, wherein: said switching means is turned off to turn on the control bias only for said second transistor out of said second and third transistors in a high-gain mode, and said switch means is turned on to turn on the control bias for both of said second and third transistors in a low-gain mode.