Patent ID: 7592869
Filing Date: 2009-09-22
Classification: H03F,H03G

Abstract:
1. An electronic amplifier circuit comprising: a differential amplifier having a pair of transistors accepting a differential input signal at base nodes of the transistor pair; a degeneration resistance coupled between emitters of the pair of transistors, the degeneration resistance comprising a first field effect transistor (FET); a load resistance coupled between collectors of the pair of transistors, the load resistance comprising a second FET; and, a control circuit for increasing the gain factor of the differential amplifier by decreasing the degeneration resistance and increasing the load resistance wherein the control circuit receives a desired gain control signal and responsively generates a first gate-voltage control signal for controlling the degeneration resistance and generates a second gate-voltage control signal for controlling the load resistance; and wherein the control circuit converts the desired gain control signal to a first and second current signal, and converts the first and second current signal to the first gate-control voltage and the second gate-control voltage, respectively.