Current Divider Based Voltage Controlled Gain Amplifier

An amplifier, comprising:

• an input stage having an input impedance determined by a plurality of current paths and configured to route first and second radio frequency (RF) currents extracted from an RF input signal through the plurality of current paths so as to provide first and second attenuated RF currents, and to maintain the input impedance substantially at a predetermined impedance over variations in current levels of the first and second attenuated RF currents;
• a buffer stage configured to provide first and second intermediate RF currents having current levels that substantially track the current levels of the first and second attenuated RF currents, respectively;
• and
• an output stage configured to convert the first and second intermediate RF currents to an RF output signal having a power level proportional to a power level of the RF input signal.

An amplifier, comprising:

• an input radio frequency (RF) terminal configured to receive an RF input signal having an RF input current and an RF input power level;
• a shunting current path including a first variable resistance element, the shunting current path configured to shunt a portion of the RF input current to a ground;
• a series current path including a second variable resistance element, the series current path configured to attenuate the RF input current to provide an attenuated RF current having an attenuated current level;
• an impedance control module configured to adjust an impedance of the first and second variable resistance elements so as to substantially maintain an input impedance of the RF input terminal for variations in the attenuated current level;
• a current regulating element configured to provide an intermediate RF current having a current level which substantially tracks the attenuated current level;
• and
• a current to power conversion module configured to convert the intermediate RF current to an RF output signal having an output power level proportional to the RF input power level.