Patent ID: 7873334

Claim:
A method for stabilizing the power level (P out ) of a signal (x(t)) to be transmitted at the output port of a variable-gain power amplifier, said method being characterized by the following steps: detecting the voltage level (V PD ) of a feedback signal which represents the reflected wave of said signal (x(t)), calculating a reference signal (V ref ) representing the nominal power level (P ref ) for the output power (P out ) of the RF output signal (x(t)) as a function of a reference ramp signal (V ramp ) and said feedback signal (V PD ), feeding the obtained reference signal (V ref ) to a first input port of a comparator stage in the feedback chain of the current sense loop, feeding a signal representing the DC supply current (I PA ) of the variable-gain power amplifier to a second input port of said comparator stage, comparing the voltage level of the signal derived from said voltage drop (U RM ) with the voltage level of said reference signal (V ref ), feeding a signal being a function of the difference between the signal derived from said voltage drop (U RM ) and the calculated reference signal (V ref ) to a first input port of the power amplifier, and adjusting the current power level (P out ) by amplifying the difference between the output signal of said comparator stage and the signal (x(t)) to be transmitted before being amplified at a second input port of the variable-gain power amplifier.