Power control circuitry for a mobile terminal application

摘要

The present invention generally relates to the field of automatic power control (APC) circuitries used in the analog front end of a mobile transmitter. It particularly refers to a power control circuitry and a corresponding method for controlling the power level of an RF signal to be transmitted at the output port of a variable-gain power amplifier by performing an additional regulation of the APC loop's reference signal. Thereby, it is proposed to increase the radiated RF power in case a transmitting antenna is mismatched to said power amplifier in order to not release an ongoing call. In case there is a subject very close to the terminal antenna, the antenna load is changed and the increased reflected signal is measured. In a closed loop this increased reflected signal is mixed with a reference ramp signal which is used to calculate a reference signal representing the nominal power level for the power of the RF signal to be transmitted, which leads to an increasing of the radiated power and prevents said call from being released. The step of calculating the reference signal as a function of the reference ramp signal and a DC feedback signal is realized by the substeps of multiplying a processed version of the DC feedback signal by the reference ramp signal and adding the output signal of the multiplication step to the reference ramp signal thereby yielding said reference signal.