POWER AMPLIFIER.

摘要

A radiofrequency power amplifier (PWA) comprises two output transistors (Q61, Q62) in a differential pair configuration for converting a differential input signal voltage (VRFS) into a differential output signal current (IRFO)- A common mode control loop (Q55, Q56, XN, CS5, Q51, Q52) controls a sum (ICM) of respective biasing currents that flow through the two output transistors on the basis of a difference between a measured direct current value (ICR), which represents the sum of the respective biasing currents, and a reference direct current value (IB), which represents a desired sum of biasing currents for the two output transistors.