POWER DETECTION CIRCUIT FOR USE IN A POWER AMPLIFIER

摘要

A shorting element, preferably a resonant inductor-capacitor circuit, is inserted in parallel with a sense transistor, which itself is in parallel with a power transistor. The use of the shorting element in combination with the sense transistor, provides a technique to have a monotonic power detection. The shorting element eliminates extraneous currents caused by inherent collector-base and collector-substrate diodes of sense transistor, and also eliminates the extraneous collector voltage swing of the sense transistor caused by mutual coupling between inductors connected to the power and sense transistors.