AN ACCURATE POWER DETECTION CIRCUIT FOR USE IN A POWER AMPLIFIER

摘要

A power amplifier circuit for amplifying an input signal includes an amplifying transistor and a power detection circuit. The power detection circuit includes a circuit for generating a signal which is directly proportional to the power level in the amplifying transistor. This may be accomplished by generating a voltage proportional to the square of a current in the amplifying transistor and then averaging that voltage. In this manner, a more accurate indication of the power level in the amplifying transistor is obtained.