The present invention provides an efficient way to detect the transmit
power provided by an amplifier. A power sense signal indicative of the
transmit power of the amplifier is generated and fed back to a control
system, which will react accordingly to control input signal levels,
bias, gain, or a combination thereof for the amplifier in traditional
fashion to control transmit power. Detection circuitry representing a
scaled version of the amplifier receives the radio frequency (RF) drive
in parallel with the amplifier to provide a scaled output signal. The
scaled output signal is rectified and filtered to generate the power
sense signal.