Patent ID: 7167055

Claim:
A power amplifier comprising: an output block including power transistor and an output terminal connected to a load; a bias block including a standby pin and being allowed to bias other blocks of the power amplifier in activated states, especially the power transistor conductive, when the standby pin stays active; a voltage level detector including: a fault detecting block for monitoring the voltage level at the standby pin during power-up, and upon detection of the voltage level reaching a threshold level, detecting fault conditions of the power transistor and the output terminal; and a cutoff signal generating block for issuing the cutoff signal when the fault detection block detects a fault condition of one of the power transistor and the output terminal; a protection switch block for cutting off the output block from the bias block and connecting the fault detection block to the bias block during reception of the cutoff signal, wherein the voltage level detector includes a recovery block for monitoring the voltage level at the standby pin during power-up, and upon detection of the voltage level reaching a second threshold level, causing the cutoff signal generating block to terminate issue of the cutoff signal.