Power amplifier with overcurrent protection

The invention discloses a power amplifier with overcurrent protection, which is used for protecting a field effect transistor in the output stage of the power amplifier. The power amplifier with overcurrent protection works as the following steps: sampling current is obtained by sampling the current of the drain electrode of the field effect transistor by a sampling circuit which consists of a current mirror circuit; the sampling current is converted into sampling voltage and then is input into an offset comparator; the offset comparator compares the sampling voltage with a reference voltage, generates a [1.1] overcurrent signal and sends the overcurrent signal to the offset comparator; an adjusting circuit generates an adjusting signal according to the overcurrent signal and sends the adjusting signal to a pulse width modulator; the pulse width modulator adjusts the PWM signal according to the adjusting signal so as to adjust the duty cycle of the field effect transistor signal, thus lowering the current of the drain electrode thereof, and realizing the real time, highly efficient and precise protection for the field effect transistor. Simultaneously, the power amplifier with overcurrent protection decreases the power consumption of the sampling circuit by the micro-sampling for the current mirror circuit, thereby reducing static power consumption of the power amplifier and improving work efficiency of the power amplifier.