Power amplifier with overcurrent protection

• Main Authors: SHI LIYONG, XU LEPING, ZHENG HAO, ZHU ZHANGMING
• Format: Patent
• Language: Chinese; English
• Published: 14.10.2009
• Subjects: AMPLIFIERS; BASIC ELECTRONIC CIRCUITRY; ELECTRICITY

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