PROTECTION CIRCUIT FOR RADIO FREQUENCY POWER AMPLIFIER

摘要

PURPOSE: A protection circuit for a RF(Radio Frequency) power amplifier is provided to improve an operation under a mismatch state by restricting not only a peak current but also a peak output voltage. CONSTITUTION: An overdrive protection circuit(100) comprises a first and a second transistors(102,104) and a detection resistance(106). The first and the second transistor are arranged in a Darlington structure. The overdrive protection circuit is combined with a RF(Radio Frequency) transmit line(108) through the detection resistance and a shunt line(110). The RF transmit line is combined with the input source of a RF signal(112) which generates a RF signal. The RF transmit line is combined with a current source(114) which offers a base bias current. The input source of the RF signal is able to be included in a transceiver. The RF transmit line is combined with the base of a primary power transistor(116) which serves as a power amplifier for the radio frequency signal.