| 摘要 |
PROBLEM TO BE SOLVED: To provide a power amplifier having a circuit which can protect transistors for output at the time of operations with a large voltage magnitude. SOLUTION: The power amplifier is provided with a transistor Q1 which amplifies an input signal and outputs an amplified signal to an output terminal 19 and a protective circuit 15 which has a transistor Q3 whose base is connected with a cathode of one end of a diode column DL1, an anode of the other end of the diode column DL1 being connected with the output terminal 19, and whose collector is connected with the output terminal 19 and a transistor Q4 whose base is connected with a cathode of one end of a diode column DL2, an anode of the other end of the diode column DL2 being connected with the emitter of the transistor Q3, whose collector is connected with the emitter of Q3 and whose emitter is connected with a ground terminal and is set so that the minimum value of its operation voltage may exceed the maximum output voltage between the collector and the emitter of the transistor Q1 whose output is matched and may not exceed the breakdown voltage between the collector and the emitter of the transistor Q1. COPYRIGHT: (C)2009,JPO&INPIT
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