| 摘要 |
PROBLEM TO BE SOLVED: To avoid an RF signal leakage to a base bias circuit and to enable the omission of choke inductance, by greatly reducing the temperature fluctuation of an idle current and making the output impedance of the base bias circuit low in a DC and high to an RF. SOLUTION: The temperature compensation of an idle current is performed by a transistor Q3 having diode connection between a base and a collector via a resistor R4, and a resistor R1 so as to enable the temperature compensation of a collector current at a base bias control voltage Vcon of a low voltage. At the time of high output power with a configuration to supply a base current via a transistor Q4, and to use a base bias circuit in which the base potential of the transistor Q4 is given by a transistor Q2 and a grounded emitter transistor Q1, it becomes possible to omit a choke coil L necessary for connection between an amplifying transistor RFTr and the base bias circuit. COPYRIGHT: (C)2007,JPO&INPIT
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