| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem that the heat generation of a circuit becomes large to cause the thermal run away of a power amplifier since the circuit currents of the power amplifier is increased when the control voltage of the bias circuit of a power amplifier for transmission power amplification is increased. SOLUTION: This bias circuit is provided with: a voltage stabilizing part connected from a control voltage input terminal through a current limiting resistance to a ground potential; an emitter follower for bias supply whose base is connected through the resistance to a node between the current limiting resistance and the voltage stabilizing part; and a current limiting part connected between the base and emitter of the emitter follower for bias supply. Thus, it is possible to reduce bias currents when the control voltage of the bias circuit rises. Therefore, it is possible to prevent the thermal runaway of a transistor for amplification due to the rising of the control voltage. COPYRIGHT: (C)2006,JPO&NCIPI
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