| 摘要 |
PROBLEM TO BE SOLVED: To provide an electric power amplifier which reduces fluctuations of high frequency characteristics corresponding to fluctuations of power supply voltage and can compensate fluctuations of bias current due to manufacturing variability of transistors. SOLUTION: The electric power amplifier has an electric power amplifying transistor 101 which amplifies high frequency signals, a power supply voltage depending current generation circuit 104 which generates a reference current corresponding to a power supply voltage, a reference current detection resistance 105 which detects a reference current to convert it to a first reference voltage V1, a bias current detection resistance 106 which detects a bias current of the amplifying transistor 101 to convert it to a second reference voltage V2, and an operation amplifier 107 which compares the first and the second reference voltages to voltage control terminals of the amplifying transistor 101. The electric power amplifier controls the bias current that flows in the electric power amplifying transistor 101 to maintain stable high frequency characteristics. COPYRIGHT: (C)2008,JPO&INPIT
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