| 摘要 |
PROBLEM TO BE SOLVED: To provide an amplifying circuit that can correct a characteristic difference caused by a temperature difference between an NMOS transistor of a power amplifier and an NMOS transistor of a bias part and obtain a characteristic that satisfies a constant specification in a wide temperature range, and to provide a bias generation circuit that generates a bias current to be applied to the amplifying circuit. SOLUTION: In a structure where a bias is supplied from an adaptive bias generating part 110 and a fixed bias generating part 130 to a gate of a source-grounded NMOS transistor M2 in a power amplifying part 120, a drain current of an MOS transistor M1 of the adaptive bias generating part 110 is detected from voltage drop in a resistance R1 in which the drain current flows. The current, accordingly a bias current, is adjusted by current controllers 111 and 112 based on the detected value. As a result, the MOS transistor M2 of the power amplifying part 120 can be operated while maintaining bias conditions by which linearity can be maintained. COPYRIGHT: (C)2012,JPO&INPIT
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