| 摘要 |
PROBLEM TO BE SOLVED: To provide a low cost power amplifier module that can be manufactured at a high yield by obtaining a stable idling current even when an environment such as ambient temperature and control voltage change so as to form a bias circuit and a power amplifier section only with a stable transistor process. SOLUTION: The bias circuit is provided with, ambient temperature and control voltage fluctuation detection circuits, and an error amplifier circuit that commonly amplifies fluctuations detected by them. A current corresponding to a change in a control current fluctuating with changes in temperature and control voltage is supplied to an error amplifier to cancel a change in the control current so as to supply a stable idling current to a power amplifier. A temperature detection circuit has a function as a reference voltage source against fluctuations in the control voltage in addition to a temperature detection function, a control voltage detection circuit has a function as a reference voltage source against temperature fluctuations in addition to the control voltage detection function, and the temperature detection circuit and the control voltage detection circuit function as the detection circuits or the reference voltage sources against the respective fluctuations.
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