| 摘要 |
PROBLEM TO BE SOLVED: To reduce current consumption as much as possible in order to secure speaking or waiting time since a power source of a portable telephone is a battery. SOLUTION: In a compound semiconductor FET high frequency amplifier circuit connecting a resistor Rs1 and a capacitor Cs, which are connected in parallel, between the source terminal of an FET Qa for high frequency signal amplification and the ground and applying a bias voltage from a dividing point P of resistors R1 and R2, which are connected in series between a power source VDD and the ground, to the gate terminal of the FET Qa for amplification, an FET Qs for bias current cutoff and a resistor Rs2 are connected in series, these components are connected parallel to the resistor Rs1 and further, an FET Qg for gate bias switching is connected in parallel to the resistor R2 so as to simultaneously switch the gate bias voltage of the FET Qa for amplification while being linked with switching of the drain bias current of the FET Qa for amplification.
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