| 摘要 |
PROBLEM TO BE SOLVED: To realize an FET amplifier circuit in which an FET amplifier element has further improved switching speed. SOLUTION: The FET amplifier circuit 10 is provided with: a bias voltage sudden step-up circuit 6 and a bias voltage sudden drop circuit 7. The bias voltage sudden step-up circuit 6 includes: a capacitor 62 connected in series between a terminal of a bias resistor 2 connected to a gate of an FET amplifier circuit 1 and a predetermined power supply Vcc; and a switching FET 61, wherein the switching FET 61 is turned on when a control signal S<SB>CTR</SB>is on, and thus, a transitional current is applied from the predetermined power supply Vcc to the bias resistor 2, thereby suddenly stepping up a bias voltage between a gate and a source of the FET amplifier element 1. The bias voltage sudden drop circuit 7 includes a switching FET 71 connected in parallel to the bias resistor 2, wherein the switching FET 71 is turned on when the control signal S<SB>CTR</SB>is off, thereby suddenly dropping the bias voltage between the gate and the source of the FET amplifier element 1. COPYRIGHT: (C)2009,JPO&INPIT
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