| 摘要 |
PROBLEM TO BE SOLVED: To provide a high frequency amplifier circuit which functions even when a supply voltage to a bias supply circuit is low. SOLUTION: The bias supply circuit includes a second hetero-junction bipolar transistor of which the emitter is grounded, a depression type FET, and first and second resistors. One end of the first resistor is connected to the collector of the second hetero-junction bipolar transistor, and the other end of the first resistor is connected to a first node. One end of the second resistor is connected to the first node and the other end of the second resistor is grounded. The gate of the depression type FET is connected to the first node, the source of the depression type FET is connected to the base of the second hetero-junction bipolar transistor directly or via a resistor, and a bias voltage is output from the source of the depression type FET. COPYRIGHT: (C)2011,JPO&INPIT
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