| 摘要 |
PROBLEM TO BE SOLVED: To reduce current consumption of the transmitter system which is used up to a high-frequency range, sets an idling current and an open gain independently, and selects a plurality of power outputs. SOLUTION: An idling current setting circuit 3 is equipped with: current setting transistors Q3 and Q4 which are connected to output transistors Q1 and Q2 of a driver 2 in a current mirror manner; a plurality of current setting resistances R1 to R4; and a plurality of switches ASW1 to ASW4 for switching to one of the plurality of current setting resistances R1 to R4. The idling current is thereby set with the current mirror ratio of the current transistor Q3 and Q4 and the output transistor Q1 and Q2 which do not participate in the open gain of a power amplifier, and the idling current is optionally set independently of the open gain. COPYRIGHT: (C)2007,JPO&INPIT
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