| 摘要 |
PROBLEM TO BE SOLVED: To provide an amplifier circuit capable of making large the temperature coefficient of idle current. SOLUTION: The amplifier circuit includes an amplifying stage circuit 11 having a transistor Q1 for amplifying and outputting a signal, and a bias circuit 21 which has: a transistor Q2 having substantially the same layer structure as the transistor Q1 has, wherein a collector is connected to a voltage supply terminal Vdc, and an emitter is connected to the base of the transistor Q1; a diode D1 whose anode is connected to the emitter of the transistor Q2 and whose cathode is grounded and which has on-voltage lower than on-voltage of the transistor Q2; and a voltage supply circuit 23 for setting voltage supplied from a control voltage supply terminal Vcon so as to have a negative coefficient for reducing voltage with respect to a temperature rise and supplying the voltage to the base of the transistor Q2, and is formed on the same substrate as the transistor Q1. COPYRIGHT: (C)2009,JPO&INPIT
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