| 摘要 |
PROBLEM TO BE SOLVED: To provide a bias circuit which makes bias voltage low while suppressing a current increase in the bias circuit and a decrease in output voltage when an input of an amplifying element is large and has small change in bias current due to environmental temperature or voltage fluctuations. SOLUTION: The bias circuit 60 includes a bipolar transistor 1 having an emitter connected to a bias terminal 4 for an amplifying element and a collector connected to a voltage supply terminal 11 for a bias circuit, a bipolar transistor 3 having a collector connected to the base of the transistor 1 and an emitter connected to ground, a diode 2 having an anode connected to the base of the transistor 1 and a cathode connected to the base of the transistor 3, and a resistor 5 connected between the base of the transistor 1 and the voltage supply terminal 11 for a bias circuit. COPYRIGHT: (C)2008,JPO&INPIT
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