| 摘要 |
PROBLEM TO BE SOLVED: To stabilize the bias of a field-effect transistor FET constituting an amplifier and to stabilize the gain of the amplifier. SOLUTION: A Gm compensating bias circuit providing a bias for the FET constituting the amplifier has a first FET having a first electrode and a second electrode where a reference current flows and also having a gate connected to the first electrode, a second FET having a first electrode and a second electrode where a bias current flows and also having a gate connected to the gate of the first FET, and a comparator to output a signal based on results of comparison between a first potential of the first electrode of the first FET and a second potential at the first electrode of the second FET. With the signal output from the comparator, the reference current and bias current are controlled to be equal to each other. COPYRIGHT: (C)2009,JPO&INPIT
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