| 摘要 |
PROBLEM TO BE SOLVED: To provide a semiconductor circuit having sufficient high-frequency characteristics, capable of obtaining an output signal, of which the operating point is determined by bottom supply voltage for an input signal whose operating point is determined by top supply voltage, and the operating point of the output signal is not affected by variation of top supply voltage. SOLUTION: In a bias voltage generating unit 30, a second bias voltage V<SB>bs2</SB>and a first bias voltage V<SB>bs1</SB>are generated by an operational amplifier AMP1, according to a reference voltage V<SB>ref</SB>. The first bias voltage V<SB>bs1</SB>is applied to the base of transistors Q3 and Q4 of an output unit 20, and the second bias voltage V<SB>bs2</SB>is applied to the gate of transistors N1 and N2 of the output unit. Accordingly, the base and collector voltages of the transistors Q3 and Q4 of the output unit are controlled, according to the reference voltage V<SB>ref</SB>, and an output signal, of which the operating point is controlled according to the reference voltage V<SB>ref</SB>for an input signal whose operating point is controlled according to supply voltage, can be obtained. COPYRIGHT: (C)2004,JPO&NCIPI
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