| 摘要 |
PROBLEM TO BE SOLVED: To provide an amplifier circuit that is prevented from being adversely influenced by a parasitic capacitance and is operated at a low power supply voltage. SOLUTION: A constant voltage generating circuit 30 is constituted of a Wilkinson type current mirror circuit, a node N 32 on this negative feedback loop is used for a voltage source outputting a constant voltage S32 and connected to a bias supply line 35. A plurality of stages of amplifier sections 40-1 to 40-4 are connected in cascade, gate terminals of bias current generating NMOSes 45-1 to 45-4 in the amplifier sections 40-1 to 40-4 are connected to the bias supply line 35 and a constant voltage 35 received from the bias supply line 35 permits the NMOSes 45-1 to 45-4 to produce bias currents I4-1 to I4-4. Input signals INP, INN are amplified by the amplifier sections 40-1 to 40-4 at a prescribed amplification factor on the basis of the bias currents I4-1 to I4-4. COPYRIGHT: (C)2004,JPO
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