| 摘要 |
PURPOSE:To obtain a CMOS amplifier circuit with high accuracy without any offset voltage by connecting a capacitor to an input side so as to store the offset voltage of the amplifier circuit at the input side and amplifying a signal in the form that the offset voltage of the amplifier is cancelled. CONSTITUTION:When the amplifier circuit is in inoperating state, a switch 32 is turned off, switches 33, 34, 35 are turned on, and when the amplifier circuit is in operating state, the switch 32 is turned on and the switches 33, 34, 35 are turned off. A potential of a node 7 in the inoperating state is an equipotential to that of an input terminal 4 applied with a reference voltage, the offset voltage appearing at nodes 121, 122 appears at nodes 37, 36 and is stored in capacitors 30, 31. An input signal applied to an input terminal 3 in the operating state is applied to a transistor 15 after the offset voltage stored in the capacitor 30 is subtracted from the input signal, and a reference applied to the input terminal 4 is applied to a transistor 17 after the offset voltage stored in the capacitor 31 is subtracted from the reference voltage, thereby causing an output voltage without any offset voltage at output terminals 5, 6.
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