| 摘要 |
PROBLEM TO BE SOLVED: To provide a balance type operation amplifier by which in-phase signals can be sufficiently suppressed by using two gain stages suitable for use under a low power source voltage. SOLUTION: The operation amplifier is provided with first and second input terminals IN1 and IN2 for respectively receiving first and second input signals which are differential with respect to each other, a first inverting amplifier circuit A1 for amplifying the first input signal, a second inverting amplifier circuit A2 for amplifying the second input signal, a third inverting amplifier circuit A3 for outputting a first output signal which is the result of multiplication of the output signal of the first inverting amplifier circuit A1 by the first gain and a second output signal which is the result of its multiplication by the second gain, a fourth inverting amplifier circuit A4 for outputting a third output signal which is the result of multiplication of the output signal of the second inverting amplifying circuit A2 by the first gain and a fourth output signal which is the result of its multiplication by the second gain and first and second noninverting amplifier circuits A5 and A6 which amplify quasi-in-phase output signals Voc which are obtained by summing the second output signal and the fourth output signal and feeding them back to the inputs of the third and fourth inverting amplifying circuits A3 and A4. COPYRIGHT: (C)2005,JPO&NCIPI
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