| 摘要 |
PROBLEM TO BE SOLVED: To provide a processing amplifier of high precision which has a low offset voltage by a simple circuit configuration. SOLUTION: A differential amplifier comprises an input stage circuit, a first current mirror circuit, a second current mirror circuit, an output stage circuit, an operation point setting circuit, and a floating constant current source. The input stage circuit comprises a first differential pair and a second differential pair which are in a complementary relation. The first current mirror circuit is connected to the first differential pair, becoming its active load. The second current mirror circuit is connected to the second differential pair, becoming its active load. The output stage circuit comprises a pair of output transistors that is serially connected between a positive voltage source and a negative voltage source. The floating constant current source is connected between the input terminal of the first current mirror circuit and that of the second current mirror circuit, supplying a constant current. The first and second current mirror circuits superpose the output of the input stage circuit on the current corresponding to the constant current supplied by the floating constant current source, which is supplied to the operation point setting circuit. COPYRIGHT: (C)2007,JPO&INPIT
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