| 摘要 |
PROBLEM TO BE SOLVED: To increase phase tolerance; to stabilize changes in output voltage at the start of operation; and to prevent excess currents. SOLUTION: An amplifier includes an input-stage amplifying circuit 30A; an output-stage amplifying circuit 30B; and a negative feedback circuit 50. The circuit 30A performs differential amplification of a first input voltage input to a positive-phase input node (gate of NMOS 35) and a second input voltage input to a reverse-phase input node (gate of NMOS 34) and outputs the result from a positive-phase output node N35. The circuit 30B amplifies the output voltage of the node N35, outputs the result from an output terminal REGOUT, produces a second input voltage matching an output voltage Vout, and inputs the second input voltage to the gate of the NMOS 34 for feedback. The circuit 50 has a current-source PMOS 51 whose output current varies depending on the output voltage of the node N35, and a differential amplification part comprising PMOSs 52, 53 which perform differential amplification of the first and second input voltage when the output current of the PMOS 51 is supplied thereto. The circuit 50 feeds back a positive-phase current corresponding to the output current of the differential amplification part to the reverse-phase output node N34. COPYRIGHT: (C)2007,JPO&INPIT
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