| 摘要 |
PROBLEM TO BE SOLVED: To provide a constant voltage power supply circuit which is composed of a single operational amplifier without the preparation of two or more output transistors, operational amplifiers and feedback resistors, respectively. SOLUTION: A stabilizing voltage source is composed of one operational amplifier 11 to which a reference voltage Vref is supplied from a power supply terminal Tref, one output transistor MPa comprising a P-channel type MOS transistor, one feedback resistor 12 in which resistor elements R1 and R2 are connected in series, and one output capacity Cout. The stabilizing voltage source supplies a loading circuit 13 with an output voltage Vout. The operational amplifier 11 is provided with four input difference pairs, and the input connection or inner node connection of the operational amplifier 11 is switched to make the input transistor of one of the difference pairs have a high impedance, and consequently amplifying circuits of different characteristics can be switched and used. COPYRIGHT: (C)2006,JPO&NCIPI
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