| 摘要 |
PURPOSE: A constant voltage power supply is provided to obtain a high speed response characteristic as well as a stable operation during a sleep mode. CONSTITUTION: A constant voltage power supply includes a series control transistor connected between of input and output terminals of the constant voltage power supply, and an error amplifier circuit having an output terminal connected to a control terminal of the series control transistor. The operation of the series control transistor is controlled according to an output voltage signal supplied to one input terminal of the error amplifier circuit from the series control transistor and a reference voltage signal supplied to another input terminal of the error amplifier circuit. The constant voltage power supply further includes a first amplifier circuit(A1) having first and second transistors(M1,M2), a second amplifier circuit(A2) having a third transistor(M3), a fourth transistor(M4) and a first switch(M5). The ends of the respective main current paths of the first and second transistors are connected with a common node to enable the first and second transistors to be formed as a differential pair. The first switch is connected in series to an end of the main current path of the fourth transistor and is switched in response to an external control signal(Sg).
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