| 摘要 |
PROBLEM TO BE SOLVED: To provide a constant voltage circuit having an overcurrent protective circuit decreasing a consumed current while having a characteristic similar to a conventional fold-back characteristic. SOLUTION: A current output from a transistor M1 is restrained from increasing to decrease an output voltage Vo, when an output current io reaches a current value ia, without being crossed with a load meridian of connecting an intersection of a prescribed value of the output current io and a prescribed constant voltage value Vx, to a zero point where both the output voltage Vo and the output current io are zero, transistors M24, M16 are turned off when the output voltage Vo is reduced to a voltage value Vb, a gate voltage of a transistor M20 is increased therein, the output current io is limited by a current value ic to decrease the output voltage Vo, transistors M22, M21 are turned off when the output voltage Vo is reduced a voltage value Vd, the gate voltage of a transistor M20 is increased further, and the output current io is limited by a current value ie to decrease further the output voltage Vo. COPYRIGHT: (C)2008,JPO&INPIT
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