| 摘要 |
PURPOSE: An auto voltage conversion device is provided to prevent a breakdown of a power supply unit by cutting off a load supply power temporarily in case of an overload. CONSTITUTION: A driving voltage generation unit(10) generates a power relay voltage, a relay voltage, and a circuit voltage. A phase current detector(80) and a neutral current detector(90) detect a phase current and a neutral current on a load line. A first and a second detected current output unit(20,30) rectify the detected phase current and the detected neutral current. A control IC(Integrated Circuit)(40) delays the outputs of the first and the second detected current output unit(20,30), and generates a relay driving control logic signal. A delay unit(45) determines an output delay time value of the control IC(40). A relay unit(60) includes a plurality of transistor(61-64) for generating a power relay driving junction point, a general load(102) cutoff junction point and a buzzer(103) driving junction point respectively, and a plurality of relay(65-68). An inductive load power unit(70,70') includes a power relay and a power transformer for starting an inductive load(100,101).
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