| 摘要 |
PROBLEM TO BE SOLVED: To provide a small and inexpensive protection circuit capable of protecting a target of protection, with which a coil is connected in series from over-current and a load current detection circuit suitable for such a protection circuit. SOLUTION: The load current detecting circuit detects the load current of a load with which a coil is connected in series. Then, the series circuit of a resistor and a capacitor is connected in parallel with the coil, the voltage between both ends of the capacitor is turned into a detection voltage, and values of respective elements are selected so that L1/R1=C2×R2 is satisfied, if the inductance of the coil is L1, the resistance value of the resistance component of the coil is R1, and the resistance value and the capacitance of the resistor and the capacitor in the series circuit are R2 and C2. The protection circuit utilizes the load current detecting circuit. COPYRIGHT: (C)2008,JPO&INPIT
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