| 摘要 |
PROBLEM TO BE SOLVED: To provide a circuit suppressing an increase of a circuit scale while materializing accurate monitoring, as for a current monitoring circuit to monitor charging and discharging currents of a secondary battery. SOLUTION: An amplification part 16 amplifies the voltage of a current sensing resistance 14 caused by charging and discharging currents with plural kinds of amplification degrees. A comparison part 17 compares the output voltage of the amplification part 16 with a reference voltage, and a control part 11 controls the reference voltage to supply to each part by the compared result and controls the amplification degree of the amplification part 16. An A/D conversion part 18 converts the output voltage of the amplification part 16 from analog to digital, and a value conversion part 19 converts the digital value converted by the A/D conversion part 18 under control of the control part 11 to a value equivalent to the charging and discharging currents. If an excess current is detected, a battery 13 is separated from an external device by switching off a switch part 12.
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