| 摘要 |
PROBLEM TO BE SOLVED: To provide a small-sized and high breakdown voltage charging and discharging protective circuit and a battery pack in which a voltage value in an internal circuit (overcurrent detecting voltage or short-circuit detecting voltage value) will not fluctuate even in case of continuous connection of an abnormal charger for a long time. SOLUTION: This charging and discharging protective circuit involves an overcharge detecting circuit 22 detecting the overcharge of a secondary battery 12, an over-discharge detecting circuit 27 detecting the over-discharge of the secondary battery 12, an overcurrent detecting circuit 25 detecting the overcurrent of the secondary battery 12, and an abnormal-charger detecting circuit 28 detecting an abnormal charger and is provided with means (transistors Q3, Q4) preventing the voltage of a charger form being applied directly to the overcurrent detecting circuit 25 or a shirt-circuit detecting circuit 24 if a charger 14 connected is detected to be an abnormal charger. A circuit element applied with the voltage of the secondary battery is formed out of a low breakdown voltage structure and a circuit element applied with the voltage of the charger is formed out of a high breakdown voltage structure.
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