| 摘要 |
PROBLEM TO BE SOLVED: To provide a compact charge/discharge protection circuit having high breakdown strength, of which a voltage value of an internal circuit (overcurrent detection voltage or short-circuit detection voltage value) does not fluctuate even if an abnormal charger is connected for a long time. SOLUTION: The charge/discharge protection circuit comprises an overcharge detection circuit (22) for detecting overcharge of a secondary battery (12), an overdischarge detection circuit (27) for detecting overdischarge of the secondary battery (12), overcurrent detection circuit (25) for detecting overcurrent of the secondary battery (12), and an abnormal charger detecting circuit (28) for detecting an abnormal charger. Protective means (transistors Q3 and Q4) are provided to prevent a voltage from a charger (14) from being directly applied to the overcurrent detection circuit (25) or a short-circuit detection circuit (24) if the charger connected is detected as an abnormal charger. A circuit element applied with a voltage of the secondary battery has a low breakdown strength structure, while a circuit element applied with a voltage of the charger has a high breakdown strength structure. COPYRIGHT: (C)2008,JPO&INPIT
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