| 摘要 |
PROBLEM TO BE SOLVED: To provide a battery-protecting circuit, by which a part across an input side and a battery can be cut off surely, even when a PNP transistor Q1 as a charging control element is damaged so that an overvoltage is applied and by which the battery can be protected surely from the overvoltage. SOLUTION: The battery-protecting circuit is formed, in such a way that the emitter of the first PNP transistor Q1 is connected to the input side, that its base is connected to a charging circuit and that its collector is connected to the battery. A P-channel FET Q2 is connected across the collector of the transistor Q1 and the battery. A second PNP transistor Q3 is connected across the gate and the source of the FET Q2. A resistor R1 is connected to the collector of the transistor Q3, and a voltage-regulating diode is connected to its base to be grounded.
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