| 摘要 |
PROBLEM TO BE SOLVED: To enable an overcharge protective circuit to detect the overcharging of a battery and stop the charging of the battery even when a capacitor short- circuits. SOLUTION: An overcharge protective circuit for battery is provided with a first comparing means 16 which compares the charging voltage of a battery with a first reference voltage, a charging means Q10 which charges a capacitor C1 having grounded one end when the charging voltage is low, and a discharging means 36 which discharges the capacitor C1 when the charging voltage is high. The protective circuit is also provided with a second comparing means 34 which compares the charged voltage of the capacitor C1 with a second reference voltage and, when the charged voltage is lower than the second reference voltage, generates an alarm signal indicating the overcharging of the battery. When the capacitor C1 shortcircuits, consequently, the capacitor C1 is discharged and the voltage of the capacitor C1 becomes lower than the second reference voltage. In addition, the alarm signal indicating the overcharging of the battery is generated. Therefore, the overcharging of the battery can be detected and the charging can be stopped even when the capacitor C1 short-circuits.
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