| 摘要 |
PROBLEM TO BE SOLVED: To provide a battery pack by which a discharge control FET and a charging control FET are controlled by impressing a voltage higher than a battery voltage to a gate terminal and the energy loss is suppressed to a minimum. SOLUTION: A protection circuit 30 monitors the voltage of a secondary battery 2. When the voltage exceeds a lower limit value in a rated voltage range, the protection circuit 30 provides a signal for allowing the discharge to the gate terminal of the discharge control FET. When the discharge control FET receives the signal, it is in a connection state and allows a discharge current to pass. In the cases other than that, the discharge control FET intercepts the discharge current. Further, when the voltage exceeds a prescribed value, the signal of a voltage higher than a battery voltage is provided to the gate terminal from a voltage converter 11. Also, when the voltage is below an upper limit value in the rated voltage range, the protection circuit 30 provides a signal for allowing the charging to the gate terminal of the charging control FET. Further, when the voltage exceeds a prescribed value, the voltage output from the voltage converter 11 is provided to the gate terminal. COPYRIGHT: (C)2005,JPO&NCIPI
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