BATTERY PACK

摘要

A battery pack (1) is connected to an external device (9) and to a power supply circuit (10) for the external device (9), and it energizes the external device (9) or is charged by the power supply circuit (10). An analog circuit (12) and a microcomputer (11) inside the battery pack (1) detect an ON/OFF state of the external device (9) and execute control in such a manner as to effect charging by the balance of power obtained by subtracting the maximum power consumption of the external device (9) from the total capacity of the power supply circuit (10) under the ON state and to effect charging by full use of the supply power from the power supply circuit (10) under the OFF state. This charge/discharge control is executed when the microcomputer (11) makes ON/OFF control of a charging switch (S1), a discharging switch (S2) and a switch (S4).