| 摘要 |
PURPOSE:To shorten the replacement time of a battery and to prevent stored data from vanishing by a method wherein the consumed state of a secondary battery which has been built in a cordless electronic apparatus is monitored and the charging start time of a spare secondary battery is decided. CONSTITUTION:The title charging device refers to a device wherein, when the voltage of a secondary battery 3 used as a power supply for an electronic apparatus 1 is dropped to a prescribed level or lower, the secondary battery is replaced by a spare secondary battery 9 which has been charged in advance and the operation of the electronic apparatus is continued. The title charging device is provided with a discharge-state monitoring circuit 10 which is composed of a timer switch 11, a discharge-state detection circuit 12 and a detected-data transmission circuit 17 and which transmits the discharge state of the secondary battery as an optical signal 105 having a time width proportional to the discharge state and with a spare-secondary- battery charger 20 which includes a detected-data reception circuit 21, a charging control circuit 24 and a charging circuit 31 and which controls the start and the finish of the charging operation of the spare secondary battery 9 by collating a received signal with judgment data. |
