US Patent 7394224 Charge control device

A charge control device of a secondary battery that allows the use of an electronic apparatus for a long period using a single initial charging, and is capable of extending battery life. The charging device includes a charge circuit for supplying charging current to secondary batteries, a voltage detection circuit for detecting the voltage of secondary batteries, a current detection circuit for detecting the charging current in secondary batteries, a memory such as an EEPROM for recording the number of times of charging or total charge integrated amount in secondary batteries, and a microcontroller for controlling charge circuit, changing over to constant voltage charge after charging secondary batteries 2 at constant current, and decreasing the voltage in constant voltage charging depending on the number of times of charge or total charge integrated amount recorded in the memory of EEPROM.