Patent ID: 7274171

Claim:
A charging circuit for charging a secondary battery, comprising; a constant-current circuit that outputs, to the secondary battery, one of first and second constant currents in response to an input control signal; a constant-voltage circuit that charges the secondary battery by applying a predetermined constant voltage thereto; a battery voltage detection circuit that detects and outputs a battery voltage of the secondary battery; a charge current detection circuit that outputs a predetermined charge completion signal when a predetermined current flows to said secondary battery; and a charge control circuit that stops operations of said constant-current circuit and said constant-voltage circuit when the charge completion signal is input, wherein, when the battery voltage of the secondary battery is lower than a predetermined voltage, said charge control circuit outputs, to said constant-current circuit, the control signal to cause said constant-current circuit to output the first constant current, and when the battery voltage of the secondary battery is equal to or greater than the predetermined voltage, said charge control circuit outputs, to said constant-current circuit, the control signal to cause the constant-current circuit to output the second constant current that is greater than the first constant current.