Patent ID: 7479765

Claim:
An integrated circuit for charging a secondary battery via a charging transistor, comprising: a charge current detection circuit which detects a charge current output from the charging transistor, and generates and outputs a signal including the charge current information; a voltage comparison circuit which compares a voltage of the secondary battery with one or more predetermined voltages, and generates and outputs a signal including the voltage comparison information; and a charge controlling circuit which controls the charging transistor according to information on the voltage of the secondary battery and the signals output from the charge current detection circuit and the voltage comparison circuit such that the charging transistor performs constant current charging in which a predetermined current is output or constant voltage charging in which a charge current is output so that the secondary battery has a predetermined voltage, wherein the charge controlling circuit stops applying a charge current for a predetermined time T 1 in beginning of charging of the secondary battery, wherein, when the voltage comparison circuit detects that the voltage of the secondary battery becomes less than a predetermined voltage V 1 within the predetermined time T 1 , the charge controlling circuit judges that the secondary battery is abnormally connected and performs an abnormality correction treatment, wherein when the voltage comparison circuit detects that the voltage of the secondary battery becomes not less than a predetermined voltage V 2 greater than the voltage V 1 , the charge controlling circuit stops applying a charge current for a predetermined time T 2 , and wherein, when the voltage comparison circuit detects that the voltage of the secondary battery becomes less than a predetermined voltage V 2 −, which is greater than the voltage V 1 and less than the voltage V 2 , within the time T 2 , the charge controlling circuit judges that the secondary battery is abnormally connected and performs an abnormality correction treatment.