Charging circuit for secondary battery

Abstract

A charging circuit for a secondary battery includes a constant-voltage circuit part outputting one of a plurality of predetermined constant voltages and charges the secondary battery by applying the constant voltage thereto, a detection circuit part detecting a battery voltage of the secondary battery, and a control circuit part controlling the selection of the constant-voltage in response to the detected battery voltage. Another charging circuit includes a constant-current circuit part outputting, to the secondary battery, one of two predetermined constant currents, a constant-voltage circuit part charging the secondary battery by applying a predetermined constant voltage thereto, a battery voltage detection circuit part detecting a battery voltage of the secondary battery, a charge current detection circuit part outputting a predetermined charge completion signal, and a charge control circuit part stopping operations of the constant-current circuit part and constant-voltage circuit part when receiving the charge completion signal.

1 - 14 . (canceled)  
   
   
       15 . A charging circuit for charging a secondary battery using a constant-current/constant voltage charging method, comprising: 
 a constant-voltage circuit configured to charge the secondary battery in a constant-voltage mode;    a constant-current circuit configured to charge the secondary battery in a constant current mode, wherein, when a battery voltage of the secondary battery is lower than a predetermined voltage, the constant-current circuit outputs a first constant current, and when the battery voltage of the secondary battery is equal to or greater than a predetermined voltage, the constant-current circuit outputs a second constant current that is greater than the first constant current.    
   
   
       16 - 19 . (canceled)  
   
   
       20 . A charging circuit for charging a secondary battery using a constant-current/constant voltage charging method, comprising: 
 a voltage comparator that compares a battery voltage of the secondary battery with a predetermined voltage and outputs a comparison signal indicating a comparison result;    a constant-voltage circuit configured to charge the secondary battery in a constant-voltage mode;    a constant-current circuit configured to charge the secondary battery in a constant current mode, the constant-current circuit outputs a first constant current in response to a first comparison result, the constant-current circuit outputs a second constant current that is greater than the first constant current in response to a second comparison result.