Patent ID: 7474079
Filing Date: 2009-01-06
Classification: H02J

Abstract:
1. A charger that receives power supply from an external power supply and charges a secondary battery, the charger comprising: a DC/DC converter that receives supply voltage from the external power supply, outputs a predetermined DC voltage when the supply voltage is greater than or equal to a first supply voltage value, and sets a low resistance between the input and output when the supply voltage is less than the first supply voltage value; a charging control section that receives the output voltage of the DC/DC converter and performs control of supplying a predetermined charging current to the secondary battery when the battery voltage of the secondary battery is greater than or equal to a first battery voltage value, and not supplying a charging current when the battery voltage of the secondary battery is less than the first battery voltage value; and a backup charging circuit that receives supply voltage from the external power supply, and, when the battery voltage of the secondary battery is less than or equal to a second voltage value, performs charging using a current that is less than the charging current of the charging control section.