Patent ID: 7541780
Filing Date: 2009-06-02
Classification: H02J

Abstract:
1. A charge controlling circuit employed in an electronic device to perform specified operations using a mounted secondary battery as a power source and to control a charging current to be supplied to said secondary battery, wherein a temperature of a main body of said electronic device or an ambient temperature thereof is detected and, when said temperature is higher than or equal to a lower limit in a proper temperature range required by said secondary battery and is lower than a specified reference value, a charging current having a first current value is fed to said secondary battery and, when said temperature is lower than or equal to an upper limit in said proper temperature range required by said secondary battery and is higher than or equal to said specified reference value, a charging current having a second current value being less than said first current value is found to said secondary battery and, when said temperature is a value outside of said proper temperature range, charging of said secondary battery is stopped; and a temperature detecting unit to detect a temperature of a main body of said electronic device or an ambient temperature thereof and to output a temperature detecting voltage corresponding to the detected temperature; a level judging unit to output an active-mode judging signal when said temperature detecting voltage is a value corresponding to a temperature within said proper temperature rang and a non-active mode judging signal when said temperature detecting voltage is not a value corresponding to said temperature within said proper temperature range; a charge controlling unit to feed a charging current set by using supply power supplied from an external power source to said secondary battery when said judging signal is in an active mode and to stop supply of said charging current when said judging signal is in a non-active mode; and a charging current setting unit to set said charging current at said first current value when said temperature detecting voltage is a value corresponding to a temperature being higher than or equal to a lower limit value within said proper temperature range and bring lower than said specified reference value and to set said charging current at said second current value when said temperature detecting voltage is a value corresponding to a temperature being lower than or equal to an upper limit value within said proper temperature range and being higher than or equal to said reference value.