CHARGE DEVICE AND ITS FAILURE DETECTION METHOD

PROBLEM TO BE SOLVED: To specify a cause of a failure of a damaged charge device when a non-standardized item is fitted to an external DC power supply such as an AC adaptor. SOLUTION: A current detection resistor 8, a MOS transistor 10 and an AC adaptor 1 are connected to the passage of a charge current of a secondary battery 2. A current detection circuit 5 monitors both end voltages of the current detection resistor 8, a charge current value is inputted in a charge control circuit 6 and a comparator 12, the charge control circuit 6 controls the MOS transistors 10, 11 to adjust the charge current flowing into the secondary battery 2, and the comparator 12 compares the detected charge current value with a first specified value (1b) and outputs it. The output of the comparator 12 is inputted into an over-current detection circuit 15 and a timer 13 is used to monitor for a specific period. When the output voltage signal 21 of the AC adaptor 1 agrees with the output signal 20 of the over-current detection circuit 15 at a pre-coincidence circuit 22, "1" is outputted to a backup resistor 24 as an output signal 23, allowing the access of an outer device to confirm the signal of the back-up resistor 24, to specify the cause of the failure. COPYRIGHT: (C)2007,JPO&INPIT