Patent ID: 8854007

Claim:
A protection circuit of a battery pack having a battery cell charged by a charging device, the protection circuit comprising: a charge switch coupled to a high current path (HCP), the charge switch disposed between the battery cell and the charging device configured to charge the battery cell; a detecting unit coupled to the HCP at a node between the charge switch and the charging device and configured to detect a voltage or a current on the HCP of the charging device; a controller configured to sense the voltage or the current of the charging device through the detecting unit during a charge stop period stopping a charging of the battery cell and to determine whether or not an error of the charging device occurs according to the voltage or the current of the charging device, and a blocking unit configured to block coupling between the charging device and the battery cell when the error occurs, wherein the blocking unit comprises: a fuse coupled to the HCP in series; a heater having a first terminal coupled to an end of the fuse; and a control switch coupled between a second terminal of the heater and a ground, wherein a gate terminal of the control switch is coupled to the controller.