A protection circuit of a battery pack capable of detecting the error of a charging device from the battery pack. The protection circuit of the battery pack having a battery cell charged by a charging device, the protection circuit including a charge switch coupled to a high current path (HCP), the charge switch disposed between the battery cell and the charging device charging the battery cell and a controller sensing a voltage or a current of the charging device during a charge stop period stopping a charging of the battery cell and determining whether an error of the charging device occurs according to the voltage or the current of the charging device.