A portable computing device is disclosed. The portable computing device includes a processor, a removable battery pack, a battery detection unit, and an internal power-supplying unit. The battery detection unit detects removal of the battery pack from the portable computing device. The internal power-supplying unit provides operating power to the portable computing device after the battery pack is removed from the portable computing device. The battery detection unit may generate an interrupt signal to the processor upon detection of removal of the battery pack such that the processor may begin executing a hibernation routine. The internal power-supplying unit may be a super capacitor or an internal battery.