A battery management system for a battery pack including a plurality of battery cells connected in series is provided. The battery management system includes a first switching unit coupled to an anode of a first battery cell of the battery pack, having a first P-type transistor coupled to the anode of the first battery cell, a first resistor coupled between the anode of the first battery cell and a gate of the first P-type transistor, and a current mirror coupled to the gate of the first P-type transistor and the first resistor, draining a first mirror current from the first resistor in response to a control signal, so as to turn on the first P-type transistor. The system further includes a detection circuit coupled to the first switching unit.