Cell balancing circuit and cell balancing method using the same

A battery cell balancing system (100) is disclosed. In one embodiment, the system includes a plurality of battery cells (B1, B2, B3) arranged in series and a power supply (110) configured to receive the cumulative voltage of the battery cells (B1, B2, B3) and output a first charging voltage to one of the battery cells that has a voltage less than a reference voltage. According to one embodiment, it is possible to implement a cell balancing operation using the cumulative voltage of the battery cells.