An apparatus for providing a charging voltage, which is configured to provide a charging voltage through two voltage sources for providing different voltages, the apparatus comprising: an input unit configured to receive AC input power from an outside; a converter configured to convert the AC input power from the input unit to DC input power; a microcontroller unit, MCU, configured to control that a voltage of the DC input power from the converter is delivered to one of the two voltage sources, wherein the MCU is further configured to be controlled by a battery management system of a battery pack; and a switching unit connected to one voltage source circuit between the two voltage sources according to a control of the MCU and for delivering the voltage of the DC input power, characterised in that the two voltage sources are: a pack charging voltage source configured to convert the voltage of the DC input power to output a pack charging voltage so as to charge the battery pack made of two or more battery cells; and a cell balancing voltage source configured to convert the voltage of the DC input power to output a cell balancing voltage so as to charge a battery cell requiring cell balancing, among the two or more battery cells, wherein the cell balancing voltage source decreases the DC input power to a voltage necessary for balancing the battery cells; and the apparatus further comprising: a voltage output unit configured to receive voltages from the pack charging voltage source and the cell balancing voltage source to output the voltages to the battery pack or the two or more battery cells. an input unit configured to receive AC input power from an outside; a converter configured to convert the AC input power from the input unit to DC input power; a microcontroller unit, MCU, configured to control that a voltage of the DC input power from the converter is delivered to one of the two voltage sources, wherein the MCU is further configured to be controlled by a battery management system of a battery pack; and a switching unit connected to one voltage source circuit between the two voltage sources according to a control of the MCU and for delivering the voltage of the DC input power, characterised in that the two voltage sources are: a pack charging voltage source configured to convert the voltage of the DC input power to output a pack charging voltage so as to charge the battery pack made of two or more battery cells; and a cell balancing voltage source configured to convert the voltage of the DC input power to output a cell balancing voltage so as to charge a battery cell requiring cell balancing, among the two or more battery cells, wherein the cell balancing voltage source decreases the DC input power to a voltage necessary for balancing the battery cells; and the apparatus further comprising: a voltage output unit configured to receive voltages from the pack charging voltage source and the cell balancing voltage source to output the voltages to the battery pack or the two or more battery cells. a pack charging voltage source configured to convert the voltage of the DC input power to output a pack charging voltage so as to charge the battery pack made of two or more battery cells; and a cell balancing voltage source configured to convert the voltage of the DC input power to output a cell balancing voltage so as to charge a battery cell requiring cell balancing, among the two or more battery cells, wherein the cell balancing voltage source decreases the DC input power to a voltage necessary for balancing the battery cells; and the apparatus further comprising: a voltage output unit configured to receive voltages from the pack charging voltage source and the cell balancing voltage source to output the voltages to the battery pack or the two or more battery cells.