Abstract: The present invention relates to a charger capable of performing the integrated control and separate control of parallel operations. The charger includes a plurality of charging modules connected in parallel with each other. Each of the charging modules includes a rectification unit for converting input AC power into DC power. The system also includes a power conversion unit, a switching control unit, a DC unit, a detection unit, and a computation control unit. The computation control unit receives the voltage and current, detected by and fed back from the detection unit, computes the voltage and the current, and transmits a control signal required to allow the DC unit to supply a primary constant current, a constant voltage, and a secondary constant current to a battery.