Low voltage dc-dc converter for vehicle and electric power control method thereof

PURPOSE: A low voltage direct current converter for a vehicle and a power controlling method thereof are provided to charge a high voltage battery with a low voltage battery when the high voltage battery is discharged or lacking a SOC by implementing power control from high voltage to low voltage and low voltage to high voltage. CONSTITUTION: A first side MOSFET part(10) converts DC voltage, which is inputted from a high voltage battery(HB) to an input terminal, into AC voltage by outer control and outputs to an output terminal. A second side MOSFET part(20) converts the DC voltage, which is inputted from a low voltage supplying source to an output terminal, into the AC voltage and outputs to the input terminal. A primary side and a secondary side of a transformer(30) are respectively connected to the output terminal of the first side MOSFET part and the input terminal of a second side MOSFET part. A controller(40) comprises a first control module(44) for controlling the second side MOSFET part to perform a second rectifying action and a second control module(46) for controlling the first side MOSFET part to perform a first rectifying action. The second control module is activated when a high voltage charging command signal from an interlocking ECU is received. [Reference numerals] (40) Controller; (42) Information collecting module; (44) First control module; (46) Second control module; (HB) High voltage battery; (LB) Low voltage battery