DC-DC CONVERTER

摘要

PROBLEM TO BE SOLVED: To provide a DC-DC converter including a coupling transformer which reduces leakage flux to enable designing close to a theoretical value.SOLUTION: The DC-DC converter comprises: a coupling transformer 1 including a coil 11 and a coil 12; a switch Tr1 connected via the coil 11 to opposite ends of a DC power supply Vi; a switch Tr2 connected via the coil 12 to opposite ends of the DC power supply; a series circuit between a diode D1 and a smoothing capacitor Co which is connected to opposite ends of the switch Tr1; a series circuit between a diode D2 and the smoothing capacitor Co which is connected to opposite ends of the switch Tr2; and a control circuit 100 which turns the switch Tr1 and the switch Tr2 on alternately and also turns the switch Tr1 and the switch Tr2 on at the same time every 1/2 cycle for only a predetermined overlapping period. The coupling transformer 1 has an I-shaped core 4 sandwiched between two E-shaped cores 2 and 3, in which composition there is a gap 5 provided between a center leg 2a of the E-shaped core 2 and the I-shaped core 4 and there is a gap 5 provided between a center leg 3a of the E-shaped core 3 and the I-shaped core 4, with the coil 11 and the coil 12 wound around the I-shaped core 4.