| 摘要 |
PROBLEM TO BE SOLVED: To improve efficiency in a light load, using a simple configuration. SOLUTION: At the primary side of a transformer 38 of a power-supply unit 36, MOSFETs 50 and 52 are connected to both ends of a DC voltage source 48 in series, and at the same time, capacitors 54 and 56 are connected in series, one end of primary coil winding 38A of the transformer 38 is connected to the connection point of the capacitors 54 and 56, with the other coil winding 38A connected to the connection point of the MOSFETs 50 and 52 via an inductance 58 for resonance and a primary coil winding 60A of a transformer 60, and one end of a capacitor 62 for resonance, where the other end is connected to the negative terminal of the DC voltage source 48 is connected between the inductance 58 for resonance and the primary coil winding 60A via a secondary coil winding 60B of the transformer 60. A surge current, which flows when the MOSFET 50 or 52 is turned on in a light load, is suppressed by an electromotive force induced by either the primary coil winding 60B or the secondary coil winding 60B of the transformer 60.
|
