| 摘要 |
PROBLEM TO BE SOLVED: To enhance efficiency by suppressing the flyback voltage added to a switch element, even if a sufficient value of inductance to control the recovery current from an output rectifying diode is inserted. SOLUTION: A path leading to a switch element SW from an output rectifying diode D1 of a boosting chopper is provided with an inductance L2 for current control, to control the recovery current to an output rectifying diode D1 in a transient period, when the switching element SW is shifted from on to off. Moreover, a snubber circuit A, where a diode D2 for absorbing the flyback voltage generated in the inductance L2 for recovery current control during the transition period when the switching element SW is shifted from off to on, and a capacitor C2 are connected in series, is connected in parallel with the switching element SW. Furthermore, this power unit is provided with an energy shifting course which causes the energy accumulated in the capacitor of the snubber circuit to shift from the junction between the diode D2 and the capacitor C2 of the snubber circuit A to the positive side of the capacitor C1 for smoothing of output via an inductance L3.
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