Switching circuit for soft switching and high power factor of step-down converter

摘要

The present invention relates to a diode rectifier circuit comprising a small-capacity input-capacitor snubber-type switch connected in parallel between an output end of a diode rectifier circuit and a switch circuit so as to increase a low output voltage which is a drawback of a step- The present invention relates to a switching circuit for soft switching and a high power factor of a step-down converter capable of improving the efficiency of a converter circuit by achieving zero current and zero voltage soft switching in response to a reactor current discontinuous mode operation, A full bridge diode BD for full-wave rectifying an input AC power supply voltage e _s into a direct current, a capacitor C 20 connected in parallel to an output terminal of the full bridge diode BD, A first switch S11 branching to the output terminal of the first switch BD, a first diode D11, a first switch S11, A second diode D12 connected in series to the first diode D11, a second switch S12,;A snubber capacitor C10 connected to both the connection points of the switches S11 and S12 and the diodes D11 and D12 and a snubber capacitor C10 connected in the reverse direction between the output connection point of the second switch S12 and the second diode D12 and the ground And a capacitor Cd so as to increase the DC output voltage and improve the input power factor and to increase the efficiency of the converter, A special switching sequence is not required, so that an open / close circuit can be easily constructed, and the current stress of the device can be reduced to prolong the lifetime of the device.