Bridgeless PFC switch power circuit

Abstract

The present invention discloses a bridgeless PFC switch power circuit. The bridgeless PFC switch power circuit comprises n totem-pole circuits, each totem-pole circuit consisting of a first MOS tube, a second MOS tube, a first inductor, a second inductor, a first diode and a second diode. The drain electrode of the first MOS tube is connected with the cathode of the first diode and the positive pole of the direct current output end, and the source electrode of the first MOS tube is connected with the drain electrode of the second MOS tube; the source electrode of the second MOS tube is connected with the anode of the second diode and the cathode of the direct current output end, and the anode of the first diode is connected with the cathode of the second diode; the first end of the first inductor is connected with the first end of the alternating current input end, and the second end o the first inductor is connected with the source electrode of the first MOS tube and the first end of the second inductor; the second end of the second inductor is connected with the anode of the first diode; and the second end of the alternating current input end is connected with the anode of the first output diode and the cathode of the second output diode, the cathode of the first output diode is connected with the anode of the direct current output end, and the anode of the second output diode is connected with the negative pole of the direct current output end. The present invention is able to improve the PFC efficiency of the switch power supply.

Description

[technical field] [0001] The invention relates to a high-frequency switching power supply, in particular to a bridgeless PFC switching power supply circuit. [Background technique] [0002] With the development of switching power supply technology, due to the limitation of input harmonic current, PFC (powerfactorcorrection, power factor correction) circuit has become an indispensable part of switching power supply, and the volume requirement of switching power supply is getting smaller and smaller, and the efficiency requirement is getting higher and higher. high to save energy. [0003] Bridgeless PFC and interleaved parallel PFC circuits have attracted more and more attention because they can improve efficiency compared with traditional single-tube bridged PFC. If you want to improve efficiency, dual BOOST semi-bridgeless PFC is a good choice, see typical topology figure 1 ,but figure 1 The shown PFC circuit adopts dual inductors, the utilization rate of the magnetic cor...

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Problems solved by technology

Figure 4 The PFC topology shown takes into account the advantages of interleaved parallel PFC and dual BOOST bridgeless PFC, and the efficiency is very high. However, since the body diode of the MOS is used as the output diode of the PFC, the reverse recovery characteristic is poor, so the power is difficult to increase

With the development of power devices, this interleaved totem pole bridgeless PFC topology switching device can use silicon carbide MOS to reduce the reverse recovery current, but the body diode forward voltage drop of silicon carbide MOS is too large, generally greater than 4V, resulting in continuous The flow process loss is too large, which reduces the efficiency

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