HIGH-POWER-FACTOR VALLEY-FILL CIRCUIT FOR DRIVING SWITCH TYPE LOAD, AND SWITCHING POWER SUPPLY

摘要

A high-power-factor valley-fill circuit for driving a switch type load, and a switching power supply. The high-power-factor valley-fill circuit comprises three ports. A first terminal of a first switch tube (G1) is a first port. The first terminal of the first switch tube is connected to a positive output terminal of a pulsating direct current power supply, and a second terminal of the first switch tube is connected to a first node (A). A first terminal of a second switch tube (G2) is connected to the first node, and a second terminal of the second switch tube is connected to a negative output terminal of the pulsating direct current power supply. The second terminal of the second switch tube is a second port. A first terminal of a first inductor (L1) is connected to the positive output terminal of the pulsating direct current power supply, and a second terminal of the first inductor is connected to a second node (B). The second node is a third port. A first terminal of a first capacitor (C1) is connected to the first node, and a second terminal of the first capacitor is connected to the second node. The switch type load is connected between the second port and the third port. The first capacitor in the circuit may be a low-voltage capacitor and the type can be easily selected. The switching power supply is characterized by having a high power factor and a low harmonic.