High-power factor valley-filled circuit for driving switch type load and switching power supply

Abstract

The invention provides a high-power factor valley-filled circuit for driving a switch type load and a switching power supply. The high-power factor valley-filled circuit comprises three ports, wherein the first end of a first switching tube is the first port; the first end of the first switching tube is connected with the positive output end of a pulsating DC power supply, and the second end of the first switching tube is connected with a first joint; the first end of a second switching tube is connected with the first joint, and the second end of the second switching tube is connected with the negative output end of the pulsating DC power supply; the second end of the second switching tube is the second port; the first end of a first inductor is connected with the positive output end of the pulsating DC power supply, and the second end of the first inductor is connected with a second joint; the second joint is the third port; the first end of a first capacitor is connected with the first joint, and the second end of the first capacitor is connected with the second joint; the switch type load is connected between the second port and the third port. The first capacitor in the circuit can be a low-voltage capacitor, so the types of the capacitor can be selected easily; power factors can be controlled by adjusting the conduction angle of a rectifier bridge.

Description

technical field [0001] The invention relates to the field of electronic technology, in particular to a high power factor valley filling circuit and a switching power supply for driving a switching load. Background technique [0002] In the current field of power conversion, switching power supplies are widely used in national industries due to their high efficiency and small size. For the mains AC / DC switching power supply, according to the regulations of various countries, it is generally necessary to add power factor correction (PFC, Power Factor Correction) to improve the power factor of the electrical equipment and reduce the harmonic pollution of the equipment to the power grid. [0003] There are two main types of current power factor correction: active power factor correction and passive power factor correction. Active power factor correction is the main method adopted by high-performance switching power supply. It has the characteristics of high power factor (greate...

AI Technical Summary

Problems solved by technology

[0004] The minimum output voltage of this passive valley filling circuit is half of the peak value of the AC voltage, it is not adjustable, its application is limited, and its power factor is not high, generally less than 0.9

Of course, a multi-level expansion method can also be used, but at this time the number of components will increase greatly, and the cost will also increase accordingly, so it is almost not used in practical applications.

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