Synchronous rectification BUCK converter for soft switch with small power

Abstract

The invention discloses a synchronous rectification BUCK converter for a soft switch with small power. The converter comprises a power supply, a main switch pipe, an auxiliary switch pipe, three capacitors, two diodes and an inductor, wherein the positive pole of the power supply is connected with the main switch pipe in series, the main switch pipe and the auxiliary switch pipe are connected in series, the auxiliary switch pipe is connected with the negative pole of the power supply, the main switch is also connected with the inductor in series, the inductor is connected with a first capacitor in series and is connected with the negative pole of the power supply, the main switch pipe is connected with a first capacitor and a first diode in parallel, the auxiliary switch pipe is connected with a second capacitor and a second diode in parallel, and the two ends of a third capacitor are connected with the two ends of a load. The synchronous rectification BUCK converter is applied to occasions with the small power, and breaks the condition of direction reversion of inductive current due to the fact that backflow of capacitance energy is not allowed in the conventional synchronous rectification BUCK converter; the condition of switch on / off of the main switch pipe and the auxiliary switch pipe of the converter with zero voltage comes true, and the efficiency of the converter is remarkably improved.

Description

technical field [0001] The invention relates to the field of power conversion, in particular to a soft-switching synchronous rectification BUCK converter for low power. Background technique [0002] The existing buck converters are divided into ordinary buck converters and synchronous rectification buck converters. In common BUCK converters, when the main switching tube is turned off, the inductance continues to flow through the diode, and the forward voltage drop of the general diode is a fixed value. Therefore, when the converter outputs a large current, the loss on this diode is very large. In traditional synchronous rectification buck converters, the drivers of the main switch and auxiliary switch are complementary, and a fixed dead time will be set between the drivers to prevent the two switches from being directly connected. When the switching tube is working, the voltage and current overlap, which will generate a large switching loss and affect the efficiency of th...

AI Technical Summary

Problems solved by technology

When the switching tube is working, the voltage and current overlap, which will generate a large switching loss and affect the efficiency of the converter.

For very small power BUCK converters, the switching loss is generally ignored

In fact, since the rated power of the converter itself is very small, the existence of switching loss will occupy a large proportion of the rated power of the converter, making it difficult for the efficiency of the low-power BUCK converter to reach a higher level

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