A bootstrap drive circuit for buck converter without negative current

Abstract

The invention relates to a bootstrap drive circuit for a BUCK converter without negative current, at least including a first switch tube, a second switch tube, and a main switch in the BUCK converter that drives the first switch tube, the second switch tube, and the BUCK converter respectively. A drive assembly for a switch tube, the first switch tube and the second switch tube are connected in series, and the drive component is configured to drive the main switch tube and the second switch tube based on a first drive signal, and based on the second switch tube A drive signal drives the first switch tube, and the first drive signal and the second drive signal are complementary to each other to prevent the first switch tube and the second switch tube from being turned on at the same time or reduce the first switch tube. tube and the second switch tube are turned on at the same time.

Description

technical field [0001] The invention relates to the technical field of switching power supplies of Buck topology, in particular to a bootstrap drive circuit for a Buck converter without negative current. Background technique [0002] As one of the most basic DC-DC converters in power electronics, the BUCK circuit is very mature in its current development. Due to its advantages of simple topology, small number of components and easy design of parameters, it is widely used in various modern industrial products, such as military equipment, aerospace field, medical equipment, power equipment, communication equipment, LED driver, instrumentation, industrial control equipment And some medium and high power consumer electronics or household appliances and many other fields. [0003] Such as image 3 As shown, the BUCK converter (that is, the BUCK circuit) generally includes a MOS-type main switch tube Q 1 , Freewheeling diode D 1 , energy storage inductor L, output filter capaci...

AI Technical Summary

Problems solved by technology

If the switch tube M 2 The conduction time is long, considering that the BUCK converter is in the current discontinuous working mode, at this time, there will inevitably be no current in the loop, resulting in the voltage on the output side being higher than the voltage on the switching tube side, so that the capacitor on the output side Discharge through this circuit, so the current is poured back, and this kind of inductive current negative occurs.

If the negative inductor current is too large, the MOS tube (switch tube) added in the bootstrap startup circuit needs to use a high-current MOS tube, resulting in an increase in cost

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