BUCK converter bootstrap drive circuit without negative current

Abstract

The invention relates to a BUCK converter bootstrap drive circuit without a negative current, which at least comprises a first switch tube, a second switch tube and a drive assembly for respectively driving the first switch tube, the second switch tube and a main switch tube in a BUCK converter, and the first switch tube and the second switch tube are connected in series; and the driving assemblyis configured to drive the main switch tube and the second switch tube based on a first driving signal and drive the first switch tube based on a second driving signal. The first driving signal and the second driving signal are complementary to each other so as to avoid simultaneous conduction of the first switch tube and the second switch tube or reduce the simultaneous conduction time of the first switch tube and the second switch tube.

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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