A dual-transistor forward converter with dual rcd clamps

Abstract

The invention discloses a two-transistor forward converter with dual RCD clamping circuits, and belongs to the technical field of a DC-DC converter. The drain electrode of a switch tube M1 is connected with the positive electrode of a power supply Vs; the source electrode of the M1 is connected with the non-dotted terminal of a T1 first secondary-side winding, and the dotted terminal of a T2 primary-side winding; the gate electrode of the M1 is connected with the dotted terminal of the T1 first secondary-side winding; the source electrode of an M2 is connected with the negative electrode of the Vs and the non-dotted terminal of a T1 second secondary-side winding; the drain electrode of the M2 is connected with the non-dotted terminal of the T2 primary-side winding; the gate electrode of the M2 is connected with the dotted terminal of the T1 second secondary-side winding; one RCD clamping circuit is positioned between the connection points of the drain electrode of the M1 and the non-dotted terminal of the T2 primary-side winding; the other RCD clamping circuit is positioned between the connection points of the source electrode of the M2 and the dotted terminal of the T2 primary-side winding; and the secondary-side winding of the T2 is connected with a rectifying circuit. The two-transistor forward converter adopts the dual RCD clamping circuits, so that it is ensured that the input can change within a relatively wide range; and particularly, the duty ratio can be further improved under low input and heavy load so as to realize stable output.

Description

technical field [0001] The invention relates to a DC-DC converter, more specifically, to a double-tube forward converter with double RCD clamps. Background technique [0002] The forward DC / DC converter has been widely used because of its characteristics of electrical isolation of input and output, wide range of voltage rise and fall, easy multi-channel output, and suitable for small and medium power power conversion occasions. The single switch tube DC-DC conversion circuit has the advantages of simple structure and low cost. However, because the switching tube has to bear excessive switching stress, it is prone to failure and has low stability. Compared with the single-tube DC-DC conversion circuit of ordinary double-tube, the voltage stress of the unit switch tube is reduced by half. However, the PWM duty cycle cannot exceed 50%, which cannot meet the voltage regulation requirements of the switching power supply under high input and light load conditions. [0003] In o...

AI Technical Summary

Problems solved by technology

However, the switching stress of the switching tube in this application is different under the two extremely unfavorable conditions of low input voltage heavy load and high input voltage light load, that is, the application is prone to overvoltage burnout of the switching tube when used in a harsh environment Or the problem that the switch performance cannot be effectively exerted, still needs further improvement

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