Forward reset circuit suitable for low voltage input

Abstract

The invention provides a forward reset circuit suitable for low voltage input. The forward reset circuit comprises a forward transformer and a switching tube, wherein the switching tube is connected with the forward transformer. The forward reset circuit also comprises a magnetic reset circuit which is used for resetting the forward transformer in each switching period. The forward reset circuit has the beneficial effects that the magnetic reset of the transformer is realized through a magnetic reset capacitor and a magnetic reset diode, and the energy consumption of a resonant capacitor in a resonant magnetic reset circuit is avoided; the conversion efficiency, the temperature rise property index and the like of a power supply are increased; and the circuit is simple, reliable, convenient and fast.

Description

Technical field [0001] The invention relates to a reset circuit, in particular to a forward reset circuit suitable for low voltage input. Background technique [0002] The forward circuit has the most extensive application in the field of small and medium power switching power supplies. It has many advantages such as simple topology, high efficiency, and convenient synchronous rectification. However, it must be magnetically reset in each switching cycle, otherwise it will cause magnetic saturation. [0003] There are many magnetic reset methods for forward circuits, such as reset winding method, RCD method, active clamp method, dual-tube forward method and resonance reset. The independent reset winding method needs to add a reset winding to the primary side, and the primary side switch tube needs to withstand twice the input voltage. If the reset winding is not well coupled, the peak voltage will be larger; the R in the RCD reset method will cause power loss and reduce efficiency ...

AI Technical Summary

Problems solved by technology

The single reset winding method needs to add a reset winding on the primary side, and the switching tube on the primary side needs to withstand twice the input voltage. If the coupling of the reset winding is not good, the peak voltage will be larger; the R in the RCD reset method will cause power loss, resulting in a drop in efficiency ;Active clamping is a better solution, which realizes soft switching and has the highest efficiency, but the structure is complex and the cost is also the highest; the double-tube forward method has high reliability, but it needs 2 switch tubes and 2 diodes. The largest number; resonant reset uses the resonance of the primary inductance and reset capacitor, the primary switch tube withstands high voltage and low efficiency

All kinds of magnetic reset methods have advantages and disadvantages, and they are applied in different occasions.

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