AC-DC power supply switching circuit

Abstract

The invention discloses an AC-DC power supply switching circuit, and belongs to the field of power supply design. The AC-DC power supply switching circuit comprises an input end, an EMI filtering module, an LLC module, a synchronous rectification module, an output filtering module, an output end, an LLC driving module, a current detection module, a rectification driving module, an auxiliary powersupply module, a control module and a voltage detection module, wherein the input end is connected with the output end sequentially through the EMI filtering module, the LLC module, the synchronous rectification module and the output filtering module. According to the invention, based on LLC half-bridge resonance and synchronous rectification technologies, a high-efficiency AC / DC switching power supply switching circuit is realized, has the advantages of high efficiency, small heat productivity, good stability, small size and the like, can achieve different output voltages and powers by adjusting parameters, and can meet the requirements of multiple fields such as electric vehicles, security equipment computer adapters and the like.

Description

technical field [0001] The invention relates to the field of power supply design, in particular to an AC-DC power switch circuit. Background technique [0002] Improving the efficiency of the power supply is the relentless pursuit of a switching power supply designer. In order to improve the efficiency of the switching power supply, the loss of the switching power supply must be reduced. The three major losses of the switching power supply are the switching loss of the power device, the conversion loss of the transformer and the conversion loss of the rectification part. The conversion loss of the transformer is difficult to use a new circuit structure to break through, so start from the remaining two parts: use the LLC resonant circuit, which can effectively reduce the switching loss of the power device; use synchronous rectification technology, which can greatly reduce the rectification part. loss. [0003] Traditional hard switching has a large turn-on loss and turn-off...

AI Technical Summary

Problems solved by technology

However, since the voltage feedback is used at the output of the power supply and is not directly connected to the primary current, additional circuitry needs to be added to provide overload and short-circuit protection

When the input and output have transient changes, the transient response speed is relatively slow

Moreover, in the absence of current feed-forward, the error interference of the LLC pre-stage cannot be processed in time by the control chip in time, and it is easy to affect the realization of soft switching

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