Turn ratio adjustable type matrix transformer integrated with synchronous rectifier tubes

Abstract

The invention relates to a turn ratio adjustable type matrix transformer integrated with synchronous rectifier tubes. The matrix transformer is applicable to a half-bridge LLC resonant converter undera MHz switch frequency. The matrix transformer comprises four separated transformers, each transformer is provided with a primary winding and a center-tapped secondary winding symmetrically coupled with the primary winding, the primary windings of the four separated transformers are connected in series and the center-tapped secondary windings symmetrically coupled with the primary windings are connected in parallel, a primary winding control switch tube is connected to each primary winding in parallel, and one resonant inductor and one magnetic inductor in the LLC resonant converter are respectively integrated to each primary winding; and two synchronous rectifier tubes and two output capacitors are respectively integrated to each secondary winding, the working modes of the synchronous rectifier tubes are influenced by the primary winding control switch tubes, the effective numbers of turns of the primary windings are changed through switching on or off the primary winding control switch tubes, and then the turn ratio of the primary windings to the secondary windings is adjusted.

Description

technical field [0001] The invention relates to a matrix transformer, in particular to a matrix transformer with an adjustable turn ratio integrated with a synchronous rectifier tube, which can be applied to a high-frequency adjustable matrix transformer in a half-bridge LLC resonant converter. Background technique [0002] Resonant converter is a kind of power converter that is currently researched more hotly. Compared with PWM converter, it has high switching frequency, small switching loss, wide input voltage range, high efficiency, small size, low EMI noise, small switching stress, etc. advantage. The LLC resonant converter can realize the zero-voltage turn-on (ZVS) of the primary switch tube and the zero-current switch (ZCS) of the secondary rectifier tube in the full load range, so that the switching loss is greatly reduced, and it can work at a very high frequency ( >5MHz). The resonant inductor and transformer in the LLC resonant converter are easy to realize th...

AI Technical Summary

Problems solved by technology

Using a planar transformer, the primary windings are connected in series and the secondary windings are connected in parallel. Although the loss of the power transformer is greatly reduced, in fact the secondary winding of the power transformer still has relatively large losses, and the primary and secondary winding turns Relatively large, the commonly used four-layer board cannot meet the requirements, and more layers of PCB boards are needed, which will greatly increase the cost

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