Drive circuit

Abstract

The invention discloses a drive circuit suitable for a syntonic circuit composed by adopting an externally connected transformer-typed drive circuit. The drive circuit comprises a high end MOS tube, a low end MOS tube and a transformer. Two secondary windings of the transformer are included and the like end of the transformer is arranged reversely; wherein, the like end of a first secondary winding is connected with the grid of the high end MOS tube, the unlike end thereof is connected with the source electrode of the high end MOS tube; the unlike end of a second secondary winding is connected with the grid of the low end MOS tube, the like end thereof is connected with the source electrode of the low end MOS tube. By adopting the drive circuit in the invention, drive pulse signals acted on the grids of the high end MOS tube and low end MOS tube can generate negative impulse waveforms; therefore, in a negative impulse period, if interfering signals such as peak or burr and the like appear at a driving end (the grid of the MOS tube), the interfering signals can be effectively weakened by the bucking effect of the negative impulse, thus preventing the problem of common-mode conduction appearing in the two MOS tubes and enhancing the reliability of the system.

Description

technical field [0001] The invention belongs to the technical field of resonant circuits, and in particular relates to an improvement of the drive circuit part in a resonant half-bridge circuit composed of a drive chip and an external transformer-type drive circuit. Background technique [0002] For the resonant half-bridge circuit, since it is necessary to alternately drive two MOS tubes to achieve turn-on, for the high-end driver, it needs "floating" processing, and some chips have the driving part built into the integrated chip, such as ST's L6598 , L6599 chip; some circuits are realized in the form of a resonant chip + an external drive circuit, such as the resonant controller NCP1395 of ON Semiconductor. Among them, the form of the external drive circuit can be divided into a special drive chip and an external transformer drive circuit form. The drive chip can be realized by the NCP5181 chip of ON Semiconductor, such as figure 1 shown. The NCP5181 chip is a high-volta...

AI Technical Summary

Problems solved by technology

[0004] In order to solve the problem that two MOS tubes are prone to common conduction in the existing external transformer drive circuit, the present invention provides a new drive circuit structure, which can effectively prevent the common conduction of two MOS tubes to protect The MOS tube is protected from damage, which enhances the reliability of the system

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