LLC synchronous rectifying device and control method, electronic device and storage medium thereof

Abstract

The invention provides an LLC synchronous rectifying device. The LLC synchronous rectifying device comprises an input end, a switching circuit, a resonant network circuit, a transformer, a rectifyingand filtering circuit, an output end and a driving device, the driving device comprises a driving module, a resonant frequency detecting module, an excitation current detecting module, and a rectification shutdown module, the driving module is connected to the switching circuit, the driving module outputs the driving signals to drive the switching circuit to be turned on, the resonant frequency detecting module and the excitation current detecting module are respectively connected with the resonant network circuit, and the resonant frequency detecting module acquires the resonant current of the resonant network circuit, and resonant frequency detecting module sends the resonant current to the rectification shutdown module, the excitation current detecting module obtains the excitation current of the resonant network circuit, and sends the excitation current to the rectification shutdown module, and the rectification shutdown module receives the resonant current and the excitation current, and monitors the corresponding time of driving signal when the resonant current and excitation are equal. The LLC synchronous rectifying device can effectively, quickly and accurately determine the turn-off time of the secondary MOSFET and the control is simple and the cost is low.

Description

technical field [0001] The invention relates to the technical field of protection circuits, in particular to an LLC synchronous rectification device and a control method thereof, electronic equipment, and a storage medium. Background technique [0002] LLC resonant converters are widely used in the field of DC / DC converters because they can realize soft switching of power devices in the full load range. However, when outputting low voltage and high current, the rectification loss accounts for a considerable proportion of the total loss due to the increase in the forward conduction voltage drop of the secondary diode of the LLC resonant converter, which is not conducive to the improvement of efficiency. At present, most of the existing LLC synchronous rectification devices use a dedicated control chip, and it is difficult to set the circuit parameters. During the debugging process, the circuit parameters may cause damage to the MOSFET of the synchronous rectification. The on...

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Problems solved by technology

However, when outputting low voltage and high current, the rectification loss accounts for a considerable proportion of the total loss due to the increase in the forward conduction voltage drop of the secondary diode of the LLC resonant converter, which is not conducive to the improvement of efficiency.

At present, most of the existing LLC synchronous rectification devices use a dedicated control chip, and it is difficult to set the circuit parameters. The circuit parameters may cause damage to the MOSFET of the synchronous rectification during the debugging process. In addition, there are pure software control synchronization On-off of the rectifier MOSFET, but when the switching frequency is less than the resonant frequency (fs<fr), it is difficult to determine the turn-off time of the secondary MOSFET, so it is troublesome to calculate the turn-off time of the secondary MOSFET by software

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