A synchronous rectification method for lclcl resonant converter

Abstract

The present invention provides a synchronous rectification method for an LCLCL resonant converter, which realizes self-adaptive dynamic adjustment of the synchronous rectification process based on a pulse detection method, and can completely avoid the synchronous rectification of some complex external circuits only through a simple system structure In the rectification scheme, the adverse effects of the parasitic inductance brought by the PCB wiring and the parasitic capacitance of the switch tube, and at the same time achieve higher efficiency and lower cost. Utilizing the method provided by the invention greatly shortens the rising time and falling time of the driving, and lays the driving foundation for the ultra-high frequency of the switching converter.

Description

technical field [0001] The invention belongs to the technical field of power converter rectification, and in particular relates to a synchronous rectification method of an LCLCL resonant converter. Background technique [0002] For the LLC converter, the synchronous rectification technology can greatly reduce the loss of the rectification link and improve the efficiency of the converter. However, the synchronous rectification drive signal of the LLC resonant converter is different from the primary side half-bridge drive signal, which brings great challenges to the design of the synchronous rectification drive. The drive signal of the primary side half-bridge usually cannot be directly used for synchronization rectification, [0003] In the prior art, some synchronous rectification is based on detection voltage V ds_SR The synchronous rectification MOSFET is driven independently on the secondary side without the primary side control signal. This means due to the rectificat...

AI Technical Summary

Problems solved by technology

This means due to the rectification MOSFET package inductance will result in a voltage of V ds_SR ahead of the current i SR , the duty cycle of the synchronous rectification driving signal will be partially lost, and the synchronous rectification MOSFET will be turned off in advance

This problem is exacerbated at high frequencies, where even a small package inductance can cause a large phase lead

Moreover, the prior art also has the defect that the CPU utilization rate of the controller in the synchronous rectification process is too high, so that it cannot provide enough CPU space for functions other than rectification

In order to improve conduction loss and other problems in synchronous rectification, it is still difficult to reduce the cost of the circuit structure or controller chip used in the prior art

Images