Single-level step-down LED driving circuit of leakage energy feedback

Abstract

The present invention relates to a single-level step-down LED driving circuit of leakage energy feedback. The circuit comprises an input AC power supply Vin and an LED lamp load, a power MOS switch tube Q1, a power MOS switch tube Q2, a rectifier power diode D1, a rectifier power diode D2, a rectifier power diode D3, a rectifier power diode D4, a fast recovery diode D5, a fast recovery diode D6, a fast recovery diode D7, a fast recovery diode D8, a fast recovery diode D9, a fast recovery diode D10, an intermediate electrolytic capacitor CB, an output electrolytic capacitor Co, a pre-stage Buck circuit inductor LBuck, a transformer Tr and an equivalent leakage inductor Llk thereof. According to the single-level step-down LED driving circuit, a pre-stage Buck circuit and a double-tube flyback circuit used by a back-stage leakage energy feedback are integrated into a single-stage LED driving circuit, and the functions of low voltage switch stress, high conversion efficiency and constant current output are realized.

Description

technical field [0001] The invention relates to the technical field of power electronics, in particular to a single-stage step-down LED drive circuit for leakage inductance energy feedback. Background technique [0002] Leakage inductance is caused by incomplete coupling of coils, so leakage inductance mainly occurs in the occasions where coils are coupled, such as transformers and inductors. The leakage inductance of the transformer can be described as the magnetic flux generated by the primary coil of the transformer cannot completely pass through the secondary coil, so a leakage flux is generated, which is equivalent to the magnetic flux generated by the leakage inductance. Due to the existence of transformer leakage inductance, the energy of the primary side of the transformer cannot be transferred to the secondary side 100%, resulting in incomplete utilization of energy and increasing losses. [0003] The existence of the high-frequency leakage inductance in the switc...

AI Technical Summary

Problems solved by technology

Due to the existence of transformer leakage inductance, the energy of the primary side of the transformer cannot be transferred to the secondary side 100%, resulting in incomplete energy utilization and increased loss

[0003] The existence of the high-frequency leakage inductance in the switching converter has a great influence on the stress of the switching devices in the circuit topology. When the main switching tube of the circuit is disconnected, the leakage inductance of the stored energy will generate a back electromotive force stress peak, which will easily cause the switching device to overheat. Voltage breakdown, leakage inductance may also form an oscillation circuit with the distributed capacitance in the circuit and the distributed capacitance of the transformer coil, causing the circuit to oscillate and radiate electromagnetic energy outward, causing electromagnetic interference

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