Research On The Modeling Of Conducted Interference In LED Driver Topologies

This dissertation focuses on modeling of conducted interference for the power LED driver. Itincludes following modeling works for power MOSFET and passive components, and LED drivers’conducted interference. Conducted interference of the LED drive power problems are analyzed andstudied in this article.Currently the high frequency models of power MOSFET model and transformer are notaccurate, which can not make the simulation waveform of conducted interference consistent withthe actual test conducted interference waveform. This dissertation described the principle of PNjunction, and then analyzed the switching characteristics of power MOSFET and the operatingcharacteristics of the parasitic capacitance. Through analysis, this dissertation established ahigh-frequency model of power MOSFET for the conduction interference simulation of LED driver,based on the model coming with Saber software. Meanwhile, the working status of transformer areanalyzed, the parasitic capacitance and leakage inductance of transformer and the effect ofconducted interference are analyzed, and then create the high-frequency model of the transformer.Moreover, model parameters of power MOSFET and high frequency transformer model can becalculated by the product of the technical documentation and the corresponding formula.This dissertation analyzed the model of passive components, analyzed the parasitic wire andPCB board, and then analyzed the circuit conducted interference coupling path. Eventually, thisdissertation built a interference model of flyback LED driver circuit. Through simulation, thisdissertation got the differential mode interference waveforms.This dissertation analyzes the simulation waveform and the test waveform of hardware circuit,which demonstrates the applicability of the model. The modeling method can also be applied to theLED drive power other topologies.