Abstract:  In order to explore the driving method of LED ( Light Emitting Diode), to improve the stability of LED output brightness, a LLC resonant converter controlled by frequency conversion to control the constant current output is proposed. LLC half-bridge resonant converter has the advantages of high switching frequency, power-off retention, wide allowable input voltage range, high efficiency, light weight, small size, low EMI (Electromagnetic Interference) noise, low switching stress, etc. Therefore, LLC half-bridge resonant converter is a good topology choice for LED constant current output. And the frequency conversion control method is adopted and the simulation analysis is carried out with PSIM(Power Simulation) software. The simulation results show that the LLC resonant converter controlled by frequency conversion has good steady-state performance and transient performance, which also has far-reaching significance for engineering applications. 

Key words:  ')">

 , light emitting diode ( LED) drive, constant current output, LLC resonant converter, frequency conversion control method