Development Of60W LED Driver

LED is a cold light source driven by low-voltage and its performance is influenced by the environment and the performance of drivers, so a special driver is needed to provide power for LED. Currently, the LED power supplies are suffered by several problems, such as low reliability, low efficiency, and unacceptable EMC (Electro Magnetic Compatibility) performance. The research and development of high efficiency LED driver hold a strong theoretical and practical significance.Based on a brief introduction of power LED’s light-emitting characteristics, volt-ampere characteristics and its drive mode. Key techniques which involved in the LED driver are also researched, such as power factor correction, flyback converter, high-frequency transformer and other key technology for a more in-depth study. On that basis, designed a60W LED driver. In this research, the LED driver use a single-stage power factor correction (PFC) converter, which is composed of a Boost converter and a DC/DC converter. In this single-stage PFC converter, PFC stage and DC/DC stage share a switch and a control circuit, while achieving the input current and output voltage regulation, it has the advantage of simple circuit and low cost. PFC stage using a power factor correction controller L6562A which is work in the transition mode, firstly, paper introduces the basic principles of the transition mode power factor correction, and then based on L6562A of PFC controller circuit, the main circuit parameters are derived and designed; DC/DC stage is use a flyback converter, the basic principle of the flyback converter and the main parameters are analyzed, and according to this analysis, design the high-frequency transformer. Limit voltage and constant current feedback use the AP4310to achieve double-loop voltage and current feedback. Finally, the factors leading to EMI (Electro Magnetic Interruption) are analyzed, EMC design considerations of the driver and the reliability design of key components are also provided.Adopting the proposed scheme, at the test of the60W LED driver, the key point of the waveforms collected and analyzed. The test results indicate that the LED driver works stably, power factor above0.93, and efficiency more than90%.