使用TOP250YN离线式开关带单级PFC的75W反激式LED电源设计

Design of A 75W Flyback LED Power Supply Using TOP250YN Off-line Switch and With Single Stage PFC

为利用单级反激式转换器提供一个高功率因数,功率MOSFET的占空比在单个AC线路周期内必须保持恒定。基于TOP250YN和单级PFC的恒压/恒流75W输出LED驱动电源,在208～277VAC输入范围内,平均效率>85%,功率因数>0.97,符合IEC61 000-3-2中对C类设备规定的谐波电流限制和EN5501 5B传导EMI限制。

To provide a high power factor with a single-stage flyback converter, the power MOSFET＇s duty cycle must be kept constant over a single AC line cycle. In a constant-voltage and constant-current 75W output LED drive power supply, the average efficiency is 〉85% and power factor is 〉0.97 over 208-277VAC input range. This power supply meets harmonic constant limits as specified in IEC61000-3-2 for Class C and EN55015B conducted EMI limits.