不使用光耦反馈的低成本反激式转换器设计

　　Abstract: This reference design is for a highly efficient, flyback, 12V, Class 3 powered device (PD). The design features the MAX5969B as its controller. The design also uses the MAX5974A, which controls current-mode PWM converters and provides frequency foldback for PoE applicaTIons. Using these devices, this reference design is IEEE® 802.3af/at compliant and is a high-performance, compact, and cost efficient soluTIon for a Class 3 PD. The design can also be customized to 12V/2A Class 4 PD.