This highly integrated PWM controller with power MOSFET, FLS3217, provides several features to enhance the performance of low-power flyback converters. The proprietary topology enables simplified circuit design for LED lighting applications.By using the single-stage topology with primary-side regulation, an LED lighting board can be implemented with the few external components and minimized cost; requiring no input bulk capacitor or feedback circuitry. To implement good power factor and low THD, constant on-time control is utilized with an external capacitor connected to COMI.Precise constant-current control regulates accurate output current versus changes in input voltage and output voltage. The operating frequency is proportionally changed by the output voltage to guarantee DCM operation with higher efficiency and simple design.FLS3217 provides protection features such as open-LED, short-LED, and over-temperature protection. The current-limit level is automatically reduced to minimize the output current and protect external components in short-LED condition.