LED Driver, Single-Stage PFC Primary-Side-Regulation Offline

This highly integrated PWM controller 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 single-stage topology with primary-side regulation, a LED lighting board can be implemented with few external components and minimized cost. No input bulk capacitor or feedback circuitry is required. To implement good power factor and low THD, constant on-time control is utilized with an external capacitor connected to the COMI pin. Precise constant-current control regulates accurate output current versus changes in input voltage and output voltage. The operating frequency is proportionally adjusted by the output voltage to guarantee DCM operation with higher efficiency and simpler design. FL7732 provides open-LED, short-LED, and over-temperature protection features. The current limit level is automatically reduced to minimize output current and protect external components in a short-LED condition. The FL7732 controller is available in an 8-pin SOP package.