• High PF>0.9, Low THD<10%
• Primary Side Control Eliminates the Opto-coupler
• Valley Turn-on of the Primary MOSFET to Achieve Low Switching Losses
• Input Over/Under Voltage Protection
• Programmable Thermal Fold-back Function
• Reliable Short LED and Open LED Protection
• Quick Start up <500ms
• Low Start up Current:34µA Typical
•  Package: SO8

The SY5842 is a single stage Flyback and PFC controller targeting at LED lighting applications. It is a primary side controller without applying any secondary feedback circuit for low cost, and drives the Flyback converter in the quasi-resonant mode to achieve higher efficiency. It integrates PFC compensating circuit to achieve high power factor and low THD while keeping accurate constant current. It adopts special design to achieve quick start up and reliable protection for safety requirement.