SY5810
General Description
The SY5810 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 keeps the Flyback converter in constant on time operation to achieve high power factor.

Features
* Primary side control eliminates the opto-coupler.
* Valley turn-on of the primary MOSFET to achieve
low switching losses
* 0.3V primary current sense reference voltage leads to a lower sense resistance thus a lower conduction loss.
* Internal high current MOSFET driver: 0.25A sourcing and 0.5A sinking
*Low start up current: 15μA typical
*Reliable short LED and Open LED protection
*Power factor >0.90 with single-stage conversion.
*Compact package: SOT23-6
高效率高 PFC,SY5810,1. 集成 PFC, 功率因数很高 , 隔离效率大部分情况下在 88% 、 89%, 高达 92%,PFC 0.95 到 0.99, 2. 原边控制 QR 模式 , 省去光耦和相关电路 , 降低 BOM cost 3. 独特的 MOSFET 控制技术 , 对 MOSFET 和快恢复二极管的要求降低很多 , 不必选择昂贵的 MOSFET 和二极管 , 高功率因数、精度 3% 以内 ,QR 模式、 高效率、稳定性高、一致性好、外围器件少、空间小、性价比高。