SY5802 - Single Stage Flyback PFC Controller With Primary Side Regulation and PWM/Analog dimming


  • Primary side control eliminates the opto-coupler
  • PWM or Analog Dimming
  • 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: 1A  sourcing and 2A sinking
  • Low start up current: 15uA typical
  • Reliable short LED and Open LED protection
  • Power factor >0.90 with single-stage conversion.(Analog dimming only)
  • Compact package: SO8

Typical Application


The SY5802 is a single stage Flyback and PFC controller targeting at LED lighting applications with PWM/Analog dimming. 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.


  • LED lighting
  • Down light
  • Tube lamp
  • PAR lamp
  • Bulb lamp