Single Stage Flyback And PFC Regulator
With Primary Side Control For LED Lighting
The SY58203A1 is a single stage Flyback and PFC
regulator targeting at LED lighting applications. It
integrates a 700V MOSFET to decrease physical volume.
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.
Optional Spec Code
• Integrated 700V MOSFET
• Primary side control eliminate to 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.
• Low start up current: 15µA typical
• Reliable short LED and Open LED protection
• Power factor >0.90 with single-stage conversion.
• Maximum frequency limit: 120kHz
• Compact package: SO8
• LED lighting
R commended operating output power
R2 C2 NP
Figure 1. Schematic Diagram SO8
Figure 2. Efficiency vs Input Voltage
AN_SY58203A1 Rev. 0.9 Silergy Corp. Confidential-Prepared for Customer Use Only 1