FTM Board Club
Fairchild Semiconductor
Flyback LED Driver Eval board

The FL7733A is an active Power Factor Correction (PFC) controller for use in single- stage flyback topology or buck-boost topology.

Primary-side regulation and single-stage topology minimize cost by reducing external components such as the input bulk capacitor and secondary side feedback circuitry. To improve power factor and Total Harmonic Distortion (THD), constant on-time control is utilized with an internal error amplifier and a low bandwidth compensator.

Precise constant-current control provides accurate output current, independent of input voltage and output voltage. Operating frequency is proportionally changed by the output voltage to guarantee Discontinuous Current Mode (DCM) operation, resulting in high efficiency and simple designs. The FL7733A also provides open-LED, short-LED, and over-temperature protection functions.

  • < 3% Total Constant Current Tolerance Over All Conditions
  • < 1% Over Universal Line Voltage Variation
  • < 1% from 50% to 100% Load Voltage Variation
  • < 1% with 20% Magnetizing Inductance Variation
  • Primary-Side Regulation (PSR) Control for Cost-Effective Solution without Requiring Input Bulk Capacitor and Secondary Feedback Circuitry
  • Application Input Voltage Range: 80 VAC - 308 VAC  High PF and Low THD Over Universal Line Input Range
  • Fast < 200 ms Startup (at 90 VAC) using Internal High-Voltage Startup with VDD Regulation
  • Adaptive Feedback Loop Control for Startup without Overshoot