FL7730: Dimmable Single-Stage PFC PSR Offline LED Driver

This highly integrated PWM controller, FL7730, provides several features to enhance the performance of single-stage flyback converters. The proprietary TRUECURRENT® technology enables the simplified circuit design for LED lighting applications.

TRIAC dimming is smoothly managed by dimming brightness control without flicker. By using single-stage topology with primary-side regulation, an LED lighting board can be implemented with few external components and minimized cost. It does not require an input bulk capacitor or feedback circuitry. To implement good power factor and low total harmonic distortion, constant on-time control is utilized with an external capacitor connected to the COMI pin.

Precise constant-current control regulates accurate output current versus changes in input voltage and output voltage. The operating frequency is proportionally changed by the output voltage to guarantee Discontinuous Conduction Mode (DCM) operation with higher efficiency and simpler design. The FL7730 provides protections such as open-LED, short-LED, and over-temperature protections. Current-limit level is automatically reduced to minimize output current and protect external components in a short-LED condition.

The FL7730 controller is available in an 8-pin SOP package.

Features

• Compatible with Traditional TRIAC Control (No need to change existing lamp infrastructure: wall switch & wire)
• Compatible with Non-Dimming Lamp Designs
• Cost-Effective Solution without Input Bulk Capacitor and Feedback Circuitry
• Power Factor Correction (PFC)
• Accurate Constant-Current (CC) Control, Independent Online Voltage, Output Voltage, Magnetizing Inductance Variation
• Line Voltage Compensation for CC Control
• Linear Frequency Control for Better Efficiency and Simple Design
• Open-LED Protection
• Short-LED Protection
• Cycle-by-Cycle Current Limiting
• Over-Temperature Protection with Auto Restart
• Low Startup Current: 20 μA
• Low Operating Current: 5 mA
• SOP-8 Package Available
• Application Voltage Range: 80 V_AC ~ 308 V_AC

Application Notes