Fairchild FLS324710W Offline LED Driver Solution

/a>LED” title=”LED”>LED” title=”LED”>LED driver, including PWM controller and power MOSFET, can enhance the performance of low power flyback converter, application voltage range 80VAC ~ 308VAC, provide LED Open circuit, short circuit and over temperature protection functions. Mainly used in LED lighting systems. This article introduces the FLS3247 main features, block diagram, universal input 10W LED driver circuit diagram and 10W LED driver evaluation board main specifications, circuit diagram, bill of materials and PCB layout.

This highly integrated PWM controller with power MOSFET, FLS3217 / FLS3247, provides several features to enhance the performance of low-power flyback converters. The proprietary topology enables simplified circuit design for LED lighting applications.

By using the single-stage topology with primary-side regulation, an LED lighting board can be implemented with the few external components and minimized cost; requiring no input bulk capacitor or feedback circuitry.

To implement good power factor and low THD, constant on-time control is utilized with an external capacitor connected to COMI. 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 DCM operation with higher efficiency and simple design.

FLS3217 and FLS3247 provide protection features such as open-LED, short-LED, and over-temperature protection. The current-limit level is automatically reduced to minimize the output current and protect external components in short-LED condition.

FLS3247 main features:

 Cost-Effective Solution without Input Bulk Capacitor and Feedback Circuitry

 Power-Factor Correction (PFC)

 Integrated Power MOSFETs

 Accurate Constant-Current (CC) Control Independent Online Voltage, Output Voltage, and Magnetizing Inductance Variation

 Linear Frequency Control for Increased Efficiency

 Open / Short-LED Protection

 Cycle-by-Cycle Current Limiting

 Over-Temperature Protection with Auto Restart

 Low Startup Current: 20μA

 Low Operating Current: 5mA

 VDD Over-Voltage Protection (OVP)

 VDD Under-Voltage Lockout (UVLO)

 Application Voltage Range: 80VAC ~ 308VAC

FLS3247 application:

 LED Lighting System
Fairchild FLS324710W Offline LED Driver Solution
Figure 1. FLS3247 block diagram
Fairchild FLS324710W Offline LED Driver Solution
Figure 2. FLS3247 Universal Input 10W LED Driver Circuit Diagram

10W LED Driver Evaluation Board

This document describes the proposed solution for a universal line voltage LED ballast using the FLS3247N Primary-Side Regulator (PSR) single-stage controller. The input voltage range is 90VRMS – 265VRMS and there is one DC output with a constant current of 400mA at 25VMAX . This document contains a general description of the FLS3247N, the power supply specification, schematic, bill of materials, and typical operating Characteristics.

10W LED Driver Evaluation Board Main Specifications:
Fairchild FLS324710W Offline LED Driver Solution
Fairchild FLS324710W Offline LED Driver Solution
Fairchild FLS324710W Offline LED Driver Solution
Figure 3. 10W LED Driver Evaluation Board Outline Drawing (59mm (L) × 25.5mm (W) × 20.0mm (H))

10W LED Driver Evaluation Board Key Features:

 Cost effective solution without input bulk capacitor and feedback circuitry

 Power Factor Correction

 Accurate constant-current (CC) Control

 Linear frequency control for better efficiency and easy design

 Constant current regulation vs. output voltage change (11~28V) : <± 2.85%

 Constant current regulation vs. line voltage change (90~265VAC) : <± 2.85%

 Output open & short circuit protection with auto restart

 System efficiency up to 86.8%

 PF and THD: PF (> 0.9), THD (< 20%)
Fairchild FLS324710W Offline LED Driver Solution
Figure 4. 10W LED Driver Evaluation Board Circuit Diagram

10W LED Driver Evaluation Board Bill of Materials:
Fairchild FLS324710W Offline LED Driver Solution
Fairchild FLS324710W Offline LED Driver Solution
Figure 5. 10W LED Driver Evaluation Board Layout (Top Layer)
Fairchild FLS324710W Offline LED Driver Solution
Figure 6. 10W LED Driver Evaluation Board Layout (Bottom Layer)
For details, see:
http://www.fairchildsemi.com/ds/FL/FLS3247.pdf
and
http://www.fairchildsemi.com/an/AN/AN-FEBL042.pdf

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