Fairchild 公司的FL7730是可调光的单级PFC离线LED驱动器,和传统的TRIAC控制兼容,和无调光灯设计兼容,不需要输入大电容和反馈电路,具有开路,短路保护,逐个周期的限流,起动电流20uA,工作电流5mA,应用电压倒80VAC ~ 308VAC,主要用于照明.本文介绍了FL7730主要特性,方框图以及8.4W LED照明灯主要性能指标,灯外形,PCB电路图,材料清单和PCB元件布局图.

This highly integrated PWM controller, FL7730MY, provides several features to enhance the performance of single-stage flyback converters. The proprietary topology, TRUECURRENT™, enables the simplified circuit design for LED lighting applications.

The FL7730 is an active Power Factor Correction (PFC) controller using single-stage flyback topology. Dimming control with no flicker is implemented by an analog sensing method. Primary-side regulation and single-stage topology reduce external components such as input bulk capacitor and feedback circuitry and minimize cost. To improve good power factor and Total Harmonic Distortion (THD), constant on-time control is utilized with internal error amplifier and a low-bandwidth compensator. Precise constant-current control regulates accurate output current, independent of input voltage and output voltage. Operating frequency is proportionally changed by output voltage to guarantee DCM operation with higher efficiency. FL7730 provides protections such as open-LED,short-LED, and over-temperature protection.

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 FL7730MY 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 FL7730MY controller is available in an 8-pin SOP package.

FL7730主要特性:

￭ 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: 20µA

￭ Low Operating Current: 5mA

￭ SOP-8 Package Available

￭ Application Voltage Range: 80VAC ~ 308VAC

FL7730应用:
Lighting

图1.FL7730方框图
LED照明灯主要性能指标:


图2.8.4W LED灯 PCB外形图:顶视图

图3.8.4W LED灯 PCB外形图:底视图

图4.8.4W LED灯外形图

图5.8.4W LED灯电路图

图6.8.4W LED灯变压器电路图

8.4W LED灯材料清单(BOM):




图7.8.4W LED灯PCB元件布局图:顶层

图8.8.4W LED灯PCB元件布局图:底层
详情请见:
http://www.fairchildsemi.com/an/AN/AN-FEB020H.pdf
和
http://www.fairchildsemi.com/support/referencedesign/docs/RD-L020-2.pdf