FL7730单级初级端调节控制器设计指南（独家）

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        Fairchild公司的FL7730是高度集成的PWM控制器,为单级反激转换器提供增强的性能,其有所有权的TRUECURRENT™拓扑简化了LED照明的电路设计.应用电压80VAC ~ 308VAC,起动电流20uA,工作电流5mA,采用跳频有更好的EMI性能,主要用在LED照明系统.本文介绍了FL7730主要特性,方框图,典型应用电路以及采用FL7730的TRIAC调光180V-265VAC和90-140VAC 的LED驱动器参考设计电路图.

         

        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 nd Feedback Circuitry       
  
•                 Power Factor Correction (PFC)       
  
•                 Accurate Constant-Current (CC) Control, ndependent Online Voltage, Output Voltage, gnetizing Inductance Variation       
  
•                 Line Voltage Compensation for CC Control       
  
•                 Linear Frequency Control for Better Efficiency and imple 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 VAC ~ 308 VAC
  

         
        描述：

        This highly integrated PWM controller, FL7730, provides everal features to enhance the performance of singlestage lyback converters. The proprietary topology, RUECURRENT enables the simplified circuit design or LED lighting applications.

         

        TRIAC dimming is smoothly managed by dimming rightness control without flicker. By using single-stage opology with primary-side regulation, an LED lighting oard can be implemented with few external omponents and minimized cost. It does not require an nput bulk capacitor or feedback circuitry. To implementgood power factor and low total harmonic distortion,constant on-time control is utilized with an externalcapacitor connected to the COMI pin.Precise constant-current control regulates accurateoutput current versus changes in input voltage andoutput voltage.

         

        The operating frequency is proportionallychanged by the output voltage to guaranteeDiscontinuous Conduction Mode (DCM) operation withhigher efficiency and simpler design. The FL7730provides protections such as open-LED, short-LED, andover-temperature protections. Current-limit level isautomatically reduced to minimize output current andprotect external components in a short-LED condition.The FL7730 controller is available in an 8-pin SmallOutline Package (SOP).

         

        典型应用框图：

         

       

        Typical Application

         

        内部框图：
         

       

         Functional Block Diagram

         

        引脚：
         

       

         Pin Configuration

         

       

        Pin Definitions

         

        推荐阅读：
        1.FL7730单级初级端调节控制器概述
        摘 要：LED 照明已经发展成为最有前景的解决方案，能够替代如荧光灯和白炽灯等普通光源。然而，设计人员在最高20W的住宅和商业LED照明(包括灯泡、下射灯 (GU10/E17, E26/27, PAR30/38)以及管/棒灯)应用方面面临着一些障碍。由于调光器兼容性的原因，在普通TRIAC调光器结构中实现LED调光能力会有相当的困难。此 外，小空间尺寸仍然是一项考虑因素。
         
        2.FL7730应用：TRIAC调光LED驱动器设计指南(独家收录）
        摘 要：对 于TRIAC调光LED灯泡，目前最大的问题在于调光器的兼容性。传统TRIAC调光器的原始设计是要处理数百瓦白炽灯泡消耗的功率。消耗功率小于 20W的LED灯泡，会和采用由大功率开关器件构成的调光器产生相互影响。如果调光器和LED灯泡的相互影响不稳定，会出现可见闪烁。