Fairchild公司的FL7730是高度集成的PWM控制器,為單級反激轉換器提供增強的性能,其有所有權的TRUECURRENT™拓撲簡化了LED照明的電路設計.應用電壓80VAC ~ 308VAC,起動電流20uA,工作電流5mA,采用跳頻有更好的EMI性能,主要用在LED照明系統.本文介紹了FL7730主要特性,方框圖,典型應用電路以及采用FL7730的TRIAC調光180V-265VAC和90-140VAC 的LED驅動器參考設計電路圖.

特性

Compatible with Traditional TRIAC Control No need to change existing lamp infrastructure:wall switch & wire)Compatible with Non-Dimming Lamp DesignsCost-Effective Solution without Input Bulk Capacitor nd Feedback CircuitryPower Factor Correction (PFC)Accurate Constant-Current (CC) Control, ndependent Online Voltage, Output Voltage, gnetizing Inductance VariationLine Voltage Compensation for CC ControlLinear Frequency Control for Better Efficiency and imple DesignOpen-LED ProtectionShort-LED ProtectionCycle-by-Cycle Current LimitingOver-Temperature Protection with Auto RestartLow Startup Current: 20 μALow Operating Current: 5 mASOP-8 Package AvailableApplication 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).

典型應用框圖：

Typical Application

內部框圖：

Functional Block Diagram

引腳：

Pin Configuration

Pin Definitions

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1.FL7730單級初級端調節(jié)控制器概述

摘 要：LED 照明已經發(fā)展成為最有前景的解決方案，能夠替代如熒光燈和白熾燈等普通光源。然而，設計人員在最高20W的住宅和商業(yè)LED照明(包括燈泡、下射燈 (GU10/E17, E26/27, PAR30/38)以及管/棒燈)應用方面面臨著一些障礙。由于調光器兼容性的原因，在普通TRIAC調光器結構中實現LED調光能力會有相當的困難。此 外，小空間尺寸仍然是一項考慮因素。

2.FL7730應用：TRIAC調光LED驅動器設計指南(獨家收錄）

摘 要：對 于TRIAC調光LED燈泡，目前最大的問題在于調光器的兼容性。傳統TRIAC調光器的原始設計是要處理數百瓦白熾燈泡消耗的功率。消耗功率小于 20W的LED燈泡，會和采用由大功率開關器件構成的調光器產生相互影響。如果調光器和LED燈泡的相互影響不穩(wěn)定，會出現可見閃爍。