Fairchild FL7794 PWM调光大功率LED AC直接驱动方案
时间：2016-06-06 12:52:06 作者：Fairchild 来源：中电网
Fairchild公司的FL7794是直接从AC线驱动的LED驱动器,从而最小化外接RC无源元件的数量,输入电压90~305 VAC.正常配置下一个电阻可调整LED功率,一个电容提供稳定电压来偏置内部并联稳压器.器件提供模拟/PWM可调光特性,采用高PF和低的THD可获得高效率,主要用于高稳定的大功率LED照明系统.本文介绍了FL77944主要特性,框图,以及12W评估板FEBFL77944A4测试条件,电路图和材料清单.
The FL77944 is a direct AC line LED driver with a minimal number of external RC passive components. In normal configuration, one resistor is to adjust LED power, and one capacitor is to provide a stable voltage to an internal biasing shunt regulator.
The FL77944 provides phase-cut dimming with wide dimming range, smooth dimming control and good dimmer compatibility. It achieves high efficiency with high PF and low THD, which makes the FL77944 suitable for high-efficiency LED lighting systems. The FL77944 has a dedicated DIM pin which can be used with analog or digital PWM dimming. The FL77944 can also be used with a rheostat dimmer switch which is suitable for desktop or indoor lamps.
Operation of FL77944 admits driving higher-wattage systems, such as street lights and down lights, by simply parallel connecting the driver ICs.
FL77944主要特性:
The simplest Direct AC LED Driver with Only Two External RC Passive Component Wide AC Input Range: 90~305 VAC
Four Integrated High-Voltage LED Constant Current Sinks of up to 150 mA (RMS) Capability
TRIAC Dimmable (Leading/Trailing Edge) Rheostat Dimmable
Analog/Digital PWM Dimming Function
High Power Factor (above 0.98 in normal configuration) Adjustable LED Power with an External Current Sense Resistor Low Harmonic Content (THD under 20% in normal configuration) Flexible LED Forward Voltage Configuration Power Scalability with Multiple Driver ICs
Over-Temperature Protection (OTP) SOP16 EP Package
FL77944应用:
LED Lighting–High Power-Analog/PWM dimming LED Lighting–Low Power–Analog/PWM dimming LED Lighting–Mid Power- Analog/PWM dimming Lighting
图1.FL77944简化框图
12W评估板FEBFL77944A4
High Line 12 W Down Lighting Reference Design for LED Direct AC Driver with Low Flicker Index.
This document describes a direct AC line LED driver with a minimal number of external components. The input voltage range of the LED driver board is classed as high-line application for 198 VAC ~ 242 VAC, with a single DC output, constant current depends on the Rcs value. This document contains a general description of the FL77944, the normal configuration specification, schematic, bill of materials, and typical operating characteristics.
12W评估板FEBFL77944A4测试条件:
图2.12W评估板FEBFL77944A4外形和PCB图
12W评估板FEBFL77944A4材料清单:
图3.12W评估板FEBFL77944A4电路图(1):不带SVF 不带SVF的12W评估板FEBFL77944A4电路参数:
Fairchild FL7794 PWM调光大功率LED AC直接驱动方案
