原标题：STLED5000 850kHz固定开关频率3A LED驱动方案

　　ST公司的LED5000是850kHz固定开关频率单片降压DC/DC转换控制器,驱动电流可高达3A,PWM LED亮度调光,输入电压5.5V-48V,± 3%输出电流精度,主要用于高亮度LED驱动,街灯照明,信号标志牌和通用照明.本文介绍了LED5000主要特性,功能框图,几种典型应用电路,以及3A降压LED驱动器STEVAL-ILL056V1主要特性和电路图.

　　The LED5000 device is an 850 kHz fixedswitching frequency monolithic step-down DC-DC converter designed to operate as a preciseconstant current source with an adjustable current capability up to 3 A DC. The embedded PWMdimming circuitry features LED brightness control. The regulated output current level is set byconnecting a sensing resistor to the feedback pin.

　　The 200 mV typical RSENSE voltage dropenhances performance in terms of efficiency. Thesize of the overall application is minimized thanksto the high switching frequency and itscompatibility with ceramic output capacitors. Thedevice is fully protected against overheating,overcurrent and output short-circuit. TheLED5000 is available in an HSOP8 package.

　　LED5000主要特性:

　　 5.5 V to 48 V operating input voltage range

　　 850 kHz fixed switching frequency

　　 200 mV typ. current sense voltage drop

　　 Buck / buck-boost / floating boost topologies

　　 PWM dimming

　　 ± 3% output current accuracy overtemperature

　　 200 m ohmtypical RDSON

　　 Peak current mode architecture

　　 Short-circuit protection

　　 Compliant with ceramic output capacitors

　　 Inhibit for zero current consumption

　　 Thermal shutdown

　　LED5000应用:

　　 High brightness LED driving

　　 Street lighting

　　 Signage

　　 Halogen bulb replacement

　　 General lighting

　　图1.LED5000功能框图

　　图2.LED5000典型应用电路图

　　图3.LED5000评估板应用电路图

　　图4.LED5000采用反相升-降压(BB)拓扑的LED电流源电路图

　　图5.LED5000基于浮点升压拓扑的LED电流源电路图

　　3A降压LED驱动器STEVAL-ILL056V1

　　The STEVAL-ILL056V1 is a product evaluation board based on the LED5000, an 850 kHz fixed switching frequency monolithic step-down DC-DC converter designed to operate as a precise constant current source with an adjustable current capability up to 3 A DC. The embedded PWM dimming circuitry features LED brightness control. The regulated output current level is set by connecting a sensing resistor to the feedback pin. The 200 mV typical RSENSE voltage drop enhances performance in terms of efficiency. The size of the overall application is minimized thanks to the high switching frequency and its compatibility with ceramic output capacitors. The device is fully protected against overheating, overcurrent and output short-circuit.

　　3A降压LED驱动器STEVAL-ILL056V1主要特性:

　　5.5 V to 48 V operating input voltage range

　　850 kHz fixed switching frequency

　　200 mV typ. current sense voltage drop

　　Buck / buck-boost / floating boost topologies

　　PWM dimming

　　±3% output current accuracy over temperature

　　200 mOhm typical RDS(on)

　　Peak current mode architecture

　　Short-circuit protection

　　Compliant with ceramic output capacitors

　　Inhibit for zero current consumption

　　Thermal shutdown

　　RoHS compliant

　　图6.3A降压LED驱动器STEVAL-ILL056V1外形图

　　图7.3A降压LED驱动器STEVAL-ILL056V1电路图