原标题：NS LM3424 恒流控制和热管理LED驱动方案

　　NS 公司的LM3424是带热管理的恒流N沟MOSFET控制器的LED驱动方案,有多个高压N-MOSFET控制器,可以配置成降压,升压,降-升压和SEPIC拓扑,输入电压高达75V,2Ω, 1A 峰值MOSFET栅极驱动器,主要应用在LED驱动器,室内和室外的SSL,汽车电子,通用照明和恒流稳压器.本文介绍了LM3424主要特性,方框图,典型应用电路以及降压,升压,降-升压和SEPIC应用电路与相应的材料清单.

　　LM3424: Constant Current N-Channel Controller with Thermal Foldback for Driving LEDs

　　The LM3424 is a versatile high voltage N-channel MosFET controller for LED drivers . It can be easily configured in buck, boost, buck-boost and SEPIC topologies. In addition, the LM3424 includes a thermal foldback feature for temperature management of the LEDs. This flexibility, along with an input voltage rating of 75V, makes the LM3424 ideal for illuminating LEDs in a very diverse, large family of applications. Adjustable high-side current sense voltage allows for tight regulation of the LED current with the highest efficiency possible.

　　The LM3424 uses standard peak current-mode control providing inherent input voltage feed-forward compensation for better noise immunity. It is designed to provide accurate thermal foldback with a programmable foldback breakpoint and slope. In addition, a 2.45V reference is provided.

　　The LM3424 includes a high-voltage startup regulator that operates over a wide input range of 4.5V to 75V. The internal PWM controller is designed for adjustable switching frequencies of up to 2.0 MHz and external synchronization is possible.

　　The controller is capable of high speed PWM dimming and analog dimming. Additional features include slope compensation, softstart, over-voltage and under-voltage lock-out, cycle- by-cycle current limit, and thermal shutdown.

　　LM3424主要特性:

　　■ VIN range from 4.5V to 75V

　　■ High-side adjustable current sense

　　■ 2Ω, 1A Peak MosFET gate driver

　　■ Input under-voltage and output over-voltage protection

　　■ PWM and analog dimming

　　■ Cycle-by-cycle current limit

　　■ Programmable slope compensation

　　■ Programmable, synchronizable switching frequency

　　■ Programmable thermal foldback

　　■ Programmable softstart

　　■ Precision voltage reference

　　■ Low power shutdown and thermal shutdown

　　LM3424应用:

　　■ LED Drivers - Buck, Boost, Buck-Boost, and SEPIC

　　■ Indoor and Outdoor Area SSL

　　■ Automotive

　　■ General Illumination

　　■ Constant-Current Regulators

　　图1.LM3424方框图

　　图2.LM3424典型应用电路

　　图3.LM3424降压-升压应用电路

　　降压-升压应用电路材料清单:

　　图4.LM3424升压应用电路

　　升压应用电路材料清单:

　　图5.LM3424降压-升压应用电路(2)

　　降压-升压应用电路(2)材料清单:

　　图6.LM3424升压应用电路

　　升压应用电路清单:

　　图7.LM3424降压-升压应用电路(3)

　　降压-升压应用电路(3)材料清单:

　　图8.LM3424降压应用电路

　　降压应用电路材料清单:

　　图9.LM3424降压-升压应用电路(4)

　　降压-升压应用电路(4)材料清单:

　　图10.LM3424 SEPIC应用电路

　　SEPIC应用电路材料清单:

　　LM3424 升压评估板

　　图11.LM3424 升压评估板电路图

　　LM3424 升压评估板材料清单:

　　LM3424 降压-升压评估板

　　图12.LM3424 降压-升压评估板电路图

　　降压-升压评估板材料清单: