Linear LT3754 16路3000:1调光LED驱动方案

Linear 公司的LT3754 是带升压DC/DC控制器的16路3000:1调光LED驱动器,能驱动高达45V的LED,每路电流的精度在±2.8%,每串LED电流用单个电阻可在10mA-50mA间编程,输出电压能根据LED VF而变,以获得最佳的效率,同时LED开路故障不影响所连接的LED串的工作.LT3754的输入电压从6V到40V,采用PWM调光,调光范围达3000:1,主要用在汽车电子,笔记本电脑和TV监视器的背景光.本文介绍了LT3754的主要特性,方框图以及典型应用电路,包括效率92% 36W背景光LED驱动电路, 6串,每串50mA 36W背景光LED驱动电路,以及32W和17W LED驱动电路.

The LT3754 is a 16-channel LED driver with a step-up DC/DC controller capable of driving up to 45V of LEDs. Each channel contains an accurate current sink with ±2.8% current matching. Channels follow a master programmable current to allow between 10mA to 50mA of LED current per string. Channels can be paralleled for higher LED current. Output voltage adapts to variations in LED VF for optimum efficiency and open LED faults do not affect the operation of connected LED strings.

The LT3754 allows a PWM dimming range up to 3000:1 and an analog dimming range up to 25:1. Operating frequency can be programmed from 100kHz up to 1MHz using a single resistor or synchronized to an external clock.

Additional features include: programmable maximum VOUT for open LED protection, a fault flag for open LED, programmable LED current derating vs temperature, micropower shutdown and internal soft-start. The LT3754 is available in a thermally enhanced 5mm x5mm 32-pin QFN Package.

LT3754主要特性:

Up to 45V of LEDs 50mA, 16-Channel LED Driver

Wide Input Range:6V to 40V

±2.8% LED Current Matching at 20mA (Typ ±0.7%)

Up to 3000:1 True Color PWM™ Dimming Range

Single Resistor Sets LED Current (10mA to 50mA)

LED Current Regulated Even for PVIN > VOUT

Output Adapts to LED VF for Optimum Effi ciency

Fault Flag Protection for Open LED Strings

Protection for LED Pin to VOUT Short

Parallel Channels for Higher LED Current

Programmable LED Current Derating vs Temperature

Accurate Undervoltage Lockout Threshold with Programmable Hysteresis

Programmable Frequency (100kHz to 1MHz)

Synchronizable to an External Clock

LT3754应用:

Automotive, Notebook and TV Monitor Backlighting


图1.LT3754方框图

图2.LT3754效率92% 36W背景光LED驱动电路


图3.LT3754效率92% 36W背景光LED驱动电路(16串,每串50mA)

图4.LT3754 17W LED驱动电路(16串)



图5.LT3754 31W背景光LED驱动电路(3串,每串250mA)


图6.LT3754 14W背景光LED驱动电路(4串,每串80mA