原标题：Linear LT3745 16路50mA LED驱动方案

　　Linear公司的LT3745是带55V降压控制器的16路50mA LED驱动器,每路可点亮75mA/36V 串联LED,而降压控制器产生合适的总线电压给并联LED串供电.每路有6位点阵电流修正,12位灰度PWM调光.LED电流匹配在+/-3%内.主要用在大屏幕显示器LED背光,单色/多色/全色LED显示器以及LED信号板.本文介绍了LT3745 主要特性,方框图以及典型应用电路.

　　LT3745:16-Channel 50mA LED Driver with Buck Controller

　　The LT.3745 integrates a 16-channel LED driver with a 55V buck controller. The LED driver lights up to 75mA/36V of LEDs in series per channel, and the buck controller generates an adaptive bus voltage supplying the parallel LED strings. Each channel has individual 6-bit dot correction current adjustment and 12-bit grayscale PWM dimming.

　　Both dot correction and grayscale are accessible via a serial data interface in TTL/CMOS logic. A +/-3% LED current matching and a 0.5μs minimum LED on-time can be achieved at 50mA per channel.

　　The LT3745 performs full diagnostic and protection against open/short LED and overtemperature fault. The fault status is sent back through the serial data interface.

　　The 30MHz fully-buffered, skew-balanced, cascadable serial data interface makes the chip extremely suitable for large screen LCD dynamic backlighting and mono-,multi-, full-color LED displays.

　　LT3745 主要特性:

　　6V to 55V Power Input Voltage Range

　　16 Independent LED Outputs Up to 75mA/36V

　　±3% LED Current Matching at 50mA (Typ ±1%)

　　6-Bit Dot Correction Current Adjustment

　　12-Bit Grayscale PWM Dimming

　　0.5μs Minimum LED On-Time

　　Adaptive LED Bus Voltage for High Efficiency

　　Cascadable 30MHz Serial Data Interface

　　Full Diagnostic and Protection: Individual Open/Short

　　LED and Overtemperature Fault

　　40-Lead 6mmx6mm QFN Package

　　LT3745应用:

　　Large Screen Display LED Backlighting

　　Mono-, Multi-, Full-Color LED Displays

　　LED Billboards and Signboards

　　图1. LT3745方框图

　　图2. LT3745 16路LED驱动器: 500kHz降压,每路LED电流25mA 到75mA,100Hz 12位调光

　　图3. LT3745 16路LED驱动器: 1MHz降压,每路10个LED,电流25mA 到75mA,500Hz 12位调光