Maxim MAX16836多个高亮LED驱动方案

Maxim 公司的MAX16836是电流稳压器,工作电压6.5V到40V,能够驱动总电流为350mA的一串或多串高亮LED(HBLED). MAX16836有可调的LED电流(从35mA到350mA),LED电流精度+/-3.5%.高压DIM引脚用来调光接口,并联工作可使LED电流大于350mA,差分LED电流检测,关断电流为35uA.主要用于汽车内部照明,汽车外部照明,急救车的告警照明,导航和海上指示灯以及通用照明等.本文介绍了MAX16836的主要特性, 功能方框图,多种调光连接图以及用于LCD背景光的多路HB LED 驱动电路等.

The MAX16836 current regulator operates from a 6.5V to 40V input-voltage range and delivers up to a total of 350mA to one or more strings of high-brightness LEDs (HB LEDs). The output current of the MAX16836 is adjusted by using an external current-sense resistor in series with the LEDs. A dimming input allows widerange “pulsed” PWM operation. Wave-shaping circuitry reduces EMI. The differential current-sense input increases noise immunity. The MAX16836 is well suited for applications requiring a high-voltage input and is able to withstand automotive load-dump events up to 40V. An on-board pass element minimizes external components while providing ±3.5% output-current accuracy. Additional features include a 5V regulated output and short-circuit and thermal protection.

The MAX16836 is available in a thermally enhanced, 5mm x 5mm, 16-pin TQFN package and in an 8-pin SO package with exposed pad. The MAX16836 is specified over the automotive -40℃ to +125℃ temperature range.

MAX16836主要特性:

+6.5V to +40V Operating Range

Adjustable LED Current (35mA to 350mA)

±3.5% LED Current Accuracy

High-Voltage DIM Pin for Dimming Interface

Integrated Pass Element with Low-Dropout Voltage (0.55V typ)

+5V Regulated Output with 4mA Source Capability

Parallel Operation for LED Current > 350mA

Differential LED Current Sense

Low Shutdown Supply Current (35μA typ)

Low 200mV Current-Sense Reference Reduces Power Losses

Wave-Shaped Edges Reduce Radiated EMI During PWM Dimming

Thermal Shutdown

Output Short-Circuit Protection

Available in Small, Thermally Enhanced, 5mm x 5mm, 16-Pin TQFN Package and in 8-Pin SO with Exposed Pad Package

-40℃ to +125℃ Operating Temperature Range

MAX16836应用:

Automotive Interior: Map, Courtesy, and Cluster Lighting

Automotive Exterior: Tail Lights and CHMSL

Emergency Vehicle Warning Lights

Navigation and Marine Indicators

General Lighting

Signage, Gasoline Canopies, Beacons



图1.MAX16836功能方框图



图2.MAX16836采用EN连接到VIN的调光

Dimming with EN Connected to VIN at a Constant Voltage and DIM Pulsed



图3.MAX16836采用DIM连接5V,EN连接到VIN的调光

Dimming with DIM Connected to V5, EN Connected to VIN



图4.MAX16836并联连接图



图5.MAX16836采用ICM7555的PWM 调光连接图



图6.MAX16836采用NTC电热调节器的LED电流热监视图



图7.MAX16836采用电流电平开关的两种亮度连接图



图8.MAX16836采用单个BJT来增加LED电流(安培级)



图9.用于LCD背景光的多路HB LED 驱动电路