原标题：Maxim MAX16834大功率LED驱动方案

　　Maxim 公司的MAX16834是集成了高边LED电流检测和PWM调光MOSFET驱动器的大功率LED驱动器。这种恒流模式高亮度LED(HBLED)驱动器适合于升压，升-降压，SEPIC和高边降压拓扑。工作电压从.4.75V到28V，PWM调光/模拟调光比3000：1，可编程工作频率100kHz到1MHz，主要应用在单串LED LCD背光，汽车前后灯照明，投映RGB　LED光源，环境照明和DC-DC升压/降压-升压转换器。本文介绍了MAX16834主要特性，方框图以及多种应用电路。

　　High-Power LED Driver with Integrated High-Side LED Current Sense and PWM Dimming MOSFET Driver

　　The MAX16834 is a current-mode high-brightness LED (HB LED) driver for boost, boost-buck, SEPIC, and highside buck topologies. In addition to driving an n-channel power MOSFET switch controlled by the switching controller, it also drives an n-channel PWM dimming switch to achieve LED PWM dimming. The MAX16834 integrates all the building blocks necessary to implement a fixed-frequency HB LED driver with wide-range dimming control.

　　The MAX16834 features constant-frequency peak current-mode control with programmable slope compensation to control the duty cycle of the PWM controller.

　　A dimming driver designed to drive an external n-channel MOSFET in series with the LED string provides wide-range dimming control up to 20kHz. In addition to PWM dimming, the MAX16834 provides analog dimming using a DC input at REFI. The programmable switching frequency (100kHz to 1MHz) allows design optimization for efficiency and board space reduction.

　　A single resistor from RT/SYNC to ground sets the switching frequency from 100kHz to 1MHz while an external clock signal at RT/SYNC disables the internal oscillator and allows the MAX16834 to synchronize to an external clock. The MAX16834’s integrated highside current-sense amplifier eliminates the need for a separate high-side LED current-sense amplifier in boost-buck applications.

　　The MAX16834 operates over a wide supply range of 4.75V to 28V and includes a 3A sink/source gate driver for driving a power MOSFET in high-power LED driver applications. It can also operate at input voltages greater than 28V in boost configuration with an external voltage clamp. The MAX16834 is also suitable for DCDC converter applications such as boost or boostbuck.

　　Additional features include external enable/disable input, an on-chip oscillator, fault indicator output (FLT) for LED open/short or overtemperature conditions, and an overvoltage protection sense input (OVP+) for true overvoltage protection.

　　The MAX16834 is available in a thermally enhanced 4mm x 4mm, 20-pin TQFN-EP package and in a thermally enhanced 20-pin TSSOP-EP package and is specified over the automotive -40°C to +125°C temperature range.

　　MAX16834主要特性：

　　Wide Input Operating Voltage Range (4.75V to 28V)

　　Works for Input Voltage > 28V with External Voltage Clamp on VIN for Boost Converter

　　3000:1 PWM Dimming/Analog Dimming

　　Integrated PWM Dimming MOSFET Driver

　　Integrated High-Side Current-Sense Amplifier for LED Current Sense in Boost-Buck Converter

　　100kHz to 1MHz Programmable High-Frequency Operation

　　External Clock Synchronization Input

　　Programmable UVLO

　　Internal 7V Low-Dropout Regulator

　　Fault Output (FLT) for Overvoltage, Overcurrent, and Thermal Warning Faults

　　Programmable True Differential Overvoltage Protection

　　20-Pin TQFN-EP and TSSOP-EP Packages

　　MAX16834应用：

　　Single-String LED LCD Backlighting

　　Automotive Rear and Front Lighting

　　Projection System RGB LED Light Sources

　　Architectural and Decorative Lighting (MR16, M111)

　　Spot and Ambient Lights

　　DC-DC Boost/Boost-Buck Converters

　　图1。MAX16834方框图

　　图2。MAX16834升压LED驱动器

　　图3。MAX16834升压/降压LED驱动器(VLED+ < 28V)

　　图4。MAX16834带汽车负载突变保护的升压LED驱动器

　　图5。MAX16834高边降压LED驱动器

　　图6。MAX16834升压DC/DC转换器

　　图7。MAX16834升压-降压DC/DC转换器