MAXIM MAX16834 大功率LED驅(qū)動方案

MAXIM公司的MAX16834是一款電流模式高亮度LED（HB LED）驅(qū)動器，具有升壓、降壓升壓、SEPIC、高側(cè)降壓拓?fù)浣Y(jié)構(gòu)。除了通過開關(guān)控制器控制驅(qū)動n溝道功率MOSFET開關(guān)，MAX16834還驅(qū)動一個n溝道PWM調(diào)光開關(guān)實(shí)現(xiàn)LED PWM調(diào)光。MAX16834工作電壓范圍為4.75V~28V，包括一個3A沉/源柵極驅(qū)動器。MAX16834具有可編程的斜率補(bǔ)償?shù)暮愣l率峰值電流模式控制，以控制PWM控制器的占空比。主要用于單串LED LCD背景光，汽車前后端照明，投影系統(tǒng)RGB LED照明源，建筑和裝飾照明(MR16, M111)，場所和環(huán)境照明，以及DC-DC升壓/降壓轉(zhuǎn)換器。本文介紹了MAX16834主要特性、方框圖和各種應(yīng)用電路包括升壓LED驅(qū)動器, 升-降壓LED驅(qū)動器,有汽車負(fù)載保護(hù)的升壓LED驅(qū)動器以及高側(cè)降壓型LED驅(qū)動器, 升壓型DC-DC轉(zhuǎn)換器和降壓-升壓型DC-DC轉(zhuǎn)換器。

The MAX16834 is a current-mode high-brightness LED (HB LED) driver for boost, buck-boost, 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 buck-boost 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 buckboost. 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℃ to +125℃ temperature range.

MAX16834的主要應(yīng)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/Buck-Boost Converters

MAX16834的主要性能：

Wide Input Operating Voltage Range (4.75V to28V)

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 Buck-Boost 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 Packages


簡單應(yīng)用電路圖

圖1內(nèi)部方框圖



圖2. 升壓LED驅(qū)動器

圖3.升-降壓LED驅(qū)動器（VLED+28V）

圖4.帶有汽車負(fù)載保護(hù)的升壓LED驅(qū)動器

圖5.高側(cè)降壓型LED驅(qū)動器

圖6.升壓型DC-DC轉(zhuǎn)換器

圖7.降壓-升壓型DC-DC轉(zhuǎn)換器

詳情請見：
http://datasheets.maxim-ic.com/en/ds/MAX16834.pdf