Rainbow-electronics MAX16831 Manual de usuario descargar pdf

General Description

The MAX16831 is a current-mode, high-brightness LED

(HBLED) driver designed to control two external

n-channel MOSFETs for the single-string LED current

regulation. The MAX16831 integrates all the building

blocks necessary to implement fixed-frequency HBLED

drivers with wide-range dimming control. The

MAX16831 is configurable to operate as a step-down

(buck), step-up (boost), or step-up/-down (buck-boost)

current regulator.

Current-mode control with leading-edge blanking simpli-

fies control-loop design. Internal slope compensation

stabilizes the current loop when operating at duty cycles

above 50%. The MAX16831 operates over a wide input

voltage range and is capable of withstanding automo-

tive load-dump events. Multiple MAX16831s can be

synchronized to each other or to an external clock. The

MAX16831 includes a floating dimming driver for

brightness control with an external n-channel MOSFET

in series with the LED string.

HBLED drivers using the MAX16831 achieve efficien-

cies of over 90% in automotive applications. The

MAX16831 also includes a 1.4A source and 2.5A sink

gate driver for driving switching MOSFETs in high-power

LED driver applications, such as front light assemblies.

The dimming control allows for wide PWM dimming at

frequencies up to 2kHz. Higher dimming ratios of up to

1000:1 are achievable at lower dimming frequencies.

The MAX16831 is available in a 32-pin thin QFN package

with exposed pad and operates over the -40°C to

+125°C automotive temperature range.

Applications

Automotive Exterior Lighting:

High-Beam/Low-Beam/Signal Lights

Rear Combination Lights (RCL)

Daytime Running Lights (DRL)

Fog Light and Adaptive Front Light Assemblies

Industrial and Architectural Lighting

Emergency Lighting

Projectors with RGB LED Light Sources

Navigation and Marine Indicators

Features

o Wide Input Range: 6V to 76V With Cold-Start

Operation to 5.5V

o Integrated Differential LED Current-Sense

Amplifier

o Floating Dimming Driver Capable of Driving an

n-Channel MOSFET

o 5% LED Current Accuracy

o 200Hz On-Board Ramp Syncs to External PWM

Dimming Signal

o Programmable Switching Frequency (125kHz to

600kHz) and Synchronization

o Output Overvoltage Load Dump, LED Short,

Overtemperature Protection

o Low 107mV LED Current Sense for High

Efficiency

o Enable/Shutdown Input with Shutdown Current

Below 45µA

MAX16831

High-Voltage, High-Power LED Driver with

Analog and PWM Dimming Control

________________________________________________________________

Maxim Integrated Products

19-0809; Rev 0; 4/07

For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at

1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.

Ordering Information

PART TEMP RANGE

PIN-

PACKAGE

PKG

CODE

MAX16831ATJ+ -40°C to +125°C 32 TQFN-EP* T3255M-4

Denotes lead-free package.

EP = Exposed pad.

DIM

REG1

UV2

DRV

DRI

REG1

DIM

SNS+

QGND

RTSYNC

CS-

CS+

COMP

REG2

DGT

UVEN

SNS-

AGND

SENSE

OV1

OV2

CLMP

SGND

CLMP

REG2

LEDs

BUCK-BOOST CONFIGURATION

UV1

UVEN

MAX16831

Typical Operating Circuits

Pin Configuration appears at end of data sheet.

Typical Operating Circuits continued at end of data sheet.

1 2 3 4 5 6 ... 19 20

MAX16831 1

Indice de contenidos

Pagina 1 - MAX16831

General DescriptionThe MAX16831 is a current-mode, high-brightness LED(HBLED) driver designed to control two externaln-channel MOSFETs for the single-

Pagina 2

MAX16831The MAX16831 features a differential high-side levelshifter to drive an external n-channel MOSFET for dim-ming. Wide contrast “pulsed” dimming

Pagina 3

Reference Voltage OutputThe MAX16831 includes a 5% accurate 3V (typ)buffered reference output, REF. REF is a push-pull out-put capable of sourcing/sin

Pagina 4

MAX16831Connect the clock signal to the RTSYNC input. TheMAX16831 synchronizes to the external clock signalafter the detection of five successive cloc

Pagina 5

capacitor to hold the charge when the DIM signal hasturned off the gate drive. When DIM is high again, thevoltage on the compensation capacitors, C1 a

Pagina 6

MAX16831Applications InformationInductor SelectionThe minimum required inductance is a function of oper-ating frequency, input-to-output voltage diffe

Pagina 7

When using the MAX16831 in a boost or buck-boostconfiguration, the input RMS current is low and theinput capacitance can be small.Operating the MAX168

Pagina 8

MAX16831High-Voltage, High-Power LED Driver withAnalog and PWM Dimming Control16 _____________________________________________________________________

Pagina 9

MAX16831VINRCSCFRTCREG1RUV2DRVDRIREG1CSVCCSNS+FBQGNDRTSYNCCS-CS+LOCOMPREG2DGTOVUVENSNS-AGNDRSENSER2C2ROV1ROV2CLMPSGNDCCLMPCREG2R1C1RDLEDsBOOST CONFIGU

Pagina 10

MAX16831High-Voltage, High-Power LED Driver withAnalog and PWM Dimming Control18 _____________________________________________________________________

Pagina 11