Rainbow-electronics MAX16834 Bedienungsanleitung PDF herunterladen

General Description

The MAX16834 is a current-mode high-brightness LED

(HB LED) driver for boost, buck-boost, SEPIC, and high-

side buck topologies. In addition to driving an n-channel

power MOSFET switch controlled by the switching con-

troller, 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-fre-

quency HB LED driver with wide-range dimming control.

The MAX16834 features constant-frequency peak cur-

rent-mode control with programmable slope compensa-

tion to control the duty cycle of the PWM controller.

A dimming driver designed to drive an external n-chan-

nel MOSFET in series with the LED string provides

wide-range dimming control up to 20kHz. In addition to

PWM dimming, the MAX16834 provides analog dim-

ming 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 high-

side 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. The MAX16834 is also suitable for DC-DC

converter applications such as boost or buck-boost.

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 is specified

over the automotive -40°C to +125°C temperature range.

Applications

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

Features

o Wide Input Operating Voltage Range (4.75V to

28V)

o 3000:1 PWM Dimming

o Analog Dimming

o Integrated PWM Dimming MOSFET Driver

o Integrated High-Side Current-Sense Amplifier for

LED Current Sense in Buck-Boost Converter

o 100kHz to 1MHz Programmable High-Frequency

Operation

o External Clock Synchronization Input

o Programmable UVLO

o Internal 7V Low-Dropout Regulator

o Fault Output (FLT) for Overvoltage, Overcurrent,

and Thermal Warning Faults

o Programmable True Differential Overvoltage

Protection

o 20-Pin TQFN-EP Package

MAX16834

High-Power LED Driver with Integrated High-Side LED

Current Sense and PWM Dimming MOSFET Driver

________________________________________________________________

Maxim Integrated Products

BOOST LED DRIVER

NDRV

ANALOG

DIM

OFF

DIMOUT

SENSE+

PWMDIM

PGND

LED+

LEDs

LED-

MAX16834

REFI

Simplified Application Circuit

Ordering Information

19-4235; Rev 0; 8/08

For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,

or visit Maxim’s website at www.maxim-ic.com.

EVALUATION KIT

AVAILABLE

Denotes a lead-free/RoHS-compliant package.

EP = Exposed pad.

PART TEMP RANGE

PIN-PACKAGE

MAX16834ATP+

-40°C to +125°C 20 TQFN-EP*

Pin Configuration appears at end of data sheet.

1 2 3 4 5 6 ... 21 22

MAX16834 1

Inhaltsverzeichnis

Seite 1 - MAX16834

General DescriptionThe MAX16834 is a current-mode high-brightness LED(HB LED) driver for boost, buck-boost, SEPIC, and high-side buck topologies. In a

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MAX16834High-Power LED Driver with Integrated High-Side LEDCurrent Sense and PWM Dimming MOSFET Driver10 _____________________________________________

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MAX16834High-Power LED Driver with Integrated High-Side LEDCurrent Sense and PWM Dimming MOSFET Driver________________________________________________

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MAX16834High-Power LED Driver with Integrated High-Side LEDCurrent Sense and PWM Dimming MOSFET Driver12 _____________________________________________

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MAX16834High-Power LED Driver with Integrated High-Side LEDCurrent Sense and PWM Dimming MOSFET Driver________________________________________________

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MAX16834configuration, the input current is the inductor currentminus the LED current. But for both configurations, theripple current that the input f

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lowing equation. The MOSFET must be mounted on aboard as per manufacturer specifications to dissipatethe heat.The RMS current rating of the switching

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MAX16834Boost configuration:Buck-boost configuration:where RLEDis the dynamic impedance (rate of changeof voltage with current) of the LED string at t

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MAX16834High-Power LED Driver with Integrated High-Side LEDCurrent Sense and PWM Dimming MOSFET Driver________________________________________________

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MAX16834High-Power LED Driver with Integrated High-Side LEDCurrent Sense and PWM Dimming MOSFET Driver18 _____________________________________________

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MAX16834High-Power LED Driver with Integrated High-Side LEDCurrent Sense and PWM Dimming MOSFET Driver________________________________________________

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MAX16834High-Power LED Driver with Integrated High-Side LEDCurrent Sense and PWM Dimming MOSFET Driver2 ______________________________________________

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MAX16834High-Power LED Driver with Integrated High-Side LEDCurrent Sense and PWM Dimming MOSFET Driver20 _____________________________________________

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MAX16834High-Power LED Driver with Integrated High-Side LEDCurrent Sense and PWM Dimming MOSFET Driver________________________________________________

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MAX16834High-Power LED Driver with Integrated High-Side LEDCurrent Sense and PWM Dimming MOSFET DriverMaxim cannot assume responsibility for use of an

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MAX16834High-Power LED Driver with Integrated High-Side LEDCurrent Sense and PWM Dimming MOSFET Driver________________________________________________

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MAX16834High-Power LED Driver with Integrated High-Side LEDCurrent Sense and PWM Dimming MOSFET Driver4 ______________________________________________

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MAX16834High-Power LED Driver with Integrated High-Side LEDCurrent Sense and PWM Dimming MOSFET Driver________________________________________________

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Pin DescriptionPIN NAME FUNCTION1 OVP+LED-String Overvoltage Protection Input. Connect a resistive voltage-divider between the positiveoutput, OVP+, a

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MAX16834High-Power LED Driver with Integrated High-Side LEDCurrent Sense and PWM Dimming MOSFET Driver________________________________________________

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MAX16834High-Power LED Driver with Integrated High-Side LEDCurrent Sense and PWM Dimming MOSFET Driver8 ______________________________________________

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MAX16834Undervoltage Lockout/EnableThe MAX16834 features an adjustable UVLO using theenable input (UVEN). Connect UVEN to VINthrough aresistive divide

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Rainbow-electronics MAX16834 Bedienungsanleitung

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Inhaltsverzeichnis

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