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

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

• 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 Package