MAX16834_15 Datasheet, PDF (1/23 Pages) Maxim Integrated Products – High-Power LED Driver with Integrated High-Side LED Current Sense and PWM Dimming MOSFET Driver

EVALUATION KIT AVAILABLE
MAX16834
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, boost-buck, 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
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 DC-
DC converter applications such as boost or boost-
buck. Additional features include external enable/
disable input, an on-chip oscillator, fault indicator out-
put (FLT) for LED open/short or overtemperature condi-
tions, 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 thermal-
ly enhanced 20-pin TSSOP-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/Boost-Buck Converters
Benefits and Features
• Integration Minimizes BOM for High-Brightness LED
Driver with a Wide Dimming Range Saving Space
and Cost
• Constant-Frequency, Peak Current-Mode Control
with Programmable Slope Compensation
• Integrated PWM Dimming MOSFET Driver
• 3000:1 PWM Dimming/Analog Dimming
• Integrated High-Side Current-Sense Amplifier for
LED Current Sense in Boost-Buck Converter
• Internal 7V Low-Dropout Regulator
• Simple Optimization for Efficiency, Board Space and
Input Operating Range
• Supports Boost, Buck-Boost, SEPIC, and High-
Side Buck Topologies
• 100kHz to 1MHz Programmable High-Frequency
Operation
• External Clock Synchronization Input
• Wide Input Operating Voltage Range (4.75V to 28V)
• Works for Input Voltage > 28V with External
Voltage Clamp on V_IN for Boost Converter
• 20-Pin TQFN-EP and TSSOP-EP Packages
• Protection Features Increase System Reliability
• Programmable UVLO
• Programmable True Differential Overvoltage
Protection
• Fault Output (FLT) for Overvoltage, Overcurrent,
and Thermal-Warning Faults
Simplified Application Circuit
VIN
BOOST LED DRIVER
LED+
IN
NDRV
LEDs
MAX16834
ON
OFF
PWMDIM
CS
LED-
ANALOG
DIM
REFI
DIMOUT
PGND
SENSE+
Ordering Information and Pin Configurations appear at end
of data sheet.
19-4235; Rev 5; 1/15