MAX16838B Datasheet, PDF (1/21 Pages) Maxim Integrated Products – Integrated, 2-Channel, High-Brightness LED Driver with High-Voltage Boost and SEPIC Controller

MAX16838B
EVALUATION KIT AVAILABLE
Integrated, 2-Channel, High-Brightness LED Driver
with High-Voltage Boost and SEPIC Controller
General Description
The MAX16838B is a dual-channel LED driver that inte-
grates both the DC-DC switching boost regulator and two
150mA current sinks. A current-mode switching DC-DC
controller provides the necessary voltage to both strings
of HB LEDs. The device accepts a wide 4.75V to 40V
input voltage range and directly withstands automotive
load-dump events. For a 5V ±10% input voltage, connect
V_IN to V_CC. The wide input range allows powering HB
LEDs for small-to-medium-sized LCD displays in automo-
tive and display backlight applications.
An internal current-mode switching DC-DC controller
supports the boost or SEPIC topologies and operates
in an adjustable frequency range between 200kHz and
2MHz. The current-mode control provides fast response
and simplifies loop compensation. The device also fea-
tures an adaptive output-voltage adjustment scheme
that minimizes the power dissipation in the LED current-
sink paths. The MAX16838B can be combined with the
MAX15054 to achieve a buck-boost LED driver with two
integrated current sinks.
The channel current is adjustable from 20mA to 150mA
using an external resistor. The external resistor sets both
channel currents to the same value. The device allows
connecting both strings in parallel to achieve a maximum
current of 300mA in a single channel. The MAX16838B
also features pulsed dimming control with minimum pulse
widths as low as 500ns on both channels through a logic
input (DIM).
The device includes output overvoltage
protection, open-LED/shorted-LED detection, and
overtemperature protection. The device is available in
20-pin TSSOP (4.4mm) and TQFN (4mm x 4mm) pack-
ages and operates over the -40ºC to +125ºC automotive
temperature range.
Applications
●● Automotive Display Backlights
●● LCD Display Backlights
●● Automotive Lighting Applications
Benefits and Features
●● High Integration Provides for a Compact Solution
• Integrates 2-Channel, 20mA to 150mA Linear LED
Current Sinks
• Internal Slope Compensation and Switching
MOSFET
●● Flexible IC Fits Many Applications
• Boost or SEPIC Converter Topologies
• Wide 4.75V to 40V or 5V ±10% Input Operating
• Range
• 200kHz to 2MHz Resistor-Programmable Switching
Frequency with External Synchronization
●● Wide Contrast Ratio Ideal for High Quality TFT and
Head-Up Displays
• PWM Dimming Ratio of 10,000:1 at 200Hz
●● Robust with Respect to Temperature and Fault
Conditions
• Current Foldback Reference Input
• LED Open/Short Detection and Protection
• Output Overvoltage and Overtemperature
Protection
• Thermally Enhanced 20-Pin TSSOP (4.4mm) and
TQFN (4mm x 4mm) Packages
Typical Operating Circuit and Ordering Information appear at
end of data sheet.
Simplified Schematic
4.75V TO 40V
L
D
CIN
R2OV
COUT
CCOMP
RCOMP
IN
DRAIN OV
EN
NDRV
CFB
GATE
VCC
OUT1
DRV _MAX16838B OUT2
ISET
FLT
DIM
CS
COMP
RT
SGND PGND LEDGND
R1OV
RISET
RRT RCS
LED
STRINGS
19-7112; Rev 2; 3/16