MAX16826 Datasheet, PDF (1/26 Pages) Maxim Integrated Products – Programmable, Four-String HB LED Driver with Output-Voltage Optimization and Fault Detection

19-4047; Rev 2; 12 /09
Programmable, Four-String HB LED Driver with
Output-Voltage Optimization and Fault Detection
General Description
The MAX16826 high-brightness LED (HB LED) driver is
designed for backlighting automotive LCD displays and
other display applications such as industrial or desktop
monitors and LCD televisions. The MAX16826 integrates
a switching regulator controller, a 4-channel linear cur-
rent sink driver, an analog-to-digital converter (ADC),
and an I²C interface. The IC is designed to withstand
automotive load dump transients up to 40V and can
operate under cold crank conditions.
The MAX16826 contains a current-mode PWM switching
regulator controller that regulates the output voltage to
the LED array. The switching regulator section is config-
urable as a boost or SEPIC converter and its switching
frequency is programmable from 100kHz to 1MHz.
The MAX16826 includes 4 channels of programmable,
fault-protected, constant-current sink driver controllers
that are able to drive all white, RGB, or RGB plus amber
LED configurations. LED dimming control for each chan-
nel is implemented by direct PWM signals for each of the
four linear current sinks. An internal ADC measures the
drain voltage of the external driver transistors and the
output of the switching regulator. These measurements
are then made available through the I²C interface to an
external microcontroller (µC) to enable output voltage
optimization and fault monitoring of the LEDs.
The amplitude of the LED current in each linear current-
sink channel and the switch-mode regulator output volt-
age is programmed using the I²C interface. Additional
features include: cycle-by-cycle current limit, shorted
LED string protection, and overtemperature protection.
The MAX16826 is available in a thermally enhanced,
5mm x 5mm, 32-pin thin QFN package and is specified
over the automotive -40°C to +125°C temperature range.
Applications
LCD Backlighting:
Automotive Infotainment Displays
Automotive Cluster Displays
Industrial and Desktop Monitors
LCD TVs
Automotive Lighting:
Adaptive Front Lighting
Low- and High-Beam Assemblies
Typical Application Circuit and Pin Configuration appear at
end of data sheet.
Features
o External MOSFETs Allow Wide-Range LED
Current with Multiple LEDs per String
o Individual PWM Dimming Inputs per String
o Very Wide Dimming Range
o LED String Short and Open Protection
o Adjustable LED Current Rise/Fall Times Improve
EMI Control
o Microcontroller Interface Using I²C Allows
LED Voltage Monitoring and Optimization
Using a 7-Bit Internal ADC
LED Short and Open Detection
Dynamic Adjustment of LED String Currents
and Output Voltage
Standby Mode
o Integrated Boost/SEPIC Controller
o External Switching Frequency Synchronization
o 4.75V to 24V Operating Voltage Range and
Withstands 40V Load Dump
o Overvoltage and Overtemperature Protection
Ordering Information
PART
TEMP RANGE
PIN-PACKAGE
MAX16826ATJ+
-40°C to +125°C
32 TQFN-EP*
MAX16826ATJ/V+ -40°C to +125°C
32 TQFN-EP*
+Denotes a lead(Pb)-free/RoHS-compliant package.
*EP = Exposed pad.
/V denotes an automotive qualified part.
Simplified Diagram
VIN
IN
DL CS
DIM1
DIM2
DIM3
DIM4
DIMMING
INPUTS
MAX16826
SDA I²C
SCL ^INTERFACE
FB
DR4
DR1
DL1
CS1
DL4
CS4
GND
BOOST LED DRIVER
________________________________________________________________ Maxim Integrated Products 1
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or visit Maxim’s website at www.maxim-ic.com.