Rainbow Electronics MAX16831 - Manual

General Description
The MAX16831 is a current-mode, high-brightness LED
(HBLED) driver designed to control two external
n-channel MOSFETs for the single-string LED current
regulation. The MAX16831 integrates all the building
blocks necessary to implement fixed-frequency HBLED
drivers with wide-range dimming control. The
MAX16831 is configurable to operate as a step-down
(buck), step-up (boost), or step-up/-down (buck-boost)
current regulator.
Current-mode control with leading-edge blanking simpli-
fies control-loop design. Internal slope compensation
stabilizes the current loop when operating at duty cycles
above 50%. The MAX16831 operates over a wide input
voltage range and is capable of withstanding automo-
tive load-dump events. Multiple MAX16831s can be
synchronized to each other or to an external clock. The
MAX16831 includes a floating dimming driver for
brightness control with an external n-channel MOSFET
in series with the LED string.
HBLED drivers using the MAX16831 achieve efficien-
cies of over 90% in automotive applications. The
MAX16831 also includes a 1.4A source and 2.5A sink
gate driver for driving switching MOSFETs in high-power
LED driver applications, such as front light assemblies.
The dimming control allows for wide PWM dimming at
frequencies up to 2kHz. Higher dimming ratios of up to
1000:1 are achievable at lower dimming frequencies.
The MAX16831 is available in a 32-pin thin QFN package
with exposed pad and operates over the -40
°C to
+125 °C automotive temperature range.
Applications
Automotive Exterior Lighting:
High-Beam/Low-Beam/Signal Lights
Rear Combination Lights (RCL)
Daytime Running Lights (DRL)
Fog Light and Adaptive Front Light Assemblies
Industrial and Architectural Lighting
Emergency Lighting
Projectors with RGB LED Light Sources
Navigation and Marine Indicators
Features
♦ Wide Input Range: 6V to 76V With Cold-Start
Operation to 5.5V
♦ Integrated Differential LED Current-Sense
Amplifier
♦ Floating Dimming Driver Capable of Driving an
n-Channel MOSFET
♦ 5% LED Current Accuracy
♦ 200Hz On-Board Ramp Syncs to External PWM
Dimming Signal
♦ Programmable Switching Frequency (125kHz to
600kHz) and Synchronization
♦ Output Overvoltage Load Dump, LED Short,
Overtemperature Protection
♦ Low 107mV LED Current Sense for High
Efficiency
♦ Enable/Shutdown Input with Shutdown Current
Below 45µA
MAX16831
High-Voltage, High-Power LED Driver with
Analog and PWM Dimming Control
________________________________________________________________ Maxim Integrated Products 1
19-0809; Rev 0; 4/07
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
Ordering Information
PART TEMP RANGE
PIN-
PACKAGE PKG
CODE
MAX16831ATJ+ -40°C to +125°C 32 TQFN-EP* T3255M-4
+ Denotes lead-free package.
* EP = Exposed pad.
V IN
DIM
R CS
C F
R T
C REG1
R UV2
DRV
DRI
REG1
DIM
CS
V CC
SNS+
FB
QGND
RTSYNC
CS- CS+ LO
COMP REG2
DGT
HI
OV
UVEN
SNS-
AGND
R SENSE
R2
C2
R OV1
R OV2
CLMP
SGND
C CLMP
C REG2
R1
C1
R D
LEDs
BUCK-BOOST CONFIGURATION
R UV1
C UVEN
Q S
MAX16831
Typical Operating Circuits
Pin Configuration appears at end of data sheet. Typical Operating Circuits continued at end of data sheet.