Integrated 8-Channel LED Drivers with Switch-Mode Boost and SEPIC Controller
High-Efficiency, 8-Channel, Constant-Current, Linear LED Drivers with a Switch-Mode Controller and ±3% Current Matching Among Strings that Enables Paralleling of Output Currents Higher than 55mA per LED String
The MAX16807/MAX16808 are integrated, high-efficiency
white or RGB LED drivers. They are designed for
LCD backlighting and other LED lighting applications
with multiple strings of LEDs. The MAX16807/MAX16808's current-mode PWM controller regulates the necessary voltage to the LED array. Depending on
the input voltage and LED voltage range, it can be
used with boost or buck-boost (SEPIC) topologies. The
MAX16807/MAX16808 feature an 8V to 26.5V input voltage
range. A wide range of adjustable frequency
(20kHz to 1MHz) allows design optimization for efficiency
and minimum board space.
The MAX16807/MAX16808 LED drivers include eight
open-drain, constant-current-sinking LED driver outputs
rated for 36V continuous operation. The LED current-control
circuitry achieves ±3% current matching among
strings and enables paralleling of outputs for LED string
currents higher than 55mA. The output-enable pin is
used for simultaneous PWM dimming of all output channels.
Dimming frequency range is 50Hz to 30kHz and
dimming ratio is up to 5000:1. The constant-current outputs
are single resistor programmable and the LED current
can be adjusted up to 55mA per output channel.
The MAX16807/MAX16808 operate either in stand-alone
mode or with a microcontroller (µC) using an industry-standard,
4-wire serial interface. The MAX16808 includes
circuitry that automatically detects open-circuit LEDs.
The MAX16807/MAX16808 include overtemperature
protection, operate over the full -40°C to +125°C temperature
range, and are available in a thermally
enhanced, 28-pin TSSOP exposed paddle package.
MAX16807/MAX16808
EEPW Analog/Mixed-Signal IC Market Application
Award Winner 2006
Key Features
Applications/Uses
Eight Constant-Current Output Channels (Up to 55mA Each)
±3% Current Matching Among Outputs
Paralleling Channels Allows Higher Current per LED String
Outputs Rated for 36V Continuous Voltage
Output-Enable Pin for PWM Dimming (Up to 30kHz)
One Resistor Sets LED Current for All Channels
Wide Dimming Ratio Up to 5000:1
Low Current-Sense Reference (300mV) for High Efficiency
8V to 26.5V Input Voltage or Higher with External Biasing Devices
Open LED Detection (MAX16808)
4-Wire Serial Interface to Control Individual Output Channels
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