SC443 Datasheet, PDF (1/1 Pages) Semtech Corporation – High Efficiency Integrated Boost Driver for 3-Strings of 30mA LEDs

SC443
POWER MANAGEMENT
High Efficiency Integrated Boost Driver
for 3-Strings of 30mA LEDs
Features
Description
 Wide input voltage range from 4.5V to 27V
 42V maximum operating output voltage
 Programmable LED current for up to 30mA per
string
 +/- 1% typical string-to-string current matching
 Greater than 90% efficiency
 Wide 0.4% to 100% PWM dimming range
 Integrated 1A power switch
 Programmable switching frequency for small size
 Low current sense voltage for high efficiency
 Adjustable OVP for cost-effective output cap
selection
 LED open circuit protection
 Thermal protection with auto-recovery
 3mm × 3mm ×0.6mm MLP-UT-16 lead-free package
(WEEE and RoHS compliant)
Applications
The SC443 is a high-efficiency multiple string WLED driver
with an integrated boost converter. It operates over a wide
input range from 4.5V to 27V with a maximum output
voltage of 42V and a 1A internal power switch.
It can drive 3 strings with current up to 30mA per string.
The string-to-string current matching is within, typically,
1% and the overall efficiency is greater than 90% due
to the low current sense voltage and a low-impedance
internal power switch. The wide PWM dimming range
boasts a ratio of 250: 1.
The programmable switching frequency enables the
user to optimize the external component sizes for high
efficiency. When there are fewer LEDs in each string, users
can use a lower output voltage protection level which
yields an allowable reduction in associated costs, size
and voltage ratings of the output capacitor.
 Small to Medium Size LCD Panel
 Notebook Display
 White LED Power Supplies
 Sub-Notebook and Tablet Computer Displays
 Portable Media Players
 LCD Monitors
 Digital Video Cameras
The SC443 also features an open circuit LED protection
function. It disables the corresponding strings with LED
open while keeping other strings under normal operation.
This feature allows LCD panels to remain viewable even
under LED failure and wire disconnectons. The internal
thermal shutdown protects the IC from overheating at
abnormal conditions. The SC443 is available in a 3mm
× 3mm × 0.6mm MLP-UT 16 Lead-free package.
Typical Application Circuit
V_IN
January 21, 2009
Enable
Dimming
SW
VIN
COMP
VOUT
OVPIN
AGND
SS _SC443
3
IO1- 3
FSET
IOSET
EN
IOGND
PWM _PGND
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